Low-dose dynamic myocardial perfusion CT image reconstruction using pre-contrast normal-dose CT scan induced structure tensor total variation regularization

NASA Astrophysics Data System (ADS)

Gong, Changfei; Han, Ce; Gan, Guanghui; Deng, Zhenxiang; Zhou, Yongqiang; Yi, Jinling; Zheng, Xiaomin; Xie, Congying; Jin, Xiance

2017-04-01

Dynamic myocardial perfusion CT (DMP-CT) imaging provides quantitative functional information for diagnosis and risk stratification of coronary artery disease by calculating myocardial perfusion hemodynamic parameter (MPHP) maps. However, the level of radiation delivered by dynamic sequential scan protocol can be potentially high. The purpose of this work is to develop a pre-contrast normal-dose scan induced structure tensor total variation regularization based on the penalized weighted least-squares (PWLS) criteria to improve the image quality of DMP-CT with a low-mAs CT acquisition. For simplicity, the present approach was termed as ‘PWLS-ndiSTV’. Specifically, the ndiSTV regularization takes into account the spatial-temporal structure information of DMP-CT data and further exploits the higher order derivatives of the objective images to enhance denoising performance. Subsequently, an effective optimization algorithm based on the split-Bregman approach was adopted to minimize the associative objective function. Evaluations with modified dynamic XCAT phantom and preclinical porcine datasets have demonstrated that the proposed PWLS-ndiSTV approach can achieve promising gains over other existing approaches in terms of noise-induced artifacts mitigation, edge details preservation, and accurate MPHP maps calculation.

Lung texture in serial thoracic CT scans: Assessment of change introduced by image registration1

PubMed Central

Cunliffe, Alexandra R.; Al-Hallaq, Hania A.; Labby, Zacariah E.; Pelizzari, Charles A.; Straus, Christopher; Sensakovic, William F.; Ludwig, Michelle; Armato, Samuel G.

2012-01-01

Purpose: The aim of this study was to quantify the effect of four image registration methods on lung texture features extracted from serial computed tomography (CT) scans obtained from healthy human subjects. Methods: Two chest CT scans acquired at different time points were collected retrospectively for each of 27 patients. Following automated lung segmentation, each follow-up CT scan was registered to the baseline scan using four algorithms: (1) rigid, (2) affine, (3) B-splines deformable, and (4) demons deformable. The registration accuracy for each scan pair was evaluated by measuring the Euclidean distance between 150 identified landmarks. On average, 1432 spatially matched 32 × 32-pixel region-of-interest (ROI) pairs were automatically extracted from each scan pair. First-order, fractal, Fourier, Laws’ filter, and gray-level co-occurrence matrix texture features were calculated in each ROI, for a total of 140 features. Agreement between baseline and follow-up scan ROI feature values was assessed by Bland–Altman analysis for each feature; the range spanned by the 95% limits of agreement of feature value differences was calculated and normalized by the average feature value to obtain the normalized range of agreement (nRoA). Features with small nRoA were considered “registration-stable.” The normalized bias for each feature was calculated from the feature value differences between baseline and follow-up scans averaged across all ROIs in every patient. Because patients had “normal” chest CT scans, minimal change in texture feature values between scan pairs was anticipated, with the expectation of small bias and narrow limits of agreement. Results: Registration with demons reduced the Euclidean distance between landmarks such that only 9% of landmarks were separated by ≥1 mm, compared with rigid (98%), affine (95%), and B-splines (90%). Ninety-nine of the 140 (71%) features analyzed yielded nRoA > 50% for all registration methods, indicating that the majority of feature values were perturbed following registration. Nineteen of the features (14%) had nRoA < 15% following demons registration, indicating relative feature value stability. Student's t-tests showed that the nRoA of these 19 features was significantly larger when rigid, affine, or B-splines registration methods were used compared with demons registration. Demons registration yielded greater normalized bias in feature value change than B-splines registration, though this difference was not significant (p = 0.15). Conclusions: Demons registration provided higher spatial accuracy between matched anatomic landmarks in serial CT scans than rigid, affine, or B-splines algorithms. Texture feature changes calculated in healthy lung tissue from serial CT scans were smaller following demons registration compared with all other algorithms. Though registration altered the values of the majority of texture features, 19 features remained relatively stable after demons registration, indicating their potential for detecting pathologic change in serial CT scans. Combined use of accurate deformable registration using demons and texture analysis may allow for quantitative evaluation of local changes in lung tissue due to disease progression or treatment response. PMID:22894392

Patient-specific dose estimation for pediatric abdomen-pelvis CT

NASA Astrophysics Data System (ADS)

Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

2009-02-01

The purpose of this study is to develop a method for estimating patient-specific dose from abdomen-pelvis CT examinations and to investigate dose variation across patients in the same weight group. Our study consisted of seven pediatric patients in the same weight/protocol group, for whom full-body computer models were previously created based on the patients' CT data obtained for clinical indications. Organ and effective dose of these patients from an abdomen-pelvis scan protocol (LightSpeed VCT scanner, 120-kVp, 85-90 mA, 0.4-s gantry rotation period, 1.375-pitch, 40-mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated for the same CT system. The seven patients had effective dose of 2.4-2.8 mSv, corresponding to normalized effective dose of 6.6-8.3 mSv/100mAs (coefficient of variation: 7.6%). Dose variations across the patients were small for large organs in the scan coverage (mean: 6.6%; range: 4.9%-9.2%), larger for small organs in the scan coverage (mean: 10.3%; range: 1.4%-15.6%), and the largest for organs partially or completely outside the scan coverage (mean: 14.8%; range: 5.7%-27.7%). Normalized effective dose correlated strongly with body weight (correlation coefficient: r = -0.94). Normalized dose to the kidney and the adrenal gland correlated strongly with mid-liver equivalent diameter (kidney: r = -0.97; adrenal glands: r = -0.98). Normalized dose to the small intestine correlated strongly with mid-intestine equivalent diameter (r = -0.97). These strong correlations suggest that patient-specific dose may be estimated for any other child in the same size group who undergoes the abdomen-pelvis scan.

Lumbar vertebral pedicles: radiologic anatomy and pathology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, N.P.; Kumar, R.; Kinkhabwala, M.

1988-01-01

With the advancement of high-resolution computed tomography (CT) scanning the spine has added new knowledge to the various conditions affecting the pedicles. We wish to review the entire spectrum of pedicular lesions: the embryology, normal anatomy, normal variants, pitfalls, congenital anomalies, and pathological conditions are discussed. Different imaging modalities involving CT, isotope bone scanning, and Magnetic Resonance Imaging (MRI) are used to complement plain films of the lumbar spine. This subject review is an excellent source for future reference to lumbar pedicular lesions. 27 references.

The promise of dynamic contrast-enhanced imaging in radiation therapy.

PubMed

Cao, Yue

2011-04-01

Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and computed tomography (CT) scanning are emerging as valuable tools to quantitatively map the spatial distribution of vascular parameters, such as perfusion, vascular permeability, blood volume, and mean transit time in tumors and normal organs. DCE MRI/CT have shown prognostic and predictive value for response of certain cancers to chemotherapy and radiation therapy. DCE MRI/CT offer the promise of early assessment of tumor response to radiation therapy, opening a window for adaptively optimizing radiation therapy based upon functional alterations that occur earlier than morphologic changes. DCE MRI/CT has also shown the potential of mapping dose responses in normal organs and tissue for evaluation of individual sensitivity to radiation, providing additional opportunities to minimize risks of radiation injury. The evidence for potentially applying DCE MRI and CT for selection and delineation of radiation boost targets is growing. The clinical use of DCE MRI and CT scanning as a biomarker or even a surrogate endpoint for radiation therapy assessment of tumor and normal organs must consider technical validation issues, including standardization, reproducibility, accuracy and robustness, and clinical validation of the sensitivity and specificity for each specific problem of interest. Although holding great promise, to date, DCE MRI and CT scanning have not been qualified as a surrogate endpoint for radiation therapy assessment or for treatment modification in any prospective phase III clinical trial for any tumor site. Copyright © 2011 Elsevier Inc. All rights reserved.

Brain CT scan indexes in the normal pressure hydrocephalus: predictive value in the outcome of patients and correlation to the clinical symptoms.

PubMed

Chatzidakis, Emmanuel M; Barlas, George; Condilis, Nicolas; Bouramas, Dimos; Anagnostopoulos, Demetrios; Volikas, Zacharias; Simopoulos, Konstantinos

2008-01-01

The aim of this study is to find out the correlation of the ventricular size of the brain, as it is estimated using brain computed tomography (CT) scan indexes in patients with normal pressure hydrocephalus (NPH), to: a) the clinical symptoms, and b) the results of cerebrospinal fluid (CSF) shunting procedures. We looked for any predictive value in the estimation of brain CT scan indexes, in patients as above, in whom a shunt is going to be placed. It is well known that it is very difficult to decide who is going to improve after shunting. We studied 40 cases of patients with the diagnosis "NPH" in whom the ventricular shunts were placed. Every symptom (motor disturbance, deficit of memory, incontinence) was separately evaluated preoperatively. The outcome of shunting was also evaluated and the patients were graded. The following CT scan indexes were estimated from the preoperative CT scans of the brain in every case: the ventricle-brain ratio (VBR), the bi-caudate and bi-frontal ratios, the third ventricle-Sylvian fissure (3V-SF) ratio, and the four largest cortical gyri. The method we have used for statistics is "one way analysis of variance", correlating the CT scan indexes to the symptoms of the patients preoperatively, and the outcome of them postoperatively. The main conclusion is that the size of the lateral ventricles of the brain preoperatively is not correlated to the outcome after CSF shunting surgery, but it is correlated to the symptoms of NPH preoperatively.

Safe cervical spine clearance in adult obtunded blunt trauma patients on the basis of a normal multidetector CT scan--a meta-analysis and cohort study.

PubMed

Raza, Mushahid; Elkhodair, Samer; Zaheer, Asif; Yousaf, Sohail

2013-11-01

A true gold standard to rule out a significant cervical spine injury in subset of blunt trauma patients with altered sensorium is still to be agreed upon. The objective of this study is to determine whether in obtunded adult patients with blunt trauma, a clinically significant injury to the cervical spine be ruled out on the basis of a normal multidetector cervical spine computed tomography. Comprehensive database search was conducted to include all the prospective and retrospective studies on blunt trauma patients with altered sensorium undergoing cervical spine multidetector CT scan as core imaging modality to "clear" the cervical spine. The studies used two main gold standards, magnetic resonance imaging of the cervical spine and/or prolonged clinical follow-up. The data was extracted to report true positive, true negatives, false positives and false negatives. Meta-analysis of sensitivity, specificity, negative and positive predictive values was performed using Meta Analyst Beta 3.13 software. We also performed a retrospective investigation comparing a robust clinical follow-up and/or cervical spine MR findings in 53 obtunded blunt trauma patients, who previously had undergone a normal multidetector CT scan of the cervical spine reported by a radiologist. A total of 10 studies involving 1850 obtunded blunt trauma patients with initial cervical spine CT scan reported as normal were included in the final meta-analysis. The cumulative negative predictive value and specificity of cervical spine CT of the ten studies was 99.7% (99.4-99.9%, 95% confidence interval). The positive predictive value and sensitivity was 93.7% (84.0-97.7%, 95% confidence interval). In the retrospective review of our obtunded blunt trauma patients, none was later diagnosed to have significant cervical spine injury that required a change in clinical management. In a blunt trauma patient with altered sensorium, a normal cervical spine CT scan is conclusive to safely rule out a clinically significant cervical spine injury. The results of this meta-analysis strongly support the removal of cervical precautions in obtunded blunt trauma patient after normal cervical spine computed tomography. Any further imaging like magnetic resonance imaging of the cervical spine should be performed on case-to-case basis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of Asynchronous Training on Radiology Learning Curve among Emergency Medicine Residents and Clerkship Students

PubMed Central

Pourmand, Ali; Woodward, Christina; Shokoohi, Hamid; King, Jordan B; Taheri, M Reza; King, Jackson; Lawrence, Christopher

2018-01-01

Context Web-based learning (WBL) modules are effectively used to improve medical education curriculum; however, they have not been evaluated to improve head computed tomography (CT) scan interpretation in an emergency medicine (EM) setting. Objective To evaluate the effectiveness of a WBL module to aid identification of cranial structures on CT and to improve ability to distinguish between normal and abnormal findings. Design Prospective, before-and-after trial in the Emergency Department of an academic center. Baseline head CT knowledge was assessed via a standardized test containing ten head CT scans, including normal scans and those showing hemorrhagic stroke, trauma, and infection (abscess). All trainees then participated in a WBL intervention. Three weeks later, they were given the same ten CT scans to evaluate in a standardized posttest. Main Outcome Measures Improvement in test scores. Results A total of 131 EM clerkship students and 32 EM residents were enrolled. Pretest scores correlated with stage of training, with students and first-year residents demonstrating the lowest scores. Overall, there was a significant improvement in percentage of correctly classified CT images after the training intervention from a mean pretest score of 32% ± 12% to posttest score of 67% ± 13% (mean improvement = 35% ± 13%, p < 0.001). Among subsets by training level, all subgroups except first-year residents demonstrated a statistically significant increase in scores after the training. Conclusion Incorporating asynchronous WBL modules into EM clerkship and residency curriculum provides early radiographic exposure in their clinical training and can enhance diagnostic head CT scan interpretation. PMID:29272248

Automated lung volumetry from routine thoracic CT scans: how reliable is the result?

PubMed

Haas, Matthias; Hamm, Bernd; Niehues, Stefan M

2014-05-01

Today, lung volumes can be easily calculated from chest computed tomography (CT) scans. Modern postprocessing workstations allow automated volume measurement of data sets acquired. However, there are challenges in the use of lung volume as an indicator of pulmonary disease when it is obtained from routine CT. Intra-individual variation and methodologic aspects have to be considered. Our goal was to assess the reliability of volumetric measurements in routine CT lung scans. Forty adult cancer patients whose lungs were unaffected by the disease underwent routine chest CT scans in 3-month intervals, resulting in a total number of 302 chest CT scans. Lung volume was calculated by automatic volumetry software. On average of 7.2 CT scans were successfully evaluable per patient (range 2-15). Intra-individual changes were assessed. In the set of patients investigated, lung volume was approximately normally distributed, with a mean of 5283 cm(3) (standard deviation = 947 cm(3), skewness = -0.34, and curtosis = 0.16). Between different scans in one and the same patient the median intra-individual standard deviation in lung volume was 853 cm(3) (16% of the mean lung volume). Automatic lung segmentation of routine chest CT scans allows a technically stable estimation of lung volume. However, substantial intra-individual variations have to be considered. A median intra-individual deviation of 16% in lung volume between different routine scans was found. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

PET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy: Single Cohort Comparison With Pretreatment Planning on (99m)Tc-MAA Imaging and Correlation With Treatment Efficacy.

PubMed

Song, Yoo Sung; Paeng, Jin Chul; Kim, Hyo-Cheol; Chung, Jin Wook; Cheon, Gi Jeong; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

2015-06-01

⁹⁰Y PET/CT can be acquired after ⁹⁰Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using ⁹⁰Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from (99m)Tc-MAA scan and SPECT/CT. Twenty-three patients with liver malignancy were included in the study. (99m)Tc-MAA was injected during planning angiography and whole body (99m)Tc-MAA scan and liver SPECT/CT were acquired. After SIRT using ⁹⁰Y-resin microsphere, ⁹⁰Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT results. Lung shunt fraction was overestimated on (99m)Tc-MAA scan compared with ⁹⁰Y-microsphere PET/CT (0.060 ± 0.037 vs. 0.018 ± 0.026, P < 0.01). Tumor absorbed dose exhibited a close correlation between the results from (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT (r = 0.64, P < 0.01), although the result from (99m)Tc-MAA SPECT/CT was significantly lower than that from ⁹⁰Y-microsphere PET/CT (135.4 ± 64.2 Gy vs. 185.0 ± 87.8 Gy, P < 0.01). Absorbed dose to in-target normal liver was overestimated on (99m)Tc-MAA SPECT/CT compared with PET/CT (62.6 ± 38.2 Gy vs. 45.2 ± 32.0 Gy, P = 0.02). Absorbed dose to out-target normal liver did not differ between (99m)Tc-MAA SPECT/CT and ⁹⁰Y-microsphere PET/CT (P = 0.49). Patients with tumor absorbed dose >200 Gy on ⁹⁰Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ≤200 Gy (286 ± 56 days vs. 92 ± 20 days, P = 0.046). Tumor absorbed dose calculated by (99m)Tc-MAA SPECT/CT was not a significant predictor for PFS. Activity planning based on (99m)Tc-MAA scan and SPECT/CT can be effectively used as a conservative method. Post-SIRT dosimetry based on ⁹⁰Y-microsphere PET/CT is an effective method to predict treatment efficacy.

PET/CT-Based Dosimetry in 90Y-Microsphere Selective Internal Radiation Therapy: Single Cohort Comparison With Pretreatment Planning on 99mTc-MAA Imaging and Correlation With Treatment Efficacy

PubMed Central

Song, Yoo Sung; Paeng, Jin Chul; Kim, Hyo-Cheol; Chung, Jin Wook; Cheon, Gi Jeong; Chung, June-Key; Lee, Dong Soo; Kang, Keon Wook

2015-01-01

Abstract 90Y PET/CT can be acquired after 90Y-microsphere selective radiation internal therapy (SIRT) to describe radioactivity distribution. We performed dosimetry using 90Y-microsphere PET/CT data to evaluate treatment efficacy and appropriateness of activity planning from 99mTc-MAA scan and SPECT/CT. Twenty-three patients with liver malignancy were included in the study. 99mTc-MAA was injected during planning angiography and whole body 99mTc-MAA scan and liver SPECT/CT were acquired. After SIRT using 90Y-resin microsphere, 90Y-microsphere PET/CT was acquired. A partition model (PM) using 4 compartments (tumor, intarget normal liver, out-target normal liver, and lung) was adopted, and absorbed dose to each compartment was calculated based on measurements from 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT, respectively, to be compared with each other. Progression-free survival (PFS) was evaluated in terms of tumor absorbed doses calculated by 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT results. Lung shunt fraction was overestimated on 99mTc-MAA scan compared with 90Y-microsphere PET/CT (0.060 ± 0.037 vs. 0.018 ± 0.026, P < 0.01). Tumor absorbed dose exhibited a close correlation between the results from 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT (r = 0.64, P < 0.01), although the result from 99mTc-MAA SPECT/CT was significantly lower than that from 90Y-microsphere PET/CT (135.4 ± 64.2 Gy vs. 185.0 ± 87.8 Gy, P < 0.01). Absorbed dose to in-target normal liver was overestimated on 99mTc-MAA SPECT/CT compared with PET/CT (62.6 ± 38.2 Gy vs. 45.2 ± 32.0 Gy, P = 0.02). Absorbed dose to out-target normal liver did not differ between 99mTc-MAA SPECT/CT and 90Y-microsphere PET/CT (P = 0.49). Patients with tumor absorbed dose >200 Gy on 90Y-microsphere PET/CT had longer PFS than those with tumor absorbed dose ≤200 Gy (286 ± 56 days vs. 92 ± 20 days, P = 0.046). Tumor absorbed dose calculated by 99mTc-MAA SPECT/CT was not a significant predictor for PFS. Activity planning based on 99mTc-MAA scan and SPECT/CT can be effectively used as a conservative method. Post-SIRT dosimetry based on 90Y-microsphere PET/CT is an effective method to predict treatment efficacy. PMID:26061323

99mTc-HMPAO SPECT of the brain in mild to moderate traumatic brain injury patients: compared with CT--a prospective study.

PubMed

Nedd, K; Sfakianakis, G; Ganz, W; Uricchio, B; Vernberg, D; Villanueva, P; Jabir, A M; Bartlett, J; Keena, J

1993-01-01

Single photon emission computed tomography (SPECT) with Technetium-99m hexamethyl propylenamine oxime (Tc-99m-HMPAO) was used in 20 patients with mild to moderate traumatic brain injury (TBI) to evaluate the effects of brain trauma on regional cerebral blood flow (rCBF). SPECT scan was compared with CT scan in 16 patients. SPECT showed intraparenchymal differences in rCBF more often than lesions diagnosed with CT scans (87.5% vs. 37.5%). In five of six patients with lesions in both modalities, the area of involvement was relatively larger on SPECT scans than on CT scans. Contrecoup changes were seen in five patients on SPECT alone, two patients with CT alone and one patient had contrecoup lesions on CT and SPECT. Of the eight patients (50%) with skull fractures, seven (43.7%) had rCBF findings on SPECT scan and five (31.3%) demonstrated decrease in rCBF in brain underlying the fracture. All these patients with fractures had normal brain on CT scans. Conversely, extra-axial lesions and fractures evident on CT did not visualize on SPECT, but SPECT demonstrated associated changes in rCBF. Although there is still lack of clinical and pathological correlation, SPECT appears to be a promising method for a more sensitive evaluation of axial lesions in patients with mild to moderate TBI.

Malignant external otitis: the role of computed tomography and radionuclides in evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendelson, D.S.; Som, P.M.; Mendelson, M.H.

1983-12-01

Nine patients with malignant external otitis (MEO) were evaluated with Tc-99m bone scans, Ga-67 citrate scans, pluridirectional tomography, and computed tomographic (CT) scans in order to assess the role of each in the diagnosis and management of MEO. The Tc-99m and Ga-67 citrate scans were the most accurate studies in the initial identification of disease activity, while the return to normal or improvement of the Ga-67 citrate scan has been shown to correlate best with clinical resolution of MEO. CT demonstrated soft-tissue disease and central skull base osteomyelitis better than pluridirectional tomography. CT is excellent for localizing and following themore » progression of bone disease; however, because reossification of the skull base is a very slow process, CT cannot be used to follow accurately regression or inactivity of MEO affecting this area. CT is the best modality for following soft-tissue extension of MEO.« less

Bicuspid aortic valves: diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT.

PubMed

Murphy, David J; McEvoy, Sinead H; Iyengar, Sri; Feuchtner, Gudrun; Cury, Ricardo C; Roobottom, Carl; Baumueller, Stephan; Alkadhi, Hatem; Dodd, Jonathan D

2014-08-01

To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P=0.001). Kappa analysis=0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥ 3.8 cm(2), 3.2 cm and 1.6mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P<0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54-1.0), 100%, 100% and 70% respectively. The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT features. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

TU-H-207A-09: An Automated Technique for Estimating Patient-Specific Regional Imparted Energy and Dose From TCM CT Exams Across 13 Protocols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanders, J; Tian, X; Segars, P

2016-06-15

Purpose: To develop an automated technique for estimating patient-specific regional imparted energy and dose from tube current modulated (TCM) computed tomography (CT) exams across a diverse set of head and body protocols. Methods: A library of 58 adult computational anthropomorphic extended cardiac-torso (XCAT) phantoms were used to model a patient population. A validated Monte Carlo program was used to simulate TCM CT exams on the entire library of phantoms for three head and 10 body protocols. The net imparted energy to the phantoms, normalized by dose length product (DLP), and the net tissue mass in each of the scan regionsmore » were computed. A knowledgebase containing relationships between normalized imparted energy and scanned mass was established. An automated computer algorithm was written to estimate the scanned mass from actual clinical CT exams. The scanned mass estimate, DLP of the exam, and knowledgebase were used to estimate the imparted energy to the patient. The algorithm was tested on 20 chest and 20 abdominopelvic TCM CT exams. Results: The normalized imparted energy increased with increasing kV for all protocols. However, the normalized imparted energy was relatively unaffected by the strength of the TCM. The average imparted energy was 681 ± 376 mJ for abdominopelvic exams and 274 ± 141 mJ for chest exams. Overall, the method was successful in providing patientspecific estimates of imparted energy for 98% of the cases tested. Conclusion: Imparted energy normalized by DLP increased with increasing tube potential. However, the strength of the TCM did not have a significant effect on the net amount of energy deposited to tissue. The automated program can be implemented into the clinical workflow to provide estimates of regional imparted energy and dose across a diverse set of clinical protocols.« less

Normal bone and soft tissue distribution of fluorine-18-sodium fluoride and artifacts on 18F-NaF PET/CT bone scan: a pictorial review.

PubMed

Sarikaya, Ismet; Elgazzar, Abdelhamid H; Sarikaya, Ali; Alfeeli, Mahmoud

2017-10-01

Fluorine-18-sodium fluoride (F-NaF) PET/CT is a relatively new and high-resolution bone imaging modality. Since the use of F-NaF PET/CT has been increasing, it is important to accurately assess the images and be aware of normal distribution and major artifacts. In this pictorial review article, we will describe the normal uptake patterns of F-NaF in the bone tissues, particularly in complex structures, as well as its physiologic soft tissue distribution and certain artifacts seen on F-NaF PET/CT images.

Colitis detection on abdominal CT scans by rich feature hierarchies

NASA Astrophysics Data System (ADS)

Liu, Jiamin; Lay, Nathan; Wei, Zhuoshi; Lu, Le; Kim, Lauren; Turkbey, Evrim; Summers, Ronald M.

2016-03-01

Colitis is inflammation of the colon due to neutropenia, inflammatory bowel disease (such as Crohn disease), infection and immune compromise. Colitis is often associated with thickening of the colon wall. The wall of a colon afflicted with colitis is much thicker than normal. For example, the mean wall thickness in Crohn disease is 11-13 mm compared to the wall of the normal colon that should measure less than 3 mm. Colitis can be debilitating or life threatening, and early detection is essential to initiate proper treatment. In this work, we apply high-capacity convolutional neural networks (CNNs) to bottom-up region proposals to detect potential colitis on CT scans. Our method first generates around 3000 category-independent region proposals for each slice of the input CT scan using selective search. Then, a fixed-length feature vector is extracted from each region proposal using a CNN. Finally, each region proposal is classified and assigned a confidence score with linear SVMs. We applied the detection method to 260 images from 26 CT scans of patients with colitis for evaluation. The detection system can achieve 0.85 sensitivity at 1 false positive per image.

Feasibility of Computed Tomography-Guided Methods for Spatial Normalization of Dopamine Transporter Positron Emission Tomography Image.

PubMed

Kim, Jin Su; Cho, Hanna; Choi, Jae Yong; Lee, Seung Ha; Ryu, Young Hoon; Lyoo, Chul Hyoung; Lee, Myung Sik

2015-01-01

Spatial normalization is a prerequisite step for analyzing positron emission tomography (PET) images both by using volume-of-interest (VOI) template and voxel-based analysis. Magnetic resonance (MR) or ligand-specific PET templates are currently used for spatial normalization of PET images. We used computed tomography (CT) images acquired with PET/CT scanner for the spatial normalization for [18F]-N-3-fluoropropyl-2-betacarboxymethoxy-3-beta-(4-iodophenyl) nortropane (FP-CIT) PET images and compared target-to-cerebellar standardized uptake value ratio (SUVR) values with those obtained from MR- or PET-guided spatial normalization method in healthy controls and patients with Parkinson's disease (PD). We included 71 healthy controls and 56 patients with PD who underwent [18F]-FP-CIT PET scans with a PET/CT scanner and T1-weighted MR scans. Spatial normalization of MR images was done with a conventional spatial normalization tool (cvMR) and with DARTEL toolbox (dtMR) in statistical parametric mapping software. The CT images were modified in two ways, skull-stripping (ssCT) and intensity transformation (itCT). We normalized PET images with cvMR-, dtMR-, ssCT-, itCT-, and PET-guided methods by using specific templates for each modality and measured striatal SUVR with a VOI template. The SUVR values measured with FreeSurfer-generated VOIs (FSVOI) overlaid on original PET images were also used as a gold standard for comparison. The SUVR values derived from all four structure-guided spatial normalization methods were highly correlated with those measured with FSVOI (P < 0.0001). Putaminal SUVR values were highly effective for discriminating PD patients from controls. However, the PET-guided method excessively overestimated striatal SUVR values in the PD patients by more than 30% in caudate and putamen, and thereby spoiled the linearity between the striatal SUVR values in all subjects and showed lower disease discrimination ability. Two CT-guided methods showed comparable capability with the MR-guided methods in separating PD patients from controls and showed better correlation between putaminal SUVR values and the parkinsonian motor severity than the PET-guided method. CT-guided spatial normalization methods provided reliable striatal SUVR values comparable to those obtained with MR-guided methods. CT-guided methods can be useful for analyzing dopamine transporter PET images when MR images are unavailable.

Feasibility of Computed Tomography-Guided Methods for Spatial Normalization of Dopamine Transporter Positron Emission Tomography Image

PubMed Central

Kim, Jin Su; Cho, Hanna; Choi, Jae Yong; Lee, Seung Ha; Ryu, Young Hoon; Lyoo, Chul Hyoung; Lee, Myung Sik

2015-01-01

Background Spatial normalization is a prerequisite step for analyzing positron emission tomography (PET) images both by using volume-of-interest (VOI) template and voxel-based analysis. Magnetic resonance (MR) or ligand-specific PET templates are currently used for spatial normalization of PET images. We used computed tomography (CT) images acquired with PET/CT scanner for the spatial normalization for [18F]-N-3-fluoropropyl-2-betacarboxymethoxy-3-beta-(4-iodophenyl) nortropane (FP-CIT) PET images and compared target-to-cerebellar standardized uptake value ratio (SUVR) values with those obtained from MR- or PET-guided spatial normalization method in healthy controls and patients with Parkinson’s disease (PD). Methods We included 71 healthy controls and 56 patients with PD who underwent [18F]-FP-CIT PET scans with a PET/CT scanner and T1-weighted MR scans. Spatial normalization of MR images was done with a conventional spatial normalization tool (cvMR) and with DARTEL toolbox (dtMR) in statistical parametric mapping software. The CT images were modified in two ways, skull-stripping (ssCT) and intensity transformation (itCT). We normalized PET images with cvMR-, dtMR-, ssCT-, itCT-, and PET-guided methods by using specific templates for each modality and measured striatal SUVR with a VOI template. The SUVR values measured with FreeSurfer-generated VOIs (FSVOI) overlaid on original PET images were also used as a gold standard for comparison. Results The SUVR values derived from all four structure-guided spatial normalization methods were highly correlated with those measured with FSVOI (P < 0.0001). Putaminal SUVR values were highly effective for discriminating PD patients from controls. However, the PET-guided method excessively overestimated striatal SUVR values in the PD patients by more than 30% in caudate and putamen, and thereby spoiled the linearity between the striatal SUVR values in all subjects and showed lower disease discrimination ability. Two CT-guided methods showed comparable capability with the MR-guided methods in separating PD patients from controls and showed better correlation between putaminal SUVR values and the parkinsonian motor severity than the PET-guided method. Conclusion CT-guided spatial normalization methods provided reliable striatal SUVR values comparable to those obtained with MR-guided methods. CT-guided methods can be useful for analyzing dopamine transporter PET images when MR images are unavailable. PMID:26147749

Automated assessment of aortic and main pulmonary arterial diameters using model-based blood vessel segmentation for predicting chronic thromboembolic pulmonary hypertension in low-dose CT lung screening

NASA Astrophysics Data System (ADS)

Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Sugiura, Toshihiko; Tanabe, Nobuhiro; Kusumoto, Masahiko; Eguchi, Kenji; Kaneko, Masahiro

2018-02-01

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by obstruction of the pulmonary vasculature by residual organized thrombi. A morphological abnormality inside mediastinum of CTEPH patient is enlargement of pulmonary artery. This paper presents an automated assessment of aortic and main pulmonary arterial diameters for predicting CTEPH in low-dose CT lung screening. The distinctive feature of our method is to segment aorta and main pulmonary artery using both of prior probability and vascular direction which were estimated from mediastinal vascular region using principal curvatures of four-dimensional hyper surface. The method was applied to two datasets, 64 lowdose CT scans of lung cancer screening and 19 normal-dose CT scans of CTEPH patients through the training phase with 121 low-dose CT scans. This paper demonstrates effectiveness of our method for predicting CTEPH in low-dose CT screening.

Patient-specific Radiation Dose and Cancer Risk for Pediatric Chest CT

PubMed Central

Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

2011-01-01

Purpose: To estimate patient-specific radiation dose and cancer risk for pediatric chest computed tomography (CT) and to evaluate factors affecting dose and risk, including patient size, patient age, and scanning parameters. Materials and Methods: The institutional review board approved this study and waived informed consent. This study was HIPAA compliant. The study included 30 patients (0–16 years old), for whom full-body computer models were recently created from clinical CT data. A validated Monte Carlo program was used to estimate organ dose from eight chest protocols, representing clinically relevant combinations of bow tie filter, collimation, pitch, and tube potential. Organ dose was used to calculate effective dose and risk index (an index of total cancer incidence risk). The dose and risk estimates before and after normalization by volume-weighted CT dose index (CTDIvol) or dose–length product (DLP) were correlated with patient size and age. The effect of each scanning parameter was studied. Results: Organ dose normalized by tube current–time product or CTDIvol decreased exponentially with increasing average chest diameter. Effective dose normalized by tube current–time product or DLP decreased exponentially with increasing chest diameter. Chest diameter was a stronger predictor of dose than weight and total scan length. Risk index normalized by tube current–time product or DLP decreased exponentially with both chest diameter and age. When normalized by DLP, effective dose and risk index were independent of collimation, pitch, and tube potential (<10% variation). Conclusion: The correlations of dose and risk with patient size and age can be used to estimate patient-specific dose and risk. They can further guide the design and optimization of pediatric chest CT protocols. © RSNA, 2011 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101900/-/DC1 PMID:21467251

Patient-specific radiation dose and cancer risk for pediatric chest CT.

PubMed

Li, Xiang; Samei, Ehsan; Segars, W Paul; Sturgeon, Gregory M; Colsher, James G; Frush, Donald P

2011-06-01

To estimate patient-specific radiation dose and cancer risk for pediatric chest computed tomography (CT) and to evaluate factors affecting dose and risk, including patient size, patient age, and scanning parameters. The institutional review board approved this study and waived informed consent. This study was HIPAA compliant. The study included 30 patients (0-16 years old), for whom full-body computer models were recently created from clinical CT data. A validated Monte Carlo program was used to estimate organ dose from eight chest protocols, representing clinically relevant combinations of bow tie filter, collimation, pitch, and tube potential. Organ dose was used to calculate effective dose and risk index (an index of total cancer incidence risk). The dose and risk estimates before and after normalization by volume-weighted CT dose index (CTDI(vol)) or dose-length product (DLP) were correlated with patient size and age. The effect of each scanning parameter was studied. Organ dose normalized by tube current-time product or CTDI(vol) decreased exponentially with increasing average chest diameter. Effective dose normalized by tube current-time product or DLP decreased exponentially with increasing chest diameter. Chest diameter was a stronger predictor of dose than weight and total scan length. Risk index normalized by tube current-time product or DLP decreased exponentially with both chest diameter and age. When normalized by DLP, effective dose and risk index were independent of collimation, pitch, and tube potential (<10% variation). The correlations of dose and risk with patient size and age can be used to estimate patient-specific dose and risk. They can further guide the design and optimization of pediatric chest CT protocols. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101900/-/DC1. RSNA, 2011

Computed tomography versus water-soluble contrast swallow in the detection of intrathoracic anastomotic leak complicating esophagogastrectomy (Ivor Lewis): a prospective study in 97 patients.

PubMed

Strauss, Christiane; Mal, Frederic; Perniceni, Thierry; Bouzar, Nadia; Lenoir, Stephane; Gayet, Brice; Palau, Robert

2010-04-01

Water-soluble contrast swallow (CS) is usually performed before refeeding for anastomosis assessment after esophagectomy with intrathoracic anastomosis but the sensitivity of CS is low. Another diagnostic approach is based on analysis of computed tomography (CT) scan with oral contrast and of CT mediastinal air images. We undertook to compare them prospectively. Ninety-seven patients with an esophageal carcinoma operated by intrathoracic anastomosis were included prospectively in a study based on a CT scan at postoperative day 3 (without oral and intravenous contrast) and CT scan and CS at day 7. CT scan analysis consisted of assessing contrast and air leakage. In case of doubt, an endoscopy was done. A diagnosis of anastomotic leak was made in 13 patients (13.4%), in 2 cases before day 7 and in 3 beyond day 7. At day 3, 94 CT scans were performed, but the diagnostic value was poor. In 95 patients with both CS and CT scan at day 7, CS disclosed a leak in 5 of 11, and CT scan was abnormal in 8 of 11. Leakage of contrast and/or presence of mediastinal gas had the best negative predictive value (95.8%). Endoscopy was done in 16 patients with only mediastinal gas at day 7 CT scan. It disclosed a normal anastomosis in 11, fibrin deposits in 4, and a leak in 1. In comparison with CS only, CT at day 7 improves the sensitivity and negative predictive value for diagnosing an anastomotic leak. In case of doubt endoscopy is advisable. This approach provides an accurate assessment of the anastomosis before refeeding.

Computed tomography of patients with head trauma following road traffic accident in Benin City, Nigeria.

PubMed

Eze, K C; Mazeli, F O

2011-01-01

The outcome of head trauma as a result of road accident rests with increased use of CT scan and other radiological imaging modalities for prompt diagnosis is important. To find out the time of presentation for CT scan, symptoms for referral for CT scan and pattern of injuries in patients with cranial CT scan following road traffic accidents. Retrospective analysis of cranial computed tomography (CT) films, request cards, duplicate copy of radiology reports, soft copy CT images and case notes of 61 patients who underwent cranial CT scan on account of road traffic accidents. The study CT scans were performed at the radiology department of University Teaching Hospital between 1st January 2002 and 31st December 2004. 51 patients (83.6%) were male while 10 (16.4%) were female with male to female ratio of 5:1. Thirty - eight (62.3%) patients were aged 20-39 years. Forty two patients (68.9%) presented after one week of injury. No patient presented within the first six hours of injury. The symptoms needing referral for CT scan included head injury 30 (49.2%), seizures 10 16.4%), skull fractures 8 (13.1%) and persistent headache 6 (5.6%). A total of 113 lesions were seen as some patients presented with more than one lesion. The findings on CT scan included 10 patients with normal findings , 21 (34.4%) skull fractures , 21 (34.4%) intra-cerebral haemorrhage , 19 (31.2%) brain contusion , 18 (29.5%) paranasal sinus collection,11 (18.0%) cerebral oedema, 10 (16.4%) subdural haematoma and 5 (8.2%) epidural haematoma. Over 80% of the subdural and epidural haematomas were associated with skull fractures. The yield from plain radiography was poor being positive in only 8 (13.1%) while CT scan was positive in 51 (83.61%). Also 75 (about 66%) of the 113 lesions seen on CT scan were treatable surgically. CT scan is an effective imaging modality of patient with road traffic accident and should be promptly requested in symptomatic patients who sustain trauma to the head toward identification of lesions that are amenable to surgical treatment.

Radiation doses in volume-of-interest breast computed tomography—A Monte Carlo simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, Chao-Jen, E-mail: cjlai3711@gmail.com; Zhong, Yuncheng; Yi, Ying

2015-06-15

Purpose: Cone beam breast computed tomography (breast CT) with true three-dimensional, nearly isotropic spatial resolution has been developed and investigated over the past decade to overcome the problem of lesions overlapping with breast anatomical structures on two-dimensional mammographic images. However, the ability of breast CT to detect small objects, such as tissue structure edges and small calcifications, is limited. To resolve this problem, the authors proposed and developed a volume-of-interest (VOI) breast CT technique to image a small VOI using a higher radiation dose to improve that region’s visibility. In this study, the authors performed Monte Carlo simulations to estimatemore » average breast dose and average glandular dose (AGD) for the VOI breast CT technique. Methods: Electron–Gamma-Shower system code-based Monte Carlo codes were used to simulate breast CT. The Monte Carlo codes estimated were validated using physical measurements of air kerma ratios and point doses in phantoms with an ion chamber and optically stimulated luminescence dosimeters. The validated full cone x-ray source was then collimated to simulate half cone beam x-rays to image digital pendant-geometry, hemi-ellipsoidal, homogeneous breast phantoms and to estimate breast doses with full field scans. 13-cm in diameter, 10-cm long hemi-ellipsoidal homogeneous phantoms were used to simulate median breasts. Breast compositions of 25% and 50% volumetric glandular fractions (VGFs) were used to investigate the influence on breast dose. The simulated half cone beam x-rays were then collimated to a narrow x-ray beam with an area of 2.5 × 2.5 cm{sup 2} field of view at the isocenter plane and to perform VOI field scans. The Monte Carlo results for the full field scans and the VOI field scans were then used to estimate the AGD for the VOI breast CT technique. Results: The ratios of air kerma ratios and dose measurement results from the Monte Carlo simulation to those from the physical measurements were 0.97 ± 0.03 and 1.10 ± 0.13, respectively, indicating that the accuracy of the Monte Carlo simulation was adequate. The normalized AGD with VOI field scans was substantially reduced by a factor of about 2 over the VOI region and by a factor of 18 over the entire breast for both 25% and 50% VGF simulated breasts compared with the normalized AGD with full field scans. The normalized AGD for the VOI breast CT technique can be kept the same as or lower than that for a full field scan with the exposure level for the VOI field scan increased by a factor of as much as 12. Conclusions: The authors’ Monte Carlo estimates of normalized AGDs for the VOI breast CT technique show that this technique can be used to markedly increase the dose to the breast and thus the visibility of the VOI region without increasing the dose to the breast. The results of this investigation should be helpful for those interested in using VOI breast CT technique to image small calcifications with dose concern.« less

Radiation doses in volume-of-interest breast computed tomography—A Monte Carlo simulation study

PubMed Central

Lai, Chao-Jen; Zhong, Yuncheng; Yi, Ying; Wang, Tianpeng; Shaw, Chris C.

2015-01-01

Purpose: Cone beam breast computed tomography (breast CT) with true three-dimensional, nearly isotropic spatial resolution has been developed and investigated over the past decade to overcome the problem of lesions overlapping with breast anatomical structures on two-dimensional mammographic images. However, the ability of breast CT to detect small objects, such as tissue structure edges and small calcifications, is limited. To resolve this problem, the authors proposed and developed a volume-of-interest (VOI) breast CT technique to image a small VOI using a higher radiation dose to improve that region’s visibility. In this study, the authors performed Monte Carlo simulations to estimate average breast dose and average glandular dose (AGD) for the VOI breast CT technique. Methods: Electron–Gamma-Shower system code-based Monte Carlo codes were used to simulate breast CT. The Monte Carlo codes estimated were validated using physical measurements of air kerma ratios and point doses in phantoms with an ion chamber and optically stimulated luminescence dosimeters. The validated full cone x-ray source was then collimated to simulate half cone beam x-rays to image digital pendant-geometry, hemi-ellipsoidal, homogeneous breast phantoms and to estimate breast doses with full field scans. 13-cm in diameter, 10-cm long hemi-ellipsoidal homogeneous phantoms were used to simulate median breasts. Breast compositions of 25% and 50% volumetric glandular fractions (VGFs) were used to investigate the influence on breast dose. The simulated half cone beam x-rays were then collimated to a narrow x-ray beam with an area of 2.5 × 2.5 cm2 field of view at the isocenter plane and to perform VOI field scans. The Monte Carlo results for the full field scans and the VOI field scans were then used to estimate the AGD for the VOI breast CT technique. Results: The ratios of air kerma ratios and dose measurement results from the Monte Carlo simulation to those from the physical measurements were 0.97 ± 0.03 and 1.10 ± 0.13, respectively, indicating that the accuracy of the Monte Carlo simulation was adequate. The normalized AGD with VOI field scans was substantially reduced by a factor of about 2 over the VOI region and by a factor of 18 over the entire breast for both 25% and 50% VGF simulated breasts compared with the normalized AGD with full field scans. The normalized AGD for the VOI breast CT technique can be kept the same as or lower than that for a full field scan with the exposure level for the VOI field scan increased by a factor of as much as 12. Conclusions: The authors’ Monte Carlo estimates of normalized AGDs for the VOI breast CT technique show that this technique can be used to markedly increase the dose to the breast and thus the visibility of the VOI region without increasing the dose to the breast. The results of this investigation should be helpful for those interested in using VOI breast CT technique to image small calcifications with dose concern. PMID:26127058

FDG-Avid Portal Vein Tumor Thrombosis from Hepatocellular Carcinoma in Contrast-Enhanced FDG PET/CT

PubMed Central

Nguyen, Xuan Canh; Nguyen, Dinh Song Huy; Ngo, Van Tan; Maurea, Simone

2015-01-01

Objective(s): In this study, we aimed to describe the characteristics of portal vein tumor thrombosis (PVTT), complicating hepatocellular carcinoma (HCC) in contrast-enhanced FDG PET/CT scan. Methods: In this retrospective study, 9 HCC patients with FDG-avid PVTT were diagnosed by contrast-enhanced fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), which is a combination of dynamic liver CT scan, multiphase imaging, and whole-body PET scan. PET and CT DICOM images of patients were imported into the PET/CT imaging system for the re-analysis of contrast enhancement and FDG uptake in thrombus, the diameter of the involved portal vein, and characteristics of liver tumors and metastasis. Results: Two patients with previously untreated HCC and 7 cases with previously treated HCC had FDG-avid PVTT in contrast-enhanced FDG PET/CT scan. During the arterial phase of CT scan, portal vein thrombus showed contrast enhancement in 8 out of 9 patients (88.9%). PET scan showed an increased linear FDG uptake along the thrombosed portal vein in all patients. The mean greatest diameter of thrombosed portal veins was 1.8 ± 0.2 cm, which was significantly greater than that observed in normal portal veins (P<0.001). FDG uptake level in portal vein thrombus was significantly higher than that of blood pool in the reference normal portal vein (P=0.001). PVTT was caused by the direct extension of liver tumors. All patients had visible FDG-avid liver tumors in contrast-enhanced images. Five out of 9 patients (55.6%) had no extrahepatic metastasis, 3 cases (33.3%) had metastasis of regional lymph nodes, and 1 case (11.1%) presented with distant metastasis. The median estimated survival time of patients was 5 months. Conclusion: The intraluminal filling defect consistent with thrombous within the portal vein, expansion of the involved portal vein, contrast enhancement, and linear increased FDG uptake of the thrombus extended from liver tumor are findings of FDG-avid PVTT from HCC in contrast-enhanced FDG PET/CT. PMID:27408876

The role of chest computed tomography (CT) as a surveillance tool in children with high-risk neuroblastoma.

PubMed

Federico, Sara M; Brady, Samuel L; Pappo, Alberto; Wu, Jianrong; Mao, Shenghua; McPherson, Valerie J; Young, Alison; Furman, Wayne L; Kaufman, Robert; Kaste, Sue

2015-06-01

Standardization of imaging obtained in children with neuroblastoma is not well established. This study examines chest CT in pediatric patients with high-risk neuroblastoma. Medical records and imaging from 88 patients with high-risk neuroblastoma, diagnosed at St. Jude Children's Research Hospital between January, 2002 and December, 2009, were reviewed. Surveillance imaging was conducted through 2013. Ten patients with thoracic disease at diagnosis were excluded. Event free survival (EFS) and overall survival (OS) were estimated. Size specific dose estimates for CT scans of the chest, abdomen, and pelvis were used to estimate absolute organ doses to 23 organs. Organ dosimetry was used to calculate cohort effective dose. The 5 year OS and EFS were 51.9% ± 6.5% and 42.6% ± 6.5%, respectively. Forty-six (58.9%) patients progressed/recurred and 41 (52.6%) died of disease. Eleven patients (14%) developed thoracic disease progression/recurrence identified by chest CT (1 paraspinal mass, 1 pulmonary nodules, and 9 nodal). MIBG (metaiodobenzylguanidine) scans identified thoracic disease in six patients. Five of the 11 had normal chest MIBG scans; three were symptomatic and two were asymptomatic with normal chest MIBG scans but avid bone disease. The estimated radiation dose savings from surveillance without CT chest imaging was 42%, 34% when accounting for modern CT acquisition (2011-2013). Neuroblastoma progression/recurrence in the chest is rare and often presents with symptoms or is identified using standard non-CT imaging modalities. For patients with non-thoracic high-risk neuroblastoma at diagnosis, omission of surveillance chest CT imaging can save 35-42% of the radiation burden without compromising disease detection. © 2015 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eun-Young Kang; Patz, E.F. Jr.; Mueller, N.L.

Our goal was to assess the CT findings of cytomegalovirus (CMV) pneumonia in transplant patients. The study included 10 transplant patients who had chest CT scan and pathologically proven isolated pulmonary CMV infection. Five patients had bone marrow transplant and five had solid organ transplant. The CT scans were retrospectively reviewed for pattern and distribution of disease and the CT findings compared with the findings on open lung biopsy (n = 9) and autopsy (n = 1). Nine of 10 patients had parenchymal abnormalities apparent at CT and I had normal CT scans. The findings in the nine patients includedmore » small nodules (n = 6), consolidation (n = 4), ground-glass attenuation (n = 4), and irregular lines (n = 1). The nodules had a bilateral and symmetric distribution and involved all lung zones. The consolidation was most marked in the lower lung zones. The CT findings of CMV pneumonia in transplant patients are heterogeneous. The most common patterns include small nodules and areas of consolidation. 13 refs., 4 figs., 1 tab.« less

A fully automated non-external marker 4D-CT sorting algorithm using a serial cine scanning protocol.

PubMed

Carnes, Greg; Gaede, Stewart; Yu, Edward; Van Dyk, Jake; Battista, Jerry; Lee, Ting-Yim

2009-04-07

Current 4D-CT methods require external marker data to retrospectively sort image data and generate CT volumes. In this work we develop an automated 4D-CT sorting algorithm that performs without the aid of data collected from an external respiratory surrogate. The sorting algorithm requires an overlapping cine scan protocol. The overlapping protocol provides a spatial link between couch positions. Beginning with a starting scan position, images from the adjacent scan position (which spatial match the starting scan position) are selected by maximizing the normalized cross correlation (NCC) of the images at the overlapping slice position. The process was continued by 'daisy chaining' all couch positions using the selected images until an entire 3D volume was produced. The algorithm produced 16 phase volumes to complete a 4D-CT dataset. Additional 4D-CT datasets were also produced using external marker amplitude and phase angle sorting methods. The image quality of the volumes produced by the different methods was quantified by calculating the mean difference of the sorted overlapping slices from adjacent couch positions. The NCC sorted images showed a significant decrease in the mean difference (p < 0.01) for the five patients.

Reference Values for Central Airway Dimensions on CT Images of Children and Adolescents.

PubMed

Kuo, Wieying; Ciet, Pierluigi; Andrinopoulou, Eleni-Rosalina; Chen, Yong; Pullens, Bas; Garcia-Peña, Pilar; Fleck, Robert J; Paoletti, Matteo; McCartin, Michael; Vermeulen, Francois; Morana, Giovanni; Lee, Edward Y; Tiddens, Harm A W M

2018-02-01

The purpose of this study was to acquire normative data on central airway dimensions on chest CT scans in the pediatric population. Chest CT findings reported as normal by a radiologist were collected retrospectively at 10 international centers. An experienced and independent thoracic radiologist reevaluated all CT scans for image quality and for normal findings. Semiautomated image analysis was performed to measure dimensions of the trachea and right and left main bronchi at inspiration. Intrathoracic tracheal length was measured from carina to thorax inlet. Cross-sectional area and short and long axes were measured perpendicular to the longitudinal airway axis starting from the carina every centimeter upward for the trachea and every 0.5 cm downward for the main bronchi. The effects on airway diameters of age, sex, intrathoracic tracheal length, and distance from the carina were investigated by use of mixed-effects models analysis. Among 1160 CT scans collected, 388 were evaluated as normal by the independent radiologist with sufficient image quality and adequate inspiratory volume level. Central airways were successfully semiautomatically analyzed in 294 of 388 CT studies. Age, sex, intrathoracic tracheal length, and distance from carina were all significant predictors in the models for tracheal and right and left main bronchial diameters (p < 0.001). The central airway dimensions increased with age up to 20 years, and dimensions were larger in male than in female adolescents. Normative data were determined for the central airways of children and adolescents. Central airway dimensions depended on distance from the carina and on intrathoracic tracheal length.

Indications of Brain Computed Tomography Scan in Children Younger Than 3 Years of Age with Minor Head Trauma

PubMed Central

Gülşen, İsmail; Ak, Hakan; Karadaş, Sevdegül; Demır, İsmail; Bulut, Mehmet Deniz; Yaycioğlu, Soner

2014-01-01

Objective. To investigate the indications to receive brain computed tomography (CT) scan and to define the pathological findings in children younger than three years of age with minor head trauma in emergency departments. Methods. In this study, hospital case notes of 1350 children attending the emergency department of Bitlis State Hospital between January 2011 and June 2013 were retrospectively reviewed. 508 children under 3 years of age with minor head trauma were included in this study. We also asked 37 physicians about the indications for requiring CT in these children. Results. This study included 508 children, 233 (45,9%) of whom were female and 275 were male. In 476 (93,7%) children, the brain CT was completely normal. 89,2% of physicians asked in the emergency department during that time interval reported that they requested CT scan to protect themselves against malpractice litigation. Conclusion. In infants and children with minor head trauma, most CT scans were unnecessary and the fear of malpractice litigation of physicians was the most common reason for requesting a CT. PMID:24724031

Thoracic CT

MedlinePlus

... CT scan Vertebra, thoracic (mid back) Normal lung anatomy Thoracic organs References Gotway MB, Panse PM, Gruden JF, Elicker BM. Thoracic radiology. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier ...

Computed tomography of orbital tumors in the dog.

PubMed

LeCouteur, R A; Fike, J R; Scagliotti, R H; Cann, C E

1982-04-15

Computed tomography (CT) was used to investigate orbital tumors in 3 dogs. Tumors were clearly defined on transverse CT scans by their inherent density and gross distortion of normal orbital anatomy. Dorsal images synthesized from the original transverse scans were also used to visualize size and extent of tumors. Use of an iodinated contrast medium did not appear to improve localization of tumors in the orbit but was useful for identification of tumor extension into the calvaria. It was concluded that CT offered advantages over existing methods of radiographic diagnosis of orbital tumors and exophthalmos.

Image quality of conventional images of dual-layer SPECTRAL CT: A phantom study.

PubMed

van Ommen, Fasco; Bennink, Edwin; Vlassenbroek, Alain; Dankbaar, Jan Willem; Schilham, Arnold M R; Viergever, Max A; de Jong, Hugo W A M

2018-05-10

Spectral CT using a dual layer detector offers the possibility of retrospectively introducing spectral information to conventional CT images. In theory, the dual-layer technology should not come with a dose or image quality penalty for conventional images. In this study, we evaluate the influence of a dual-layer detector (IQon Spectral CT, Philips Healthcare) on the image quality of conventional CT images, by comparing these images with those of a conventional but otherwise technically comparable single-layer CT scanner (Brilliance iCT, Philips Healthcare), by means of phantom experiments. For both CT scanners, conventional CT images were acquired using four adult scanning protocols: (a) body helical, (b) body axial, (c) head helical, and (d) head axial. A CATPHAN 600 phantom was scanned to conduct an assessment of image quality metrics at equivalent (CTDI) dose levels. Noise was characterized by means of noise power spectra (NPS) and standard deviation (SD) of a uniform region, and spatial resolution was evaluated with modulation transfer functions (MTF) of a tungsten wire. In addition, contrast-to-noise ratio (CNR), image uniformity, CT number linearity, slice thickness, slice spacing, and spatial linearity were measured and evaluated. Additional measurements of CNR, resolution and noise were performed in two larger phantoms. The resolution levels at 50%, 10%, and 5% MTF of the iCT and IQon showed small, but significant differences up to 0.25 lp/cm for body scans, and up to 0.2 lp/cm for head scans in favor of the IQon. The iCT and IQon showed perfect CT linearity for body scans, but for head scans both scanners showed an underestimation of the CT numbers of materials with a high opacity. Slice thickness was slightly overestimated for both scanners. Slice spacing was comparable and reconstructed correctly. In addition, spatial linearity was excellent for both scanners, with a maximum error of 0.11 mm. CNR was higher on the IQon compared to the iCT for both normal and larger phantoms with differences up to 0.51. Spatial resolution did not change with phantom size, but noise levels increased significantly. For head scans, IQon had a noise level that was significantly lower than the iCT, on the other hand IQon showed noise levels significantly higher than the iCT for body scans. Still, these differences were well within the specified range of performance of iCT scanners. At equivalent dose levels, this study showed similar quality of conventional images acquired on iCT and IQon for medium-sized phantoms and slightly degraded image quality for (very) large phantoms at lower tube voltages on the IQon. Accordingly, it may be concluded that the introduction of a dual-layer detector neither compromises image quality of conventional images nor increases radiation dose for normal-sized patients, and slightly degrades dose efficiency for large patients at 120 kVp and lower tube voltages. © 2018 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

SU-F-T-403: Impact of Dose Reduction for Simulation CT On Radiation Therapy Treatment Planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Q; Shah, P; Li, S

Purpose: To investigate the feasibility of applying ALARA principles to current treatment planning CT scans. The study aims to quantitatively verify lower dose scans does not alter treatment planning. Method: Gammex 467 tissue characterization phantom with inserts of 14 different materials was scanned at seven different mA levels (30∼300 mA). CT numbers of different inserts were measured. Auto contouring for bone and lung in treatment planning system (Pinnacle) was used to evaluate the effect of CT number accuracy from treatment planning aspect, on the 30 and 300 mA-scanned images. A head CT scan intended for a 3D whole brain radiationmore » treatment was evaluated. Dose calculations were performed on normal scanned images using clinical protocol (120 kVP, Smart mA, maximum 291 mA), and the images with added simulating noise mimicking a 70 mA scan. Plan parameters including isocenter, beam arrangements, block shapes, dose grid size and resolution, and prescriptions were kept the same for these two plans. The calculated monitor units (MUs) for these two plans were compared. Results: No significant degradation of CT number accuracy was found at lower dose levels from both the phantom scans, and the patient images with added noise. The CT numbers kept consistent when mA is higher than 60 mA. The auto contoured volumes for lung and cortical bone show 0.3% and 0.12% of differences between 30 mA and 300 mA respectively. The two forward plans created on regular and low dose images gave the same calculated MU, and 98.3% of points having <1% of dose difference. Conclusion: Both phantom and patient studies quantitatively verified low dose CT provides similar quality for treatment planning at 20–25% of regular scan dose. Therefore, there is the potential to optimize simulation CT scan protocol to fulfil the ALARA principle and limit unnecessary radiation exposure to non-targeted tissues.« less

An automatic approach for 3D registration of CT scans

NASA Astrophysics Data System (ADS)

Hu, Yang; Saber, Eli; Dianat, Sohail; Vantaram, Sreenath Rao; Abhyankar, Vishwas

2012-03-01

CT (Computed tomography) is a widely employed imaging modality in the medical field. Normally, a volume of CT scans is prescribed by a doctor when a specific region of the body (typically neck to groin) is suspected of being abnormal. The doctors are required to make professional diagnoses based upon the obtained datasets. In this paper, we propose an automatic registration algorithm that helps healthcare personnel to automatically align corresponding scans from 'Study' to 'Atlas'. The proposed algorithm is capable of aligning both 'Atlas' and 'Study' into the same resolution through 3D interpolation. After retrieving the scanned slice volume in the 'Study' and the corresponding volume in the original 'Atlas' dataset, a 3D cross correlation method is used to identify and register various body parts.

Single-energy computed tomography-based pulmonary perfusion imaging: Proof-of-principle in a canine model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Tokihiro, E-mail: toyamamoto@ucdavis.edu

Purpose: Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging. Methods: Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those twomore » CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t-test. Results: The mean TRE (and standard deviation) was 0.6 ± 0.7 mm (smaller than the voxel dimension) for DIR between pre contrast and postcontrast end-inspiratory CT image data sets. No singularities were observed in the displacement vector fields. The mean HU enhancement (and standard deviation) was 37.3 ± 10.5 HU for normal lung subjects and 30.7 ± 13.5 HU for diseased lung subjects. Spatial heterogeneity of regional perfusion was found to be higher for diseased lung subjects than for normal lung subjects, i.e., a mean coefficient of variation of 2.06 vs 1.59 (p = 0.07). The average gravitationally directed gradient was strong and significant (R{sup 2} = 0.99, p < 0.01) for normal lung dogs, whereas it was moderate and nonsignificant (R{sup 2} = 0.61, p = 0.12) for diseased lung dogs. Conclusions: This canine study demonstrated the accuracy of DIR with subvoxel TREs on average, higher spatial heterogeneity of regional perfusion for diseased lung subjects than for normal lung subjects, and a strong gravitationally directed gradient for normal lung subjects, providing proof-of-principle for single-energy CT pulmonary perfusion imaging. Further studies such as comparison with other perfusion imaging modalities will be necessary to validate the physiological significance.« less

Cranial CT with adaptive statistical iterative reconstruction: improved image quality with concomitant radiation dose reduction.

PubMed

Rapalino, O; Kamalian, Shervin; Kamalian, Shahmir; Payabvash, S; Souza, L C S; Zhang, D; Mukta, J; Sahani, D V; Lev, M H; Pomerantz, S R

2012-04-01

To safeguard patient health, there is great interest in CT radiation-dose reduction. The purpose of this study was to evaluate the impact of an iterative-reconstruction algorithm, ASIR, on image-quality measures in reduced-dose head CT scans for adult patients. Using a 64-section scanner, we analyzed 100 reduced-dose adult head CT scans at 6 predefined levels of ASIR blended with FBP reconstruction. These scans were compared with 50 CT scans previously obtained at a higher routine dose without ASIR reconstruction. SNR and CNR were computed from Hounsfield unit measurements of normal GM and WM of brain parenchyma. A blinded qualitative analysis was performed in 10 lower-dose CT datasets compared with higher-dose ones without ASIR. Phantom data analysis was also performed. Lower-dose scans without ASIR had significantly lower mean GM and WM SNR (P = .003) and similar GM-WM CNR values compared with higher routine-dose scans. However, at ASIR levels of 20%-40%, there was no statistically significant difference in SNR, and at ASIR levels of ≥60%, the SNR values of the reduced-dose scans were significantly higher (P < .01). CNR values were also significantly higher at ASIR levels of ≥40% (P < .01). Blinded qualitative review demonstrated significant improvements in perceived image noise, artifacts, and GM-WM differentiation at ASIR levels ≥60% (P < .01). These results demonstrate that the use of ASIR in adult head CT scans reduces image noise and increases low-contrast resolution, while allowing lower radiation doses without affecting spatial resolution.

Radiation dose and image quality in pediatric chest CT: effects of iterative reconstruction in normal weight and overweight children.

PubMed

Yoon, Haesung; Kim, Myung-Joon; Yoon, Choon-Sik; Choi, Jiin; Shin, Hyun Joo; Kim, Hyun Gi; Lee, Mi-Jung

2015-03-01

New CT reconstruction techniques may help reduce the burden of ionizing radiation. To quantify radiation dose reduction when performing pediatric chest CT using a low-dose protocol and 50% adaptive statistical iterative reconstruction (ASIR) compared with age/gender-matched chest CT using a conventional dose protocol and reconstructed with filtered back projection (control group) and to determine its effect on image quality in normal weight and overweight children. We retrospectively reviewed 40 pediatric chest CT (M:F = 21:19; range: 0.1-17 years) in both groups. Radiation dose was compared between the two groups using paired Student's t-test. Image quality including noise, sharpness, artifacts and diagnostic acceptability was subjectively assessed by three pediatric radiologists using a four-point scale (superior, average, suboptimal, unacceptable). Eight children in the ASIR group and seven in the control group were overweight. All radiation dose parameters were significantly lower in the ASIR group (P < 0.01) with a greater than 57% dose reduction in overweight children. Image noise was higher in the ASIR group in both normal weight and overweight children. Only one scan in the ASIR group (1/40, 2.5%) was rated as diagnostically suboptimal and there was no unacceptable study. In both normal weight and overweight children, the ASIR technique is associated with a greater than 57% mean dose reduction, without significantly impacting diagnostic image quality in pediatric chest CT examinations. However, CT scans in overweight children may have a greater noise level, even when using the ASIR technique.

Patient-specific radiation dose and cancer risk estimation in pediatric chest CT: a study in 30 patients

NASA Astrophysics Data System (ADS)

Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

2010-04-01

Radiation-dose awareness and optimization in CT can greatly benefit from a dosereporting system that provides radiation dose and cancer risk estimates specific to each patient and each CT examination. Recently, we reported a method for estimating patientspecific dose from pediatric chest CT. The purpose of this study is to extend that effort to patient-specific risk estimation and to a population of pediatric CT patients. Our study included thirty pediatric CT patients (16 males and 14 females; 0-16 years old), for whom full-body computer models were recently created based on the patients' clinical CT data. Using a validated Monte Carlo program, organ dose received by the thirty patients from a chest scan protocol (LightSpeed VCT, 120 kVp, 1.375 pitch, 40-mm collimation, pediatric body scan field-of-view) was simulated and used to estimate patient-specific effective dose. Risks of cancer incidence were calculated for radiosensitive organs using gender-, age-, and tissue-specific risk coefficients and were used to derive patientspecific effective risk. The thirty patients had normalized effective dose of 3.7-10.4 mSv/100 mAs and normalized effective risk of 0.5-5.8 cases/1000 exposed persons/100 mAs. Normalized lung dose and risk of lung cancer correlated strongly with average chest diameter (correlation coefficient: r = -0.98 to -0.99). Normalized effective risk also correlated strongly with average chest diameter (r = -0.97 to -0.98). These strong correlations can be used to estimate patient-specific dose and risk prior to or after an imaging study to potentially guide healthcare providers in justifying CT examinations and to guide individualized protocol design and optimization.

Organ doses for reference pediatric and adolescent patients undergoing computed tomography estimated by Monte Carlo simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel J.

Purpose: To establish an organ dose database for pediatric and adolescent reference individuals undergoing computed tomography (CT) examinations by using Monte Carlo simulation. The data will permit rapid estimates of organ and effective doses for patients of different age, gender, examination type, and CT scanner model. Methods: The Monte Carlo simulation model of a Siemens Sensation 16 CT scanner previously published was employed as a base CT scanner model. A set of absorbed doses for 33 organs/tissues normalized to the product of 100 mAs and CTDI{sub vol} (mGy/100 mAs mGy) was established by coupling the CT scanner model with age-dependentmore » reference pediatric hybrid phantoms. A series of single axial scans from the top of head to the feet of the phantoms was performed at a slice thickness of 10 mm, and at tube potentials of 80, 100, and 120 kVp. Using the established CTDI{sub vol}- and 100 mAs-normalized dose matrix, organ doses for different pediatric phantoms undergoing head, chest, abdomen-pelvis, and chest-abdomen-pelvis (CAP) scans with the Siemens Sensation 16 scanner were estimated and analyzed. The results were then compared with the values obtained from three independent published methods: CT-Expo software, organ dose for abdominal CT scan derived empirically from patient abdominal circumference, and effective dose per dose-length product (DLP). Results: Organ and effective doses were calculated and normalized to 100 mAs and CTDI{sub vol} for different CT examinations. At the same technical setting, dose to the organs, which were entirely included in the CT beam coverage, were higher by from 40 to 80% for newborn phantoms compared to those of 15-year phantoms. An increase of tube potential from 80 to 120 kVp resulted in 2.5-2.9-fold greater brain dose for head scans. The results from this study were compared with three different published studies and/or techniques. First, organ doses were compared to those given by CT-Expo which revealed dose differences up to several-fold when organs were partially included in the scan coverage. Second, selected organ doses from our calculations agreed to within 20% of values derived from empirical formulae based upon measured patient abdominal circumference. Third, the existing DLP-to-effective dose conversion coefficients tended to be smaller than values given in the present study for all examinations except head scans. Conclusions: A comprehensive organ/effective dose database was established to readily calculate doses for given patients undergoing different CT examinations. The comparisons of our results with the existing studies highlight that use of hybrid phantoms with realistic anatomy is important to improve the accuracy of CT organ dosimetry. The comprehensive pediatric dose data developed here are the first organ-specific pediatric CT scan database based on the realistic pediatric hybrid phantoms which are compliant with the reference data from the International Commission on Radiological Protection (ICRP). The organ dose database is being coupled with an adult organ dose database recently published as part of the development of a user-friendly computer program enabling rapid estimates of organ and effective dose doses for patients of any age, gender, examination types, and CT scanner model.« less

Building a medical image processing algorithm verification database

NASA Astrophysics Data System (ADS)

Brown, C. Wayne

2000-06-01

The design of a database containing head Computed Tomography (CT) studies is presented, along with a justification for the database's composition. The database will be used to validate software algorithms that screen normal head CT studies from studies that contain pathology. The database is designed to have the following major properties: (1) a size sufficient for statistical viability, (2) inclusion of both normal (no pathology) and abnormal scans, (3) inclusion of scans due to equipment malfunction, technologist error, and uncooperative patients, (4) inclusion of data sets from multiple scanner manufacturers, (5) inclusion of data sets from different gender and age groups, and (6) three independent diagnosis of each data set. Designed correctly, the database will provide a partial basis for FDA (United States Food and Drug Administration) approval of image processing algorithms for clinical use. Our goal for the database is the proof of viability of screening head CT's for normal anatomy using computer algorithms. To put this work into context, a classification scheme for 'computer aided diagnosis' systems is proposed.

Outcome after Discontinuing Long-Term Benzimidazole Treatment in 11 Patients with Non-resectable Alveolar Echinococcosis with Negative FDG-PET/CT and Anti-EmII/3-10 Serology

PubMed Central

Stumpe, Katrin D. M.; Grimm, Felix; Deplazes, Peter; Huber, Sabine; Bertogg, Kaja; Fischer, Dorothee R.; Müllhaupt, Beat

2015-01-01

Background/Aims Benzimidazoles are efficacious for treating non-resectable alveolar echinococcosis (AE), but their long-term parasitocidal (curative) effect is disputed. In this study, we prospectively analyzed the potential parasitocidal effect of benzimidazoles and whether normalization of FDG-PET/CT scans and anti-Emll/3-10-antibody levels could act as reliable "in vivo" parameters of AE-inactivation permitting to abrogate chemotherapy with a low risk for AE-recurrence. Method This prospective study included 34 patients with non-resectable AE subdivided into group A (n = 11), followed-up after diagnosis and begin of chemotherapy at months 6, 12 and 24, and group B (n = 23) with a medium duration of chemotherapy of 10 (range 2–25) years. All patients were assessed by FDG-PET/CT examinations and anti-EmII/3-10 serology. Chemotherapy was abrogated in patients with normalization of FDG-PET/CT and serum anti-EmII/3-10 levels. These patients were closely followed-up for AE recurrence. Endpoint (parasitocidal efficacy) was defined by the absence of AE-recurrence >24 months after stopping treatment. Results Normalization of FDG-PET/CT scan and anti-EmII/3-10 levels occurred in 11 of 34 patients (32%). After abrogation of chemotherapy in these 11 patients, there was no evidence of AE-recurrence within a median of 70.5 (range 16–82) months. However, the patients’ immunocompetence appears pivotal for the described long-term parasitocidal effect of benzimidazoles. Conclusions The combination of negative FDG-PET/CT-scans and anti-EmII/3-10 antibody levels seem to be reliable parameters for assessing in vivo AE-larval inactivity after long-term benzimidazole chemotherapy. Trial Registration clinicaltrials.gov: NCT00658294 PMID:26389799

A fully automatic end-to-end method for content-based image retrieval of CT scans with similar liver lesion annotations.

PubMed

Spanier, A B; Caplan, N; Sosna, J; Acar, B; Joskowicz, L

2018-01-01

The goal of medical content-based image retrieval (M-CBIR) is to assist radiologists in the decision-making process by retrieving medical cases similar to a given image. One of the key interests of radiologists is lesions and their annotations, since the patient treatment depends on the lesion diagnosis. Therefore, a key feature of M-CBIR systems is the retrieval of scans with the most similar lesion annotations. To be of value, M-CBIR systems should be fully automatic to handle large case databases. We present a fully automatic end-to-end method for the retrieval of CT scans with similar liver lesion annotations. The input is a database of abdominal CT scans labeled with liver lesions, a query CT scan, and optionally one radiologist-specified lesion annotation of interest. The output is an ordered list of the database CT scans with the most similar liver lesion annotations. The method starts by automatically segmenting the liver in the scan. It then extracts a histogram-based features vector from the segmented region, learns the features' relative importance, and ranks the database scans according to the relative importance measure. The main advantages of our method are that it fully automates the end-to-end querying process, that it uses simple and efficient techniques that are scalable to large datasets, and that it produces quality retrieval results using an unannotated CT scan. Our experimental results on 9 CT queries on a dataset of 41 volumetric CT scans from the 2014 Image CLEF Liver Annotation Task yield an average retrieval accuracy (Normalized Discounted Cumulative Gain index) of 0.77 and 0.84 without/with annotation, respectively. Fully automatic end-to-end retrieval of similar cases based on image information alone, rather that on disease diagnosis, may help radiologists to better diagnose liver lesions.

The early detection of antral malignancy in the postmaxillectomy patient

DOE Office of Scientific and Technical Information (OSTI.GOV)

Som, P.M.; Shugar, J.M.; Biller, H.F.

1982-05-01

A protocol was developed for the radiographic evaluation of the postmaxillectomy patient that called for a six- to eight-week postoperative, baseline computed tomography (CT) scan, followed by CT scans at four- to six-month intervals for at least three years. This protocol allowed for an early, more complete assessment of clinically discovered recurrences and the detection of clinically occult recurrences in three out of 18 patients who followed the protocol. The CT appearance of the normal partial and total maxillectomy is discussed, as well as the focal nodular soft-tissue findings suggestive of recurrent disease.

Density Resolution Artifacts Encountered When Scanning Infant Heads With X-Ray Computed Tomography (CT)

NASA Astrophysics Data System (ADS)

Thompson, Joseph R.; M oore, Robert J.; Hinshaw, David B.; Hasso, Anton N.

1982-12-01

Density resolution the accuracy of CT numbers) is generally recognized by radiologists w'ao interpret Children's, CT to be very poor. A CT scanning phantom was made. in order to document the brain attenuation inaccuracies which do occur and also to derive normal brain attenuation values for varying sized heads, given. the skull diameters and thicknesses. In scanning' this phantom, other factors, some of equal importance, to small head size, were found to affect the Hounsfield numbers of brain. The phantom was scanned in order to determine the magnitude of these specific factors, using the GE 8800 model scanner. After head size (412 to 25, H), the variables of the head support (up to 15 H) and centering within the field of view (6-23 H) were of similar importance, for small heads. Kilovoltage, software, and machine drift were less, important, although only kVp settings, of 105 and 120 were employed. Manufacturers may improve CT number accuracy if they recognize the relative, magnitude of the various factors which alter measured attenuation.

SU-E-J-113: Effects of Deformable Registration On First-Order Texture Maps Calculated From Thoracic Lung CT Scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, C; Cunliffe, A; Al-Hallaq, H

Purpose: To determine the stability of eight first-order texture features following the deformable registration of serial computed tomography (CT) scans. Methods: CT scans at two different time points from 10 patients deemed to have no lung abnormalities by a radiologist were collected. Following lung segmentation using an in-house program, texture maps were calculated from 32×32-pixel regions of interest centered at every pixel in the lungs. The texture feature value of the ROI was assigned to the center pixel of the ROI in the corresponding location of the texture map. Pixels in the square ROI not contained within the segmented lungmore » were not included in the calculation. To quantify the agreement between ROI texture features in corresponding pixels of the baseline and follow-up texture maps, the Fraunhofer MEVIS EMPIRE10 deformable registration algorithm was used to register the baseline and follow-up scans. Bland-Altman analysis was used to compare registered scan pairs by computing normalized bias (nBias), defined as the feature value change normalized to the mean feature value, and normalized range of agreement (nRoA), defined as the range spanned by the 95% limits of agreement normalized to the mean feature value. Results: Each patient’s scans contained between 6.8–15.4 million ROIs. All of the first-order features investigated were found to have an nBias value less than 0.04% and an nRoA less than 19%, indicating that the variability introduced by deformable registration was low. Conclusion: The eight first-order features investigated were found to be registration stable. Changes in CT texture maps could allow for temporal-spatial evaluation of the evolution of lung abnormalities relating to a variety of diseases on a patient-by-patient basis. SGA and HA receives royalties and licensing fees through the University of Chicago for computer-aided diagnosis technology. Research reported in this publication was supported by the National Institute Of General Medical Sciences of the National Institutes of Health under Award Number R25GM109439.« less

Patient-specific dose estimation for pediatric chest CT

PubMed Central

Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

2008-01-01

Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9–18.2kg) were created based on the patients’ actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120kVp, 70 or 75mA, 0.4s gantry rotation period, pitch of 1.375, 20mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7–5.3mSv∕100mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4–12.6mGy∕100mAs and 11.2–13.3mGy∕100mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%–18%) and for partially or indirectly exposed organs (11%–77%). Normalized effective dose correlated weakly with body weight (correlation coefficient:r=−0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=−0.99, heart: r=−0.93); these strong correlation relationships can be used to estimate patient-specific organ dose for any other patient in the same size/protocol group who undergoes the chest scan. In summary, this work reported the first assessment of dose variations across pediatric CT patients in the same size/protocol group due to the variability of patient anatomy and body habitus and provided a previously unavailable method for patient-specific organ dose estimation, which will help in assessing patient risk and optimizing dose reduction strategies, including the development of scan protocols. PMID:19175138

Patient-specific dose estimation for pediatric chest CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Xiang; Samei, Ehsan; Segars, W. Paul

2008-12-15

Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structuresmore » were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ dose for any other patient in the same size/protocol group who undergoes the chest scan. In summary, this work reported the first assessment of dose variations across pediatric CT patients in the same size/protocol group due to the variability of patient anatomy and body habitus and provided a previously unavailable method for patient-specific organ dose estimation, which will help in assessing patient risk and optimizing dose reduction strategies, including the development of scan protocols.« less

Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ-based CT scan planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Zhye, E-mail: yin@ge.com; De Man, Bruno; Yao, Yangyang

Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies tomore » achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors’ pictorial-structures based organ localization algorithm successfully located the major abdominal-thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.« less

Lung texture in serial thoracic CT scans: correlation with radiologist-defined severity of acute changes following radiation therapy

NASA Astrophysics Data System (ADS)

Cunliffe, Alexandra R.; Armato, Samuel G., III; Straus, Christopher; Malik, Renuka; Al-Hallaq, Hania A.

2014-09-01

This study examines the correlation between the radiologist-defined severity of normal tissue damage following radiation therapy (RT) for lung cancer treatment and a set of mathematical descriptors of computed tomography (CT) scan texture (‘texture features’). A pre-therapy CT scan and a post-therapy CT scan were retrospectively collected under IRB approval for each of the 25 patients who underwent definitive RT (median dose: 66 Gy). Sixty regions of interest (ROIs) were automatically identified in the non-cancerous lung tissue of each post-therapy scan. A radiologist compared post-therapy scan ROIs with pre-therapy scans and categorized each as containing no abnormality, mild abnormality, moderate abnormality, or severe abnormality. Twenty texture features that characterize gray-level intensity, region morphology, and gray-level distribution were calculated in post-therapy scan ROIs and compared with anatomically matched ROIs in the pre-therapy scan. Linear regression and receiver operating characteristic (ROC) analysis were used to compare the percent feature value change (ΔFV) between ROIs at each category of visible radiation damage. Most ROIs contained no (65%) or mild abnormality (30%). ROIs with moderate (3%) or severe (2%) abnormalities were observed in 9 patients. For 19 of 20 features, ΔFV was significantly different among severity levels. For 12 features, significant differences were observed at every level. Compared with regions with no abnormalities, ΔFV for these 12 features increased, on average, by 1.5%, 12%, and 30%, respectively, for mild, moderate, and severe abnormalitites. Area under the ROC curve was largest when comparing ΔFV in the highest severity level with the remaining three categories (mean AUC across features: 0.84). In conclusion, 19 features that characterized the severity of radiologic changes from pre-therapy scans were identified. These features may be used in future studies to quantify acute normal lung tissue damage following RT. Presented, in part at the IASLC 15th World Conference on Lung Conference, Sydney, AUS (2013).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paliwal, B; Asprey, W; Yan, Y

Purpose: In order to take advantage of the high resolution soft tissue imaging available in MR images, we investigated 3D images obtained with the low field 0.35 T MR in ViewRay to serve as an alternative to CT scans for radiotherapy treatment planning. In these images, normal and target structure delineation can be visualized. Assessment is based upon comparison with the CT images and the ability to produce comparable contours. Methods: Routine radiation oncology CT scans were acquired on five patients. Contours of brain, brainstem, esophagus, heart, lungs, spinal cord, and the external body were drawn. The same five patientsmore » were then scanned on the ViewRay TrueFISP-based imaging pulse sequence. The same organs were selected on the MR images and compared to those from the CT scan. Physical volume and the Dice Similarity Coefficient (DSC) were used to assess the contours from the two systems. Image quality stability was quantitatively ensured throughout the study following the recommendations of the ACR MR accreditation procedure. Results: The highest DSC of 0.985, 0.863, and 0.843 were observed for brain, lungs, and heart respectively. On the other hand, the brainstem, spinal cord, and esophagus had the lowest DSC. Volume agreement was most satisfied for the heart (within 5%) and the brain (within 2%). Contour volume for the brainstem and lung (a widely dynamic organ) varied the most (27% and 19%). Conclusion: The DSC and volume measurements suggest that the results obtained from ViewRay images are quantitatively consistent and comparable to those obtained from CT scans for the brain, heart, and lungs. MR images from ViewRay are well-suited for treatment planning and for adaptive MRI-guided radiotherapy. The physical data from 0.35 T MR imaging is consistent with our geometrical understanding of normal structures.« less

Intracranial meningioma causing partial amaurosis in a cat.

PubMed

Goulle, Frédéric; Meige, Frédéric; Durieux, Franck; Malet, Christophe; Toulza, Olivier; Isard, Pierre-François; Peiffer, Robert L; Dulaurent, Thomas

2011-09-01

To describe a case of intracranial meningioma causing visual impairment in a cat, successfully treated by surgery. An adult neutered male domestic cat was referred with a 10-month history of progressive visual impairment and altered behavior. Investigations included physical, ophthalmologic and neurological examinations as well as hematology, serum biochemistry and CT scan of the head. The menace response was absent in the left eye and decreased in the right eye. Electroretinograms were normal on both eyes, as was ophthalmic examination, ruling out an ocular cause and allowing a presumptive diagnosis of partial amaurosis due to a post-retinal lesion. CT scan demonstrated a large sessile extra axial mass along the right parietal bone and thickening of the adjacent bone. Cerebrospinal fluid was not collected because high intracranial pressure represented a risk for brain herniation. A right rostrotentorial craniectomy was performed to remove the tumor. Ten days after surgery, vision was improved, neurological examination was normal and normal behavior was restored. Ten months after surgery, ophthalmological examination showed no visual deficit and CT scan did not reveal any sign of recurrence. Advanced imaging techniques allow veterinarians to detect early cerebral diseases and to provide specific treatment when it is possible. In cases of feline amaurosis due to intracranial meningioma, the vital prognosis is good while the visual prognosis is more uncertain, but recovery of normal vision and normal behavior is possible as demonstrated in the present case. © 2011 American College of Veterinary Ophthalmologists.

Correlation between differential renal function estimation using CT-based functional renal parenchymal volume and (99m)Tc - DTPA renal scan.

PubMed

Sarma, Debanga; Barua, Sasanka K; Rajeev, T P; Baruah, Saumar J

2012-10-01

Nuclear renal scan is currently the gold standard imaging study to determine differential renal function. We propose helical CT as single modality for both the anatomical and functional evaluation of kidney with impaired function. In the present study renal parenchymal volume is measured and percent total renal volume is used as a surrogate marker for differential renal function. The objective of this study is to correlate between differential renal function estimation using CT-based renal parenchymal volume measurement with differential renal function estimation using (99m)TC - DTPA renal scan. Twenty-one patients with unilateral obstructive uropathy were enrolled in this prospective comparative study. They were subjected to (99m)Tc - DTPA renal scan and 64 slice helical CT scan which estimates the renal volume depending on the reconstruction of arterial phase images followed by volume rendering and percent renal volume was calculated. Percent renal volume was correlated with percent renal function, as determined by nuclear renal scan using Pearson coefficient. RESULTS AND OBSERVATION: A strong correlation is observed between percent renal volume and percent renal function in obstructed units (r = 0.828, P < 0.001) as well as in nonobstructed units (r = 0.827, P < 0.001). There is a strong correlation between percent renal volume determined by CT scan and percent renal function determined by (99m)TC - DTPA renal scan both in obstructed and in normal units. CT-based percent renal volume can be used as a single radiological tests for both functional and anatomical assessment of impaired renal units.

What is the role of florine-18 fluorodeoxyglucose/positron emission tomography/computed tomography imaging in well-differentiated thyroid cancers with negative iodine-131 scan high thyroglobulin and normal anti-thyroglobulin levels.

PubMed

Döner, Rana Kaya; Sager, Sait; Görtan, Fatma Arzu; Topuz, Özge Vural; Akyel, Reşit; Vatankulu, Betül; Baran, Ahmet; Teksoz, Serkan; Sönmezoglu, Kerim

2016-01-01

This retrospective study aims to assess the cut-off value of thyroglobulin (Tg) levels in nux or metastatic well-differentiated thyroid cancers (DTCs) with normal anti-Tg levels using with fluorodeoxyglucose/positron emission tomography/computed tomography (FDG PET/CT). We reviewed FDG PET/CT images of 104 patients with well DTC (28 men, 76 women) whose: Iodine-131 (131 I) whole-body scanning was negative but had elevated Tg with normal anti-Tg levels. The overall sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of florine-18-FDG PET/CT findings were found to be 95.92%, 87.27%, 87.04%, 96.00%, and 91.35%, respectively. The best Tg cut-off value was found to be 10.4 ng/ml. In the Tg level <10.4 ng/ml group, the sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT were found to be 94.1%, 91.30%, 88.8%, 95.4%, and 92.5%, respectively. In the other group, which Tg level ≥10.4 ng/ml, sensitivity, specificity, PPV, NPV, and accuracy of FDG PET/CT exams were found to be 96.8%, 84.3%, 86.1%, 96.4%, and 90.6%, respectively. FDG PET/CT imaging is a valuable imaging method in the evaluation of patients with elevated serum Tg levels and normal anti-Tg levels. Furthermore, it has potential utility in the dedifferentiation of active foci that are present, and in assessing optimal decision making during follow-up.

Computed tomography, anatomy and morphometry of the lower extremity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoogewoud, H.M.; Rager, G.; Burch, H.

1989-01-01

This book presents up-to-date information on CT imaging of the lower extremity. It includes an atlas correlating new, high-resolution CT scans with identical thin anatomical slices covering the lower extremity from the crista iliaca to the planta pedis. Additional figures, including CT arthrograms of the hip, knee and ankle, depict the anatomy in detail The technique and clinical relevance of CT measurements especially in orthopedic surgery are also clearly explained. Of special interest is the new method developed by the authors for assessing the coverage of the femoral head. The special morphometry software and a 3D program allowing representation inmore » space make it possible to precisely and accurately measure the coverage with normal CT scans of the hip.« less

Normal cross-sectional anatomy of the bovine digit: comparison of computed tomography and limb anatomy.

PubMed

Raji, A R; Sardari, K; Mohammadi, H R

2008-06-01

The purpose of this study was to define the structures of the digits and hoof in Holstein dairy cattle by using computed tomography scan (CT scan). Transverse, sagittal and dorsoplantar CT images of two isolated cattle cadaver digits were obtained using a Siemens ARTX2 Somatom. The CT images were compared to corresponding frozen cross-sections. Relevant anatomical structures were identified and labelled at each level. The CT images provided anatomical detail of the digits and hoof in Holstein dairy cattle. Transversal images provided excellent depiction of anatomical structures when compared to corresponding frozen cross-sections. The information presented in this paper would serve as an initial reference to the evaluation of CT images of the digits and hoof in Holstein dairy cattle.

Computed tomography has an important role in hollow viscus and mesenteric injuries after blunt abdominal trauma.

PubMed

Tan, Ker-Kan; Liu, Jody Zhiyang; Go, Tsung-Shyen; Vijayan, Appasamy; Chiu, Ming-Terk

2010-05-01

Computed tomographic (CT) scans have become invaluable in the management of patients with blunt abdominal trauma. No clear consensus exists on its role in hollow viscus injuries (HVI) and mesenteric injuries (MI). The aim of this study was to correlate operative findings of HVI and MI to findings on pre-operative CT. All patients treated for blunt abdominal trauma at Tan Tock Seng Hospital from January 2003 to January 2008 were reviewed. CT scans were only performed if the patients were haemodynamically stable and indicated. All scans were performed with intravenous contrast using a 4-slice CT scanner from 2003 to December 2004 and a 64-slice CT scanner from January 2005 onwards. All cases with documented HVI/MI that underwent both CT scans and exploratory laparotomy were analysed. Thirty-one patients formed the study group, with median age of 40 (range, 22-65) years and a significant male (83.9%) predominance. Vehicular-related incidents accounted for 67.7% of the injuries and the median Injury Severity Score (ISS) was 13 (4-50). The 2 commonest findings on CT scans were extra-luminal gas (35.5%) and free fluid without significant solid organ injuries (93.5%). During exploratory laparotomy, perforation of hollow viscus (51.6%) occurred more frequently than suspected from the initial CT findings of extra-luminal gas. Other notable findings included haemoperitoneum (64.5%), and mesenteric tears (67.7%). None of our patients with HVI and MI had a normal pre-operative CT scan. Our study suggests that patients with surgically confirmed HVI and MI found at laparotomy were very likely to have an abnormal pre-operative CT scan. Unexplained free fluid was a very common finding in blunt HVI/MI and is one major indication to consider exploratory laparotomy. (c) 2009 Elsevier Ltd. All rights reserved.

Investigation of practical approaches to evaluating cumulative dose for cone beam computed tomography (CBCT) from standard CT dosimetry measurements: a Monte Carlo study.

PubMed

Abuhaimed, Abdullah; Martin, Colin J; Sankaralingam, Marimuthu; Gentle, David J

2015-07-21

A function called Gx(L) was introduced by the International Commission on Radiation Units and Measurements (ICRU) Report-87 to facilitate measurement of cumulative dose for CT scans within long phantoms as recommended by the American Association of Physicists in Medicine (AAPM) TG-111. The Gx(L) function is equal to the ratio of the cumulative dose at the middle of a CT scan to the volume weighted CTDI (CTDIvol), and was investigated for conventional multi-slice CT scanners operating with a moving table. As the stationary table mode, which is the basis for cone beam CT (CBCT) scans, differs from that used for conventional CT scans, the aim of this study was to investigate the extension of the Gx(L) function to CBCT scans. An On-Board Imager (OBI) system integrated with a TrueBeam linac was simulated with Monte Carlo EGSnrc/BEAMnrc, and the absorbed dose was calculated within PMMA, polyethylene (PE), and water head and body phantoms using EGSnrc/DOSXYZnrc, where the body PE body phantom emulated the ICRU/AAPM phantom. Beams of width 40-500 mm and beam qualities at tube potentials of 80-140 kV were studied. Application of a modified function of beam width (W) termed Gx(W), for which the cumulative dose for CBCT scans f (0) is normalized to the weighted CTDI (CTDIw) for a reference beam of width 40 mm, was investigated as a possible option. However, differences were found in Gx(W) with tube potential, especially for body phantoms, and these were considered to be due to differences in geometry between wide beams used for CBCT scans and those for conventional CT. Therefore, a modified function Gx(W)100 has been proposed, taking the form of values of f (0) at each position in a long phantom, normalized with respect to dose indices f 100(150)x measured with a 100 mm pencil ionization chamber within standard 150 mm PMMA phantoms, using the same scanning parameters, beam widths and positions within the phantom. f 100(150)x averages the dose resulting from a CBCT scan over the 100 mm length. Like the Gx(L) function, the Gx(W)100 function showed only a weak dependency on tube potential at most positions for the phantoms studied. The results were fitted to polynomial equations from which f (0) within the longer PMMA, PE, or water phantoms can be evaluated from measurements of f 100(150)x. Comparisons with other studies, suggest that these functions may be suitable for application to any CT or CBCT scan acquired with stationary table mode.

A combined pulmonary-radiology workshop for visual evaluation of COPD: study design, chest CT findings and concordance with quantitative evaluation.

PubMed

Barr, R Graham; Berkowitz, Eugene A; Bigazzi, Francesca; Bode, Frederick; Bon, Jessica; Bowler, Russell P; Chiles, Caroline; Crapo, James D; Criner, Gerard J; Curtis, Jeffrey L; Dass, Chandra; Dirksen, Asger; Dransfield, Mark T; Edula, Goutham; Erikkson, Leif; Friedlander, Adam; Galperin-Aizenberg, Maya; Gefter, Warren B; Gierada, David S; Grenier, Philippe A; Goldin, Jonathan; Han, MeiLan K; Hanania, Nicola A; Hansel, Nadia N; Jacobson, Francine L; Kauczor, Hans-Ulrich; Kinnula, Vuokko L; Lipson, David A; Lynch, David A; MacNee, William; Make, Barry J; Mamary, A James; Mann, Howard; Marchetti, Nathaniel; Mascalchi, Mario; McLennan, Geoffrey; Murphy, James R; Naidich, David; Nath, Hrudaya; Newell, John D; Pistolesi, Massimo; Regan, Elizabeth A; Reilly, John J; Sandhaus, Robert; Schroeder, Joyce D; Sciurba, Frank; Shaker, Saher; Sharafkhaneh, Amir; Silverman, Edwin K; Steiner, Robert M; Strange, Charlton; Sverzellati, Nicola; Tashjian, Joseph H; van Beek, Edwin J R; Washington, Lacey; Washko, George R; Westney, Gloria; Wood, Susan A; Woodruff, Prescott G

2012-04-01

The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring. Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9-11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements. Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively. Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.

SU-F-J-117: Impact of Motion Artifacts On Image Quality and Accuracy of Tumor Motion Reconstruction in 4D CT-On-Rails and MV-CBCT Scans: A Phantom Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, T; Ma, C

Purpose: To compare and quantify respiratory motion artifacts in images from free breathing 4D-CT-on-Rails(CTOR) and those from MV-Cone-beam-CT(MVCB) and facilitate respiratory motion guided radiation therapy. Methods: 4D-CTOR: Siemens Somatom CT-on-Rails system with Anzai belt loaded with pressure sensor load cells. 4D scans were performed in helical mode, pitch 0.1, gantry rotation time 0.5s, 1.5mm slice thickness, 120kVp, 400 mAs. Normal and fast breathing (>12rpm) scanning protocols were investigated. Helical scan, AIP(average intensity projection) and MIP(maximum intensity projection) were generated from 4D-CTOR scans with amplitude sorting into 10 phases.MVCB: Siemens Artiste diamond view(1MV)MVCB was performed with 5MU thorax protocol with 60more » second of full rotation.Phantom: Anzai AZ-733V respiratory phantom. The settings were set to normal and resp. modes with repetition rates at 15 rpm and 10 rpm. Surgical clips, acrylic, wooden, rubber and lung density, total six mock-ups were scanned and compared in this study.Signal-to-noise ratio(SNR), contrast-to-noise ratio(CNR) and reconstructed motion volume were compared to different respiratory setups for the mock-ups. Results: Reconstructed motion volume was compared to the real object volume for the six test mock-ups. It shows that free breathing helical in all instances underestimates the object excursions largest to −67.4% and least −6.3%. Under normal breathing settings, MIP can predict very precise motion volume with minimum 0.4% and largest −13.9%. MVCB shows underestimate of the motion volume with −1.11% minimum and −18.0% maximum. With fast breathing, AIP provides bad representation of the object motion; however, the MIP can predict the motion volume with −2.0% to −11.4% underestimate. Conclusion: Respiratory motion guided radiation therapy requires good motion recording. This study shows that regular CTOR helical scans provides bad guidance, 4D CTOR AIP cannot represent the fast breathing pattern, MIP can represent the best motion volume, MVCBCT can only be used for normal breathing with acceptable uncertainties.« less

Community-Acquired Pneumonia Visualized on CT Scans but Not Chest Radiographs: Pathogens, Severity, and Clinical Outcomes.

PubMed

Upchurch, Cameron P; Grijalva, Carlos G; Wunderink, Richard G; Williams, Derek J; Waterer, Grant W; Anderson, Evan J; Zhu, Yuwei; Hart, Eric M; Carroll, Frank; Bramley, Anna M; Jain, Seema; Edwards, Kathryn M; Self, Wesley H

2018-03-01

The clinical significance of pneumonia visualized on CT scan in the setting of a normal chest radiograph is uncertain. In a multicenter prospective surveillance study of adults hospitalized with community-acquired pneumonia (CAP), we compared the presenting clinical features, pathogens present, and outcomes of patients with pneumonia visualized on a CT scan but not on a concurrent chest radiograph (CT-only pneumonia) and those with pneumonia visualized on a chest radiograph. All patients underwent chest radiography; the decision to obtain CT imaging was determined by the treating clinicians. Chest radiographs and CT images were interpreted by study-dedicated thoracic radiologists blinded to the clinical data. The study population included 2,251 adults with CAP; 2,185 patients (97%) had pneumonia visualized on chest radiography, whereas 66 patients (3%) had pneumonia visualized on CT scan but not on concurrent chest radiography. Overall, these patients with CT-only pneumonia had a clinical profile similar to those with pneumonia visualized on chest radiography, including comorbidities, vital signs, hospital length of stay, prevalence of viral (30% vs 26%) and bacterial (12% vs 14%) pathogens, ICU admission (23% vs 21%), use of mechanical ventilation (6% vs 5%), septic shock (5% vs 4%), and inhospital mortality (0 vs 2%). Adults hospitalized with CAP who had radiological evidence of pneumonia on CT scan but not on concurrent chest radiograph had pathogens, disease severity, and outcomes similar to patients who had signs of pneumonia on chest radiography. These findings support using the same management principles for patients with CT-only pneumonia and those with pneumonia seen on chest radiography. Copyright © 2017 American College of Chest Physicians. All rights reserved.

Comparison of demons deformable registration-based methods for texture analysis of serial thoracic CT scans

NASA Astrophysics Data System (ADS)

Cunliffe, Alexandra R.; Al-Hallaq, Hania A.; Fei, Xianhan M.; Tuohy, Rachel E.; Armato, Samuel G.

2013-02-01

To determine how 19 image texture features may be altered by three image registration methods, "normal" baseline and follow-up computed tomography (CT) scans from 27 patients were analyzed. Nineteen texture feature values were calculated in over 1,000 32x32-pixel regions of interest (ROIs) randomly placed in each baseline scan. All three methods used demons registration to map baseline scan ROIs to anatomically matched locations in the corresponding transformed follow-up scan. For the first method, the follow-up scan transformation was subsampled to achieve a voxel size identical to that of the baseline scan. For the second method, the follow-up scan was transformed through affine registration to achieve global alignment with the baseline scan. For the third method, the follow-up scan was directly deformed to the baseline scan using demons deformable registration. Feature values in matched ROIs were compared using Bland- Altman 95% limits of agreement. For each feature, the range spanned by the 95% limits was normalized to the mean feature value to obtain the normalized range of agreement, nRoA. Wilcoxon signed-rank tests were used to compare nRoA values across features for the three methods. Significance for individual tests was adjusted using the Bonferroni method. nRoA was significantly smaller for affine-registered scans than for the resampled scans (p=0.003), indicating lower feature value variability between baseline and follow-up scan ROIs using this method. For both of these methods, however, nRoA was significantly higher than when feature values were calculated directly on demons-deformed followup scans (p<0.001). Across features and methods, nRoA values remained below 26%.

Rapidly Progressive Maxillary Atelectasis.

PubMed

Elkhatib, Ahmad; McMullen, Kyle; Hachem, Ralph Abi; Carrau, Ricardo L; Mastros, Nicholas

2017-07-01

Report of a patient with rapidly progressive maxillary atelectasis documented by sequential imaging. A 51-year-old man, presented with left periorbital and retro-orbital pain associated with left nasal obstruction. An initial computed tomographic (CT) scan of the paranasal sinuses failed to reveal any significant abnormality. A subsequent CT scan, indicated for recurrence of symptoms 11 months later, showed significant maxillary atelectasis. An uncinectomy, maxillary antrostomy, and anterior ethmoidectomy resulted in a complete resolution of the symptoms. Chronic maxillary atelectasis is most commonly a consequence of chronic rhinosinusitis. All previous reports have indicated a chronic process but lacked documentation of the course of the disease. This report documents a patient of rapidly progressive chronic maxillary atelectasis with CT scans that demonstrate changes in the maxillary sinus (from normal to atelectatic) within 11 months.

The prevalence of lumbar spondylolysis in young children: a retrospective analysis using CT.

PubMed

Lemoine, Thibaut; Fournier, Joseph; Odent, Thierry; Sembély-Taveau, Catherine; Merenda, Pauline; Sirinelli, Dominique; Morel, Baptiste

2018-05-01

Although lumbar spondylolysis is encountered in general population with an incidence estimated to be 3-10%, limited information is available for children. The aim of the study is to determine the prevalence of spondylolysis according to associated vertebral bony malformation and spinopelvic parameters in children under eight requiring CT evaluation for unrelated lumbar conditions. Seven hundred and seventeen abdominal and pelvic multi-detector CT scans were obtained in patients under 8 years of age were reviewed. Two board certificated radiologists and two resident radiologists retrospectively evaluated CT scans for lumbar spondylolysis and associated malformations. Pelvic incidence and spondylolisthesis were reported. Our analysis included 717 CT scans in 532 children (259 girls and 273 boys). Twenty-five cases of spondylolysis were diagnosed (16 bilateral and 9 unilateral, 64 and 36%, respectively) in 14 boys (56%) and 11 girls (44%), associating with 12 grade I spondylolisthesis. The mean normal pelvic incidence was 45° (median 44°, SD 7°). The prevalence of spondylolysis was 1% in children under age 3 (n = 3 among 292 patients), 3.7% in children under age 6 (n = 17 among 454 patients) and 4.7% among the 532 patients. Unilateral spondylolysis was significantly associated with a spinal malformation (p = 0.04, Fisher's exact test), with normal pelvic incidence. Half of the patients with bilateral spondylolysis had high pelvic incidence. We observed a prevalence peak of unilateral spondylolysis in the context of a specific malformation in young infants under age 4 with normal pelvic incidence, and, then, a progressive increase in the prevalence of bilateral isolated spondylolysis.

Modeling Early Postnatal Brain Growth and Development with CT: Changes in the Brain Radiodensity Histogram from Birth to 2 Years.

PubMed

Cauley, K A; Hu, Y; Och, J; Yorks, P J; Fielden, S W

2018-04-01

The majority of brain growth and development occur in the first 2 years of life. This study investigated these changes by analysis of the brain radiodensity histogram of head CT scans from the clinical population, 0-2 years of age. One hundred twenty consecutive head CTs with normal findings meeting the inclusion criteria from children from birth to 2 years were retrospectively identified from 3 different CT scan platforms. Histogram analysis was performed on brain-extracted images, and histogram mean, mode, full width at half maximum, skewness, kurtosis, and SD were correlated with subject age. The effects of scan platform were investigated. Normative curves were fitted by polynomial regression analysis. Average total brain volume was 360 cm 3 at birth, 948 cm 3 at 1 year, and 1072 cm 3 at 2 years. Total brain tissue density showed an 11% increase in mean density at 1 year and 19% at 2 years. Brain radiodensity histogram skewness was positive at birth, declining logarithmically in the first 200 days of life. The histogram kurtosis also decreased in the first 200 days to approach a normal distribution. Direct segmentation of CT images showed that changes in brain radiodensity histogram skewness correlated with, and can be explained by, a relative increase in gray matter volume and an increase in gray and white matter tissue density that occurs during this period of brain maturation. Normative metrics of the brain radiodensity histogram derived from routine clinical head CT images can be used to develop a model of normal brain development. © 2018 by American Journal of Neuroradiology.

CT scan range estimation using multiple body parts detection: let PACS learn the CT image content.

PubMed

Wang, Chunliang; Lundström, Claes

2016-02-01

The aim of this study was to develop an efficient CT scan range estimation method that is based on the analysis of image data itself instead of metadata analysis. This makes it possible to quantitatively compare the scan range of two studies. In our study, 3D stacks are first projected to 2D coronal images via a ray casting-like process. Trained 2D body part classifiers are then used to recognize different body parts in the projected image. The detected candidate regions go into a structure grouping process to eliminate false-positive detections. Finally, the scale and position of the patient relative to the projected figure are estimated based on the detected body parts via a structural voting. The start and end lines of the CT scan are projected to a standard human figure. The position readout is normalized so that the bottom of the feet represents 0.0, and the top of the head is 1.0. Classifiers for 18 body parts were trained using 184 CT scans. The final application was tested on 136 randomly selected heterogeneous CT scans. Ground truth was generated by asking two human observers to mark the start and end positions of each scan on the standard human figure. When compared with the human observers, the mean absolute error of the proposed method is 1.2% (max: 3.5%) and 1.6% (max: 5.4%) for the start and end positions, respectively. We proposed a scan range estimation method using multiple body parts detection and relative structure position analysis. In our preliminary tests, the proposed method delivered promising results.

Patient-based estimation of organ dose for a population of 58 adult patients across 13 protocol categories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sahbaee, Pooyan, E-mail: psahbae@ncsu.edu; Segars, W. Paul; Samei, Ehsan

2014-07-15

Purpose: This study aimed to provide a comprehensive patient-specific organ dose estimation across a multiplicity of computed tomography (CT) examination protocols. Methods: A validated Monte Carlo program was employed to model a common CT system (LightSpeed VCT, GE Healthcare). The organ and effective doses were estimated from 13 commonly used body and neurological CT examination. The dose estimation was performed on 58 adult computational extended cardiac-torso phantoms (35 male, 23 female, mean age 51.5 years, mean weight 80.2 kg). The organ dose normalized by CTDI{sub vol} (h factor) and effective dose normalized by the dose length product (DLP) (k factor)more » were calculated from the results. A mathematical model was derived for the correlation between the h and k factors with the patient size across the protocols. Based on this mathematical model, a dose estimation iPhone operating system application was designed and developed to be used as a tool to estimate dose to the patients for a variety of routinely used CT examinations. Results: The organ dose results across all the protocols showed an exponential decrease with patient body size. The correlation was generally strong for the organs which were fully or partially located inside the scan coverage (Pearson sample correlation coefficient (r) of 0.49). The correlation was weaker for organs outside the scan coverage for which distance between the organ and the irradiation area was a stronger predictor of dose to the organ. For body protocols, the effective dose before and after normalization by DLP decreased exponentially with increasing patient's body diameter (r > 0.85). The exponential relationship between effective dose and patient's body diameter was significantly weaker for neurological protocols (r < 0.41), where the trunk length was a slightly stronger predictor of effective dose (0.15 < r < 0.46). Conclusions: While the most accurate estimation of a patient dose requires specific modeling of the patient anatomy, a first order approximation of organ and effective doses from routine CT scan protocols can be reasonably estimated using size specific factors. Estimation accuracy is generally poor for organ outside the scan range and for neurological protocols. The dose calculator designed in this study can be used to conveniently estimate and report the dose values for a patient across a multiplicity of CT scan protocols.« less

Correlations between symptoms, nasal endoscopy, and in-office computed tomography in post-surgical chronic rhinosinusitis patients.

PubMed

Ryan, William R; Ramachandra, Tara; Hwang, Peter H

2011-03-01

To determine correlations between symptoms, nasal endoscopy findings, and computed tomography (CT) scan findings in post-surgical chronic rhinosinusitis (CRS) patients. Cross-sectional. A total of 51 CRS patients who had undergone endoscopic sinus surgery (ESS) completed symptom questionnaires, underwent endoscopy, and received an in-office sinus CT scan during one clinic visit. For metrics, we used the Sinonasal Outcomes Test-20 (SNOT-20) questionnaire, visual analog symptom scale (VAS), Lund-Kennedy endoscopy scoring scale, and Lund-MacKay (LM) CT scoring scale. We determined Pearson correlation coefficients, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) between scores for symptoms, endoscopy, and CT. The SNOT-20 score and most VAS symptoms had poor correlation coefficients with both endoscopy and CT scores (0.03-0.24). Nasal drainage of pus, nasal congestion, and impaired sense of smell had moderate correlation coefficients with endoscopy and CT (0.24-0.42). Endoscopy had a strong correlation coefficient with CT (0.76). Drainage, edema, and polyps had strong correlation coefficients with CT (0.80, 0.69, and 0.49, respectively). Endoscopy had a PPV of 92.5% and NPV of 45.5% for detecting an abnormal sinus CT (LM score ≥1). In post-ESS CRS patients, most symptoms do not correlate well with either endoscopy or CT findings. Endoscopy and CT scores correlate well. Abnormal endoscopy findings have the ability to confidently rule in the presence of CT opacification, thus validating the importance of endoscopy in clinical decision making. However, a normal endoscopy cannot assure a normal CT. Thus, symptoms, endoscopy, and CT are complementary in the evaluation of the post-ESS CRS patient. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc., Rhinological, and Otological Society, Inc.

COMPUTED TOMOGRAPHIC FEATURES OF INCISOR PSEUDO-ODONTOMAS IN PRAIRIE DOGS (CYNOMYS LUDOVICIANUS).

PubMed

Pelizzone, Igor; Di Ianni, Francesco; Volta, Antonella; Gnudi, Giacomo; Manfredi, Sabrina; Bertocchi, Mara; Parmigiani, Enrico

2017-05-01

Maxillary incisor pseudo-odontomas are common in pet prairie dogs and can cause progressive respiratory obstruction, while mandibular pseudo-odontomas are rarely clinically significant. The aim of this retrospective cross-sectional study was to describe CT features of maxillary and mandibular incisor pseudo-odontomas vs. normal incisors in a group of pet prairie dogs. All pet prairie dogs with head CT scans acquired during the period of 2013-2015 were included. A veterinary radiologist who was aware of final diagnosis reviewed CT scans and recorded qualitative features of affected and normal incisors. Mean density values for the pulp cavity and palatal and buccal dentin were also recorded. A total of 16 prairie dogs were sampled (12 normal maxillary incisors, 20 confirmed maxillary incisor pseudo-odontomas, 20 normal mandibular incisors, 12 presumed mandibular incisor pseudo-odontomas). Maxillary incisors with confirmed pseudo-odontomas had a significantly hyperattenuating pulp and dentin in the reserve crown and apical zone, when compared to normal maxillary incisors. Pseudo-odontomas appeared as enlargements of the apical zone with a globular/multilobular hyperattenuating mass formation haphazardly arranged, encroaching on midline and growing caudally and ventrally. Presumed mandibular incisor pseudo-odontomas had similar CT characteristics. In 60% of prairie dogs with maxillary incisor pseudo-odontomas, the hard palate was deformed and the mass bulged into the oral cavity causing loss of the palatine bone. The common nasal meatus was partially or totally obliterated in 81.8% of prairie dogs with maxillary pseudo-odontomas. Findings supported the use of CT for characterizing extent of involvement and surgical planning in prairie dogs with pseudo-odontomas. © 2017 American College of Veterinary Radiology.

Using Image Processing to Determine Emphysema Severity

NASA Astrophysics Data System (ADS)

McKenzie, Alexander; Sadun, Alberto

2010-10-01

Currently X-rays and computerized tomography (CT) scans are used to detect emphysema, but other tests are required to accurately quantify the amount of lung that has been affected by the disease. These images clearly show if a patient has emphysema, but are unable by visual scan alone, to quantify the degree of the disease, as it presents as subtle, dark spots on the lung. Our goal is to use these CT scans to accurately diagnose and determine emphysema severity levels in patients. This will be accomplished by performing several different analyses of CT scan images of several patients representing a wide range of severity of the disease. In addition to analyzing the original CT data, this process will convert the data to one and two bit images and will then examine the deviation from a normal distribution curve to determine skewness. Our preliminary results show that this method of assessment appears to be more accurate and robust than the currently utilized methods, which involve looking at percentages of radiodensities in the air passages of the lung.

Increased Regional Epicardial Fat Volume Associated with Reversible Myocardial Ischemia in Patients with Suspected Coronary Artery Disease

PubMed Central

Khawaja, Tuba; Greer, Christine; Thadani, Samir R.; Kato, Tomoko S.; Bhatia, Ketan; Shimbo, Daichi; Konkak, Andrew; Bokhari, Sabahat; Einstein, Andrew J.; Schulze, P. Christian

2015-01-01

Epicardial adipose tissue is a source of pro-inflammatory cytokines and has been linked to the development of coronary artery disease. No study has systematically assessed the relationship between local epicardial fat volume (EFV) and myocardial perfusion defects. We analyzed EFV in patients undergoing SPECT myocardial perfusion imaging combined with computed tomography (CT) for attenuation correction. Low-dose CT without contrast was performed in 396 consecutive patients undergoing SPECT imaging for evaluation of coronary artery disease. Regional thickness, cross-sectional areas, and total EFV were assessed. 295 patients had normal myocardial perfusion scans and 101 had abnormal perfusion scans. Mean EFVs in normal, ischemic, and infarcted hearts were 99.8 ± 82.3 cm3, 156.4 ± 121.9 cm3, and 96.3 ± 102.1 cm3, respectively (P < 0.001). Reversible perfusion defects were associated with increased local EFV compared to normal perfusion in the distribution of the right (69.2 ± 51.5 vs 46.6 ± 32.0 cm3; P = 0.03) and left anterior descending coronary artery (87.1 ± 76.4 vs 46.7 ± 40.6 cm3; P = 0.005). Our results demonstrate increased regional epicardial fat in patients with active myocardial ischemia compared to patients with myocardial scar or normal perfusion on nuclear perfusion scans. Our results suggest a potential role for cardiac CT to improve risk stratification in patients with suspected coronary artery disease. PMID:25339129

Computed tomography demonstrates abnormalities of contralateral ear in subjects with unilateral sensorineural hearing loss.

PubMed

Marcus, Sonya; Whitlow, Christopher T; Koonce, James; Zapadka, Michael E; Chen, Michael Y; Williams, Daniel W; Lewis, Meagan; Evans, Adele K

2014-02-01

Prior studies have associated gross inner ear abnormalities with pediatric sensorineural hearing loss (SNHL) using computed tomography (CT). No studies to date have specifically investigated morphologic inner ear abnormalities involving the contralateral unaffected ear in patients with unilateral SNHL. The purpose of this study is to evaluate contralateral inner ear structures of subjects with unilateral SNHL but no grossly abnormal findings on CT. IRB-approved retrospective analysis of pediatric temporal bone CT scans. 97 temporal bone CT scans, previously interpreted as "normal" based upon previously accepted guidelines by board certified neuroradiologists, were assessed using 12 measurements of the semicircular canals, cochlea and vestibule. The control-group consisted of 72 "normal" temporal bone CTs with underlying SNHL in the subject excluded. The study-group consisted of 25 normal-hearing contralateral temporal bones in subjects with unilateral SNHL. Multivariate analysis of covariance (MANCOVA) was then conducted to evaluate for differences between the study and control group. Cochlea basal turn lumen width was significantly greater in magnitude and central lucency of the lateral semicircular canal bony island was significantly lower in density for audiometrically normal ears of subjects with unilateral SNHL compared to controls. Abnormalities of the inner ear were present in the contralateral audiometrically normal ears of subjects with unilateral SNHL. These data suggest that patients with unilateral SNHL may have a more pervasive disease process that results in abnormalities of both ears. The findings of a cochlea basal turn lumen width disparity >5% from "normal" and/or a lateral semicircular canal bony island central lucency disparity of >5% from "normal" may indicate inherent risk to the contralateral unaffected ear in pediatric patients with unilateral sensorineural hearing loss. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

TU-A-12A-04: Quantitative Texture Features Calculated in Lung Tissue From CT Scans Demonstrate Consistency Between Two Databases From Different Institutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cunliffe, A; Armato, S; Castillo, R

Purpose: To evaluate the consistency of computed tomography (CT) scan texture features, previously identified as stable in a healthy patient cohort, in esophageal cancer patient CT scans. Methods: 116 patients receiving radiation therapy (median dose: 50.4Gy) for esophageal cancer were retrospectively identified. For each patient, diagnostic-quality pre-therapy (0-183 days) and post-therapy (5-120 days) scans (mean voxel size: 0.8mm×0.8mm×2.5mm) and a treatment planning scan and associated dose map were collected. An average of 501 32x32-pixel ROIs were placed randomly in the lungs of each pre-therapy scan. ROI centers were mapped to corresponding locations in post-therapy and planning scans using the displacementmore » vector field output by demons deformable registration. Only ROIs with mean dose <5Gy were analyzed, as these were expected to contain minimal post-treatment damage. 140 texture features were calculated in pre-therapy and post-therapy scan ROIs and compared using Bland-Altman analysis. For each feature, the mean feature value change and the distance spanned by the 95% limits of agreement were normalized to the mean feature value, yielding normalized range of agreement (nRoA) and normalized bias (nBias). Using Wilcoxon signed rank tests, nRoA and nBias were compared with values computed previously in 27 healthy patient scans (mean voxel size: 0.67mm×0.67mm×1mm) acquired at a different institution. Results: nRoA was significantly (p<0.001) larger in cancer patients than healthy patients. Differences in nBias were not significant (p=0.23). The 20 features identified previously as having nRoA<20% for healthy patients had the lowest nRoA values in the current database, with an average increase of 5.6%. Conclusion: Despite differences in CT scanner type, scan resolution, and patient health status, the same 20 features remained stable (i.e., low variability and bias) in the absence of disease changes for databases from two institutions. Identification of these features is the first step towards quantifying radiation-induced changes between preand post-therapy scans. Supported, in part, by NIH Grant Nos. S10 RR021039, and P30 CA14599, the Virginia and D. K. Ludwig Fund for Cancer Research, Imaging Research Institute, Biological Sciences Division, The University of Chicago, and The Institute for Translational Medicine Pilot Award, The University of Chicago.« less

Coronal CT scan measurements and hearing evolution in enlarged vestibular aqueduct syndrome.

PubMed

Saliba, Issam; Gingras-Charland, Marie-Eve; St-Cyr, Karine; Décarie, Jean-Claude

2012-04-01

To assess the correlation between the enlarged vestibular aqueduct (EVA) diameter and (1) the hearing loss level (mild, moderate, severe and profound and (2) the hearing evolution. The secondary objective was to obtain measurement limits on the coronal plane of the temporal bone CT scan for the diagnosis of EVA. Retrospective study in a tertiary pediatric center. Mastoid CT scans were reviewed to measure the VA diameter at its midpoint and operculum on axial and coronal planes in a pathologic and normal population. We used their serial audiograms to assess the evolution of hearing. 101 EVA was identified out of 1812 temporal bones CT scan from our radiologic database in 8 years. Bone conduction was stable after a mean follow-up of 40.9 ± 32.9 months. PTA has been the most affected in time by the EVA (p=0.006). No correlation was identified between impedancemetry and the diameter of the EVA. On the diagnostic audiogram, 61% of hearing loss were in the mild and moderate hearing levels; at the end of the follow-up 64% of hearing loss are still in the mild and moderate hearing levels. The cut-off values for the coronal midpoint and operculum planes on the CT scan to diagnose an EVA are 2.4 mm and 4.34 mm respectively. Conductive or mixed hearing loss might be the first manifestation of EVA. Coronal CT scan cuts can provide additional information to evaluate EVA especially when axial cuts are not conclusive. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Content Validity of Temporal Bone Models Printed Via Inexpensive Methods and Materials.

PubMed

Bone, T Michael; Mowry, Sarah E

2016-09-01

Computed tomographic (CT) scans of the 3-D printed temporal bone models will be within 15% accuracy of the CT scans of the cadaveric temporal bones. Previous studies have evaluated the face validity of 3-D-printed temporal bone models designed to train otolaryngology residents. The purpose of the study was to determine the content validity of temporal bone models printed using inexpensive printers and materials. Four cadaveric temporal bones were randomly selected and clinical temporal bone CT scans were obtained. Models were generated using previously described methods in acrylonitrile butadiene styrene (ABS) plastic using the Makerbot Replicator 2× and Hyrel printers. Models were radiographically scanned using the same protocol as the cadaveric bones. Four images from each cadaveric CT series and four corresponding images from the model CT series were selected, and voxel values were normalized to black or white. Scan slices were compared using PixelDiff software. Gross anatomic structures were evaluated in the model scans by four board certified otolaryngologists on a 4-point scale. Mean pixel difference between the cadaver and model scans was 14.25 ± 2.30% at the four selected CT slices. Mean cortical bone width difference and mean external auditory canal width difference were 0.58 ± 0.66 mm and 0.55 ± 0.46 mm, respectively. Expert raters felt the mastoid air cells were well represented (2.5 ± 0.5), while middle ear and otic capsule structures were not accurately rendered (all averaged <1.8). These results suggest that these models would be sufficient adjuncts to cadaver temporal bones for training residents in cortical mastoidectomies, but less effective for middle ear procedures.

Ultrasound and computed tomography of the iliosacral lymphatic centre in dogs with anal sac gland carcinoma.

PubMed

Pollard, R E; Fuller, M C; Steffey, M A

2017-06-01

In this prospective study, we hypothesized that computed tomography (CT) would identify more normal and abnormal iliosacral lymph nodes (LNs) than abdominal ultrasound in dogs with anal sac gland carcinoma (ASGC). Twelve client-owned dogs with ASGC but without distant metastasis were enrolled. Abdominal ultrasound and contrast-enhanced CT scans of the abdomen were obtained. Iliosacral LNs were counted and assessed for location, laterality and size. Significantly (P < 0.00001) more iliosacral LNs were identified with CT (61) than ultrasound (30), including significantly (P = 0.00012) more medial iliac LNs with CT (33) than ultrasound (19). There was no difference in number of internal iliac LNs identified with CT versus ultrasound. Significantly (P = 0.000061) more sacral LNs were identified with CT (15) than ultrasound (0). Ultrasound identified slightly more (7) abnormal iliosacral LNs than CT (5). Contrast CT was able to identify more normal but not more abnormal LNs than ultrasound. © 2015 John Wiley & Sons Ltd.

Ultra low-dose CT attenuation correction in PET SPM

NASA Astrophysics Data System (ADS)

Wang, Shyh-Jen; Yang, Bang-Hung; Tsai, Chia-Jung; Yang, Ching-Ching; Lee, Jason J. S.; Wu, Tung-Hsin

2010-07-01

The use of CT images for attenuation correction (CTAC) allows significantly shorter scanning time and a high quality noise-free attenuation map compared with conventional germanium-68 transmission scan because at least 10 4 times greater of photon flux would be generated from a CT scan under standard operating condition. However, this CTAC technique would potentially introduce more radiation risk to the patients owing to the higher radiation exposure from CT scan. Statistic parameters mapping (SPM) is a prominent technique in nuclear medicine community for the analysis of brain imaging data. The purpose of this study is to assess the feasibility of low-dose CT (LDCT) and ultra low-dose CT (UDCT) in PET SPM applications. The study was divided into two parts. The first part was to evaluate of tracer uptake distribution pattern and quantity analysis by using the striatal phantom to initially assess the feasibility of AC for clinical purpose. The second part was to examine the group SPM analysis using the Hoffman brain phantom. The phantom study is to simulate the human brain and to reduce the experimental uncertainty of real subjects. The initial studies show that the results of PET SPM analysis have no significant differences between LDCT and UDCT comparing to the current used default CTAC. Moreover, the dose of the LDCT is lower than that of the default CT by a factor of 9, and UDCT can even yield a 42 times dose reduction. We have demonstrated the SPM results while using LDCT and UDCT for PET AC is comparable to those using default CT setting, suggesting their feasibility in PET SPM applications. In addition, the necessity of UDCT in PET SPM studies to avoid excess radiation dose is also evident since most of the subjects involved are non-cancer patients or children and some normal subjects are even served as a comparison group in the experiment. It is our belief that additional attempts to decrease the radiation dose would be valuable, especially for children and normal volunteers, to work towards ALARA (as low as reasonably achievable) concept for PET SPM studies.

Zero-Extra-Dose PET Delayed Imaging with Data-Driven Attenuation Correction Estimation.

PubMed

Pang, Lifang; Zhu, Wentao; Dong, Yun; Lv, Yang; Shi, Hongcheng

2018-05-08

Delayed positron emission tomography (PET) imaging may improve sensitivity and specificity in lesion detection. We proposed a PET data-driven method to estimate the attenuation map (AM) for the delayed scan without an additional x-ray computed tomography (CT). An emission-attenuation-scatter joint estimation framework was developed. Several practical issues for clinical datasets were addressed. Particularly, the unknown scatter correction was incorporated in the joint estimation algorithm. The scaling problem was solved using prior information from the early CT scan. Fourteen patient datasets were added to evaluate the method. These patients went through two separate PET/CT scans. The delayed CT-based AM served as ground truth for the delayed scan. Standard uptake values (SUVmean and SUVmax) of lesion and normal tissue regions of interests (ROIs) in the early and delayed phase and the respective %DSUV (percentage change of SUVmean at two different time points) were analyzed, all with estimated and the true AM. Three radiologists participated in lesion detection tasks with images reconstructed with both AMs and rated scores for detectability. The mean relative difference of SUVmean in lesion and normal liver tissue were 3.30 and 6.69 %. The average lesion-to-background contrast (detectability) with delayed PET images using CT AM was 60 % higher than that of the earlier PET image, and was 64 % higher when using the data-based AM. %DSUV for lesions and liver backgrounds with CT-based AM were - 0.058 ± 0.25 and - 0.33 ± 0.08 while with data-based AM were - 0.00 ± 0.26 and - 0.28 ± 0.08. Only slight significance difference was found between using CT-based AM and using the data-based AM reconstruction delay phase on %DSUV of lesion. The scores associated with the two AMs matched well consistently. Our method may be used in delayed PET imaging, which allows no secondary CT radiation in delayed phase. The quantitative analysis for lesion detection purpose could be ensured.

Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

NASA Astrophysics Data System (ADS)

Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

2014-03-01

Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

Comparative effectiveness of using computed tomography alone to exclude cervical spine injuries in obtunded or intubated patients: meta-analysis of 14,327 patients with blunt trauma.

PubMed

Panczykowski, David M; Tomycz, Nestor D; Okonkwo, David O

2011-09-01

The current standard of practice for clearance of the cervical spine in obtunded patients suffering blunt trauma is to use CT and an adjuvant imaging modality (such as MR imaging). The objective of this study was to determine the comparative effectiveness of multislice helical CT alone to diagnose acute unstable cervical spine injury following blunt trauma. The authors performed a meta-analysis of studies comparing modern CT with adjunctive imaging modalities and required that studies present acute traumatic findings as well as treatment for unstable injuries. Study quality, population characteristics, diagnostic protocols, and outcome data were extracted. Positive disease status included all injuries necessitating surgical or orthotic stabilization identified on imaging and/or clinical follow-up. Seventeen studies encompassing 14,327 patients met the inclusion criteria. Overall, the sensitivity and specificity for modern CT were both > 99.9% (95% CI 0.99-1.00 and 0.99-1.00, respectively). The negative likelihood ratio of an unstable cervical injury after a CT scan negative for acute injury was < 0.001 (95% CI 0.00-0.01), while the negative predictive value of a normal CT scan was 100% (95% CI 0.96-1.00). Global severity of injury, CT slice thickness, and study quality did not significantly affect accuracy estimates. Modern CT alone is sufficient to detect unstable cervical spine injuries in trauma patients. Adjuvant imaging is unnecessary when the CT scan is negative for acute injury. Results of this meta-analysis strongly show that the cervical collar may be removed from obtunded or intubated trauma patients if a modern CT scan is negative for acute injury.

Calculation of Organ Doses for a Large Number of Patients Undergoing CT Examinations.

PubMed

Bahadori, Amir; Miglioretti, Diana; Kruger, Randell; Flynn, Michael; Weinmann, Sheila; Smith-Bindman, Rebecca; Lee, Choonsik

2015-10-01

The objective of our study was to develop an automated calculation method to provide organ dose assessment for a large cohort of pediatric and adult patients undergoing CT examinations. We adopted two dose libraries that were previously published: the volume CT dose index-normalized organ dose library and the tube current-exposure time product (100 mAs)-normalized weighted CT dose index library. We developed an algorithm to calculate organ doses using the two dose libraries and the CT parameters available from DICOM data. We calculated organ doses for pediatric (n = 2499) and adult (n = 2043) CT examinations randomly selected from four health care systems in the United States and compared the adult organ doses with the values calculated from the ImPACT calculator. The median brain dose was 20 mGy (pediatric) and 24 mGy (adult), and the brain dose was greater than 40 mGy for 11% (pediatric) and 18% (adult) of the head CT studies. Both the National Cancer Institute (NCI) and ImPACT methods provided similar organ doses (median discrepancy < 20%) for all organs except the organs located close to the scanning boundaries. The visual comparisons of scanning coverage and phantom anatomies revealed that the NCI method, which is based on realistic computational phantoms, provides more accurate organ doses than the ImPACT method. The automated organ dose calculation method developed in this study reduces the time needed to calculate doses for a large number of patients. We have successfully used this method for a variety of CT-related studies including retrospective epidemiologic studies and CT dose trend analysis studies.

Estimating local noise power spectrum from a few FBP-reconstructed CT scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Rongping, E-mail: rongping.zeng@fda.hhs.gov; Gavrielides, Marios A.; Petrick, Nicholas

Purpose: Traditional ways to estimate 2D CT noise power spectrum (NPS) involve an ensemble average of the power spectrums of many noisy scans. When only a few scans are available, regions of interest are often extracted from different locations to obtain sufficient samples to estimate the NPS. Using image samples from different locations ignores the nonstationarity of CT noise and thus cannot accurately characterize its local properties. The purpose of this work is to develop a method to estimate local NPS using only a few fan-beam CT scans. Methods: As a result of FBP reconstruction, the CT NPS has themore » same radial profile shape for all projection angles, with the magnitude varying with the noise level in the raw data measurement. This allows a 2D CT NPS to be factored into products of a 1D angular and a 1D radial function in polar coordinates. The polar separability of CT NPS greatly reduces the data requirement for estimating the NPS. The authors use this property and derive a radial NPS estimation method: in brief, the radial profile shape is estimated from a traditional NPS based on image samples extracted at multiple locations. The amplitudes are estimated by fitting the traditional local NPS to the estimated radial profile shape. The estimated radial profile shape and amplitudes are then combined to form a final estimate of the local NPS. We evaluate the accuracy of the radial NPS method and compared it to traditional NPS methods in terms of normalized mean squared error (NMSE) and signal detectability index. Results: For both simulated and real CT data sets, the local NPS estimated with no more than six scans using the radial NPS method was very close to the reference NPS, according to the metrics of NMSE and detectability index. Even with only two scans, the radial NPS method was able to achieve a fairly good accuracy. Compared to those estimated using traditional NPS methods, the accuracy improvement was substantial when a few scans were available. Conclusions: The radial NPS method was shown to be accurate and efficient in estimating the local NPS of FBP-reconstructed 2D CT images. It presents strong advantages over traditional NPS methods when the number of scans is limited and can be extended to estimate the in-plane NPS of cone-beam CT and multislice helical CT scans.« less

Solitary pulmonary nodule: A rare presentation of pulmonary mucormycosis in an immunocompetent adult

PubMed Central

Sarkar, Supriya; Jash, Debraj; Maji, Arnab; Maikap, Malay Kr

2014-01-01

Pulmonary mucormycosis is a rare opportunistic infection of immunocompromised individuals. Here, we report a case of 70-year-old male, smoker presenting with high-grade fever for 2 weeks and episodes of hemoptysis. Contrast-enhanced computed tomography (CT) thorax revealed a solitary pulmonary nodule measuring 2.3 × 1.6 cm in the right upper lobe. CT guided fine needle aspiration cytology and true cut biopsy showed plenty of typical fungal hyphae consistent with the diagnosis of mucormycosis. Fungal culture confirmed the organism as mucor. Positron emission tomography-CT scan showed a non- 18 fluorodeoxy glucose avid nodule ruling out possibility of malignancy. Investigation did not reveal any evidence of immunosuppression. Patient was treated with intravenous liposomal amphotericin B for 4 weeks. Follow-up chest X-ray and CT scan after 6 weeks were normal. PMID:24669089

Neuroblastoma with intracranial involvement: an ENSG Study.

PubMed

Shaw, P J; Eden, T

1992-01-01

We report the experience of the European Neuroblastoma Study Group (ENSG) with central nervous system (CNS) involvement of neuroblastoma. Among this series of intensively treated patients, CNS neuroblastoma was diagnosed by computerised tomography (CT) scanning, rather than by autopsy. Cranial disease occurred in 5% of ENSG patients. Of 11 patients with intracranial disease, 4 had disease in the posterior fossa, a site rarely reported previously. Furthermore, 5 cases had CNS metastases at a time when there was no detectable disease elsewhere, rather than as part of extensive relapse. The pattern of disease we observed, at least for those with parenchymal disease, is in keeping with arterial spread. Although CT scanning is the optimal modality for identifying CNS disease, 2 cases had normal head CT scans prior to the onset of CNS disease. As most patients had symptoms of raised intracranial pressure (RICP) at the time the CNS disease was diagnosed, there does not seem to be any indication for routine CT scanning of the head at diagnosis, but this should be performed as soon as any symptoms or signs appear. With patients living longer with their disease, vigilance must be maintained during follow-up.

Variation of quantitative emphysema measurements from CT scans

NASA Astrophysics Data System (ADS)

Keller, Brad M.; Reeves, Anthony P.; Henschke, Claudia I.; Barr, R. Graham; Yankelevitz, David F.

2008-03-01

Emphysema is a lung disease characterized by destruction of the alveolar air sacs and is associated with long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema, and several measures have been introduced for the quantification of the extent of disease. In this paper we compare these measures for repeatability over time. The measures of interest in this study are emphysema index, mean lung density, histogram percentile, and the fractal dimension. To allow for direct comparisons, the measures were normalized to a 0-100 scale. These measures have been computed for a set of 2,027 scan pairs in which the mean interval between scans was 1.15 years (σ: 93 days). These independent pairs were considered with respect to three different scanning conditions (a) 223 pairs where both were scanned with a 5 mm slice thickness protocol, (b) 695 with the first scanned with the 5 mm protocol and the second with a 1.25 mm protocol, and (c) 1109 pairs scanned both times using a 1.25 mm protocol. We found that average normalized emphysema index and histogram percentiles scores increased by 5.9 and 11 points respectively, while the fractal dimension showed stability with a mean difference of 1.2. We also found, a 7 point bias introduced for emphysema index under condition (b), and that the fractal dimension measure is least affected by scanner parameter changes.

A database for estimating organ dose for coronary angiography and brain perfusion CT scans for arbitrary spectra and angular tube current modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rupcich, Franco; Badal, Andreu; Kyprianou, Iacovos

Purpose: The purpose of this study was to develop a database for estimating organ dose in a voxelized patient model for coronary angiography and brain perfusion CT acquisitions with any spectra and angular tube current modulation setting. The database enables organ dose estimation for existing and novel acquisition techniques without requiring Monte Carlo simulations. Methods: The study simulated transport of monoenergetic photons between 5 and 150 keV for 1000 projections over 360 Degree-Sign through anthropomorphic voxelized female chest and head (0 Degree-Sign and 30 Degree-Sign tilt) phantoms and standard head and body CTDI dosimetry cylinders. The simulations resulted in tablesmore » of normalized dose deposition for several radiosensitive organs quantifying the organ dose per emitted photon for each incident photon energy and projection angle for coronary angiography and brain perfusion acquisitions. The values in a table can be multiplied by an incident spectrum and number of photons at each projection angle and then summed across all energies and angles to estimate total organ dose. Scanner-specific organ dose may be approximated by normalizing the database-estimated organ dose by the database-estimated CTDI{sub vol} and multiplying by a physical CTDI{sub vol} measurement. Two examples are provided demonstrating how to use the tables to estimate relative organ dose. In the first, the change in breast and lung dose during coronary angiography CT scans is calculated for reduced kVp, angular tube current modulation, and partial angle scanning protocols relative to a reference protocol. In the second example, the change in dose to the eye lens is calculated for a brain perfusion CT acquisition in which the gantry is tilted 30 Degree-Sign relative to a nontilted scan. Results: Our database provides tables of normalized dose deposition for several radiosensitive organs irradiated during coronary angiography and brain perfusion CT scans. Validation results indicate total organ doses calculated using our database are within 1% of those calculated using Monte Carlo simulations with the same geometry and scan parameters for all organs except red bone marrow (within 6%), and within 23% of published estimates for different voxelized phantoms. Results from the example of using the database to estimate organ dose for coronary angiography CT acquisitions show 2.1%, 1.1%, and -32% change in breast dose and 2.1%, -0.74%, and 4.7% change in lung dose for reduced kVp, tube current modulated, and partial angle protocols, respectively, relative to the reference protocol. Results show -19.2% difference in dose to eye lens for a tilted scan relative to a nontilted scan. The reported relative changes in organ doses are presented without quantification of image quality and are for the sole purpose of demonstrating the use of the proposed database. Conclusions: The proposed database and calculation method enable the estimation of organ dose for coronary angiography and brain perfusion CT scans utilizing any spectral shape and angular tube current modulation scheme by taking advantage of the precalculated Monte Carlo simulation results. The database can be used in conjunction with image quality studies to develop optimized acquisition techniques and may be particularly beneficial for optimizing dual kVp acquisitions for which numerous kV, mA, and filtration combinations may be investigated.« less

Head CT scan

MedlinePlus

Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...

Validation study of an interpolation method for calculating whole lung volumes and masses from reduced numbers of CT-images in ponies.

PubMed

Reich, H; Moens, Y; Braun, C; Kneissl, S; Noreikat, K; Reske, A

2014-12-01

Quantitative computer tomographic analysis (qCTA) is an accurate but time intensive method used to quantify volume, mass and aeration of the lungs. The aim of this study was to validate a time efficient interpolation technique for application of qCTA in ponies. Forty-one thoracic computer tomographic (CT) scans obtained from eight anaesthetised ponies positioned in dorsal recumbency were included. Total lung volume and mass and their distribution into four compartments (non-aerated, poorly aerated, normally aerated and hyperaerated; defined based on the attenuation in Hounsfield Units) were determined for the entire lung from all 5 mm thick CT-images, 59 (55-66) per animal. An interpolation technique validated for use in humans was then applied to calculate qCTA results for lung volumes and masses from only 10, 12, and 14 selected CT-images per scan. The time required for both procedures was recorded. Results were compared statistically using the Bland-Altman approach. The bias ± 2 SD for total lung volume calculated from interpolation of 10, 12, and 14 CT-images was -1.2 ± 5.8%, 0.1 ± 3.5%, and 0.0 ± 2.5%, respectively. The corresponding results for total lung mass were -1.1 ± 5.9%, 0.0 ± 3.5%, and 0.0 ± 3.0%. The average time for analysis of one thoracic CT-scan using the interpolation method was 1.5-2 h compared to 8 h for analysis of all images of one complete thoracic CT-scan. The calculation of pulmonary qCTA data by interpolation from 12 CT-images was applicable for equine lung CT-scans and reduced the time required for analysis by 75%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analysis of pulmonary pure ground-glass nodule in enhanced dual energy CT imaging for predicting invasive adenocarcinoma: comparing with conventional thin-section CT imaging

PubMed Central

Zhang, Ying; Tang, Jian; Xu, Jianrong

2017-01-01

Background To investigate the value of dual energy computed tomography (DECT) parameters (including iodine concentration and monochromatic CT numbers) for predicting pure ground-glass nodules (pGGNs) of invasive adenocarcinoma (IA). Methods A total of 55 resected pGGNs evaluated with both unenhanced thin-section CT (TSCT) and enhanced DECT scans were included. Correlations between histopathology [adenocarcinoma in situ (AIS), minimally IA (MIA), and IA] and CT scan characteristics were examined. CT scan and clinicodemographic data were investigated by univariate and multivariate analysis to identify features that helped distinguish IA from AIS or MIA. Results Both normalized iodine concentration (NIC) of IA and slope of spectral curve [slope(k)] were not significantly different between IA and AIS or MIA. Size, performance of pleural retraction and enhanced monochromatic CT attenuation values of 120–140 keV were significantly higher for IA. In multivariate regression analysis, size and enhanced monochromatic CT number of 140 keV were independent predictors for IA. Using the two parameters together, the diagnostic capacity of IA could be improved from 0.697 or 0.635 to 0.713. Conclusions DECT could help demonstrate blood supply and indicate invasion extent of pGGNs, and monochromatic CT number of higher energy (especially 140 keV) would be better for diagnosing IA than lower energies. Together with size of pGGNs, the diagnostic capacity of IA could be better. PMID:29312701

Evaluation of Efficacy of Bone Scan With SPECT/CT in the Management of Low Back Pain: A Study Supported by Differential Diagnostic Local Anesthetic Blocks.

PubMed

Jain, Anuj; Jain, Suruchi; Agarwal, Anil; Gambhir, Sanjay; Shamshery, Chetna; Agarwal, Amita

2015-12-01

Conventional radiologic modalities provide details only about the anatomic aspect of the various structures of the spine. Frequently the structures that show abnormal morphology may not be the cause of low back pain (LBP). Functional imaging in the form of bone scan along with single photon emission computerized tomography (SPECT/CT) may be helpful in identifying structures causing pain, whether morphologically normal or not. The objective of this study is to evaluate the role of bone scan with SPECT/CT in management of patients with LBP. This is randomized double-blinded controlled study performed on 80 patients with LBP aged 20 to 80 years, ASA physical status I to III. Patients were randomized into bone scan and control groups consisting of 40 patients each. On the basis of the clinical features and radiologic findings a clinical diagnosis was made. After making a clinical diagnosis, the patients in bone scan group were subjected to bone scan with SPECT/CT. On the basis of the finding of the bone scan and SPECT/CT, a new working diagnosis was made and intervention was performed according to the new working diagnosis. Diagnostic blocks in the control group were given based on clinical diagnosis. Controlled comparative diagnostic blocks were performed with local anesthetic. The pain score just after the diagnostic block and at the time of discharge (approximately 4 h later) was recorded; the pain relief was recorded in percentage. In both the groups, sacroilitis was the most common diagnosis followed by facet joint arthropathy. The number of patients obtaining pain relief of >50% was significantly higher in the bone scan-positive group as compared with the control group. Three new clinical conditions were identified in the bone scan group. These conditions were multiple myeloma, avascular necrosis of the femoral head, and ankylosing spondylitis. Bone scan with SPECT/CT was found to complement the clinical workup of patients with LBP. Inclusion of bone scan with SPECT/CT in LBP management protocol can help in making a correct diagnosis. At times it might bring out some new information that may be vital for further management of the patients with LBP.

The effect of decreasing computed tomography dosage on radiostereometric analysis (RSA) accuracy at the glenohumeral joint.

PubMed

Fox, Anne-Marie V; Kedgley, Angela E; Lalone, Emily A; Johnson, James A; Athwal, George S; Jenkyn, Thomas R

2011-11-10

Standard, beaded radiostereometric analysis (RSA) and markerless RSA often use computed tomography (CT) scans to create three-dimensional (3D) bone models. However, ethical concerns exist due to risks associated with CT radiation exposure. Therefore, the aim of this study was to investigate the effect of decreasing CT dosage on RSA accuracy. Four cadaveric shoulder specimens were scanned using a normal-dose CT protocol and two low-dose protocols, where the dosage was decreased by 89% and 98%. 3D computer models of the humerus and scapula were created using each CT protocol. Bi-planar fluoroscopy was used to image five different static glenohumeral positions and two dynamic glenohumeral movements, of which a total of five static and four dynamic poses were selected for analysis. For standard RSA, negligible differences were found in bead (0.21±0.31mm) and bony landmark (2.31±1.90mm) locations when the CT dosage was decreased by 98% (p-values>0.167). For markerless RSA kinematic results, excellent agreement was found between the normal-dose and lowest-dose protocol, with all Spearman rank correlation coefficients greater than 0.95. Average root mean squared errors of 1.04±0.68mm and 2.42±0.81° were also found at this reduced dosage for static positions. In summary, CT dosage can be markedly reduced when performing shoulder RSA to minimize the risks of radiation exposure. Standard RSA accuracy was negligibly affected by the 98% CT dose reduction and for markerless RSA, the benefits of decreasing CT dosage to the subject outweigh the introduced errors. Copyright © 2011 Elsevier Ltd. All rights reserved.

SU-E-J-187: Individually Optimized Contrast-Enhancement 4D-CT for Pancreatic Adenocarcinoma in Radiotherapy Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, M; Patel, K; Regine, W

2014-06-01

Purpose: To study the feasibility of individually optimized contrastenhancement (CE) 4D-CT for pancreatic adenocarcinoma (PDA) in radiotherapy simulation. To evaluate the image quality and contrast enhancement of tumor in the CE 4D-CT, compared to the clinical standard of CE 3D-CT and 4D-CT. Methods: In this IRB-approved study, each of the 7 PDA patients enrolled underwent 3 CT scans: a free-breathing 3D-CT with contrast (CE 3D-CT) followed by a 4D-CT without contrast (4D-CT) in the first study session, and a 4D-CT with individually synchronized contrast injection (CE 4D-CT) in the second study session. In CE 4D-CT, the time of full contrastmore » injection was determined based on the time of peak enhancement for the test injection, injection rate, table speed, and longitudinal location and span of the pancreatic region. Physicians contoured both the tumor (T) and the normal pancreatic parenchyma (P) on the three CTs (end-of-exhalation for 4D-CT). The contrast between the tumor and normal pancreatic tissue was computed as the difference of the mean enhancement level of three 1 cm3 regions of interests in T and P, respectively. Wilcoxon rank sum test was used to statistically compare the scores and contrasts. Results: In qualitative evaluations, both CE 3D-CT and CE 4D-CT scored significantly better than 4D-CT (4.0 and 3.6 vs. 2.6). There was no significant difference between CE 3D-CT and CE 4D-CT. In quantitative evaluations, the contrasts between the tumor and the normal pancreatic parenchyma were 0.6±23.4, −2.1±8.0, and −19.6±28.8 HU, in CE 3D-CT, 4D-CT, and CE 4D-CT, respectively. Although not statistically significant, CE 4D-CT achieved better contrast enhancement between the tumor and the normal pancreatic parenchyma than both CE 3D-CT and 4DCT. Conclusion: CE 4D-CT achieved equivalent image quality and better contrast enhancement between tumor and normal pancreatic parenchyma than the clinical standard of CE 3D-CT and 4D-CT. This study was supported in part by Philips Healthcare.« less

Predictive equations for lung volumes from computed tomography for size matching in pulmonary transplantation.

PubMed

Konheim, Jeremy A; Kon, Zachary N; Pasrija, Chetan; Luo, Qingyang; Sanchez, Pablo G; Garcia, Jose P; Griffith, Bartley P; Jeudy, Jean

2016-04-01

Size matching for lung transplantation is widely accomplished using height comparisons between donors and recipients. This gross approximation allows for wide variation in lung size and, potentially, size mismatch. Three-dimensional computed tomography (3D-CT) volumetry comparisons could offer more accurate size matching. Although recipient CT scans are universally available, donor CT scans are rarely performed. Therefore, predicted donor lung volumes could be used for comparison to measured recipient lung volumes, but no such predictive equations exist. We aimed to use 3D-CT volumetry measurements from a normal patient population to generate equations for predicted total lung volume (pTLV), predicted right lung volume (pRLV), and predicted left lung volume (pLLV), for size-matching purposes. Chest CT scans of 400 normal patients were retrospectively evaluated. 3D-CT volumetry was performed to measure total lung volume, right lung volume, and left lung volume of each patient, and predictive equations were generated. The fitted model was tested in a separate group of 100 patients. The model was externally validated by comparison of total lung volume with total lung capacity from pulmonary function tests in a subset of those patients. Age, gender, height, and race were independent predictors of lung volume. In the test group, there were strong linear correlations between predicted and actual lung volumes measured by 3D-CT volumetry for pTLV (r = 0.72), pRLV (r = 0.72), and pLLV (r = 0.69). A strong linear correlation was also observed when comparing pTLV and total lung capacity (r = 0.82). We successfully created a predictive model for pTLV, pRLV, and pLLV. These may serve as reference standards and predict donor lung volume for size matching in lung transplantation. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

[Stress fractures of the ribs with acute thoracic pain in a young woman, diagnosed by the bone scan].

PubMed

Georgitzikis, Athanasios; Siopi, Dimitra; Doumas, Argyrios; Mitka, Ekaterini; Antoniadis, Antonios

2010-01-01

We report the unusual case of a 29 -year old woman with emotional instability who presented with acute onset chest pain after severe chronic cough. The chest X-ray and the serological tests were normal but the CT scanning, and the bone scanning revealed multiple bilateral rib stress fractures, caused by severe coughing and physical activity and worsened by the patient's emotional instability.

Image Processing Diagnostics: Emphysema

NASA Astrophysics Data System (ADS)

McKenzie, Alex

2009-10-01

Currently the computerized tomography (CT) scan can detect emphysema sooner than traditional x-rays, but other tests are required to measure more accurately the amount of affected lung. CT scan images show clearly if a patient has emphysema, but is unable by visual scan alone, to quantify the degree of the disease, as it appears merely as subtle, barely distinct, dark spots on the lung. Our goal is to create a software plug-in to interface with existing open source medical imaging software, to automate the process of accurately diagnosing and determining emphysema severity levels in patients. This will be accomplished by performing a number of statistical calculations using data taken from CT scan images of several patients representing a wide range of severity of the disease. These analyses include an examination of the deviation from a normal distribution curve to determine skewness, a commonly used statistical parameter. Our preliminary results show that this method of assessment appears to be more accurate and robust than currently utilized methods which involve looking at percentages of radiodensities in air passages of the lung.

What is the best imaging strategy for acute stroke?

PubMed

Wardlaw, J M; Keir, S L; Seymour, J; Lewis, S; Sandercock, P A G; Dennis, M S; Cairns, J

2004-01-01

To determine the cost-effectiveness of computed tomographic (CT) scanning after acute stroke. To assess the contribution of brain imaging to the diagnosis and management of stroke, and to estimate the costs, benefits and risks of different imaging strategies in order to provide data to inform national and local policy on the use of brain imaging in stroke. A decision-analysis model was developed to represent the pathway of care in acute stroke using 'scan all patients within 48 hours' as the comparator against which to cost 12 alternative scan strategies. Hospitals in Scotland. Subjects were patients admitted to hospital with a first stroke and those managed as outpatients. The effect on functional outcome after ischaemic or haemorrhagic stroke, tumours or infections, of correctly administered antithrombotic or other treatment; of time to scan and stroke severity on diagnosis by CT or MRI; on management, including length of stay, functional outcome, and quality-adjusted life years (QALYs), of the diagnostic information provided by CT scanning; the cost-effectiveness (cost versus QALYs) of different strategies for use of CT after acute stroke. Death and functional outcome at long-term follow-up; accuracy of CT and MRI; cost of CT scanning by time of day and week; effect of CT diagnosis on change in health outcome, length of stay in hospital and QALYs; cost-effectiveness of various scanning strategies. CT is very sensitive and specific for haemorrhage within the first 8 days of stroke only. Suboptimal scanning used in epidemiology studies suggests that the frequency of primary intracerebral haemorrhage (PICH) has been underestimated. Aspirin increases the risk of PICH. There were no reliable data on functional outcome or on the effect of antithrombotic treatment given long term after PICH. In 60% of patients with recurrent stroke after PICH, the cause is another PICH and mortality is high among PICH patients. A specific MR sequence (gradient echo) is required to identify prior PICH reliably. CT scanners were distributed unevenly in Scotland, 65% provided CT scanning within 48 hours of stroke, and 100% within 7 days for hospital-admitted patients, but access out of hours was very variable, and for outpatients was poor. The average cost of a CT brain scan for stroke was pounds 30.23 to pounds 89.56 in normal working hours and pounds 55.05 to pounds 173.46 out of hours. Average length of stay was greatest for severe strokes and those who survived in a dependent state. For a cohort of 1000 patients aged 70-74 years, the policy 'scan all strokes within 48 hours', cost pounds 10,279,728 and achieved 1982.3 QALYS. The most cost-effective strategy was 'scan all immediately' (pounds 9,993,676 and 1982.4 QALYS). The least cost-effective was to 'scan patients on anticoagulants, in a life-threatening condition immediately and the rest within 14 days'. In general, strategies in which most patients were scanned immediately cost least and achieved the most QALYs, as the cost of providing CT (even out of hours) was less than the cost of inpatient care. Increasing independent survival by even a small proportion through early use of aspirin in the majority with ischaemic stroke, avoiding aspirin in those with haemorrhagic stroke, and appropriate early management of those who have not had a stroke, reduced costs and increased QALYs.

Comparison of electron-beam and ungated helical CT in detecting coronary arterial calcification by using a working heart phantom and artificial coronary arteries.

PubMed

Hopper, Kenneth D; Strollo, Diane C; Mauger, David T

2002-02-01

To determine the sensitivity and specificity of cardiac gated electron-beam computed tomography (CT) and ungated helical CT in detecting and quantifying coronary arterial calcification (CAC) by using a working heart phantom and artificial coronary arteries. A working heart phantom simulating normal cardiac motion and providing attenuation equal to that of an adult thorax was used. Thirty tubes with a 3-mm inner diameter were internally coated with pulverized human cortical bone mixed with epoxy glue to simulate minimal (n = 10), mild (n = 10), or severe (n = 10) calcified plaques. Ten additional tubes were not coated and served as normal controls. The tubes were attached to the same location on the phantom heart and scanned with electron-beam CT and helical CT in horizontal and vertical planes. Actual plaque calcium content was subsequently quantified with atopic spectroscopy. Two blinded experienced radiologic imaging teams, one for each CT system, separately measured calcium content in the model vessels by using a Hounsfield unit threshold of 130 or greater. The sensitivity and specificity of electron-beam CT in detecting CAC were 66.1% and 80.0%, respectively. The sensitivity and specificity of helical CT were 96.4% and 95.0%, respectively. Electron-beam CT was less reliable when vessels were oriented vertically (sensitivity and specificity, 71.4% and 70%; 95% CI: 39.0%, 75.0%) versus horizontally (sensitivity and specificity, 60.7% and 90.0%; 95% CI: 48.0%, 82.0%). When a correction factor was applied, the volume of calcified plaque was statistically better quantified with helical CT than with electron-beam CT (P =.004). Ungated helical CT depicts coronary arterial calcium better than does gated electron-beam CT. When appropriate correction factors are applied, helical CT is superior to electron-beam CT in quantifying coronary arterial calcium. Although further work must be done to optimize helical CT grading systems and scanning protocols, the data of this study demonstrated helical CT's inherent advantage over currently commercially available electron-beam CT systems in CAC detection and quantification.

Quantitative Computerized Two-Point Correlation Analysis of Lung CT Scans Correlates With Pulmonary Function in Pulmonary Sarcoidosis

PubMed Central

Erdal, Barbaros Selnur; Yildiz, Vedat; King, Mark A.; Patterson, Andrew T.; Knopp, Michael V.; Clymer, Bradley D.

2012-01-01

Background: Chest CT scans are commonly used to clinically assess disease severity in patients presenting with pulmonary sarcoidosis. Despite their ability to reliably detect subtle changes in lung disease, the utility of chest CT scans for guiding therapy is limited by the fact that image interpretation by radiologists is qualitative and highly variable. We sought to create a computerized CT image analysis tool that would provide quantitative and clinically relevant information. Methods: We established that a two-point correlation analysis approach reduced the background signal attendant to normal lung structures, such as blood vessels, airways, and lymphatics while highlighting diseased tissue. This approach was applied to multiple lung fields to generate an overall lung texture score (LTS) representing the quantity of diseased lung parenchyma. Using deidentified lung CT scan and pulmonary function test (PFT) data from The Ohio State University Medical Center’s Information Warehouse, we analyzed 71 consecutive CT scans from patients with sarcoidosis for whom simultaneous matching PFTs were available to determine whether the LTS correlated with standard PFT results. Results: We found a high correlation between LTS and FVC, total lung capacity, and diffusing capacity of the lung for carbon monoxide (P < .0001 for all comparisons). Moreover, LTS was equivalent to PFTs for the detection of active lung disease. The image analysis protocol was conducted quickly (< 1 min per study) on a standard laptop computer connected to a publicly available National Institutes of Health ImageJ toolkit. Conclusions: The two-point image analysis tool is highly practical and appears to reliably assess lung disease severity. We predict that this tool will be useful for clinical and research applications. PMID:22628487

Liver metastases from prostate cancer at 11C-Choline PET/CT: a multicenter, retrospective analysis.

PubMed

Ghedini, Pietro; Bossert, I; Zanoni, L; Ceci, F; Graziani, T; Castellucci, P; Ambrosini, V; Massari, F; Nobili, E; Melotti, B; Musto, A; Zoboli, S; Antunovic, L; Kirienko, M; Chiti, A; Mosconi, C; Ardizzoni, A; Golfieri, R; Fanti, S; Nanni, C

2018-05-01

During our daily clinical practice using 11C-Choline PET/CT for restaging patients affected by relapsing prostate cancer (rPCa) we noticed an unusual but significant occurrence of hypodense hepatic lesions with a different tracer uptake. Thus, we decided to evaluate the possible correlation between rPCa and these lesions as possible hepatic metastases. We retrospectively enrolled 542 patients diagnosed with rPCa in biochemical relapse after a radical treatment (surgery and/or radiotherapy). Among these, patients with a second tumor or other benign hepatic diseases were excluded. All patients underwent 11C-Choline PET/CT during the standard restaging workup of their disease. We analyzed CT images to evaluate the presence of hypodense lesions and PET images to identify the relative tracer uptake. In accordance to the subsequent oncological history, five clinical scenarios were recognized [Table 1]: normal low dose CT (ldCT) and normal tracer distribution (Group A); evidence of previously unknown hepatic round hypodense areas at ldCT with normal rim uptake (Group B); evidence of previously known hepatic round hypodense areas at ldCT stable over time and with normal rim uptake (Group C); evidence of previously known hepatic round hypodense areas at ldCT, in a previous PET/CT scan, with or without rim uptake and significantly changing over time in terms of size and/or uptake (Group D); evidence of hepatic round hypodense areas at ldCT with or without rim uptake confirmed as prostate liver metastases by histopathology, triple phase ceCT, ce-ultra sound (CEUS) and clinical/biochemical evaluation (Group E). We evaluated the correlation with PSA level at time of scan, rim SUVmax and association with local relapse or non-hepatic metastases (lymph nodes, bone, other parenchyma). Five hundred and forty-two consecutive patients were retrospectively enrolled. In 140 of the 542 patients more than one 11C-choline PET/CT had been performed. A total of 742 11C-Choline PET/CT scans were analyzed. Of the 542 patients enrolled, 456 (84.1%) had a normal appearance of the liver both at ldCT and PET (Group A). 19/542 (3,5%) belonged to Group B, 13/542 (2.4%) to Group C, 37/542 (6.8%) to Group D and 18/542 (3.3%) to Group E. Mean SUVmax of the rim was: 4.5 for Group B; 4.2 for Group C; 4.8 for Group D; 5.9 for Group E. Mean PSA level was 5.27 for Group A, 7.9 for Group B, 10.04 for Group C, 10.01 for Group D, 9.36 for Group E. Presence of positive findings at 11C-Choline PET/CT in any further anatomical area (local relapse, lymph node, bone, other extra hepatic sites) correlated with an higher PSA (p = 0.0285). In both the univariate and multivariate binary logistic regression analyses. PSA, SUVmax of the rim, local relapse, positive nodes were not associated to liver mets (Groups D-E) (p > 0.05). On the contrary, a significant correlation was found between the presence of liver metG (group D-E) and bone lesions (p= 0.00193). Our results indicate that liver metastases in relapsing prostate cancer may occur frequently. The real incidence evaluation needs more investigations. In this case and despite technical limitations, Choline PET/CT shows alterations of tracer distribution within the liver that could eventually be mistaken for simple cysts but can be suspected when associated to high trigger PSA, concomitant bone lesions or modification over time. In this clinical setting an accurate analysis of liver tracer distribution (increased or decreased uptake) by the nuclear medicine physician is, therefore, mandatory.

Use of CT Hounsfield unit density to identify ablated tumor after laparoscopic radiofrequency ablation of hepatic tumors.

PubMed

Berber, E; Foroutani, A; Garland, A M; Rogers, S J; Engle, K L; Ryan, T L; Siperstein, A E

2000-09-01

When attempting to interpret CT scans after radiofrequency thermal ablation (RFA) of liver tumors, it is sometimes difficult to distinguish ablated from viable tumor tissue. Identification of the two types of tissue is specially problematic for lesions that are hypodense before ablation. The aim of this study was to determine whether quantitative Hounsfield unit (HU) density measurements can be used to document the lack of tumor perfusion and thereby identify ablated tissue. Liver spiral CT scans of 13 patients with 51 lesions undergoing laparoscopic RFA for metastatic liver tumors within a 2-year time period were reviewed. HU density of the lesions as well as normal liver were measured pre- and postoperatively in each CT phase (noncontrast, arterial, portovenous). Statistical analyses were performed using Student's paired t-test and ANOVA. Normal liver parenchyma, which was used as a control, showed a similar increase with contrast injection in both pre- and postprocedure CT scans (56.4 +/- 2.4 vs 57.1 +/- 2.4 HU, respectively; p = 0.3). In contrast, ablated liver lesions showed a preablation increase of 45.7 +/- 3.4 HU but only a minimal postablation increase of 6.6 +/- 0.7 HU (p < 0.0001). This was true for highly vascular tumors (neuroendocrine) as well as hypovascular ones (adenocarcinoma). This is the first study to define quantitative radiological criteria using HU density for the evaluation of ablated tissues. A lack of increase in HU density with contrast injection indicates necrotic tissue, whereas perfused tissue shows an increase in HU density. This technique can be used in the evaluation of patients undergoing RFA.

Evaluation of acute ischemic stroke using quantitative EEG: a comparison with conventional EEG and CT scan.

PubMed

Murri, L; Gori, S; Massetani, R; Bonanni, E; Marcella, F; Milani, S

1998-06-01

The sensitivity of quantitative electroencephalogram (EEG) was compared with that of conventional EEG in patients with acute ischaemic stroke. In addition, a correlation between quantitative EEG data and computerized tomography (CT) scan findings was carried out for all the areas of lesion in order to reassess the actual role of EEG in the evaluation of stroke. Sixty-five patients were tested with conventional and quantitative EEG within 24 h from the onset of neurological symptoms, whereas CT scan was performed within 4 days from the onset of stroke. EEG was recorded from 19 electrodes placed upon the scalp according to the International 10-20 System. Spectral analysis was carried out on 30 artefact-free 4-sec epochs. For each channel absolute and relative power were calculated for the delta, theta, alpha and beta frequency bands and such data were successively represented in colour-coded maps. Ten patients with extensive lesions documented by CT scan were excluded. The results indicated that conventional EEG revealed abnormalities in 40 of 55 cases, while EEG mapping showed abnormalities in 46 of 55 cases: it showed focal abnormalities in five cases and nonfocal abnormalities in one of six cases which had appeared to be normal according to visual inspection of EEG. In a further 11 cases, where the conventional EEG revealed abnormalities in one hemisphere, the quantitative EEG and maps allowed to further localize abnormal activity in a more localized way. The sensitivity of both methods was higher for frontocentral, temporal and parieto-occipital cortical-subcortical infarctions than for basal ganglia and internal capsule lesions; however, quantitative EEG was more efficient for all areas of lesion in detecting cases that had appeared normal by visual inspection and was clearly superior in revealing focal abnormalities. When we considered the electrode related to which the maximum power of the delta frequency band is recorded, a fairly close correlation was found between the localization of the maximum delta power and the position of lesions documented by CT scan for all areas of lesion excepting those located in the striatocapsular area.

Diagnostic Value of 68Ga PSMA-11 PET/CT Imaging of Brain Tumors-Preliminary Analysis.

PubMed

Sasikumar, Arun; Joy, Ajith; Pillai, M R A; Nanabala, Raviteja; Anees K, Muhammed; Jayaprakash, P G; Madhavan, Jayaprakash; Nair, Suresh

2017-01-01

To evaluate the feasibility of using Ga PSMA-11 PET/CT for imaging brain lesions and its comparison with F-FDG. Ten patients with brain lesions were included in the study. Five patients were treated cases of glioblastoma with suspected recurrence. F-FDG and Ga PSMA-11 brain scans were done for these patients. Five patients were sent for assessing the nature (primary lesion/metastasis) of space occupying lesion in brain. They underwent whole body F-FDG PET/CT scan and a primary site elsewhere in the body was ruled out. Subsequently they underwent Ga PSMA-11 brain PET/CT imaging. Target to background ratios (TBR) for the brain lesions were calculated using contralateral cerebellar uptake as background. In five treated cases of glioblastoma with suspected recurrence the findings of Ga PSMA-11 PET/CT showed good correlation with that of F-FDG PET/CT scan. Compared to the F-FDG, Ga PSMA-11 PET/CT showed better visualization of the recurrent lesion (presence/absence) owing to its significantly high TBR. Among the five cases evaluated for lesion characterization glioma and atypical meningioma patients showed higher SUVmax in the lesion with Ga PSMA-11 than with F-FDG and converse in cases of lymphoma. TBR was better with Ga PSMA PET/CT in all cases. Ga PSMA-11 PET/CT brain imaging is a potentially useful imaging tool in the evaluation of brain lesions. Absence of physiological uptake of Ga PSMA-11 in the normal brain parenchyma results in high TBR values and consequently better visualization of metabolically active disease in brain.

Plastinated fetus: 3D CT scan (VRT) evaluation.

PubMed

Tiwari, Shilpi; Nandlal, B; Shama Sundar, N M

2012-01-01

The intent of this study was to evaluate the effect of plastination on the morphology and structure of stored organs, to find out how much accuracy a plastinated specimen has, and to look into the changes that occurred because of plastination. A human fetus of gestational age 24 weeks was plastinated, and 3D CT scan evaluation of the fetus was done. The results showed normal, well-defined, clearly identifiable organs, with no alteration in morphology and structure of organs. In our opinion, plastinated specimens are better way of visualization of morphology and structure of stored organs, which is a useful tool for teaching as well as for research purposes.

Mass preserving registration for lung CT

NASA Astrophysics Data System (ADS)

Gorbunova, Vladlena; Lo, Pechin; Loeve, Martine; Tiddens, Harm A.; Sporring, Jon; Nielsen, Mads; de Bruijne, Marleen

2009-02-01

In this paper, we evaluate a novel image registration method on a set of expiratory-inspiratory pairs of computed tomography (CT) lung scans. A free-form multi resolution image registration technique is used to match two scans of the same subject. To account for the differences in the lung intensities due to differences in inspiration level, we propose to adjust the intensity of lung tissue according to the local expansion or compression. An image registration method without intensity adjustment is compared to the proposed method. Both approaches are evaluated on a set of 10 pairs of expiration and inspiration CT scans of children with cystic fibrosis lung disease. The proposed method with mass preserving adjustment results in significantly better alignment of the vessel trees. Analysis of local volume change for regions with trapped air compared to normally ventilated regions revealed larger differences between these regions in the case of mass preserving image registration, indicating that mass preserving registration is better at capturing localized differences in lung deformation.

Thoracic-abdominal imaging with a novel dual-layer spectral detector CT: intra-individual comparison of image quality and radiation dose with 128-row single-energy acquisition.

PubMed

Haneder, Stefan; Siedek, Florian; Doerner, Jonas; Pahn, Gregor; Grosse Hokamp, Nils; Maintz, David; Wybranski, Christian

2018-01-01

Background A novel, multi-energy, dual-layer spectral detector computed tomography (SDCT) is commercially available now with the vendor's claim that it yields the same or better quality of polychromatic, conventional CT images like modern single-energy CT scanners without any radiation dose penalty. Purpose To intra-individually compare the quality of conventional polychromatic CT images acquired with a dual-layer spectral detector (SDCT) and the latest generation 128-row single-energy-detector (CT128) from the same manufacturer. Material and Methods Fifty patients underwent portal-venous phase, thoracic-abdominal CT scans with the SDCT and prior CT128 imaging. The SDCT scanning protocol was adapted to yield a similar estimated dose length product (DLP) as the CT128. Patient dose optimization by automatic tube current modulation and CT image reconstruction with a state-of-the-art iterative algorithm were identical on both scanners. CT image contrast-to-noise ratio (CNR) was compared between the SDCT and CT128 in different anatomic structures. Image quality and noise were assessed independently by two readers with 5-point-Likert-scales. Volume CT dose index (CTDI vol ), and DLP were recorded and normalized to 68 cm acquisition length (DLP 68 ). Results The SDCT yielded higher mean CNR values of 30.0% ± 2.0% (26.4-32.5%) in all anatomic structures ( P < 0.001) and excellent scores for qualitative parameters surpassing the CT128 (all P < 0.0001) with substantial inter-rater agreement (κ ≥ 0.801). Despite adapted scan protocols the SDCT yielded lower values for CTDI vol (-10.1 ± 12.8%), DLP (-13.1 ± 13.9%), and DLP 68 (-15.3 ± 16.9%) than the CT128 (all P < 0.0001). Conclusion The SDCT scanner yielded better CT image quality compared to the CT128 and lower radiation dose parameters.

Imaging and review of a large pre-auricular pilomatrixoma in a child.

PubMed

Whittemore, Kenneth R; Cohen, Michael

2012-05-28

A 10-year-old girl presented with a mildly tender mass in the right preauricular region. The mass became larger, and the overlying skin turned purple. There was no clinical response to a course of either cephalexin or clarithromycin. The remainder of the head and neck examination was normal including normal facial nerve function. Lyme titers and a computed tomographic (CT) scan with contrast of the facial region were obtained. The CT scan demonstrated the lesion to be superficial to the parotid gland. The lyme titer was elevated and doxycycline was begun. The mass appeared to reduce in size after doxycycline treatment, but then grew and turned erythematous. The lesion was surgically excised and was vascular with calcification and cheesy inclusions. The mass was quite close to the skin and the clinical diagnosis at the time of surgery was a pilomatrixoma, which was corroborated on pathological evaluation.

Texture-preserved penalized weighted least-squares reconstruction of low-dose CT image via image segmentation and high-order MRF modeling

NASA Astrophysics Data System (ADS)

Han, Hao; Zhang, Hao; Wei, Xinzhou; Moore, William; Liang, Zhengrong

2016-03-01

In this paper, we proposed a low-dose computed tomography (LdCT) image reconstruction method with the help of prior knowledge learning from previous high-quality or normal-dose CT (NdCT) scans. The well-established statistical penalized weighted least squares (PWLS) algorithm was adopted for image reconstruction, where the penalty term was formulated by a texture-based Gaussian Markov random field (gMRF) model. The NdCT scan was firstly segmented into different tissue types by a feature vector quantization (FVQ) approach. Then for each tissue type, a set of tissue-specific coefficients for the gMRF penalty was statistically learnt from the NdCT image via multiple-linear regression analysis. We also proposed a scheme to adaptively select the order of gMRF model for coefficients prediction. The tissue-specific gMRF patterns learnt from the NdCT image were finally used to form an adaptive MRF penalty for the PWLS reconstruction of LdCT image. The proposed texture-adaptive PWLS image reconstruction algorithm was shown to be more effective to preserve image textures than the conventional PWLS image reconstruction algorithm, and we further demonstrated the gain of high-order MRF modeling for texture-preserved LdCT PWLS image reconstruction.

The Value of Restaging With Chest and Abdominal CT/MRI Scan After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer.

PubMed

Liu, Guo-Chen; Zhang, Xu; Xie, E; An, Xin; Cai, Pei-Qiang; Zhu, Ying; Tang, Jing-Hua; Kong, Ling-Heng; Lin, Jun-Zhong; Pan, Zhi-Zhong; Ding, Pei-Rong

2015-11-01

Little was known with regard to the value of preoperative systemic restaging for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (CRT). This study was designed to evaluate the role of chest and abdominal computed tomography (CT) scan or magnetic resonance imaging (MRI) on preoperative restaging in LARC after neoadjuvant CRT and to assess the impact on treatment strategy.Between January 2007 and April 2013, 386 newly diagnosed consecutive patients with LARC who underwent neoadjuvant CRT and received restaging with chest and abdominal CT/MRI scan were included. Imaging results before and after CRT were analyzed.Twelve patients (3.1%) (6 liver lesions, 2 peritoneal lesions, 2 distant lymph node lesions, 1 lung lesions, 1 liver and lung lesions) were diagnosed as suspicious metastases on the restaging scan after radiotherapy. Seven patients (1.8%) were confirmed as metastases by pathology or long-term follow-up. The treatment strategy was changed in 5 of the 12 patients as a result of restaging CT/MRI findings. Another 10 patients (2.6%) who present with normal restaging imaging findings were diagnosed as metastases intra-operatively. The sensitivity, specificity accuracy, negative predictive value, and positive predictive values of restaging CT/MRI was 41.4%, 98.6%, 58.3%, and 97.3%, respectively.The low incidence of metastases and minimal consequences for the treatment plan question the clinical value of routine restaging of chest and abdomen after neoadjuvant CRT. Based on this study, a routine restaging CT/MRI of chest and abdomen in patients with rectal cancer after neoadjuvant CRT is not advocated, carcino-embryonic antigen (CEA) -guided CT/MRI restaging might be an alternative.

Brain early infarct detection using gamma correction extreme-level eliminating with weighting distribution.

PubMed

Teh, V; Sim, K S; Wong, E K

2016-11-01

According to the statistic from World Health Organization (WHO), stroke is one of the major causes of death globally. Computed tomography (CT) scan is one of the main medical diagnosis system used for diagnosis of ischemic stroke. CT scan provides brain images in Digital Imaging and Communication in Medicine (DICOM) format. The presentation of CT brain images is mainly relied on the window setting (window center and window width), which converts an image from DICOM format into normal grayscale format. Nevertheless, the ordinary window parameter could not deliver a proper contrast on CT brain images for ischemic stroke detection. In this paper, a new proposed method namely gamma correction extreme-level eliminating with weighting distribution (GCELEWD) is implemented to improve the contrast on CT brain images. GCELEWD is capable of highlighting the hypodense region for diagnosis of ischemic stroke. The performance of this new proposed technique, GCELEWD, is compared with four of the existing contrast enhancement technique such as brightness preserving bi-histogram equalization (BBHE), dualistic sub-image histogram equalization (DSIHE), extreme-level eliminating histogram equalization (ELEHE), and adaptive gamma correction with weighting distribution (AGCWD). GCELEWD shows better visualization for ischemic stroke detection and higher values with image quality assessment (IQA) module. SCANNING 38:842-856, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Pelvic CT scan

MedlinePlus

CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye CT scans do expose you to more radiation ...

Shoulder CT scan

MedlinePlus

CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye Birth defect if done during pregnancy CT scans ...

11C-Methionine Positron Emission Tomography/Computed Tomography Versus 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Evaluation of Residual or Recurrent World Health Organization Grades II and III Meningioma After Treatment.

PubMed

Tomura, Noriaki; Saginoya, Toshiyuki; Goto, Hiromi

2018-04-02

The aim of this study was to determine the assessment of positron emission tomography-computed tomography using C-methionine (MET PET/CT) for World Health Organization (WHO) grades II and III meningiomas; MET PET/CT was compared with PET/CT using F-fluorodeoxy glucose (FDG PET/CT). This study was performed in 17 cases with residual and/or recurrent WHO grades II and III meningiomas. Two neuroradiologists reviewed both PET/CT scans. For agreement, the κ coefficient was measured. Difference in tumor-to-normal brain uptake ratios (T/N ratios) between 2 PET/CT scans was analyzed. Correlation between the maximum tumor size and T/N ratio in PET/CT was studied. For agreement by both reviewers, the κ coefficient was 0.51 (P < 0.05). The T/N ratio was significantly higher for MET PET/CT (3.24 ± 1.36) than for FDG PET/CT (0.93 ± 0.44) (P < 0.01). C-methionine ratio significantly correlated with tumor size (y = 8.1x + 16.3, n = 22, P < 0.05), but FDG ratio did not CONCLUSIONS: C-methionine PET/CT has superior potential for imaging of WHO grades II and III meningiomas with residual or recurrent tumors compared with FDG PET/CT.

Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model.

PubMed

Rosow, David E; Sahani, Dushyant; Strobel, Oliver; Kalva, Sanjeeva; Mino-Kenudson, Mari; Holalkere, Nagaraj S; Alsfasser, Guido; Saini, Sanjay; Lee, Susanna I; Mueller, Peter R; Fernández-del Castillo, Carlos; Warshaw, Andrew L; Thayer, Sarah P

2005-12-01

Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

Texture classification of normal tissues in computed tomography using Gabor filters

NASA Astrophysics Data System (ADS)

Dettori, Lucia; Bashir, Alia; Hasemann, Julie

2007-03-01

The research presented in this article is aimed at developing an automated imaging system for classification of normal tissues in medical images obtained from Computed Tomography (CT) scans. Texture features based on a bank of Gabor filters are used to classify the following tissues of interests: liver, spleen, kidney, aorta, trabecular bone, lung, muscle, IP fat, and SQ fat. The approach consists of three steps: convolution of the regions of interest with a bank of 32 Gabor filters (4 frequencies and 8 orientations), extraction of two Gabor texture features per filter (mean and standard deviation), and creation of a Classification and Regression Tree-based classifier that automatically identifies the various tissues. The data set used consists of approximately 1000 DIACOM images from normal chest and abdominal CT scans of five patients. The regions of interest were labeled by expert radiologists. Optimal trees were generated using two techniques: 10-fold cross-validation and splitting of the data set into a training and a testing set. In both cases, perfect classification rules were obtained provided enough images were available for training (~65%). All performance measures (sensitivity, specificity, precision, and accuracy) for all regions of interest were at 100%. This significantly improves previous results that used Wavelet, Ridgelet, and Curvelet texture features, yielding accuracy values in the 85%-98% range The Gabor filters' ability to isolate features at different frequencies and orientations allows for a multi-resolution analysis of texture essential when dealing with, at times, very subtle differences in the texture of tissues in CT scans.

Methods for Measuring Lung Volumes: Is There a Better One?

PubMed

Tantucci, Claudio; Bottone, Damiano; Borghesi, Andrea; Guerini, Michele; Quadri, Federico; Pini, Laura

2016-01-01

Accurate measurement of lung volumes is of paramount importance to establish the presence of ventilatory defects and give insights for diagnostic and/or therapeutic purposes. It was the aim of this study to measure lung volumes in subjects with respiratory disorders and in normal controls by 3 different techniques (plethysmographic, dilutional and radiographic methods), in an attempt to clarify the role of each of them in performing such a task, without any presumptive 'a priori' superiority of one method above others. Patients andMethods: In different groups of subjects with obstructive and restrictive ventilatory defects and in a normal control group, total lung capacity, functional residual capacity (FRC) and residual volume were measured by body plethysmography, multi-breath helium (He) dilution and radiographic CT scan method with spirometric gating. The 3 methods gave comparable results in normal subjects and in patients with a restrictive defect. In patients with an obstructive defect, CT scan and plethysmography showed similar lung volumes, while on average significantly lower lung volumes were obtained with the He dilution technique. Taking into account that the He dilution technique does primarily measure FRC during tidal breathing, our data suggest that in some patients with an obstructive defect, a number of small airways can be functionally closed at end-expiratory lung volume, preventing He to reach the lung regions subserved by these airways. In all circumstances, both CT scan with spirometric gating and plethysmographic methods provide similar values of lung volumes. In contrast, the He dilution method can measure lower lung volumes in some patients with chronic airflow obstruction. © 2016 S. Karger AG, Basel.

Sinus CT scan

MedlinePlus

CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... Risks for a CT scan includes: Being exposed to radiation Allergic reaction to contrast dye CT scans expose you to more radiation than regular ...

Comparison of macular choroidal thickness among patients older than age 65 with early atrophic age-related macular degeneration and normals.

PubMed

Sigler, Eric J; Randolph, John C

2013-09-19

To compare macular choroidal thickness between patients older than 65 years with early atrophic age-related macular degeneration (AMD) and normals. This was a consecutive, cross-sectional observational study. Enhanced depth imaging spectral-domain optical coherence tomography using horizontal raster scanning at 12 locations throughout the macula was performed in one eye of consecutive patients presenting with large soft drusen alone, drusen with additional features of early AMD, or a normal fundus. Choroidal thickness was measured at 7 points for each raster scan in the central 3 mm of the macula (total 84 points per eye). In addition, a single subfoveolar measurement was obtained for each eye. One hundred fifty eyes of 150 patients were included. There was no significant difference between mean refractive error for each diagnosis category via one-way ANOVA (P = 0.451). Mean macular choroidal thickness (CT) was 235 ± 49 μm (range, 125-334 μm; median 222 μm) for normals, 161 ± 39 μm (range, 89-260 μm; median = 158 μm) for the drusen group, and 115 ± 40 μm (range, 22-256 μm; median = 112 μm) for patients with AMD. Mean macular CT was significantly different via one-way ANOVA among all diagnosis categories (P < 0.001). The presence of features of early AMD without geographic atrophy and/or soft drusen alone is associated with decreased mean macular CT in vivo compared to that in patients with no chorioretinal pathology. Using enhanced depth imaging, measurement of a single subfoveolar choroidal thickness is highly correlated to mean central macular CT.

Reproducibility of CT Perfusion Parameters in Liver Tumors and Normal Liver

PubMed Central

Ng, Chaan S.; Chandler, Adam G.; Wei, Wei; Herron, Delise H.; Anderson, Ella F.; Kurzrock, Razelle; Charnsangavej, Chusilp

2011-01-01

Purpose: To assess the reproducibility of computed tomographic (CT) perfusion measurements in liver tumors and normal liver and effects of motion and data acquisition time on parameters. Materials and Methods: Institutional review board approval and written informed consent were obtained for this prospective study. The study complied with HIPAA regulations. Two CT perfusion scans were obtained 2–7 days apart in seven patients with liver tumors with two scanning phases (phase 1: 30-second breath-hold cine; phase 2: six intermittent free-breathing cines) spanning 135 seconds. Blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability–surface area product (PS) for tumors and normal liver were calculated from phase 1 with and without rigid registration and, for combined phases 1 and 2, with manually and rigid-registered phase 2 images, by using deconvolution modeling. Variability was assessed with within-patient coefficients of variation (CVs) and Bland-Altman analyses. Results: For tumors, BF, BV, MTT, and PS values and reproducibility varied by analytical method, the former by up to 11%, 23%, 21%, and 138%, respectively. Median PS values doubled with the addition of phase 2 data to phase 1 data. The best overall reproducibility was obtained with rigidly registered phase 1 and phase 2 images, with within-patient CVs for BF, BV, MTT, and PS of 11.2%, 14.4%, 5.5% and 12.1%, respectively. Normal liver evaluations were similar, except with marginally lower variability. Conclusion: Absolute values and reproducibility of CT perfusion parameters were markedly influenced by motion and data acquisition time. PS, in particular, probably requires data acquisition beyond a single breath hold, for which motion-correction techniques are likely necessary. © RSNA, 2011 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11110331/-/DC1 PMID:21788525

7. Survey of Results of Whole Body Imaging Using the PET/CT at the University of Pittsburgh Medical Center PET Facility.

PubMed

Martinelli; Townsend; Meltzer; Villemagne

2000-07-01

Purpose: At the University Of Pittsburgh Medical Center, over 100 oncology studies have been performed using a combined PET/CT scanner. The scanner is a prototype, which combines clinical PET and clinical CT imaging in a single unit. The sensitivity achieved using three-dimensional PET imaging as well as the use of the CT for attenuation correction and image fusion make the device ideal for clinical oncology. Clinical indications imaged on the PET/CT scanner include, but are not limited to, tumor staging, solitary pulmonary nodule evaluation, and evaluation of tumor reoccurrence in melanoma, lymphoma, colorectal cancer, lung cancer, pancreatic cancer, head and neck cancer, and renal cancer.Methods: For all studies, seven millicuries of F(18)-fluorodeoxyglucose is injected and a forty-five minute uptake period is allowed prior to positioning the patient in the scanner. A helical CT scan is acquired over the region, or regions of interest followed by a multi-bed whole body PET scan for the same axial extent. The CT scan is used to correct the PET data for attenuation. The entire imaging session lasts 1-1.5 hours depending on the number of beds acquired, and is generally well tolerated by the patient.Results and Conclusion: Based on our experience in over 100 studies, combined PET/CT imaging offers significant advantages, including more accurate localization of focal uptake, distinction of pathology from normal physiological uptake, and improvements in evaluating therapy. These benefits will be illustrated with a number of representative, fully documented studies.

A Novel Spirometric Measure Identifies Mild COPD Unidentified by Standard Criteria.

PubMed

Dilektasli, Asli Gorek; Porszasz, Janos; Casaburi, Richard; Stringer, William W; Bhatt, Surya P; Pak, Youngju; Rossiter, Harry B; Washko, George; Castaldi, Peter J; Estepar, Raul San Jose; Hansen, James E

2016-11-01

In chronic obstructive pulmonary disease, both smaller and larger airways are affected. FEV 1 mainly reflects large airways obstruction, while the later fraction of forced exhalation reflects reduction in terminal expiratory flow. In this study, the objective was to evaluate the relationship between spirometric ratios, including the ratio of forced expiratory volume in 3 and 6 seconds (FEV 3 /FEV 6 ), and small airways measures and gas trapping at quantitative chest CT scanning, and clinical outcomes in the Genetic Epidemiology of COPD (COPDGene) cohort. Seven thousand eight hundred fifty-three current and ex-smokers were evaluated for airflow obstruction by using recently defined linear iteratively derived equations of Hansen et al to determine lower limit of normal (LLN) equations for prebronchodilator FEV 1 /FVC, FEV 1 /FEV 6 , FEV 3 /FEV 6 , and FEV 3 /FVC. General linear and ordinal regression models were applied to the relationship between prebronchodilator spirometric and radiologic and clinical data. Of the 10,311 participants included in the COPDGene phase I study, participants with incomplete quantitative CT scanning or relevant spirometric data were excluded, resulting in 7,853 participants in the present study. Of 4,386 participants with FEV 1 /FVC greater than or equal to the LLN, 15.4% had abnormal FEV 3 /FEV 6 . Compared with normal FEV 3 /FEV 6 and FEV 1 /FVC, abnormal FEV 3 /FEV 6 was associated with significantly greater gas trapping; St. George's Respiratory Questionnaire score; modified Medical Research Council dyspnea score; and BMI, airflow obstruction, dyspnea, and exercise index and with shorter 6-min walking distance (all P < .0001) but not with CT scanning evidence of emphysema. Current and ex-smokers with prebronchodilator FEV 3 /FEV 6 less than the LLN as the sole abnormality identifies a distinct population with evidence of small airways disease in quantitative CT scanning, impaired indexes of physical function and quality of life otherwise deemed normal by using the current spirometric definition. Copyright © 2016 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Technical Note: Characterization of custom 3D printed multimodality imaging phantoms.

PubMed

Bieniosek, Matthew F; Lee, Brian J; Levin, Craig S

2015-10-01

Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial "Micro Deluxe" phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom with sub-mm features. CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. This work shows that 3D printed phantoms can be functionally equivalent to commercially available phantoms. They are a viable option for quickly distributing and fabricating low cost, customized phantoms.

Radiation dose in the thyroid and the thyroid cancer risk attributable to CT scans for pediatric patients in one general hospital of China.

PubMed

Su, Yin-Ping; Niu, Hao-Wei; Chen, Jun-Bo; Fu, Ying-Hua; Xiao, Guo-Bing; Sun, Quan-Fu

2014-03-07

To quantify the radiation dose in the thyroid attributable to different CT scans and to estimate the thyroid cancer risk in pediatric patients. The information about pediatric patients who underwent CT scans was abstracted from the radiology information system in one general hospital between 1 January 2012 and 31 December 2012. The radiation doses were calculated using the ImPACT Patient Dosimetry Calculator and the lifetime attributable risk (LAR) of thyroid cancer incidence was estimated based on the National Academies Biologic Effects of Ionizing Radiation VII model. The subjects comprised 922 children, 68% were males, and received 971 CT scans. The range of typical radiation dose to the thyroid was estimated to be 0.61-0.92 mGy for paranasal sinus CT scans, 1.10-2.45 mGy for head CT scans, and 2.63-5.76 mGy for chest CT scans. The LAR of thyroid cancer were as follows: for head CT, 1.1 per 100,000 for boys and 8.7 per 100,000 for girls; for paranasal sinus CT scans, 0.4 per 100,000 for boys and 2.7 per 100,000 for girls; for chest CT scans, 2.2 per 100,000 for boys and 14.2 per 100,000 for girls. The risk of thyroid cancer was substantially higher for girls than for the boys, and from chest CT scans was higher than that from head or paransal sinus CT scans. Chest CT scans caused higher thyroid dose and the LAR of thyroid cancer incidence, compared with paransal sinus or head CT scans. Therefore, physicians should pay more attention to protect the thyroid when children underwent CT scans, especially chest CT scans.

Postpartum cortical blindness.

PubMed

Faiz, Shakeel Ahmed

2008-09-01

A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.

Attenuation-based size metric for estimating organ dose to patients undergoing tube current modulated CT exams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bostani, Maryam, E-mail: mbostani@mednet.ucla.edu; McMillan, Kyle; Lu, Peiyun

2015-02-15

Purpose: Task Group 204 introduced effective diameter (ED) as the patient size metric used to correlate size-specific-dose-estimates. However, this size metric fails to account for patient attenuation properties and has been suggested to be replaced by an attenuation-based size metric, water equivalent diameter (D{sub W}). The purpose of this study is to investigate different size metrics, effective diameter, and water equivalent diameter, in combination with regional descriptions of scanner output to establish the most appropriate size metric to be used as a predictor for organ dose in tube current modulated CT exams. Methods: 101 thoracic and 82 abdomen/pelvis scans frommore » clinically indicated CT exams were collected retrospectively from a multidetector row CT (Sensation 64, Siemens Healthcare) with Institutional Review Board approval to generate voxelized patient models. Fully irradiated organs (lung and breasts in thoracic scans and liver, kidneys, and spleen in abdominal scans) were segmented and used as tally regions in Monte Carlo simulations for reporting organ dose. Along with image data, raw projection data were collected to obtain tube current information for simulating tube current modulation scans using Monte Carlo methods. Additionally, previously described patient size metrics [ED, D{sub W}, and approximated water equivalent diameter (D{sub Wa})] were calculated for each patient and reported in three different ways: a single value averaged over the entire scan, a single value averaged over the region of interest, and a single value from a location in the middle of the scan volume. Organ doses were normalized by an appropriate mAs weighted CTDI{sub vol} to reflect regional variation of tube current. Linear regression analysis was used to evaluate the correlations between normalized organ doses and each size metric. Results: For the abdominal organs, the correlations between normalized organ dose and size metric were overall slightly higher for all three differently (global, regional, and middle slice) reported D{sub W} and D{sub Wa} than they were for ED, but the differences were not statistically significant. However, for lung dose, computed correlations using water equivalent diameter calculated in the middle of the image data (D{sub W,middle}) and averaged over the low attenuating region of lung (D{sub W,regional}) were statistically significantly higher than correlations of normalized lung dose with ED. Conclusions: To conclude, effective diameter and water equivalent diameter are very similar in abdominal regions; however, their difference becomes noticeable in lungs. Water equivalent diameter, specifically reported as a regional average and middle of scan volume, was shown to be better predictors of lung dose. Therefore, an attenuation-based size metric (water equivalent diameter) is recommended because it is more robust across different anatomic regions. Additionally, it was observed that the regional size metric reported as a single value averaged over a region of interest and the size metric calculated from a single slice/image chosen from the middle of the scan volume are highly correlated for these specific patient models and scan types.« less

Computed tomography of the anterior mediastinum in myasthemia gravis: a radiologic-pathologic correlative study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fon, G.T.; Bein, M.E.; Mancuso, A.A.

1982-01-01

Chest radiographs and computed tomographic (CT) scans of the mediastinum were correlated with pathologic findings of the thymus following thymectomy in 57 patients with myasthenia gravis. Based on the patient's age and the overall morphology of the anterior mediastinum, CT scans were assigned one of four grades in an attempt to predict thymus pathologic findings. Using this grading, 14 of 16 cases of thymoma were suspected or definitely diagnosed. One of the two cases not diagnosed on CT was a microscopic tumor. There were no false-positive diagnoses in 11 cases graded as definitely thymoma. We conclude that thymoma can bemore » sensitively diagnosed in patients older than 40 years of age. However, thymoma cannot be predicted with a high level of confidence in patients younger than 40 because of the difficulty in differentiating normal thymus or hyperplasia from thymoma. Recommendations for the use of CT in the preoperative evaluation of myasthenic patients are presented.« less

Spatial and dose–response analysis of fibrotic lung changes after stereotactic body radiation therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinogradskiy, Yevegeniy; Diot, Quentin; Kavanagh, Brian

2013-08-15

Purpose: Stereotactic body radiation therapy (SBRT) is becoming the standard of care for early stage nonoperable lung cancers. Accurate dose–response modeling is challenging for SBRT because of the decreased number of clinical toxicity events. As a surrogate for a clinical toxicity endpoint, studies have proposed to use radiographic changes in follow up computed tomography (CT) scans to evaluate lung SBRT normal tissue effects. The purpose of the current study was to use local fibrotic lung regions to spatially and dosimetrically evaluate lung changes in patients that underwent SBRT.Methods: Forty seven SBRT patients treated at our institution from 2003 to 2009more » were used for the current study. Our patient cohort had a total of 148 follow up CT scans ranging from 3 to 48 months post-therapy. Post-treatment scans were binned into intervals of 3, 6, 12, 18, 24, 30, and 36 months after the completion of treatment. Deformable image registration was used to align the follow up CT scans with the pretreatment CT and dose distribution. Areas of visible fibrotic changes were contoured. The centroid of each gross tumor volume (GTV) and contoured fibrosis volume was calculated and the fibrosis volume location and movement (magnitude and direction) relative to the GTV and 30 Gy isodose centroid were analyzed. To perform a dose–response analysis, each voxel in the fibrosis volume was sorted into 10 Gy dose bins and the average CT number value for each dose bin was calculated. Dose–response curves were generated by plotting the CT number as a function of dose bin and time posttherapy.Results: Both fibrosis and GTV centroids were concentrated in the upper third of the lung. The average radial movement of fibrosis centroids relative to the GTV centroids was 2.6 cm with movement greater than 5 cm occurring in 11% of patients. Evaluating dose–response curves revealed an overall trend of increasing CT number as a function of dose. The authors observed a CT number plateau at doses ranging from 30 to 50 Gy for the 3, 6, and 12 months posttherapy time points. There was no evident plateau for the dose–response curves generated using data from the 18, 24, 30, and 36 months posttherapy time points.Conclusions: Regions of local fibrotic lung changes in patients that underwent SBRT were evaluated spatially and dosimetrically. The authors found that the average fibrosis movement was 2.6 cm with movement greater than 5 cm possible. Evaluating dose–response curves revealed an overall trend of increasing CT number as a function of dose. Furthermore, our dose–response data also suggest that one of the possible explanations of the CT number plateau effect may be the time posttherapy of the acquired data. Understanding normal tissue dose–response is important for reducing toxicity after SBRT, especially in cases where larger tumors are treated. The methods presented in the current work build on prior quantitative studies and further enhance the understanding of normal lung dose–response after SBRT.« less

Serum metabolites associate with CT findings following TBI.

PubMed

Dickens, Alex Mountfort; Posti, Jussi P; Takala, Riikka Sk; Ala-Seppälä, Henna Maria; Mattila, Ismo; Coles, Jonathan Coles; Frantzén, Janek; Hutchinson, Peter John; Katila, Ari J; Kyllönen, Anna; Maanpää, Henna-Riikka; Newcombe, Virginia; Outtrim, Joanne; Tallus, Jussi; Carpenter, Keri; Menon, David; Hyotylainen, Tuulia; Tenovuo, Olli; Oresic, Matej

2018-06-27

There is a need to rapidly detect patients with traumatic brain injury (TBI) who require head computed tomography (CT). Given the energy crisis in the brain following TBI, we hypothesized that serum metabolomics would be a useful tool for developing a set of biomarkers to determine the need for CT and to distinguish between different types of injuries observed. Logistic regression models using metabolite data from the discovery cohort (n=144, Turku, Finland) were used to distinguish between patients with traumatic intracranial findings and negative findings on head CT. The resultant models were then tested in the validation cohort (n=66, Cambridge, UK). The levels of glial fibrillary acidic protein and ubiquitin C-terminal hydrolase-L1 were also quantified in the serum from the same patients. Despite there being significant differences in the protein biomarkers in patients with TBI, the model that determined the need for a CT scan validated poorly (AUC=0.64: Cambridge patients). However, using a combination of six metabolites (two amino acids, three sugar derivatives and one ketoacid) it was possible to discriminate patients with intracranial abnormalities on CT and patients with a normal CT (AUC=0.77 in Turku patients and AUC=0.73 in Cambridge patients). Furthermore, a combination of three metabolites could distinguish between diffuse brain injuries and mass lesions (AUC=0.87 in Turku patients and AUC=0.68 in Cambridge patients). This study identifies a set of validated serum polar metabolites, which associate with the need for a CT scan. Additionally, serum metabolites can also predict the nature of the brain injury. These metabolite markers may prevent unnecessary CT scans, thus reducing the cost of diagnostics and radiation load.

Low dose CT perfusion in acute ischemic stroke.

PubMed

Murphy, Amanda; So, Aaron; Lee, Ting-Yim; Symons, Sean; Jakubovic, Raphael; Zhang, Liying; Aviv, Richard I

2014-12-01

The purpose of this investigation is to determine if CT perfusion (CTP) measurements at low doses (LD = 20 or 50 mAs) are similar to those obtained at regular doses (RD = 100 mAs), with and without the addition of adaptive statistical iterative reconstruction (ASIR). A single-center, prospective study was performed in patients with acute ischemic stroke (n = 37; 54% male; age = 74 ± 15 years). Two CTP scans were performed on each subject: one at 100 mAs (RD) and one at either 50 or 20 mAs (LD). CTP parameters were compared between the RD and LD scans in regions of ischemia, infarction, and normal tissue. Differences were determined using a within-subjects ANOVA (p < 0.05) followed by a paired t test post hoc analysis (p < 0.01). At 50 mAs, there was no significant difference between cerebral blood flow (CBF), cerebral blood volume (CBV), or time to maximum enhancement (Tmax) values for the RD and LD scans in the ischemic, infarcted, or normal contralateral regions (p < 0.05). At 20 mAs, there were significant differences between the RD and LD scans for all parameters in the ischemic and normal tissue regions (p > 0.05). CTP-derived CBF and CBV are not different at 50 mAs compared to 100 mAs, even without the addition of ASIR. Current CTP protocols can be modified to reduce the effective dose by 50 % without altering CTP measurements.

Pitfalls and Limitations of Radionuclide Planar and Hybrid Bone Imaging.

PubMed

Agrawal, Kanhaiyalal; Marafi, Fahad; Gnanasegaran, Gopinath; Van der Wall, Hans; Fogelman, Ignac

2015-09-01

The radionuclide (99m)Tc-MDP bone scan is one of the most commonly performed nuclear medicine studies and helps in the diagnosis of different pathologies relating to the musculoskeletal system. With its increasing utility in clinical practice, it becomes more important to be aware of various limitations of this imaging modality to avoid false interpretation. It is necessary to be able to recognize various technical, radiopharmaceutical, and patient-related artifacts that can occur while carrying out a bone scan. Furthermore, several normal variations of tracer uptake may mimic pathology and should be interpreted cautiously. There is an important limitation of a bone scan in metastatic disease evaluation as the inherent mechanism of tracer uptake is not specific for tumor but primarily relies on an osteoblastic response. Thus, it is crucial to keep in mind uptake in benign lesions, which can resemble malignant pathologies. The utility of a planar bone scan in benign orthopedic diseases, especially at sites with complex anatomy, is limited owing to lack of precise anatomical information. SPECT/CT has been significantly helpful in these cases. With wider use of PET/CT and reintroduction of the (18)F-fluoride bone scan, increasing knowledge of potential pitfalls on an (18)F-fluoride bone scan and (18)F-FDG-PET/CT will help in improving the accuracy of clinical reports. Copyright © 2015 Elsevier Inc. All rights reserved.

The Impact of Sources of Variability on Parametric Response Mapping of Lung CT Scans

PubMed Central

Boes, Jennifer L.; Bule, Maria; Hoff, Benjamin A.; Chamberlain, Ryan; Lynch, David A.; Stojanovska, Jadranka; Martinez, Fernando J.; Han, Meilan K.; Kazerooni, Ella A.; Ross, Brian D.; Galbán, Craig J.

2015-01-01

Parametric response mapping (PRM) of inspiration and expiration computed tomography (CT) images improves the radiological phenotyping of chronic obstructive pulmonary disease (COPD). PRM classifies individual voxels of lung parenchyma as normal, emphysematous, or nonemphysematous air trapping. In this study, bias and noise characteristics of the PRM methodology to CT and clinical procedures were evaluated to determine best practices for this quantitative technique. Twenty patients of varying COPD status with paired volumetric inspiration and expiration CT scans of the lungs were identified from the baseline COPD-Gene cohort. The impact of CT scanner manufacturer and reconstruction kernels were evaluated as potential sources of variability in PRM measurements along with simulations to quantify the impact of inspiration/expiration lung volume levels, misregistration, and image spacing on PRM measurements. Negligible variation in PRM metrics was observed when CT scanner type and reconstruction were consistent and inspiration/expiration lung volume levels were near target volumes. CT scanner Hounsfield unit drift occurred but remained difficult to ameliorate. Increasing levels of image misregistration and CT slice spacing were found to have a minor effect on PRM measurements. PRM-derived values were found to be most sensitive to lung volume levels and mismatched reconstruction kernels. As with other quantitative imaging techniques, reliable PRM measurements are attainable when consistent clinical and CT protocols are implemented. PMID:26568983

WE-AB-BRA-11: Improved Imaging of Permanent Prostate Brachytherapy Seed Implants by Combining an Endorectal X-Ray Sensor with a CT Scanner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiner, J; Matthews, K; Jia, G

Purpose: To test feasibility of the use of a digital endorectal x-ray sensor for improved image resolution of permanent brachytherapy seed implants compared to conventional CT. Methods: Two phantoms simulating the male pelvic region were used to test the capabilities of a digital endorectal x-ray sensor for imaging permanent brachytherapy seed implants. Phantom 1 was constructed from acrylic plastic with cavities milled in the locations of the prostate and the rectum. The prostate cavity was filled a Styrofoam plug implanted with 10 training seeds. Phantom 2 was constructed from tissue-equivalent gelatins and contained a prostate phantom implanted with 18 strandsmore » of training seeds. For both phantoms, an intraoral digital dental x-ray sensor was placed in the rectum within 2 cm of the seed implants. Scout scans were taken of the phantoms over a limited arc angle using a CT scanner (80 kV, 120–200 mA). The dental sensor was removed from the phantoms and normal helical CT and scout (0 degree) scans using typical parameters for pelvic CT (120 kV, auto-mA) were collected. A shift-and add tomosynthesis algorithm was developed to localize seed plane location normal to detector face. Results: The endorectal sensor produced images with improved resolution compared to CT scans. Seed clusters and individual seed geometry were more discernable using the endorectal sensor. Seed 3D locations, including seeds that were not located in every projection image, were discernable using the shift and add algorithm. Conclusion: This work shows that digital endorectal x-ray sensors are a feasible method for improving imaging of permanent brachytherapy seed implants. Future work will consist of optimizing the tomosynthesis technique to produce higher resolution, lower dose images of 1) permanent brachytherapy seed implants for post-implant dosimetry and 2) fine anatomic details for imaging and managing prostatic disease compared to CT images. Funding: LSU Faculty Start-up Funding. Disclosure: XDR Radiography has loaned our research group the digital x-ray detector used in this work. CoI: None.« less

Acute computed tomography findings in patients with acute confusion of non-traumatic aetiology.

PubMed

West, W M; Ali, A; West, K P; Stultz, R

2011-10-01

A retrospective review was undertaken of all patients referred for computed tomography (CT) scans of the head for acute onset of confusion, not consequent on head trauma, during the period June 1, 2004 to May 31, 2007. Data were obtained by Microsoft Word search of the reports of the Radiology Department of the University Hospital of the West Indies, Kingston, Jamaica. Two hundred and twenty-one patients were reviewed: 103 men and 118 women. The mean age of the sample was 64 years; 168 patients (76%) were 50 years old or older. Computed tomography scans were reported normal in 170 (76.9%) patients; 45 patients (20.4%) had definite acute intracranial CT findings. Findings were equivocal in three patients (1.4%) and unavailable for three (1.4%); 23.2% and 15.6% of patients above and below the age of 50 years respectively showed acute abnormalities on CT The most common acute finding on CT scan was an ischaemic infarct (68%). Other abnormalities included intracerebral haemorrhage and metastases 6.2% each, toxoplasmosis and primary brain tumour 4.2% each and subdural haematoma and meningitis 2.1% each. The diagnoses of toxoplasmosis were made based on appearances typical of toxoplasmosis on CT scans in patients whose request stated that they were HIV positive. In the sample reviewed, most patients who presented with acute confusion were above the age of 50 years. Overall, 20.4% of patients from all age groups had acute abnormalities on CT with a relative higher proportion, 23.2% versus 15.6% of those over 50 years, having acute pathology. The most common abnormality was an ischaemic infarct. This finding is similar to that in developed countries and unlike that seen in other developing countries where infectious aetiologies predominate.

Radiation Dose in the Thyroid and the Thyroid Cancer Risk Attributable to CT Scans for Pediatric Patients in One General Hospital of China

PubMed Central

Su, Yin-Ping; Niu, Hao-Wei; Chen, Jun-Bo; Fu, Ying-Hua; Xiao, Guo-Bing; Sun, Quan-Fu

2014-01-01

Objective: To quantify the radiation dose in the thyroid attributable to different CT scans and to estimate the thyroid cancer risk in pediatric patients. Methods: The information about pediatric patients who underwent CT scans was abstracted from the radiology information system in one general hospital between 1 January 2012 and 31 December 2012. The radiation doses were calculated using the ImPACT Patient Dosimetry Calculator and the lifetime attributable risk (LAR) of thyroid cancer incidence was estimated based on the National Academies Biologic Effects of Ionizing Radiation VII model. Results: The subjects comprised 922 children, 68% were males, and received 971 CT scans. The range of typical radiation dose to the thyroid was estimated to be 0.61–0.92 mGy for paranasal sinus CT scans, 1.10–2.45 mGy for head CT scans, and 2.63–5.76 mGy for chest CT scans. The LAR of thyroid cancer were as follows: for head CT, 1.1 per 100,000 for boys and 8.7 per 100,000 for girls; for paranasal sinus CT scans, 0.4 per 100,000 for boys and 2.7 per 100,000 for girls; for chest CT scans, 2.1 per 100,000 for boys and 14.1 per 100,000 for girls. The risk of thyroid cancer was substantially higher for girls than for the boys, and from chest CT scans was higher than that from head or paransal sinus CT scans. Conclusions: Chest CT scans caused higher thyroid dose and the LAR of thyroid cancer incidence, compared with paransal sinus or head CT scans. Therefore, physicians should pay more attention to protect the thyroid when children underwent CT scans, especially chest CT scans. PMID:24608902

The feasibility of a regional CTDI{sub vol} to estimate organ dose from tube current modulated CT exams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khatonabadi, Maryam; Kim, Hyun J.; Lu, Peiyun

Purpose: In AAPM Task Group 204, the size-specific dose estimate (SSDE) was developed by providing size adjustment factors which are applied to the Computed Tomography (CT) standardized dose metric, CTDI{sub vol}. However, that work focused on fixed tube current scans and did not specifically address tube current modulation (TCM) scans, which are currently the majority of clinical scans performed. The purpose of this study was to extend the SSDE concept to account for TCM by investigating the feasibility of using anatomic and organ specific regions of scanner output to improve accuracy of dose estimates. Methods: Thirty-nine adult abdomen/pelvis and 32more » chest scans from clinically indicated CT exams acquired on a multidetector CT using TCM were obtained with Institutional Review Board approval for generating voxelized models. Along with image data, raw projection data were obtained to extract TCM functions for use in Monte Carlo simulations. Patient size was calculated using the effective diameter described in TG 204. In addition, the scanner-reported CTDI{sub vol} (CTDI{sub vol,global}) was obtained for each patient, which is based on the average tube current across the entire scan. For the abdomen/pelvis scans, liver, spleen, and kidneys were manually segmented from the patient datasets; for the chest scans, lungs and for female models only, glandular breast tissue were segmented. For each patient organ doses were estimated using Monte Carlo Methods. To investigate the utility of regional measures of scanner output, regional and organ anatomic boundaries were identified from image data and used to calculate regional and organ-specific average tube current values. From these regional and organ-specific averages, CTDI{sub vol} values, referred to as regional and organ-specific CTDI{sub vol}, were calculated for each patient. Using an approach similar to TG 204, all CTDI{sub vol} values were used to normalize simulated organ doses; and the ability of each normalized dose to correlate with patient size was investigated. Results: For all five organs, the correlations with patient size increased when organ doses were normalized by regional and organ-specific CTDI{sub vol} values. For example, when estimating dose to the liver, CTDI{sub vol,global} yielded a R{sup 2} value of 0.26, which improved to 0.77 and 0.86, when using the regional and organ-specific CTDI{sub vol} for abdomen and liver, respectively. For breast dose, the global CTDI{sub vol} yielded a R{sup 2} value of 0.08, which improved to 0.58 and 0.83, when using the regional and organ-specific CTDI{sub vol} for chest and breasts, respectively. The R{sup 2} values also increased once the thoracic models were separated for the analysis into females and males, indicating differences between genders in this region not explained by a simple measure of effective diameter. Conclusions: This work demonstrated the utility of regional and organ-specific CTDI{sub vol} as normalization factors when using TCM. It was demonstrated that CTDI{sub vol,global} is not an effective normalization factor in TCM exams where attenuation (and therefore tube current) varies considerably throughout the scan, such as abdomen/pelvis and even thorax. These exams can be more accurately assessed for dose using regional CTDI{sub vol} descriptors that account for local variations in scanner output present when TCM is employed.« less

Computed tomographic findings in 44 dogs and 10 cats with grass seed foreign bodies.

PubMed

Vansteenkiste, D P; Lee, K C L; Lamb, C R

2014-11-01

To supplement recent reports of computed tomographic (CT) findings in dogs and cats with grass seed foreign bodies. Retrospective review of cases that had CT scan and subsequent retrieval of a grass seed during the same period of hospitalisation from a site included in the scan. Records of 44 dogs and 10 cats were reviewed. Most were presented in the months July to December. Median duration of clinical signs was 4 weeks (range 2 days to 2 years). The most frequent clinical signs were soft tissue swelling (30% cases), coughing (28%), sneezing (28%) and discharge (26%). Grass seeds were retrieved from the thorax (35% cases), nasal cavity (31%), ear (7%), other sites in the head and neck (22%), sublumbar muscles (2%) and pelvic limb (2%). The grass seed was visible in CT images in 10 (19%) cases. Secondary lesions were visible in CT images of 52 (96%) cases, including collection of exudate (37%), abscess (24%), enlarged lymph nodes (22%) and pulmonary consolidation (20%). CT images appeared normal in 4% animals. Grass seeds within the respiratory tract are frequently visible in CT images, but in general CT appears to be more useful for localisation of secondary lesions than as a method of definite diagnosis. © 2014 British Small Animal Veterinary Association.

Computed tomography is not justified in every pediatric blunt trauma patient with a suspicious mechanism of injury.

PubMed

Hershkovitz, Yehuda; Zoarets, Itai; Stepansky, Albert; Kozer, Eran; Shapira, Zahar; Klin, Baruch; Halevy, Ariel; Jeroukhimov, Igor

2014-07-01

Computed tomography (CT) has become an important tool for the diagnosis of intra-abdominal and chest injuries in patients with blunt trauma. The role of CT in conscious asymptomatic patients with a suspicious mechanism of injury remains controversial. This controversy intensifies in the management of pediatric blunt trauma patients, who are much more susceptible to radiation exposure. The objective of this study was to evaluate the role of abdominal and chest CT imaging in asymptomatic pediatric patients with a suspicious mechanism of injury. Forty-two pediatric patients up to 15 years old were prospectively enrolled. All patients presented with a suspicious mechanism of blunt trauma and multisystem injury. They were neurologically intact and had no signs of injury to the abdomen or chest. Patients underwent CT imaging of the chest and abdomen as part of the initial evaluation. Thirty-one patients (74%) had a normal CT scan. Two patients of 11 with an abnormal CT scan required a change in management and were referred for observation in the Intensive Care Unit. None of the patients required surgical intervention. The routine use of CT in asymptomatic pediatric patients with a suspicious mechanism of blunt trauma injury is not justified. Copyright © 2014 Elsevier Inc. All rights reserved.

An optimal set of landmarks for metopic craniosynostosis diagnosis from shape analysis of pediatric CT scans of the head

NASA Astrophysics Data System (ADS)

Mendoza, Carlos S.; Safdar, Nabile; Myers, Emmarie; Kittisarapong, Tanakorn; Rogers, Gary F.; Linguraru, Marius George

2013-02-01

Craniosynostosis (premature fusion of skull sutures) is a severe condition present in one of every 2000 newborns. Metopic craniosynostosis, accounting for 20-27% of cases, is diagnosed qualitatively in terms of skull shape abnormality, a subjective call of the surgeon. In this paper we introduce a new quantitative diagnostic feature for metopic craniosynostosis derived optimally from shape analysis of CT scans of the skull. We built a robust shape analysis pipeline that is capable of obtaining local shape differences in comparison to normal anatomy. Spatial normalization using 7-degree-of-freedom registration of the base of the skull is followed by a novel bone labeling strategy based on graph-cuts according to labeling priors. The statistical shape model built from 94 normal subjects allows matching a patient's anatomy to its most similar normal subject. Subsequently, the computation of local malformations from a normal subject allows characterization of the points of maximum malformation on each of the frontal bones adjacent to the metopic suture, and on the suture itself. Our results show that the malformations at these locations vary significantly (p<0.001) between abnormal/normal subjects and that an accurate diagnosis can be achieved using linear regression from these automatic measurements with an area under the curve for the receiver operating characteristic of 0.97.

SU-C-BRA-04: Use of Esophageal Wall Thickness in Evaluation of the Response to Chemoradiation Therapy for Esophageal Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J; Kligerman, S; Lu, W

2015-06-15

Purpose: To quantitatively evaluate the esophageal cancer response to chemoradiation therapy (CRT) by measuring the esophageal wall thickness in CT. Method: Two datasets were used in this study. The first dataset is composed of CT scans of 15 esophageal cancer patients and 15 normal controls. The second dataset is composed of 20 esophageal cancer patients who underwent PET/CT scans before (Pre-CRT) and after CRT (Post-CRT). We first segmented the esophagus using a multi-atlas-based algorithm. The esophageal wall thickness was then computed, on each slice, as the equivalent circle radius of the segmented esophagus excluding the lumen. To evaluate the changesmore » of wall thickness, we computed the standard deviation (SD), coefficient of variation (COV, SD/Mean), and flatness [(Max–Min)/Mean] of wall thickness along the entire esophagus. Results: For the first dataset, the mean wall thickness of cancer patients and normal controls were 6.35 mm and 6.03 mm, respectively. The mean SD, COV, and flatness of the wall thickness were 2.59, 0.21, and 1.27 for the cancer patients and 1.99, 0.16, and 1.13 for normal controls. Statistically significant differences (p < 0.05) were identified in SD and flatness. For the second dataset, the mean wall thickness of pre-CRT and post-CRT patients was 7.13 mm and 6.84 mm, respectively. The mean SD, COV, and flatness were 1.81, 0.26, and 1.06 for pre-CRT and 1.69, 0.26, and 1.06 for post-CRT. Statistically significant difference was not identified for these measurements. Current results are based on the entire esophagus. We believe significant differences between pre- and post-CRT scans could be obtained, if we conduct the measurements at tumor sites. Conclusion: Results show thicker wall thickness in pre-CRT scans and differences in wall thickness changes between normal and abnormal esophagus. This demonstrated the potential of esophageal wall thickness as a marker in the tumor CRT response evaluation. This work was supported in part by the National Cancer Institute Grant R01CA172638.« less

Abdominal CT scan

MedlinePlus

Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... An abdominal CT scan makes detailed pictures of the structures inside your belly very quickly. This test may be used to look ...

Cervical spine CT scan

MedlinePlus

... cervical spine; Computed tomography scan of cervical spine; CT scan of cervical spine; Neck CT scan ... table that slides into the center of the CT scanner. Once you are inside the scanner, the ...

Anatomic changes of target vessels after fenestrated and branched aortic aneurysm repair.

PubMed

Kalder, J; Keschenau, P; Tamm, M; Jalaie, H; Jacobs, M J; Greiner, A

2014-04-01

Objective of this study was to evaluate the anatomic changes of the stented target vessels after endovascular repair of complex aortic aneurysms. Between July 2011 and December 2013, 53 aortic aneurysms were treated in our department with fenestrated and branched stent-graft devices. Forty-two of these patients were pre- and postoperatively scanned with a high resolution computer tomography (CT) (Cook Zenith® fenestrated or branched, Australia Pty. Ltd., Brisbane, Australia: N.=19; AnacondaTM fenestrated, Vascutek, Glasgow, Scotland, UK: N.=23). The other 11 out of the 53 patients did not receive a CT scan, because of a pre-existing renal failure. In the CT scans we retrospectively evaluated the anatomic vessel deviation at the origin of the target vessel and the vessel shift distal to the stent. For the first measurement the CT scans were loaded into OsiriX MD®, and the pre- and postoperative angles of the target vessels were measured and subtracted. For matching, the CT-scans were normalized at vertebral body lumbar 2. The second measured angle was the maximal measured angle distal to the target vessel stent-graft. Altogether, 113 target vessels were stented (celiac trunk [CT] 15, superior mesenteric arteries [SMA] 26, renal arteries [RA] 72), with 97 balloon-expandable PTFE stents: 90 Atrium V12 (Maquet Getinge group, Hudson, NH, USA), 7 BeGrafts (Bentley InnoMed, Hechingen, Germany) and 16 self-expandable fluency PTFE stents (Bard, Karlsruhe, Germany). The mean anatomic deviation at the target vessel origin was 28±17.3 and the mean vessel shift distal to the stent was 36.3±18.8. There were no significant differences between the main device and the target vessel stent types. Fenestrated and branched stent-graft solutions for aortic aneurysm repair induce changes of the target vessel anatomy. We did not observe significant differences between the several devices.

PET/CT-guided treatment planning for paediatric cancer patients: a simulation study of proton and conventional photon therapy

PubMed Central

Brodin, N P; Björk-Eriksson, T; Birk Christensen, C; Kiil-Berthelsen, A; Aznar, M C; Hollensen, C; Markova, E; Munck af Rosenschöld, P

2015-01-01

Objective: To investigate the impact of including fluorine-18 fludeoxyglucose (18F-FDG) positron emission tomography (PET) scanning in the planning of paediatric radiotherapy (RT). Methods: Target volumes were first delineated without and subsequently re-delineated with access to 18F-FDG PET scan information, on duplicate CT sets. RT plans were generated for three-dimensional conformal photon RT (3DCRT) and intensity-modulated proton therapy (IMPT). The results were evaluated by comparison of target volumes, target dose coverage parameters, normal tissue complication probability (NTCP) and estimated risk of secondary cancer (SC). Results: Considerable deviations between CT- and PET/CT-guided target volumes were seen in 3 out of the 11 patients studied. However, averaging over the whole cohort, CT or PET/CT guidance introduced no significant difference in the shape or size of the target volumes, target dose coverage, irradiated volumes, estimated NTCP or SC risk, neither for IMPT nor 3DCRT. Conclusion: Our results imply that the inclusion of PET/CT scans in the RT planning process could have considerable impact for individual patients. There were no general trends of increasing or decreasing irradiated volumes, suggesting that the long-term morbidity of RT in childhood would on average remain largely unaffected. Advances in knowledge: 18F-FDG PET-based RT planning does not systematically change NTCP or SC risk for paediatric cancer patients compared with CT only. 3 out of 11 patients had a distinct change of target volumes when PET-guided planning was introduced. Dice and mismatch metrics are not sufficient to assess the consequences of target volume differences in the context of RT. PMID:25494657

Phantom-based standardization of CT angiography images for spot sign detection.

PubMed

Morotti, Andrea; Romero, Javier M; Jessel, Michael J; Hernandez, Andrew M; Vashkevich, Anastasia; Schwab, Kristin; Burns, Joseph D; Shah, Qaisar A; Bergman, Thomas A; Suri, M Fareed K; Ezzeddine, Mustapha; Kirmani, Jawad F; Agarwal, Sachin; Shapshak, Angela Hays; Messe, Steven R; Venkatasubramanian, Chitra; Palmieri, Katherine; Lewandowski, Christopher; Chang, Tiffany R; Chang, Ira; Rose, David Z; Smith, Wade; Hsu, Chung Y; Liu, Chun-Lin; Lien, Li-Ming; Hsiao, Chen-Yu; Iwama, Toru; Afzal, Mohammad Rauf; Cassarly, Christy; Greenberg, Steven M; Martin, Renee' Hebert; Qureshi, Adnan I; Rosand, Jonathan; Boone, John M; Goldstein, Joshua N

2017-09-01

The CT angiography (CTA) spot sign is a strong predictor of hematoma expansion in intracerebral hemorrhage (ICH). However, CTA parameters vary widely across centers and may negatively impact spot sign accuracy in predicting ICH expansion. We developed a CT iodine calibration phantom that was scanned at different institutions in a large multicenter ICH clinical trial to determine the effect of image standardization on spot sign detection and performance. A custom phantom containing known concentrations of iodine was designed and scanned using the stroke CT protocol at each institution. Custom software was developed to read the CT volume datasets and calculate the Hounsfield unit as a function of iodine concentration for each phantom scan. CTA images obtained within 8 h from symptom onset were analyzed by two trained readers comparing the calibrated vs. uncalibrated density cutoffs for spot sign identification. ICH expansion was defined as hematoma volume growth >33%. A total of 90 subjects qualified for the study, of whom 17/83 (20.5%) experienced ICH expansion. The number of spot sign positive scans was higher in the calibrated analysis (67.8 vs 38.9% p < 0.001). All spot signs identified in the non-calibrated analysis remained positive after calibration. Calibrated CTA images had higher sensitivity for ICH expansion (76 vs 52%) but inferior specificity (35 vs 63%) compared with uncalibrated images. Normalization of CTA images using phantom data is a feasible strategy to obtain consistent image quantification for spot sign analysis across different sites and may improve sensitivity for identification of ICH expansion.

Shunting normal pressure hydrocephalus: the predictive value of combined clinical and CT data.

PubMed

Vanneste, J; Augustijn, P; Tan, W F; Dirven, C

1993-03-01

The value of an ordinal global scale derived from combined clinical and CT data (clin/CT scale) to predict the clinical outcome in 112 patients shunted for presumed normal pressure hydrocephalus (NPH) was analysed. The clinical data were retrospectively collected, all CT scans were re-evaluated, and the clin/CT scale was determined blind to the results of further ancillary tests and to the post-surgical outcome. The scale ranked three classes of prediction: on the basis of clinical and CT characteristics, improvement after shunting was probable, possible, or improbable. The predictive value of the clin/CT scale for the subgroup of communicating NPH was established for two different strategies, depending on the strictness of selection criteria for shunting. In the subgroup of patients with presumed communicating NPH, the prevalence of shunt responsiveness was 29%; the best strategy was to shunt only patients with probable shunt-responsive NPH: the sensitivity was 0.54, the specificity 0.84, and the predictive accuracy 0.75, with a limited number of ineffective shunts (11%) and missed improvements (13%). The study illustrates its need to assess the pre-test probability of NPH based on combined clinical and CT data, before establishing the clinical usefulness of an ancillary test.

Shunting normal pressure hydrocephalus: the predictive value of combined clinical and CT data.

PubMed Central

Vanneste, J; Augustijn, P; Tan, W F; Dirven, C

1993-01-01

The value of an ordinal global scale derived from combined clinical and CT data (clin/CT scale) to predict the clinical outcome in 112 patients shunted for presumed normal pressure hydrocephalus (NPH) was analysed. The clinical data were retrospectively collected, all CT scans were re-evaluated, and the clin/CT scale was determined blind to the results of further ancillary tests and to the post-surgical outcome. The scale ranked three classes of prediction: on the basis of clinical and CT characteristics, improvement after shunting was probable, possible, or improbable. The predictive value of the clin/CT scale for the subgroup of communicating NPH was established for two different strategies, depending on the strictness of selection criteria for shunting. In the subgroup of patients with presumed communicating NPH, the prevalence of shunt responsiveness was 29%; the best strategy was to shunt only patients with probable shunt-responsive NPH: the sensitivity was 0.54, the specificity 0.84, and the predictive accuracy 0.75, with a limited number of ineffective shunts (11%) and missed improvements (13%). The study illustrates its need to assess the pre-test probability of NPH based on combined clinical and CT data, before establishing the clinical usefulness of an ancillary test. PMID:8459240

Leg CT scan

MedlinePlus

CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... CT scan makes detailed pictures of the body very quickly. The test may help look for: An abscess ...

Arm CT scan

MedlinePlus

CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Healing problems or scar tissue following surgery A CT scan may also be used to guide a surgeon ...

Are facilities following best practices of pediatric abdominal CT scans?

PubMed

Nosek, Amy E; Hartin, Charles W; Bass, Kathryn D; Glick, Philip L; Caty, Michael G; Dayton, Merril T; Ozgediz, Doruk E

2013-05-01

Established guidelines for pediatric abdominal CT scans include reduced radiation dosage to minimize cancer risk and the use of intravenous (IV) contrast to obtain the highest-quality diagnostic images. We wish to determine if these practices are being used at nonpediatric facilities that transfer children to a pediatric facility. Children transferred to a tertiary pediatric facility over a 16-mo period with abdominal CT scans performed for evaluation of possible appendicitis were retrospectively reviewed for demographics, diagnosis, radiation dosage, CT contrast use, and scan quality. If CT scans were repeated, the radiation dosage between facilities was compared using Student t-test. Ninety-one consecutive children transferred from 29 different facilities had retrievable CT scan images and clinical information. Half of CT scans from transferring institutions used IV contrast. Due to poor quality or inconclusive CT scans, 19 patients required a change in management. Children received significantly less radiation at our institution compared to the referring adult facility for the same body area scanned on the same child (9.7 mSv versus 19.9 mSv, P = 0.0079). Pediatric facilities may be using less radiation per CT scan due to a heightened awareness of radiation risks and specific pediatric CT scanning protocols. The benefits of IV contrast for the diagnostic yield of pediatric CT scans should be considered to obtain the best possible image and to prevent additional imaging. Every facility performing pediatric CT scans should minimize radiation exposure, and pediatric facilities should provide feedback and education to other facilities scanning children. Copyright © 2013 Elsevier Inc. All rights reserved.

Childhood Psychosis and Computed Tomographic Brain Scan Findings.

ERIC Educational Resources Information Center

Gillberg, Christopher; Svendsen, Pal

1983-01-01

Computerized tomography (CT) of the brain was used to examine 27 infantile autistic children, 9 children with other kinds of childhood psychoses, 23 children with mental retardation, and 16 normal children. Gross abnormalities were seen in 26 percent of the autism cases. (Author/SEW)

Effects of hyperglycemia on fluorine-18-fluorodeoxyglucose biodistribution in a large oncology clinical practice.

PubMed

Rosica, Dillenia; Cheng, Su-Chun; Hudson, Margo; Sakellis, Christopher; Van den Abbeele, Annick D; Kim, Chun K; Jacene, Heather A

2018-05-01

Suggested cutoff points of blood glucose levels (BGL) before F-FDG PET/CT scanning vary between 120 and 200 mg/dl in current guidelines. This study's purpose was to compare the frequency of abnormal fluorine-18-fluorodeoxyglucose (F-FDG) biodistribution on PET/CT scans of patients with various ranges of abnormal BGL and to determine the effect of BGL greater than 200 mg/dl on F-FDG uptake in various organs. F-FDG PET/CT scans were retrospectively reviewed for 325 patients with BGL greater than 120 mg/dl at the time of scan and 112 with BGL less than or equal to 120 mg/dl. F-FDG biodistribution was categorized as normal, mildly abnormal, or abnormal by visual analysis of brain, background soft tissue, and muscle. Mean standardized uptake values (SUVmean) in brain, liver, fat (flank), gluteal muscle, and blood pool (aorta) were recorded. F-FDG biodistribution frequencies were assessed using a nonparametric χ-test for trend. Normal organ SUVs were compared using Kruskal-Wallis tests using the following BGL groupings: ≤120, 121-150, 151-200, and ≥201 mg/dl. Although higher BGL were significantly associated with an increased proportion of abnormal biodistribution (P<0.001), most patients with BGL less than or equal to 200 mg/dl had normal or mildly abnormal biodistribution. Average brain SUVmean significantly decreased with higher BGL groupings (P<0.001). Average aorta, gluteal muscle, and liver SUVmean did not significantly differ among groups with BGL greater than 120 mg/dl (P=0.66, 0.84, and 0.39, respectively), but were significantly lower in those with BGL less than or equal to 120 mg/dl (P≤0.001). Flank fat SUVmean was not significantly different among BGL groups (P=0.67). Abnormal F-FDG biodistribution is associated with higher BGL at the time of scan, but the effects are negligible or mild in most patients with BGL less than 200 mg/dl. Although mildly increased soft tissue uptake is seen with BGL greater than 120 mg/dl, decline in brain metabolic activity correlated the most with various BGL.

Effect of foot shape on the three-dimensional position of foot bones.

PubMed

Ledoux, William R; Rohr, Eric S; Ching, Randal P; Sangeorzan, Bruce J

2006-12-01

To eliminate some of the ambiguity in describing foot shape, we developed three-dimensional (3D), objective measures of foot type based on computerized tomography (CT) scans. Feet were classified via clinical examination as pes cavus (high arch), neutrally aligned (normal arch), asymptomatic pes planus (flat arch with no pain), or symptomatic pes planus (flat arch with pain). We enrolled 10 subjects of each foot type; if both feet were of the same foot type, then each foot was scanned (n=65 total). Partial weightbearing (20% body weight) CT scans were performed. We generated embedded coordinate systems for each foot bone by assuming uniform density and calculating the inertial matrix. Cardan angles were used to describe five bone-to-bone relationships, resulting in 15 angular measurements. Significant differences were found among foot types for 12 of the angles. The angles were also used to develop a classification tree analysis, which determined the correct foot type for 64 of the 65 feet. Our measure provides insight into how foot bone architecture differs between foot types. The classification tree analysis demonstrated that objective measures can be used to discriminate between feet with high, normal, and low arches. Copyright (c) 2006 Orthopaedic Research Society.

FDG-PET/CT in the evaluation of anal carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cotter, Shane E.; Medical Scientist Training Program, Washington University School of Medicine, St. Louis, MO; Grigsby, Perry W.

2006-07-01

Purpose: Surgical staging and treatment of anal carcinoma has been replaced by noninvasive staging studies and combined modality therapy. In this study, we compare computed tomography (CT) and physical examination to [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the staging of carcinoma of the anal canal, with special emphasis on determination of spread to inguinal lymph nodes. Methods and Materials: Between July 2003 and July 2005, 41 consecutive patients with biopsy-proved anal carcinoma underwent a complete staging evaluation including physical examination, CT, and 2-FDG-PET/CT. Patients ranged in age from 30 to 89 years. Nine men were HIV-positive. Treatment was withmore » standard Nigro regimen. Results: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) detected 91% of nonexcised primary tumors, whereas CT visualized 59%. FDG-PET/CT detected abnormal uptake in pelvic nodes of 5 patients with normal pelvic CT scans. FDG-PET/CT detected abnormal nodes in 20% of groins that were normal by CT, and in 23% without abnormality on physical examination. Furthermore, 17% of groins negative by both CT and physical examination showed abnormal uptake on FDG-PET/CT. HIV-positive patients had an increased frequency of PET-positive lymph nodes. Conclusion: [{sup 18}F]-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography detects the primary tumor more often than CT. FDG-PET/CT detects substantially more abnormal inguinal lymph nodes than are identified by standard clinical staging with CT and physical examination.« less

Accuracy of limited four-slice CT-scan in diagnosis of chronic rhinosinusitis.

PubMed

Zojaji, R; Nekooei, S; Naghibi, S; Mazloum Farsi Baf, M; Jalilian, R; Masoomi, M

2015-12-01

Chronic rhinosinusitis (CRS) is a common chronic health condition worldwide. Standard CT-scan is the method of choice for diagnosis of CRS but its high price and considerable radiation exposure have limited its application. The main goal of this study was to evaluate the accuracy of limited four-slice coronal CT-scan in the diagnosis of CRS. This cross-sectional study was conducted on 46 patients with CRS, for one year, based on American Society of Head and Neck Surgery criteria. All patients received the preoperative standard and four-slice CT-scans, after which endoscopic sinus surgery was performed. Findings of four-slice CT-scans were compared with those of conventional CT-scan and the sensitivity and specificity of four-slice CT-scan and its agreement with conventional CT-scan was calculated. In this study, 46 patients including 32 males (69.6%) and 14 females (30.46%) with a mean age of 33 and standard deviation of 9 years, were evaluated. Sensitivity and specificity of four-slice CT-scan were 97.5% and 100%, respectively. Also, positive predictive value (PPV) and negative predictive value (NPV) of four-slice CT was 100% and 85.71%, respectively. There was a strong agreement between four-slice CT and conventional CT findings. Considering the high sensitivity and specificity of four-slice CT-scan and strong agreement with conventional CT-scan in the diagnosis of CRS and the lower radiation exposure and cost, application of this method is suggested for both diagnosis and treatment follow-up in CRS. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Body CT (CAT Scan)

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses ... of CT Scanning of the Body? What is CT Scanning of the Body? Computed tomography, more commonly ...

Conventional 3D staging PET/CT in CT simulation for lung cancer: impact of rigid and deformable target volume alignments for radiotherapy treatment planning.

PubMed

Hanna, G G; Van Sörnsen De Koste, J R; Carson, K J; O'Sullivan, J M; Hounsell, A R; Senan, S

2011-10-01

Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans. 10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTV(CT)) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice's similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan. When the GTV(CT) delineated on the staging scan after both rigid registration and deformation was compared with the GTV(CT)on the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p = 0.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration. No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.

Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: a digital phantom study.

PubMed

Bernatowicz, K; Keall, P; Mishra, P; Knopf, A; Lomax, A; Kipritidis, J

2015-01-01

Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CT can significantly reduce lung imaging artifacts. Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) "conventional" 4D CT that uses a constant imaging and couch-shift frequency, (ii) "beam paused" 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) "respiratory-gated" 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm(3) spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Averaged across all simulations and phase bins, respiratory-gating reduced overall thoracic MSE by 46% compared to conventional 4D CT (p ∼ 10(-19)). Gating leads to small but significant (p < 0.02) reductions in lung volume errors (1.8%-1.4%), false positives (4.0%-2.6%), and false negatives (2.7%-1.3%). These percentage reductions correspond to gating reducing image artifacts by 24-90 cm(3) of lung tissue. Similar to earlier studies, gating reduced patient image dose by up to 22%, but with scan time increased by up to 135%. Beam paused 4D CT did not significantly impact normal lung tissue image quality, but did yield similar dose reductions as for respiratory-gating, without the added cost in scanning time. For a typical 6 L lung, respiratory-gated 4D CT can reduce image artifacts affecting up to 90 cm(3) of normal lung tissue compared to conventional acquisition. This image improvement could have important implications for dose calculations based on 4D CT. Where image quality is less critical, beam paused 4D CT is a simple strategy to reduce imaging dose without sacrificing acquisition time.

Low-dose head computed tomography in children: a single institutional experience in pediatric radiation risk reduction: clinical article.

PubMed

Morton, Ryan P; Reynolds, Renee M; Ramakrishna, Rohan; Levitt, Michael R; Hopper, Richard A; Lee, Amy; Browd, Samuel R

2013-10-01

In this study, the authors describe their experience with a low-dose head CT protocol for a preselected neurosurgical population at a dedicated pediatric hospital (Seattle Children's Hospital), the largest number of patients with this protocol reported to date. All low-dose head CT scans between October 2011 and November 2012 were reviewed. Two different low-dose radiation dosages were used, at one-half or one-quarter the dose of a standard head CT scan, based on patient characteristics agreed upon by the neurosurgery and radiology departments. Patient information was also recorded, including diagnosis and indication for CT scan. Six hundred twenty-four low-dose head CT procedures were performed within the 12-month study period. Although indications for the CT scans varied, the most common reason was to evaluate the ventricles and catheter placement in hydrocephalic patients with shunts (70%), followed by postoperative craniosynostosis imaging (12%). These scans provided adequate diagnostic imaging, and no patient required a follow-up full-dose CT scan as a result of poor image quality on a low-dose CT scan. Overall physician comfort and satisfaction with interpretation of the images was high. An additional 2150 full-dose head CT scans were performed during the same 12-month time period, making the total number of CT scans 2774. This value compares to 3730 full-dose head CT scans obtained during the year prior to the study when low-dose CT and rapid-sequence MRI was not a reliable option at Seattle Children's Hospital. Thus, over a 1-year period, 22% of the total CT scans were able to be converted to low-dose scans, and full-dose CT scans were able to be reduced by 42%. The implementation of a low-dose head CT protocol substantially reduced the amount of ionizing radiation exposure in a preselected population of pediatric neurosurgical patients. Image quality and diagnostic utility were not significantly compromised.

Technical Pitfall in 68Ga-Prostate Specific Membrane Antigen Imaging: Altered Biodistribution Caused by Free 68Ga-Citrate Due to Radiolysis Showing Increased Vascular Activity.

PubMed

Hod, Nir; Anconina, Reut; Levin, Daniel; Ezroh Kazap, Dina; Lantsberg, Sophie

2018-06-01

As with any new molecular imaging modality, accurate characterization of abnormalities on Ga-PSMA PET/CT imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants, and potential sources of false imaging findings. Altered biodistribution can have a significant impact on scan interpretation. Presented here is a rare case in which radiopharmaceutical radiolysis occurred causing excessive free Ga-citrate showing as an increased vascular activity. As Ga-PSMA PET/CT imaging is a relatively new imaging technique, it is important to be aware of such a potential technical pitfall in clinical practice in order to prevent scan misinterpretation.

Routine postoperative CT-scans after burr hole trepanation for chronic subdural hematoma - better before or after drainage removal?

PubMed

Brokinkel, Benjamin; Ewelt, Christian; Holling, Markus; Hesselmann, Volker; Heindel, Walter Leonard; Stummer, Walter; Fischer, Bernhard Robert

2013-01-01

To evaluate timing of scheduled CT-scans after burr hole trepanation for chronic subdural hematoma (cSDH). 131 patients with primary cSDH were included. Scheduled CT-scans were performed after burr hole trepanation and placement of a subdural drain. The influence of CT-scanning with or without indwelling drain was analysed regarding subsequent surgery and CT-scans, duration of hospitalization, short- and middle-term follow up by single factor analyses. Subgroup analyses were performed for patients receiving anticoagulant drugs. Median age was 74 years. Routine CT-scans with indwelling drainage were not shown to be beneficial regarding subsequent burr hole trepanations (p=0.243), craniotomies (p=1.000) and outcome at discharge (p=0.297). Mean duration of hospitalization (11 vs. 8 days, p=0.013) was significantly longer and number of subsequent CT-scans was higher when CT scan was performed with indwelling drain (2.3 vs. 1.4, p=0.001). In middle-term follow-up, beneficial effects of CT-scanning with inlaying drainage could neither be shown. Moreover, advantageous effects of CT-scans with indwelling drains could neither be shown for patients receiving anticoagulant drugs. Scheduled postoperative cranial imaging with indwelling drains was not shown to be beneficial and misses information of intracranial damage inflicted by removal of drains. We thus recommend CT-scanning after drainage removal.

An open library of CT patient projection data

NASA Astrophysics Data System (ADS)

Chen, Baiyu; Leng, Shuai; Yu, Lifeng; Holmes, David; Fletcher, Joel; McCollough, Cynthia

2016-03-01

Lack of access to projection data from patient CT scans is a major limitation for development and validation of new reconstruction algorithms. To meet this critical need, we are building a library of CT patient projection data in an open and vendor-neutral format, DICOM-CT-PD, which is an extended DICOM format that contains sinogram data, acquisition geometry, patient information, and pathology identification. The library consists of scans of various types, including head scans, chest scans, abdomen scans, electrocardiogram (ECG)-gated scans, and dual-energy scans. For each scan, three types of data are provided, including DICOM-CT-PD projection data at various dose levels, reconstructed CT images, and a free-form text file. Several instructional documents are provided to help the users extract information from DICOM-CT-PD files, including a dictionary file for the DICOM-CT-PD format, a DICOM-CT-PD reader, and a user manual. Radiologist detection performance based on the reconstructed CT images is also provided. So far 328 head cases, 228 chest cases, and 228 abdomen cases have been collected for potential inclusion. The final library will include a selection of 50 head, chest, and abdomen scans each from at least two different manufacturers, and a few ECG-gated scans and dual-source, dual-energy scans. It will be freely available to academic researchers, and is expected to greatly facilitate the development and validation of CT reconstruction algorithms.

Imaging Cellular Proliferation During Chemo-Radiotherapy: A Pilot Study of Serial {sup 18}F-FLT Positron Emission Tomography/Computed Tomography Imaging for Non-Small-Cell Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Everitt, Sarah, E-mail: Sarah.Everitt@petermac.or; Department of Medical Imaging and Radiation Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria; Hicks, Rodney J.

2009-11-15

Purpose: To establish whether {sup 18}F-3'-deoxy-3'-fluoro-L-thymidine ({sup 18}F-FLT) can monitor changes in cellular proliferation of non-small-cell lung cancer (NSCLC) during radical chemo-radiotherapy (chemo-RT). Methods and Materials: As part of a prospective pilot study, 5 patients with locally advanced NSCLC underwent serial {sup 18}F-FLT positron emission tomography (PET)/computed tomography (CT) scans during treatment. Baseline {sup 18}F-FLT PET/CT scans were compared with routine staging {sup 18}F-FDG PET/CT scans. Two on-treatment {sup 18}F-FLT scans were performed for each patient on Days 2, 8, 15 or 29, providing a range of time points for response assessment. Results: In all 5 patients, baseline lesional uptakemore » of {sup 18}F-FLT on PET/CT corresponded to staging {sup 18}F-FDG PET/CT abnormalities. {sup 18}F-FLT uptake in tumor was observed on five of nine (55%) on-treatment scans, on Days 2, 8 and 29, but not Day 15. A 'flare' of {sup 18}F-FLT uptake in the primary tumor of one case was observed after 2 Gy of radiation (1.22 x baseline). The remaining eight on-treatment scans demonstrated a mean reduction in {sup 18}F-FLT tumor uptake of 0.58 x baseline. A marked reduction of {sup 18}F-FLT uptake in irradiated bone marrow was observed for all cases. This reduction was observed even after only 2 Gy, and all patients demonstrated a complete absence of proliferating marrow after 10 Gy. Conclusions: This proof of concept study indicates that {sup 18}F-FLT uptake can monitor the distinctive biologic responses of epithelial cancers and highly radiosensitive normal tissue changes during radical chemo-RT. Further studies of {sup 18}F-FLT PET/CT imaging during therapy may suggest that this tracer is useful in developing response-adapted RT for NSCLC.« less

99mTc-HYNIC-TOC increased uptake can mimic malignancy in the pancreas uncinate process at somatostatin receptor SPECT/CT.

PubMed

Yamaga, Lilian Yuri Itaya; Neto, Guilherme Campos Carvalho; da Cunha, Marcelo Livorsi; Osawa, Akemi; Oliveira, Julio Cesar Silveira; Fonseca, Ricardo Quartim; Nogueira, Solange Amorim; Wagner, Jairo; Funari, Marcelo Gusmão

2016-03-01

The aim of this study was to assess the occurrence and frequency of increased physiologic uptake of 99mTc-HYNIC-TOC by the uncinate process of the pancreas in SPECT/CT images. Forty-six scans of 41 patients were evaluated retrospectively. The uptake of 99mTc-HYNIC-TOC was considered to be physiologic in patients with normal findings at dedicated abdominal CT or MR and lack of neoplastic lesions in clinical follow-ups. The intensity of uncinate process uptake was compared to the uptake of the normal liver. Focal uptake was attributed to the presence of pancreatic NET in 5 patients. Among the 36 patients without any evidence of malignancy in CT, MR and follow-up, 7 (19.4 %) showed increased uptake in the uncinate process. The intensity of uptake was lesser in 3 (8.3 %), similar in 3 and greater than the normal liver in 1 (2.8 %) case. Increased 99mTc-HYNIC-TOC uptake occurred in 19.4 % of those subjects without any evidence of neuroendocrine tumor in the uncinate process.

Quantification of idiopathic pulmonary fibrosis using computed tomography and histology.

PubMed

Coxson, H O; Hogg, J C; Mayo, J R; Behzad, H; Whittall, K P; Schwartz, D A; Hartley, P G; Galvin, J R; Wilson, J S; Hunninghake, G W

1997-05-01

We used computed tomography (CT) and histologic analysis to quantify lung structure in idiopathic pulmonary fibrosis (IPF). CT scans were obtained from IPF and control patients and lung volumes were estimated from measurements of voxel size, and X-ray attenuation values of each voxel. Quantitative estimates of lung structure were obtained from biopsies obtained from diseased and normal CT regions using stereologic methods. CT density was used to calculate the proportion of tissue and air, and this value was used to correct the biopsy specimens to the level of inflation during the CT scan. The data show that IPF is associated with a reduction in airspace volume with no change in tissue volume or weight compared with control lungs. Lung surface area decreased two-thirds (p < 0.001) and mean parenchymal thickness increased tenfold (p < 0.001). An exudate of fluid and cells was present in the airspace of the diseased lung regions and the number of inflammatory cells, collagen, and proteoglycans was increased per 100 g of tissue in IPF. We conclude that IPF reorganized lung tissue content causing a loss of airspace and surface area without increasing the total lung tissue.

High-kVp Assisted Metal Artifact Reduction for X-ray Computed Tomography

PubMed Central

Xi, Yan; Jin, Yannan; De Man, Bruno; Wang, Ge

2016-01-01

In X-ray computed tomography (CT), the presence of metallic parts in patients causes serious artifacts and degrades image quality. Many algorithms were published for metal artifact reduction (MAR) over the past decades with various degrees of success but without a perfect solution. Some MAR algorithms are based on the assumption that metal artifacts are due only to strong beam hardening and may fail in the case of serious photon starvation. Iterative methods handle photon starvation by discarding or underweighting corrupted data, but the results are not always stable and they come with high computational cost. In this paper, we propose a high-kVp-assisted CT scan mode combining a standard CT scan with a few projection views at a high-kVp value to obtain critical projection information near the metal parts. This method only requires minor hardware modifications on a modern CT scanner. Two MAR algorithms are proposed: dual-energy normalized MAR (DNMAR) and high-energy embedded MAR (HEMAR), aiming at situations without and with photon starvation respectively. Simulation results obtained with the CT simulator CatSim demonstrate that the proposed DNMAR and HEMAR methods can eliminate metal artifacts effectively. PMID:27891293

Chymopapain chemonucleolysis: CT changes after treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentry, L.R.; Turski, P.A.; Strother, C.M.

1985-08-01

Chymopapain chemonucleolysis is now used extensively in this country to treat lumbar disk herniation. Despite increasing experience in patient selection, there continue to be patients who do not respond to treatment and require diagnostic reevaluation. Interpretation of postchemonucleolysis computed tomographic (CT) scans in these patients requires a knowledge of the CT changes that normally occur after treatment with chemonucleolysis. To define these temporal changes, a prospective CT evaluation was performed of 29 treated interspaces in 26 patients who returned for routine postchemonucleolysis follow-up. Despite a successful clinical response in 17 of 21 patients, changes in the size, location, shape, homogeneity,more » and density of the disk herniation were uncommon at the 6 week follow-up. In 24 treated interspaces, the most common changes at 6 week CT follow-up were the development of vacuum phenomenon in three (12.5%) and a slight decrease in the size of two (8.3%) disk herniations. A successful response was noted in 17 of 21 patients scanned at 6 month follow-up, with five (22.7%) of 22 injected interspaces exhibiting vacuum phenomenon and 13 (59.1%) interspaces showing an observable decrease in the size of the disk herniation.« less

DICOM structured report to track patient's radiation dose to organs from abdominal CT exam

NASA Astrophysics Data System (ADS)

Morioka, Craig; Turner, Adam; McNitt-Gray, Michael; Zankl, Maria; Meng, Frank; El-Saden, Suzie

2011-03-01

The dramatic increase of diagnostic imaging capabilities over the past decade has contributed to increased radiation exposure to patient populations. Several factors have contributed to the increase in imaging procedures: wider availability of imaging modalities, increase in technical capabilities, rise in demand by patients and clinicians, favorable reimbursement, and lack of guidelines to control utilization. The primary focus of this research is to provide in depth information about radiation doses that patients receive as a result of CT exams, with the initial investigation involving abdominal CT exams. Current dose measurement methods (i.e. CTDIvol Computed Tomography Dose Index) do not provide direct information about a patient's organ dose. We have developed a method to determine CTDIvol normalized organ doses using a set of organ specific exponential regression equations. These exponential equations along with measured CTDIvol are used to calculate organ dose estimates from abdominal CT scans for eight different patient models. For each patient, organ dose and CTDIvol were estimated for an abdominal CT scan. We then modified the DICOM Radiation Dose Structured Report (RDSR) to store the pertinent patient information on radiation dose to their abdominal organs.

The Necessity of Follow-Up Brain Computed-Tomography Scans: Is It the Pathology Itself Or Our Fear that We Should Overcome?

PubMed Central

Öğrenci, Ahmet; Koban, Orkun; Ekşi, Murat; Yaman, Onur; Dalbayrak, Sedat

2017-01-01

AIM: This study aimed to make a retrospective analysis of pediatric patients with head traumas that were admitted to one hospital setting and to make an analysis of the patients for whom follow-up CT scans were obtained. METHODS: Pediatric head trauma cases were retrospectively retrieved from the hospital’s electronic database. Patients’ charts, CT scans and surgical notes were evaluated by one of the authors. Repeat CT scans for operated patients were excluded from the total number of repeat CT scans. RESULTS: One thousand one hundred and thirty-eight pediatric patients were admitted to the clinic due to head traumas. Brain CT scan was requested in 863 patients (76%) in the cohort. Follow-up brain CT scans were obtained in 102 patients. Additional abnormal finding requiring surgical intervention was observed in only one patient (isolated 4th ventricle hematoma) on the control CTs (1% of repeat CT scans), who developed obstructive hydrocephalus. None of the patients with no more than 1 cm epidural hematoma in its widest dimension and repeat CT scans obtained 1.5 hours after the trauma necessitated surgery. CONCLUSION: Follow-up CT scans changed clinical approach in only one patient in the present series. When ordering CT scan in the follow-up of pediatric traumas, benefits and harms should be weighted based upon time interval from trauma onset to initial CT scan and underlying pathology. PMID:29104682

Prediction value of the Canadian CT head rule and the New Orleans criteria for positive head CT scan and acute neurosurgical procedures in minor head trauma: a multicenter external validation study.

PubMed

Bouida, Wahid; Marghli, Soudani; Souissi, Sami; Ksibi, Hichem; Methammem, Mehdi; Haguiga, Habib; Khedher, Sonia; Boubaker, Hamdi; Beltaief, Kaouthar; Grissa, Mohamed Habib; Trimech, Mohamed Naceur; Kerkeni, Wiem; Chebili, Nawfel; Halila, Imen; Rejeb, Imen; Boukef, Riadh; Rekik, Noureddine; Bouhaja, Bechir; Letaief, Mondher; Nouira, Semir

2013-05-01

The New Orleans Criteria and the Canadian CT Head Rule have been developed to decrease the number of normal computed tomography (CT) results in mild head injury. We compare the performance of both decision rules for identifying patients with intracranial traumatic lesions and those who require an urgent neurosurgical intervention after mild head injury. This was an observational cohort study performed between 2008 and 2011 on patients with mild head injury who were aged 10 years or older. We collected prospectively clinical head CT scan findings and outcome. Primary outcome was need for neurosurgical intervention, defined as either death or craniotomy, or the need of intubation within 15 days of the traumatic event. Secondary outcome was the presence of traumatic lesions on head CT scan. New Orleans Criteria and Canadian CT Head Rule decision rules were compared by using sensitivity specifications and positive and negative predictive value. We enrolled 1,582 patients. Neurosurgical intervention was performed in 34 patients (2.1%) and positive CT findings were demonstrated in 218 patients (13.8%). Sensitivity and specificity for need for neurosurgical intervention were 100% (95% confidence interval [CI] 90% to 100%) and 60% (95% CI 44% to 76%) for the Canadian CT Head Rule and 82% (95% CI 69% to 95%) and 26% (95% CI 24% to 28%) for the New Orleans Criteria. Negative predictive values for the above-mentioned clinical decision rules were 100% and 99% and positive values were 5% and 2%, respectively, for the Canadian CT Head Rule and New Orleans Criteria. Sensitivity and specificity for clinical significant head CT findings were 95% (95% CI 92% to 98%) and 65% (95% CI 62% to 68%) for the Canadian CT Head Rule and 86% (95% CI 81% to 91%) and 28% (95% CI 26% to 30%) for the New Orleans Criteria. A similar trend of results was found in the subgroup of patients with a Glasgow Coma Scale score of 15. For patients with mild head injury, the Canadian CT Head Rule had higher sensitivity than the New Orleans Criteria, with higher negative predictive value. The question of whether the use of the Canadian CT Head Rule would have a greater influence on head CT scan reduction requires confirmation in real clinical practice. Copyright © 2012 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration.

PubMed

Wolthaus, J W H; Sonke, J J; van Herk, M; Damen, E M F

2008-09-01

lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods < 0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good for the clearly visible features (e.g., tumor and diaphragm). The shape of the tumor, with respect to that of the BH CT scan, was better represented by the MidP reconstructions than any of the 4D CT frames (including MidV; reduction of "shape differences" was 66%). The MidP scans contained about one-third the noise of individual 4D CT scan frames. We implemented an accurate method to estimate the motion of structures in a 4D CT scan. Subsequently, a novel method to create a midposition CT scan (time-weighted average of the anatomy) for treatment planning with reduced noise and artifacts was introduced. Tumor shape and position in the MidP CT scan represents that of the BH CT scan better than MidV CT scan and, therefore, was found to be appropriate for treatment planning.

Classification of pulmonary emphysema from chest CT scans using integral geometry descriptors

NASA Astrophysics Data System (ADS)

van Rikxoort, E. M.; Goldin, J. G.; Galperin-Aizenberg, M.; Brown, M. S.

2011-03-01

To gain insight into the underlying pathways of emphysema and monitor the effect of treatment, methods to quantify and phenotype the different types of emphysema from chest CT scans are of crucial importance. Current standard measures rely on density thresholds for individual voxels, which is influenced by inspiration level and does not take into account the spatial relationship between voxels. Measures based on texture analysis do take the interrelation between voxels into account and therefore might be useful for distinguishing different types of emphysema. In this study, we propose to use Minkowski functionals combined with rotation invariant Gaussian features to distinguish between healthy and emphysematous tissue and classify three different types of emphysema. Minkowski functionals characterize binary images in terms of geometry and topology. In 3D, four Minkowski functionals are defined. By varying the threshold and size of neighborhood around a voxel, a set of Minkowski functionals can be defined for each voxel. Ten chest CT scans with 1810 annotated regions were used to train the method. A set of 108 features was calculated for each training sample from which 10 features were selected to be most informative. A linear discriminant classifier was trained to classify each voxel in the lungs into a subtype of emphysema or normal lung. The method was applied to an independent test set of 30 chest CT scans with varying amounts and types of emphysema with 4347 annotated regions of interest. The method is shown to perform well, with an overall accuracy of 95%.

Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties

PubMed Central

Zeleznik, Michael P.; Nilsson, Kjell G.; Olivecrona, Henrik

2017-01-01

As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X-, Y-, and Z-rotation and 0.40, 0.17, and 0.37 mm for X-, Y-, and Z-translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers. PMID:28243598

Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties.

PubMed

Otten, Volker; Maguire, Gerald Q; Noz, Marilyn E; Zeleznik, Michael P; Nilsson, Kjell G; Olivecrona, Henrik

2017-01-01

As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X -, Y -, and Z -rotation and 0.40, 0.17, and 0.37 mm for X -, Y -, and Z -translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.

Computed tomography of calcaneal fractures: anatomy, pathology, dosimetry, and clinical relevance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guyer, B.H.; Levinsohn, E.M.; Fredrickson, B.E.

1985-11-01

Eighteen CT examinations were performed in 10 patients for the evaluation of acute intraarticular fractures and their follow-up. Fractures comparable to those in the patients were created in cadavers. The normal anatomy and the traumatically altered anatomy of the calcaneus in the axial, coronal, and sagittal planes are demonstrated by CT and corresponding anatomic sections. Scanning was performed in the axial plane, with subsequent reconstruction in the coronal and sagittal planes. The axial scans show disruption of the inferior part of the posterior facet, calcaneocuboid joint involvement, and widening of the calcaneus. The coronal scans show disruption of the superiormore » part of the posterior facet, sustentaculum tali depression (involvement of middle and anterior facets), peroneal and flexor hallucis longus tendon impingement, and widening and height loss of the calcaneus. The sagittal scans show disruption of the posterior facet, calcaneocuboid joint involvement, and height loss of the calcaneus and allow the evaluation of Boehler's and Gissane's angles. All three planes show the position of major fracture fragments. Radiation dose to the foot was measured to be 0.1 rad (0.001 Gy) for plain film radiography (five exposures), 18 rad (0.18 Gy) for conventional tomography (20 cuts), and 2.6 rad (0.026 Gy) for axial CT examination.« less

Grey matter brain injuries are common in Ugandan children with cerebral palsy suggesting a perinatal aetiology in full-term infants.

PubMed

Kakooza-Mwesige, Angelina; Byanyima, Rosemary K; Tumwine, James K; Eliasson, Ann-Christin; Forssberg, Hans; Flodmark, Olof

2016-06-01

There is limited literature on brain imaging studies of children with cerebral palsy (CP) in low and middle income countries. We investigated neuroimaging patterns of children with CP attending a tertiary referral centre in Uganda to determine how they differed from studies reported from high income countries and their relationship with prenatal and postnatal factors. Precontrast and postcontrast computed tomography (CT) scans of 78 CP children aged 2-12 years were conducted using a Philips MX 16-slice CT scanner. Two radiologists, blinded to the patient's clinical status, independently reviewed the scans. Abnormal CT scans were detected in 69% of the children sampled, with very few having primary white matter injuries (4%). Primary grey matter injuries (PGMI) (44%) and normal scans (31%) were most frequent. Children with a history of hospital admission following birth were three times more likely to have PGMI (odds ratio [OR] 2.8; 95% CI 1.1-7.1), suggesting a perinatal period with medical complications. Brain imaging patterns in this group of CP children differed markedly from imaging studies reported from high income countries, suggesting a perinatal aetiology in full-term infants and reduced survival in preterm infants. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Cortical bone thickening in Type A posterior atlas arch defects: experimental report.

PubMed

Sanchis-Gimeno, Juan A; Llido, Susanna; Guede, David; Martinez-Soriano, Francisco; Ramon Caeiro, Jose; Blanco-Perez, Esther

2017-03-01

To date, no information about the cortical bone microstructural properties in atlas vertebrae with posterior arch defects has been reported. To test if there is an increased cortical bone thickening in atlases with Type A posterior atlas arch defects in an experimental model. Micro-computed tomography (CT) study on cadaveric atlas vertebrae. We analyzed the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry vertebrae with a Type A atlas arch defect and normal control vertebrae. The micro-CT study revealed significant differences in cortical bone thickness (p=.005), cortical volume (p=.003), and medullary volume (p=.009) values between the normal and the Type A vertebrae. Type A congenital atlas arch defects present a cortical bone thickening that may play a protective role against atlas fractures. Copyright © 2016 Elsevier Inc. All rights reserved.

Utility of CT-compatible EEG electrodes in critically ill children.

PubMed

Abend, Nicholas S; Dlugos, Dennis J; Zhu, Xiaowei; Schwartz, Erin S

2015-04-01

Electroencephalographic monitoring is being used with increasing frequency in critically ill children who may require frequent and sometimes urgent brain CT scans. Standard metallic disk EEG electrodes commonly produce substantial imaging artifact, and they must be removed and later reapplied when CT scans are indicated. To determine whether conductive plastic electrodes caused artifact that limited CT interpretation. We describe a retrospective cohort of 13 consecutive critically ill children who underwent 17 CT scans with conductive plastic electrodes during 1 year. CT images were evaluated by a pediatric neuroradiologist for artifact presence, type and severity. All CT scans had excellent quality images without artifact that impaired CT interpretation except for one scan in which improper wire placement resulted in artifact. Conductive plastic electrodes do not cause artifact limiting CT scan interpretation and may be used in critically ill children to permit concurrent electroencephalographic monitoring and CT imaging.

Emission computed tomography of /sup 18/F-fluorodeoxyglucose and /sup 13/N-ammonia in stroke and epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, D.E.; Phelps, M.E.; Engel, J. Jr.

1980-01-01

The ECAT Positron Tomograph was used to scan normal control subjects, stroke patients at various times during recovery, and patients with partial epilepsy during EEG monitoring. /sup 18/F-fluorodeoxyglucose (/sup 18/FDG) and /sup 13/N-Ammonia (/sup 13/NH/sub 3/) were used as indicators of abnormalities in local cerebral glucose utilization (LCMR/sub glc/) and relative perfusion, respectively. Hypometabolism, due to deactivation or minimal damage, was demonstrated with the /sup 18/FDG scan in deep structures and broad zones of cerebral cortex which appeared normal on x-ray CT (XCT) and /sup 99m/Tc pertechnetate scans. In patients with partial epilepsy, who had unilateral or focal electrical abnormalities,more » interictal /sup 18/FDG scan patterns clearly showed localized regions of decreased (20 to 50%) LCMR/sub glc/, which correlated anatomically with the eventual EEG localization.« less

Technical Note: Characterization of custom 3D printed multimodality imaging phantoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bieniosek, Matthew F.; Lee, Brian J.; Levin, Craig S., E-mail: cslevin@stanford.edu

Purpose: Imaging phantoms are important tools for researchers and technicians, but they can be costly and difficult to customize. Three dimensional (3D) printing is a widely available rapid prototyping technique that enables the fabrication of objects with 3D computer generated geometries. It is ideal for quickly producing customized, low cost, multimodal, reusable imaging phantoms. This work validates the use of 3D printed phantoms by comparing CT and PET scans of a 3D printed phantom and a commercial “Micro Deluxe” phantom. This report also presents results from a customized 3D printed PET/MRI phantom, and a customized high resolution imaging phantom withmore » sub-mm features. Methods: CT and PET scans of a 3D printed phantom and a commercial Micro Deluxe (Data Spectrum Corporation, USA) phantom with 1.2, 1.6, 2.4, 3.2, 4.0, and 4.8 mm diameter hot rods were acquired. The measured PET and CT rod sizes, activities, and attenuation coefficients were compared. A PET/MRI scan of a custom 3D printed phantom with hot and cold rods was performed, with photon attenuation and normalization measurements performed with a separate 3D printed normalization phantom. X-ray transmission scans of a customized two level high resolution 3D printed phantom with sub-mm features were also performed. Results: Results show very good agreement between commercial and 3D printed micro deluxe phantoms with less than 3% difference in CT measured rod diameter, less than 5% difference in PET measured rod diameter, and a maximum of 6.2% difference in average rod activity from a 10 min, 333 kBq/ml (9 μCi/ml) Siemens Inveon (Siemens Healthcare, Germany) PET scan. In all cases, these differences were within the measurement uncertainties of our setups. PET/MRI scans successfully identified 3D printed hot and cold rods on PET and MRI modalities. X-ray projection images of a 3D printed high resolution phantom identified features as small as 350 μm wide. Conclusions: This work shows that 3D printed phantoms can be functionally equivalent to commercially available phantoms. They are a viable option for quickly distributing and fabricating low cost, customized phantoms.« less

Lumbar spine CT scan

MedlinePlus

CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... CT scans rapidly makes detailed pictures of the lower back. The test may be used to look for: ...

Metastases to the Liver from Neuroendocrine Tumors: Effect of Duration of Scan Acquisition on CT Perfusion Values

PubMed Central

Hobbs, Brian P.; Chandler, Adam G.; Anderson, Ella F.; Herron, Delise H.; Charnsangavej, Chusilp; Yao, James

2013-01-01

Purpose To assess the effects of acquisition duration on computed tomographic (CT) perfusion parameter values in neuroendocrine liver metastases and normal liver tissue. Materials and Methods This retrospective study was institutional review board approved, with waiver of informed consent. CT perfusion studies in 16 patients (median age, 57.5 years; range, 42.0–69.7 years), including six men (median, 54.1 years; range, 42.0–69.7), and 10 women (median, 59.3 years; range 43.6–66.3), with neuroendocrine liver metastases were analyzed by means of distributed parametric modeling to determine tissue blood flow, blood volume, mean transit time, permeability, and hepatic arterial fraction for tumors and normal liver tissue. Analyses were undertaken with acquisition time of 12–590 seconds. Nonparameteric regression analyses were used to evaluate the functional relationships between CT perfusion parameters and acquisition duration. Evidence for time invariance was evaluated for each parameter at multiple time points by inferring the fitted derivative to assess its proximity to zero as a function of acquisition time by using equivalence tests with three levels of confidence (20%, 70%, and 90%). Results CT perfusion parameter values varied, approaching stable values with increasing acquisition duration. Acquisition duration greater than 160 seconds was required to obtain at least low confidence stability in any of the CT perfusion parameters. At 160 seconds of acquisition, all five CT perfusion parameters stabilized with low confidence in tumor and normal tissues, with the exception of hepatic arterial fraction in tumors. After 220 seconds of acquisition, there was stabilization with moderate confidence for blood flow, blood volume, and hepatic arterial fraction in tumors and normal tissue, and for mean transit time in tumors; however, permeability values did not satisfy the moderate stabilization criteria in both tumors and normal tissue until 360 seconds of acquisition. Blood flow, mean transit time, permeability, and hepatic arterial fraction were significantly different between tumor and normal tissue at 360 seconds (P < .001). Conclusion CT perfusion parameter values are affected by acquisition duration and approach progressively stable values with increasing acquisition times. © RSNA, 2013 Online supplemental material is available for this article. PMID:23824990

Normal distribution pattern and physiological variants of 68Ga-PSMA-11 PET/CT imaging.

PubMed

Demirci, Emre; Sahin, Onur Erdem; Ocak, Meltem; Akovali, Burak; Nematyazar, Jamal; Kabasakal, Levent

2016-11-01

Ga-PSMA-11 is a novel PET tracer suggested to be used for imaging of advanced prostate cancer. In this study, we aimed to present a detailed biodistribution of Ga-PSMA-11, including physiological and benign variants of prostate-specific membrane antigen (PSMA) imaging. We carried out a retrospective analysis of 40 patients who underwent PSMA PET/computed tomography (CT) imaging and who had no evidence of residual or metastatic disease on the scans. In addition, 16 patients who underwent PSMA PET/CT imaging with any indication other than prostate cancer were included in the study to evaluate physiological uptake in the normal prostate gland. The median, minimum-maximum, and mean standardized uptake value (SUV) values were calculated for visceral organs, bone marrow and lymph nodes, and mucosal areas. Any physiological variants or benign lesions with Ga-PSMA-11 were also noted. Ga-PSMA-11 uptake was noted in the kidneys, parotid and submandibular glands, duodenum, small intestines, spleen, liver, and lacrimal glands, and mucosal uptake in the nasopharynx, vocal cords, pancreas, stomach, mediastinal blood pool, thyroid gland, adrenal gland, rectum, vertebral bone marrow, and testes. Celiac ganglia showed slight Ga-PSMA-11 uptake in 24 of 40 patients without the presence of any other pathologic lymph nodes in abdominal and pelvic areas. Variable uptake of Ga-PSMA-11 was observed in calcified choroid plexus, a thyroid nodule, an adrenal nodule, axillary lymph nodes and celiac ganglia, occasional osteophytes, and gallbladder. The patient group with PSMA PET/CT for indications other than prostate cancer (n=16) showed a slight radiotracer uptake in normal prostate gland (SUVmax: 5.5±1.6, range: 3.5-8.3). This study shows normal distribution pattern, range of SUVs, and physiological variants of Ga-PSMA-11. In addition, several potential pitfalls were documented to prevent misinterpretations of the scan.

Assessment of multislice CT to quantify pulmonary emphysema function and physiology in a rat model

NASA Astrophysics Data System (ADS)

Cao, Minsong; Stantz, Keith M.; Liang, Yun; Krishnamurthi, Ganapathy; Presson, Robert G., Jr.

2005-04-01

Purpose: The purpose of this study is to evaluate multi-slice computed tomography technology to quantify functional and physiologic changes in rats with pulmonary emphysema. Method: Seven rats were scanned using a 16-slice CT (Philips MX8000 IDT) before and after artificial inducement of emphysema. Functional parameters i.e. lung volumes were measured by non-contrast spiral scan during forced breath-hold at inspiration and expiration followed by image segmentation based on attenuation threshold. Dynamic CT imaging was performed immediately following the contrast injection to estimate physiology changes. Pulmonary perfusion, fractional blood volume, and mean transit times (MTTs) were estimated by fitting the time-density curves of contrast material using a compartmental model. Results: The preliminary results indicated that the lung volumes of emphysema rats increased by 3.52+/-1.70mL (p<0.002) at expiration and 4.77+/-3.34mL (p<0.03) at inspiration. The mean lung densities of emphysema rats decreased by 91.76+/-68.11HU (p<0.01) at expiration and low attenuation areas increased by 5.21+/-3.88% (p<0.04) at inspiration compared with normal rats. The perfusion for normal and emphysema rats were 0.25+/-0.04ml/s/ml and 0.32+/-0.09ml/s/ml respectively. The fractional blood volumes for normal and emphysema rats were 0.21+/-0.04 and 0.15+/-0.02. There was a trend toward faster MTTs for emphysema rats (0.42+/-0.08s) than normal rats (0.89+/-0.19s) with p<0.006, suggesting that blood flow crossing the capillaries increases as the capillary volume decreases and which may cause the red blood cells to leave the capillaries incompletely saturated with oxygen if the MTTs become too short. Conclusion: Quantitative measurement using CT of structural and functional changes in pulmonary emphysema appears promising for small animals.

Cost-effectiveness and accuracy of the tests used in the differential diagnosis of Cushing's syndrome.

PubMed

Puig, J; Wägner, A; Caballero, A; Rodríguez-Espinosa, J; Webb, S M

1999-01-01

Establish the minimal biochemical and radiological examinations necessary and their cost-effectiveness to accurately diagnose the etiology of Cushing's syndrome (CS). In 71 patients with CS followed between 1982 and 1997 biochemical studies (basal ACTH, 8 mg dexamethasone suppression test-HDST-, metyrapone stimulation test-MST-, or inferior petrosal sinus catheterization-IPSC-) and radiological investigations (abdominal CT scan, pituitary CT scan or MRI) were performed. Once pathology confirmed the diagnosis (48 pituitary Cushing's disease-CD, 17 adrenal neoplasms, 2 bilateral macronodular hyperplasia-BMH-, and 4 ectopic ACTH syndrome-ES-), the sensitivity, specificity, positive and negative predictive value of the different studies was calculated to establish the most accurate and cost-effective diagnostic protocol. In ACTH-independent CS (ACTH < or = 9 pg/ml; normal 9 to 54) a unilateral tumor was identified on abdominal CT scanning in 17, and BMH in 1; the other BMH had detectable ACTH (43.2 pg/ml). In ACTH-dependent CS, ACTH was > 9 pg/ml and IPSC (performed in 22) correctly identified 20 patients with CD and differentiated them from 2 with an ES (100% specificity and sensitivity). Pituitary MRI or CT did not disclose an adenoma in 41.7% of patients with CD, and was reported to exhibit a microadenoma in 2 of the 4 patients with ES. HDST and MST were of no additional use in the differentiation between CD and ES. Once CS is diagnosed low ACTH and an abdominal CT scan correctly identified all patients of adrenal origin. In ACTH-dependent CS IPSC was the best predictive test to differentiate CD from ES. BMH may behave as ACTH-dependent or independent. The other biochemical and radiological studies performed are not cost-effective and may even be misleading, and should not be routinely performed.

[Suprasellar arachnoid cyst--report of a case (author's transl)].

PubMed

Takahashi, T; Kawai, S; Kaminoh, T; Hiramatsu, K; Maekawa, M; Yuasa, T; Miyamoto, N; Hattori, Y

1982-04-01

A 4-year-old boy with suprasellar arachnoid cyst was reported. At the age of 30-month-old his aunt was aware of his squint. During the observation by ophthalmologists from the age of 1y. to 3y., enlargement of the head and impairment of the visual acuity were manifested. Cranial CT scan revealed the enlargement of the ventricular system and a round low density area located superior to the sella. Absorption coefficient of the lesion was similar to that of the cerebrospinal fluid. No abnormal contrast enhancement was seen. Examination revealed the head circumference of 53.3 cm larger than doubled standard deviation, the right external strabismus, impaired vision (R:0.03, L:0.3) and optic atrophy but no other neurological signs. Cerebral angiography showed suprasellar mass lesion. After the ventriculography with water-soluble contrast medium, V-P shunt operation was performed and then the patient was transferred to the CT room. CSF enhanced CT scan showed no communication between the ventricles and the cyst. By frontotemporal approach, microsurgical removal of the cystwall was performed and the histological diagnosis was arachnoid membrane. Several days after the operation, bilateral subdural effusion was seen on CT scan and was treated with bilateral S-P shunt and the removal of V-P shunt. Follow up CT scan disclosed the disappearance of the subdural effusion and the suprasellar cyst. The visual acuity was improved well and the endocrinological study was normal. Analysis of the 45 reported cases of suprasellar arachnoid cyst suggested that direct removal of the cyst wall is better than the V-P shunt operation and the cyst shunting is advisable for repeat recurrence of the cyst. Removal of the ventricular shunting system may be effective for the prevention of the subdural effusion as a complication after direct operation.

Fluorine-18-Labeled Fluoromisonidazole Positron Emission and Computed Tomography-Guided Intensity-Modulated Radiotherapy for Head and Neck Cancer: A Feasibility Study

PubMed Central

Lee, Nancy Y.; Mechalakos, James G.; Nehmeh, Sadek; Lin, Zhixiong; Squire, Olivia D.; Cai, Shangde; Chan, Kelvin; Zanzonico, Pasquale B.; Greco, Carlo; Ling, Clifton C.; Humm, John L.; Schöder, Heiko

2010-01-01

Purpose Hypoxia renders tumor cells radioresistant, limiting locoregional control from radiotherapy (RT). Intensity-modulated RT (IMRT) allows for targeting of the gross tumor volume (GTV) and can potentially deliver a greater dose to hypoxic subvolumes (GTVh) while sparing normal tissues. A Monte Carlo model has shown that boosting the GTVh increases the tumor control probability. This study examined the feasibility of fluorine-18–labeled fluoromisonidazole positron emission tomography/computed tomography (18F-FMISO PET/CT)–guided IMRT with the goal of maximally escalating the dose to radioresistant hypoxic zones in a cohort of head and neck cancer (HNC) patients. Methods and Materials 18F-FMISO was administered intravenously for PET imaging. The CT simulation, fluorodeoxyglucose PET/CT, and 18F-FMISO PET/CT scans were co-registered using the same immobilization methods. The tumor boundaries were defined by clinical examination and available imaging studies, including fluorodeoxyglucose PET/CT. Regions of elevated 18F-FMISO uptake within the fluorodeoxyglucose PET/CT GTV were targeted for an IMRT boost. Additional targets and/or normal structures were contoured or transferred to treatment planning to generate 18F-FMISO PET/CT-guided IMRT plans. Results The heterogeneous distribution of 18F-FMISO within the GTV demonstrated variable levels of hypoxia within the tumor. Plans directed at performing 18F-FMISO PET/CT–guided IMRT for 10 HNC patients achieved 84 Gy to the GTVh and 70 Gy to the GTV, without exceeding the normal tissue tolerance. We also attempted to deliver 105 Gy to the GTVh for 2 patients and were successful in 1, with normal tissue sparing. Conclusion It was feasible to dose escalate the GTVh to 84 Gy in all 10 patients and in 1 patient to 105 Gy without exceeding the normal tissue tolerance. This information has provided important data for subsequent hypoxia-guided IMRT trials with the goal of further improving locoregional control in HNC patients. PMID:17869020

X-ray CT core imaging of Oman Drilling Project on D/V CHIKYU

NASA Astrophysics Data System (ADS)

Michibayashi, K.; Okazaki, K.; Leong, J. A. M.; Kelemen, P. B.; Johnson, K. T. M.; Greenberger, R. N.; Manning, C. E.; Harris, M.; de Obeso, J. C.; Abe, N.; Hatakeyama, K.; Ildefonse, B.; Takazawa, E.; Teagle, D. A. H.; Coggon, J. A.

2017-12-01

We obtained X-ray computed tomography (X-ray CT) images for all cores (GT1A, GT2A, GT3A and BT1A) in Oman Drilling Project Phase 1 (OmanDP cores), since X-ray CT scanning is a routine measurement of the IODP measurement plan onboard Chikyu, which enables the non-destructive observation of the internal structure of core samples. X-ray CT images provide information about chemical compositions and densities of the cores and is useful for assessing sample locations and the quality of the whole-round samples. The X-ray CT scanner (Discovery CT 750HD, GE Medical Systems) on Chikyu scans and reconstructs the image of a 1.4 m section in 10 minutes and produces a series of scan images, each 0.625 mm thick. The X-ray tube (as an X-ray source) and the X-ray detector are installed inside of the gantry at an opposing position to each other. The core sample is scanned in the gantry with the scanning rate of 20 mm/sec. The distribution of attenuation values mapped to an individual slice comprises the raw data that are used for subsequent image processing. Successive two-dimensional (2-D) slices of 512 x 512 pixels yield a representation of attenuation values in three-dimensional (3-D) voxels of 512 x 512 by 1600 in length. Data generated for each core consist of core-axis-normal planes (XY planes) of X-ray attenuation values with dimensions of 512 × 512 pixels in 9 cm × 9 cm cross-section, meaning at the dimensions of a core section, the resolution is 0.176 mm/pixel. X-ray intensity varies as a function of X-ray path length and the linear attenuation coefficient (LAC) of the target material is a function of the chemical composition and density of the target material. The basic measure of attenuation, or radiodensity, is the CT number given in Hounsfield units (HU). CT numbers of air and water are -1000 and 0, respectively. Our preliminary results show that CT numbers of OmanDP cores are well correlated to gamma ray attenuation density (GRA density) as a function of chemical composition and mineral density, so that their profiles with respect to the core depth provide quick lithological information such as mineral identification and phase boundary etc. Moreover, X-ray CT images can be used for 3-D fabric analyses of the whole core even after core cutting into halves for individual analyses.

Composite time-lapse computed tomography and micro finite element simulations: A new imaging approach for characterizing cement flows and mechanical benefits of vertebroplasty.

PubMed

Stadelmann, Vincent A; Zderic, Ivan; Baur, Annick; Unholz, Cynthia; Eberli, Ursula; Gueorguiev, Boyko

2016-02-01

Vertebroplasty has been shown to reinforce weak vertebral bodies and reduce fracture risks, yet cement leakage is a major problem that can cause severe complications. Since cement flow is nearly impossible to control during surgery, small volumes of cement are injected, but then mechanical benefits might be limited. A better understanding of cement flows within bone structure is required to further optimize vertebroplasty and bone augmentation in general. We developed a novel imaging method, composite time-lapse CT, to characterize cement flow during injection. In brief, composite-resolution time-lapse CT exploits the qualities of microCT and clinical CT. The method consists in overlaying low-resolution time-lapse CT scans acquired during injection onto pre-operative high-resolution microCT scans, generating composite-resolution time-lapse CT series of cement flow within bone. In this in vitro study, composite-resolution time-lapse CT was applied to eight intact and five artificially fractured cadaveric vertebrae during vertebroplasty. The time-lapse scans were acquired at one-milliliter cement injection steps until a total of 10 ml cement was injected. The composite-resolution series were then converted into micro finite element models to compute strains distribution under virtual axial loading. Relocation of strain energy density within bone structure was observed throughout the progression of the procedure. Interestingly, the normalized effect of cement injection on the overall stiffness of the vertebrae was similar between intact and fractured specimens, although at different orders of magnitude. In conclusion, composite time-lapse CT can picture cement flows during bone augmentation. The composite images can also be easily converted into finite element models to compute virtual strain distributions under loading at every step of an injection, providing deeper understanding on the biomechanics of vertebroplasty. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Multislice CT of the head and body routine scans: Are scanning protocols adjusted for paediatric patients?

PubMed Central

Sun, Z; Al Ghamdi, KS; Baroum, IH

2012-01-01

Purpose: To investigate whether the multislice CT scanning protocols of head, chest and abdomen are adjusted according to patient’s age in paediatric patients. Materials and Methods: Multislice CT examination records of paediatric patients undergoing head, chest and abdomen scans from three public hospitals during a one-year period were retrospectively reviewed. Patients were categorised into the following age groups: under 4 years, 5–8 years, 9–12 years and 13–16 years, while the tube current was classified into the following ranges: < 49 mA, 50–99 mA, 100–149 mA, 150–199 mA, > 200 mA and unknown. Results: A total of 4998 patient records, comprising a combination of head, chest and abdomen CT scans, were assessed, with head CT scans representing nearly half of the total scans. Age-based adjusted CT protocols were observed in most of the scans with higher tube current setting being used with increasing age. However, a high tube current (150–199 mA) was still used in younger patients (0–8 years) undergoing head CT scans. In one hospital, CT protocols remained constant across all age groups, indicating potential overexposure to the patients. Conclusion: This analysis shows that paediatric CT scans are adjusted according to the patient’s age in most of the routine CT examinations. This indicates increased awareness regarding radiation risks associated with CT. However, high tube current settings are still used in younger patient groups, thus, optimisation of paediatric CT protocols and implementation of current guidelines, such as age-and weight-based scanning, should be recommended in daily practice. PMID:22970059

Patient-specific dose calculations for pediatric CT of the chest, abdomen and pelvis

PubMed Central

Fraser, Nicholas D.; Carver, Diana E.; Pickens, David R.; Price, Ronald R.; Hernanz-Schulman, Marta; Stabin, Michael G.

2015-01-01

Background Organ dose is essential for accurate estimates of patient dose from CT. Objective To determine organ doses from a broad range of pediatric patients undergoing diagnostic chest–abdomen–pelvis CT and investigate how these relate to patient size. Materials and methods We used a previously validated Monte Carlo simulation model of a Philips Brilliance 64 multi-detector CT scanner (Philips Healthcare, Best, The Netherlands) to calculate organ doses for 40 pediatric patients (M:F=21:19; range 0.6–17 years). Organ volumes and positions were determined from the images using standard segmentation techniques. Non-linear regression was performed to determine the relationship between volume CT dose index (CTDIvol)-normalized organ doses and abdominopelvic diameter. We then compared results with values obtained from independent studies. Results We found that CTDIvol-normalized organ dose correlated strongly with exponentially decreasing abdominopelvic diameter (R2>0.8 for most organs). A similar relationship was determined for effective dose when normalized by dose-length product (R2=0.95). Our results agreed with previous studies within 12% using similar scan parameters (i.e. bowtie filter size, beam collimation); however results varied up to 25% when compared to studies using different bowtie filters. Conclusion Our study determined that organ doses can be estimated from measurements of patient size, namely body diameter, and CTDIvol prior to CT examination. This information provides an improved method for patient dose estimation. PMID:26142256

Low Yield of Paired Head and Cervical Spine Computed Tomography in Blunt Trauma Evaluation.

PubMed

Graterol, Joseph; Beylin, Maria; Whetstone, William D; Matzoll, Ashleigh; Burke, Rennie; Talbott, Jason; Rodriguez, Robert M

2018-06-01

With increased computed tomography (CT) utilization, clinicians may simultaneously order head and neck CT scans, even when injury is suspected only in one region. We sought to determine: 1) the frequency of simultaneous ordering of a head CT scan when a neck CT scan is ordered; 2) the yields of simultaneously ordered head and neck CT scans for clinically significant injury (CSI); and 3) whether injury in one region is associated with a higher rate of injury in the other. This was a retrospective study of all adult patients who received neck CT scans (and simultaneously ordered head CT scans) as part of their blunt trauma evaluation at an urban level 1 trauma center in 2013. An expert panel determined CSI of head and neck injuries. We defined yield as number of patients with injury/number of patients who had a CT scan. Of 3223 patients who met inclusion criteria, 2888 (89.6%) had simultaneously ordered head and neck CT scans. CT yield for CSI in both the head and neck was 0.5% (95% confidence interval [CI] 0.3-0.8%), and the yield for any injury in both the head and neck was 1.4% (95% CI 1.0-1.8%). The yield for CSI in one region was higher when CSI was seen in the other region. The yield of CT for CSI in both the head and neck concomitantly is very low. When injury is seen in one region, there is higher likelihood of injury in the other. These findings argue against paired ordering of head and neck CT scans and suggest that CT scans should be ordered individually or when injury is detected in one region. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of virtual unenhanced CT images of the abdomen under different iodine flow rates.

PubMed

Li, Yongrui; Li, Ye; Jackson, Alan; Li, Xiaodong; Huang, Ning; Guo, Chunjie; Zhang, Huimao

2017-01-01

To assess the effect of varying iodine flow rate (IFR) and iodine concentration on the quality of virtual unenhanced (VUE) images of the abdomen obtained with dual-energy CT. 94 subjects underwent unenhanced and triphasic contrast-enhanced CT scan of the abdomen, including arterial phase, portal venous phase, and delayed phase using dual-energy CT. Patients were randomized into 4 groups with different IFRs or iodine concentrations. VUE images were generated at 70 keV. The CT values, image noise, SNR and CNR of aorta, portal vein, liver, liver lesion, pancreatic parenchyma, spleen, erector spinae, and retroperitoneal fat were recorded. Dose-length product and effective dose for an examination with and without plain phase scan were calculated to assess the potential dose savings. Two radiologists independently assessed subjective image quality using a five-point scale. The Kolmogorov-Smirnov test was used first to test for normal distribution. Where data conformed to a normal distribution, analysis of variance was used to compare mean HU values, image noise, SNRs and CNRs for the 4 image sets. Where data distribution was not normal, a nonparametric test (Kruskal-Wallis test followed by stepwise step-down comparisons) was used. The significance level for all tests was 0.01 (two-sided) to allow for type 2 errors due to multiple testing. The CT numbers (HU) of VUE images showed no significant differences between the 4 groups (p > 0.05) or between different phases within the same group (p > 0.05). VUE images had equal or higher SNR and CNR than true unenhanced images. VUE images received equal or lower subjective image quality scores than unenhanced images but were of acceptable quality for diagnostic use. Calculated dose-length product and estimated dose showed that the use of VUE images in place of unenhanced images would be associated with a dose saving of 25%. VUE images can replace conventional unenhanced images. VUE images are not affected by varying iodine flow rates and iodine concentrations, and diagnostic examinations could be acquired with a potential dose saving of 25%.

Frequencies of micronucleated reticulocytes, a dosimeter of DNA double-strand breaks, in infants receiving computed tomography or cardiac catheterization.

PubMed

Khattab, Mona; Walker, Dale M; Albertini, Richard J; Nicklas, Janice A; Lundblad, Lennart K A; Vacek, Pamela M; Walker, Vernon E

2017-08-01

The use of computed tomography (CT scans) has increased dramatically in recent decades, raising questions about the long-term safety of CT-emitted x-rays especially in infants who are more sensitive to radiation-induced effects. Cancer risk estimates for CT scans typically are extrapolated from models; therefore, new approaches measuring actual DNA damage are needed for improved estimations. Hence, changes in a dosimeter of DNA double-strand breaks, micronucleated reticulocytes (MN-RETs) measured by flow cytometry, were investigated in mice and infants exposed to CT scans. In male C57BL/6N mice (6-8 weeks-of-age), there was a dose-related increase in MN-RETs in blood samples collected 48h after CT scans delivering targeted exposures of 1-130 cGy x-rays (n=5-10/group, r=0.994, p=0.01), with significant increases occurring at exposure levels as low as 0.83 cGy x-rays compared to control mice (p=0.002). In paired blood specimens from infants with no history of a prior CT scan, there was no difference in MN-RET frequencies found 2h before (mean, 0.10±0.07%) versus 48h after (mean, 0.11±0.05%) a scheduled CT scan/cardiac catheterization. However, in infants having prior CT scan(s), MN-RET frequencies measured at 48h after a scheduled CT scan (mean=0.22±0.12%) were significantly higher than paired baseline values (mean, 0.17±0.07%; p=0.032). Increases in baseline (r=0.722, p<0.001) and 48-h post exposure (r=0.682, p<0.001) levels of MN-RETs in infants with a history of prior CT scans were significantly correlated with the number of previous CT scans. These preliminary findings suggest that prior CT scans increase the cellular responses to subsequent CT exposures. Thus, further investigation is needed to characterize the potential cancer risk from single versus repeated CT scans or cardiac catheterizations in infants. Copyright © 2017 Elsevier B.V. All rights reserved.

Regional CBF in chronic stable TBI treated with hyperbaric oxygen.

PubMed

Barrett, K F; Masel, B; Patterson, J; Scheibel, R S; Corson, K P; Mader, J T

2004-01-01

To investigate whether Hyperbaric Oxygen Therapy (HBO2) could improve neurologic deficits and regional cerebral blood flow (rCBF) in chronic traumatic brain injuries (TBI), the authors employed a nonrandomized control pilot trial. Five subjects, at least three years post head injury, received HBO2. Five head injured controls (HIC) were matched for age, sex, and type of injury. Five healthy subjects served as normal controls. Sixty-eight normal volunteers comprised a reference data bank against which to compare SPECT brain scans. HBO2 subjects received 120 HBO2 in blocks of 80 and 40 treatments with an interval five-month break. Normal controls underwent a single SPECT brain scan, HBO2, and repeat SPECT battery. TBI subjects were evaluated by neurologic, neuropsychometric, exercise testing, and pre and post study MRIs, or CT scans if MRI was contraindicated. Statistical Parametric Mapping was applied to SPECT scans for rCBF analysis. There were no significant objective changes in neurologic, neuropsychometric, exercise testing, MRIs, or rCBF. In this small pilot study, HBO2 did not effect clinical or regional cerebral blood flow improvement in TBI subjects.

Optical computed tomography utilizing a rotating mirror and Fresnel lenses: operating principles and preliminary results

NASA Astrophysics Data System (ADS)

Xu, Y.; Wuu, Cheng-Shie

2013-02-01

The performance of a fast optical computed tomography (CT) scanner based on a point laser source, a small area photodiode detector, and two optical-grade Fresnel lenses is evaluated. The OCTOPUS™-10× optical CT scanner (MGS Research Inc., Madison, CT) is an upgrade of the OCTOPUS™ research scanner with improved design for faster motion of the laser beam and faster data acquisition process. The motion of the laser beam in the new configuration is driven by the rotational motion of a scanning mirror. The center of the scanning mirror and the center of the photodiode detector are adjusted to be on the focal points of two coaxial Fresnel lenses. A glass water tank is placed between the two Fresnel lenses to house gel phantoms and matching liquids. The laser beam scans over the water tank in parallel beam geometry for projection data as the scanning mirror rotates at a frequency faster than 0.1 s per circle. Signal sampling is performed independently of the motion of the scanning mirror, to reduce the processing time for the synchronization of the stepper motors and the data acquisition board. An in-house developed reference image normalization mechanism is added to the image reconstruction program to correct the non-uniform light transmitting property of the Fresnel lenses. Technical issues with regard to the new design of the scanner are addressed, including projection data extraction from raw data samples, non-uniform pixel averaging and reference image normalization. To evaluate the dosimetric accuracy of the scanner, the reconstructed images from a 16 MeV, 6 cm × 6 cm electron field irradiation were compared with those from the Eclipse treatment planning system (Varian Corporation, Palo Alto, CA). The spatial resolution of the scanner is demonstrated to be of sub-millimeter accuracy. The effectiveness of the reference normalization method for correcting the non-uniform light transmitting property of the Fresnel lenses is analyzed. A sub-millimeter accuracy of the phantom positioning between the reference scan and the actual scan is demonstrated to be essential. The fast scanner is shown to be able to scan gel phantoms with a wider field of view (5 mm from the edge of the scanned dosimeters) and at a speed 10 to 20 times faster than the OCTOPUS™ scanner. A large uncertainty of 5% (defined as the ratio of the standard deviation to the mean) is typically observed in the reconstructed images, owing to the inaccuracy in the phantom positioning process. Methods for further improvement of the accuracy of the in-house modified OCTOPUS™-10× scanner are discussed.

An audit of imaging test utilization for the management of lymphoma in an oncology hospital: implications for resource planning?

PubMed

Schwartz, A; Gospodarowicz, M K; Khalili, K; Pintilie, M; Goddard, S; Keller, A; Tsang, R W

2006-02-01

The purpose of this study was to assist with resource planning by examining the pattern of physician utilization of imaging procedures for lymphoma patients in a dedicated oncology hospital. The proportion of imaging tests ordered for routine follow up with no specific clinical indication was quantified, with specific attention to CT scans. A 3-month audit was performed. The reasons for ordering all imaging procedures (X-rays, CT scans, ultrasound, nuclear scan and MRI) were determined through a retrospective chart review. 411 lymphoma patients had 686 assessments (sets of imaging tests) and 981 procedures (individual imaging tests). Most procedures were CT scans (52%) and chest radiographs (30%). The most common reasons for ordering imaging were assessing response (23%), and investigating new symptoms (19%). Routine follow up constituted 21% of the assessments (142/686), and of these, 82% were chest radiographs (116/142), while 24% (34/142) were CT scans. With analysis restricted to CT scans (296 assessments in 248 patients), the most common reason for ordering CT scans were response evaluation (40%), and suspicion of recurrence and/or new symptom (23%). Follow-up CT scans done with no clinical indication comprised 8% (25/296) of all CT assessments. Staging CT scans were under-represented at 6% of all assessments. Imaging with CT scans for follow up of asymptomatic patients is infrequent. However, scans done for staging new lymphoma patients were unexpectedly low in frequency, due to scans done elsewhere prior to referral. This analysis uncovered utilization patterns, helped resource planning and provided data to reduce unnecessary imaging procedures.

Liver metastases: imaging considerations for protocol development with Multislice CT (MSCT)

PubMed Central

Silverman, Paul M

2006-01-01

Conventional, single-slice helical computed tomography (SSCT) allowed for scanning the majority of the liver during the critical portal venous phase. This was often referred to as the ‘optimal temporal window’. The introduction of current day multislice CT (MSCT) now allows us to acquire images in a much shorter time and more precisely than ever before. This yields increased conspicuity between low attenuation lesions and the enhanced normal liver parenchyma and optimal imaging for the vast majority of hepatic hypovascular metastases. Most importantly, these scanners, when compared to conventional non-helical scanners, avoid impinging upon the ‘equilibrium’ phase when tumors can become isodense/invisible. MSCT also allows for true multiphase scanning during the arterial and late arterial phases for detection of hypervascular metastases. The MSCT imaging speed has increased significantly over the past years with the introduction of 32- and 64-detector systems and will continue to increase in the future volumetric CT. This provides a number of important gains that are discussed in detail. PMID:17098650

Anti-Ma2-associated encephalitis with normal FDG-PET: a case of pseudo-Whipple's disease.

PubMed

Castle, James; Sakonju, Ai; Dalmau, Josep; Newman-Toker, David E

2006-10-01

A 39-year-old man presented with a history of several months of progressive personality changes, social withdrawal, bradykinesia, mutism, dysphagia, worsening gait, and difficulty with daily living activities. Examination revealed an atypical parkinsonian appearance with incomplete supranuclear ophthalmoplegia and an unusual oculomotor disorder characterized by both low-amplitude, intermittent opsoclonus, and slow, nystagmoid intrusions. Routine laboratory testing, autoimmune and infectious serologies, brain MRI, lumbar puncture, electroencephalogram, whole-body CT scan, paraneoplastic serologies, small bowel biopsy, 18F-fluorodeoxyglucose positron emission tomography CT scan, brain biopsy, and testicular ultrasound. Anti-Ma2 paraneoplastic encephalitis in association with metastatic testicular cancer; initially misdiagnosed as CNS Whipple's disease. Corticosteroids, intravenous immunoglobulins, orchiectomy, muscle relaxants, mycophenolate mofetil, plasmapheresis, and bleomycin, etoposide and platinum chemotherapy.

Implementation of a CT Scan Practice Guideline for Pediatric Trauma Patients Reduces Unnecessary Scans Without Impacting Outcomes.

PubMed

McGrew, Patrick R; Chestovich, Paul J; Fisher, Jay D; Kuhls, Deborah A; Fraser, Douglas R; Patel, Purvi P; Katona, Chad W; Saquib, Syed; Fildes, John J

2018-05-04

Computed Tomography (CT) scans are useful in the evaluation of trauma patients, but are costly and pose risks from ionizing radiation in children. Recent literature has demonstrated the utility of CT scan guidelines in the management of pediatric trauma. This study objective is to review our treatment of pediatric blunt trauma patients and evaluate CT utilization before and after CT-guideline implementation. Our Pediatric Level 2 Trauma Center (TC) implemented a CT scan practice guideline for pediatric trauma patients in March 2014. The guideline recommended for or against CT of the head and abdomen/pelvis utilizing published criteria from the Pediatric Emergency Care and Research Network (PECARN). There was no chest CT guideline. We reviewed all pediatric trauma patients for CT scans obtained during initial evaluation before and after guideline implementation, excluding inpatient scans. The Trauma Registry Database was queried to include all pediatric (age<15) trauma patients seen in our TC from 2010-2016, excluding penetrating mechanism and deaths in the TC. Scans were considered positive if organ injury was detected. Primary outcome was the proportion of patients undergoing CT and percent positive CTs. Secondary outcomes were hospital length of stay (LOS), readmissions, and mortality. Categorical and continuous variables were analyzed with Chi-square and Wilcoxon rank-sum tests, respectively. P<0.05 was considered significant. We identified 1934 patients: 1106 pre- and 828 post-guideline. Absolute reductions in head, chest, and abdomen/pelvis CT scans were 17.7%, 11.5%, and 18.8% respectively (p<0.001). Percent positive head CTs were equivalent, but percent positive chest and abdomen CT increased after implementation. Secondary outcomes were unchanged. Implementation of a pediatric CT guideline significantly decreases CT utilization, reducing the radiation exposure without a difference in outcome. Trauma centers treating pediatric patients should adopt similar guidelines to decrease unnecessary CT scans in children. Level IV, Therapeutic Study.

(18)F-FDG PET-CT simulation for non-small-cell lung cancer: effect in patients already staged by PET-CT.

PubMed

Hanna, Gerard G; McAleese, Jonathan; Carson, Kathryn J; Stewart, David P; Cosgrove, Vivian P; Eakin, Ruth L; Zatari, Ashraf; Lynch, Tom; Jarritt, Peter H; Young, V A Linda; O'Sullivan, Joe M; Hounsell, Alan R

2010-05-01

Positron emission tomography (PET), in addition to computed tomography (CT), has an effect in target volume definition for radical radiotherapy (RT) for non-small-cell lung cancer (NSCLC). In previously PET-CT staged patients with NSCLC, we assessed the effect of using an additional planning PET-CT scan for gross tumor volume (GTV) definition. A total of 28 patients with Stage IA-IIIB NSCLC were enrolled. All patients had undergone staging PET-CT to ensure suitability for radical RT. Of the 28 patients, 14 received induction chemotherapy. In place of a RT planning CT scan, patients underwent scanning on a PET-CT scanner. In a virtual planning study, four oncologists independently delineated the GTV on the CT scan alone and then on the PET-CT scan. Intraobserver and interobserver variability were assessed using the concordance index (CI), and the results were compared using the Wilcoxon signed ranks test. PET-CT improved the CI between observers when defining the GTV using the PET-CT images compared with using CT alone for matched cases (median CI, 0.57 for CT and 0.64 for PET-CT, p = .032). The median of the mean percentage of volume change from GTV(CT) to GTV(FUSED) was -5.21% for the induction chemotherapy group and 18.88% for the RT-alone group. Using the Mann-Whitney U test, this was significantly different (p = .001). PET-CT RT planning scan, in addition to a staging PET-CT scan, reduces interobserver variability in GTV definition for NSCLC. The GTV size with PET-CT compared with CT in the RT-alone group increased and was reduced in the induction chemotherapy group.

Characterizing functional lung heterogeneity in COPD using reference equations for CT scan-measured lobar volumes.

PubMed

Come, Carolyn E; Diaz, Alejandro A; Curran-Everett, Douglas; Muralidhar, Nivedita; Hersh, Craig P; Zach, Jordan A; Schroeder, Joyce; Lynch, David A; Celli, Bartolome; Washko, George R

2013-06-01

CT scanning is increasingly used to characterize COPD. Although it is possible to obtain CT scan-measured lung lobe volumes, normal ranges remain unknown. Using COPDGene data, we developed reference equations for lobar volumes at maximal inflation (total lung capacity [TLC]) and relaxed exhalation (approximating functional residual capacity [FRC]). Linear regression was used to develop race-specific (non-Hispanic white [NHW], African American) reference equations for lobar volumes. Covariates included height and sex. Models were developed in a derivation cohort of 469 subjects with normal pulmonary function and validated in 546 similar subjects. These cohorts were combined to produce final prediction equations, which were applied to 2,191 subjects with old GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II to IV COPD. In the derivation cohort, women had smaller lobar volumes than men. Height positively correlated with lobar volumes. Adjusting for height, NHWs had larger total lung and lobar volumes at TLC than African Americans; at FRC, NHWs only had larger lower lobes. Age and weight had no effect on lobar volumes at TLC but had small effects at FRC. In subjects with COPD at TLC, upper lobes exceeded 100% of predicted values in GOLD II disease; lower lobes were only inflated to this degree in subjects with GOLD IV disease. At FRC, gas trapping was severe irrespective of disease severity and appeared uniform across the lobes. Reference equations for lobar volumes may be useful in assessing regional lung dysfunction and how it changes in response to pharmacologic therapies and surgical or endoscopic lung volume reduction.

Triple-phase helical computed tomography in dogs with solid splenic masses

PubMed Central

KUTARA, Kenji; SEKI, Mamiko; ISHIGAKI, Kumiko; TESHIMA, Kenji; ISHIKAWA, Chieko; KAGAWA, Yumiko; EDAMURA, Kazuya; NAKAYAMA, Tomohiro; ASANO, Kazushi

2017-01-01

We investigated the utility of triple-phase helical computed tomography (CT) in differentiating between benign and malignant splenic masses in dogs. Forty-two dogs with primary splenic masses underwent triple-phase helical CT scanning (before administration of contrast, and in the arterial phase, portal venous phase, and delayed phase) prior to splenectomy. Tissue specimens were sent for pathological diagnosis; these included hematomas (n=14), nodular hyperplasias (n=12), hemangiosarcomas (n=11), and undifferentiated sarcomas (n=5). The CT findings were compared with the histological findings. Nodular hyperplasia significantly displayed a homogeneous normal enhancement pattern in all phases. Hemangiosarcoma displayed 2 significant contrast-enhancement patterns, including a homogeneous pattern of poor enhancement in all phases, and a heterogeneous remarkable enhancement pattern in the arterial and portal venous phases. Hematoma and undifferentiated sarcoma displayed a heterogeneous normal enhancement pattern in all phases. The contrast-enhanced volumetric ratios of hematoma tended to be greater than those of undifferentiated sarcoma. Our study demonstrated that the characteristic findings on triple-phase helical CT could be useful for the preoperative differentiation of hematoma, nodular hyperplasia, hemangiosarcoma, and undifferentiated sarcoma in dogs. Triple-phase helical CT may be a useful diagnostic tool in dogs with splenic masses. PMID:28993600

Patient- and cohort-specific dose and risk estimation for abdominopelvic CT: a study based on 100 patients

NASA Astrophysics Data System (ADS)

Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Frush, Donald P.; Samei, Ehsan

2012-03-01

The purpose of this work was twofold: (a) to estimate patient- and cohort-specific radiation dose and cancer risk index for abdominopelvic computer tomography (CT) scans; (b) to evaluate the effects of patient anatomical characteristics (size, age, and gender) and CT scanner model on dose and risk conversion coefficients. The study included 100 patient models (42 pediatric models, 58 adult models) and multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which DLP-normalized-effective dose (k factor) and DLP-normalized-risk index values (q factor) were derived. The k factor showed exponential decrease with increasing patient size. For a given gender, q factor showed exponential decrease with both increasing patient size and patient age. The discrepancies in k and q factors across scanners were on average 8% and 15%, respectively. This study demonstrates the feasibility of estimating patient-specific organ dose and cohort-specific effective dose and risk index in abdominopelvic CT requiring only the knowledge of patient size, gender, and age.

Radiopaque biodegradable stent for duct-to-duct biliary reconstruction in pigs.

PubMed

Tanimoto, Yoshisato; Tashiro, Hirotaka; Mikuriya, Yoshihiro; Kuroda, Shintaro; Hashimoto, Masakazu; Kobayashi, Tsuyoshi; Taniura, Tokunori; Ohdan, Hideki

2016-06-01

Biliary stricture is a common cause of morbidity after liver transplantation. We previously developed a duct-to-duct biliary anastomosis technique using a biodegradable stent tube and confirmed the feasibility and safety of biliary stent use. However, the duration and mechanism of biliary stent absorption in the common bile duct remain unclear. Radiopaque biodegradable biliary stents were created using a copolymer of L-lactide and ε-caprolactone (70: 30) and coated with barium sulfate. Stents were surgically implanted in the common bile duct of 11 pigs. Liver function tests and computed tomography (CT) scans were performed postoperatively, and autopsies were conducted 6 months after biliary stent implantation. After the surgery, all 11 pigs had normal liver function and survived without any significant complications such as biliary leakage. A CT scan at 2 months post-procedure showed that the biliary stents were located in the hilum of the liver. The stents were not visible by CT scan at the 6-month follow-up examination. The surgical implantation of radiopaque biodegradable biliary stents in biliary surgery represents a new option for duct-to-duct biliary reconstruction. This technique appears to be feasible and safe and is not associated with any significant biliary complications. The advantage of coated biliary stent use is that it may be visualized using abdominal radiography such as CT.

Customized cranioplasty implants using three-dimensional printers and polymethyl-methacrylate casting.

PubMed

Kim, Bum-Joon; Hong, Ki-Sun; Park, Kyung-Jae; Park, Dong-Hyuk; Chung, Yong-Gu; Kang, Shin-Hyuk

2012-12-01

The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. A total of 16 patients with large skull defects (>100 cm(2)) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects.

Endoscopic ultrasonography in chronic pancreatitis: a comparative prospective study with conventional ultrasonography, computed tomography, and ERCP.

PubMed

Buscail, L; Escourrou, J; Moreau, J; Delvaux, M; Louvel, D; Lapeyre, F; Tregant, P; Frexinos, J

1995-04-01

The usefulness and accuracy rate of endoscopic ultrasonography (EUS) in the diagnosis of chronic pancreatitis (CP) were prospectively evaluated in 81 patients with suspected pancreatic disease. All underwent EUS, abdominal ultrasonography (AUS), and computed tomography (CT), and endoscopic retrograde cholangiopancreatography (ERCP) was performed in 55 of the cases. The diagnosis of CP was established in 44 patients (CP group) including 24 with a calcified form. No pancreatic disease was observed in 18 patients (control group), and 19 patients had a pancreatic tumor. In the CP group AUS was less accurate than EUS in visualizing the pancreas, performances of CT scan being identical to EUS in this respect. A good correlation was observed between EUS and ERCP for visualization and measurement of the Wirsung duct. The most significant changes observed by EUS in the CP group were dilatation of the main pancreatic duct, heterogeneous echogenicity of the pancreatic parenchyma, and cysts < 20 mm in size even in noncalcified CP or with normal pancreatograms. Sensitivity of EUS for diagnosis of CP was 88% (AUS, 58%; ERCP, 74%; CT scan, 75%), the specificity being 100% for ERCP and EUS, 95% for CT scan, and 75% for AUS. The good performances of EUS allow early diagnosis of CP in symptomatic patients since heterogeneous echogenicity of the pancreatic parenchyma seems to be almost specifically associated with the disease.

CT scans for pulmonary surveillance may be overused in lower-grade sarcoma.

PubMed

Miller, Benjamin J; Carmody Soni, Emily E; Reith, John D; Gibbs, C Parker; Scarborough, Mark T

2012-01-01

Chest CT scans are often used to monitor patients after excision of a sarcoma. Although sensitive, CT scans are more expensive than chest radiographs and are associated with possible health risks from a higher radiation dose. We hypothesized that a program based upon limited CT scans in lower-grade sarcoma could be efficacious and less expensive. We retrospectively assigned patients to a high-risk or low-risk hypothetical protocol. Eighty-three low- or intermediate-grade soft tissue sarcomas met our inclusion criteria. Eight patients had pulmonary metastasis. A protocol based on selective CT scans for high-risk patients would have identified seven out of eight lesions. The incremental cost-effectiveness ratio for routine CT scans was $731,400. A program based upon selective CT scans for higher-risk patients is accurate, spares unnecessary radiation to many patients, and is less expensive.

Barium Sulfate

MedlinePlus

... and intestine using x-rays or computed tomography (CAT scan, CT scan; a type of body scan that uses a ... be clearly seen by x-ray examination or CT scan. ... more times before an x-ray examination or CT scan.If you are using a barium sulfate enema, ...

A comparison between intrastomal 3D ultrasonography, CT scanning and findings at surgery in patients with stomal complaints.

PubMed

Näsvall, P; Wikner, F; Gunnarsson, U; Rutegård, J; Strigård, K

2014-10-01

Since there are no reliable investigative tools for imaging parastomal hernia, new techniques are needed. The aim of this study was to assess the validity of intrastomal three-dimensional ultrasonography (3D) as an alternative to CT scanning for the assessment of stomal complaints. Twenty patients with stomal complaints, indicating surgery, were examined preoperatively with a CT scan in the supine position and 3D intrastomal ultrasonography in the supine and erect positions. Comparison with findings at surgery, considered to be the true state, was made. Both imaging methods, 3D ultrasonography and CT scanning, showed high sensitivity (ultrasound 15/18, CT scan 15/18) and specificity (ultrasound 2/2, CT scan 1/2) when judged by a dedicated radiologist. Corresponding values for interpretation of CT scans in routine clinical practice was for sensitivity 17/18 and for specificity 1/2. 3D ultrasonography has a high validity and is a promising alternative to CT scanning in the supine position to distinguish a bulge from a parastomal hernia.

Systematic review on the value of CT scanning in the diagnosis of anastomotic leakage after colorectal surgery.

PubMed

Kornmann, Verena N N; Treskes, Nikki; Hoonhout, Lilian H F; Bollen, Thomas L; van Ramshorst, Bert; Boerma, Djamila

2013-04-01

Timely diagnosis of anastomotic leakage after colorectal surgery and adequate treatment is important to reduce morbidity and mortality. Abdominal computed tomography (CT) scanning is the diagnostic tool of preference, but its value may be questionable in the early postoperative period. The accuracy of CT scanning for the detection of anastomotic leakage and its role in timing of intervention was evaluated. A systematic literature search was performed. Relevant publications were identified from four electronic databases between 1990 and 2011. Inclusion criteria were human studies, studies published in English or Dutch, colorectal surgery with primary anastomosis, and abdominal CT scan with reported outcome for the detection of anastomotic leakage. Exclusion criteria were cohort of fewer than five patients, other gastrointestinal surgery, no anastomosis, and radiological imaging other than CT. Eight studies, including 221 abdominal CT scans, fulfilled the inclusion criteria. Overall, the methodological quality of the studies was poor. The overall sensitivity of CT scanning to diagnose leakage was 0.68 (95 % confidence interval 0.59-0.75) for colonic resection. Data on the sequelae of false-negative CT scanning was not available. There is limited good-quality evidence to determine the value of CT scans in the detection of anastomotic leakage. To prevent delay in diagnosis and appropriate treatment of anastomotic leakage, the relatively low sensitivity of CT scanning must be taken into account.

Effect of staff training on radiation dose in pediatric CT.

PubMed

Hojreh, Azadeh; Weber, Michael; Homolka, Peter

2015-08-01

To evaluate the efficacy of staff training on radiation doses applied in pediatric CT scans. Pediatric patient doses from five CT scanners before (1426 scans) and after staff training (2566 scans) were compared statistically. Examinations included cranial CT (CCT), thoracic, abdomen-pelvis, and trunk scans. Dose length products (DLPs) per series were extracted from CT dose reports archived in the PACS. A pooled analysis of non-traumatic scans revealed a statistically significant reduction in the dose for cranial, thoracic, and abdomen/pelvis scans (p<0.01). This trend could be demonstrated also for trunk scans, however, significance could not be established due to low patient frequencies (p>0.05). The percentage of scans performed with DLPs exceeding the German DRLs was reduced from 41% to 7% (CCT), 19% to 5% (thorax-CT), from 9% to zero (abdominal-pelvis CT), and 26% to zero (trunk; DRL taken as summed DRLs for thorax plus abdomen-pelvis, reduced by 20% accounting for overlap). Comparison with Austrian DRLs - available only for CCT and thorax CT - showed a reduction from 21% to 3% (CCT), and 15 to 2% (thorax CT). Staff training together with application of DRLs provide an efficient approach for optimizing radiation dose in pediatric CT practice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Demand for CT scans increases during transition from paediatric to adult care: an observational study from 2009 to 2015.

PubMed

Thurley, Pete; Crookdake, Jonathan; Norwood, Mark; Sturrock, Nigel; Fogarty, Andrew W

2018-02-01

Avoiding unnecessary radiation exposure is a clinical priority in children and young adults. We aimed to explore demand for CT scans in a busy general hospital with particular interest in the period of transition from paediatric to adult medical care. We used an observational epidemiological study based in a teaching hospital. Data were obtained on numbers and rates of CT scans from 2009 to 2015. The main outcome was age-stratified rates of receiving a CT scan. There were a total of 262,221 CT scans. There was a large step change in the rate of CT scans over the period of transition from paediatric to adult medical care. Individuals aged 10-15 years experienced 6.7 CT scans per 1000 clinical episodes, while those aged 19-24 years experienced 19.8 CT scans per 1000 clinical episodes (p < 0.001). This difference remained significant for all sensitivity analyses. There is almost a threefold increase in rates of CT scans in the two populations before and after the period of transition from paediatric to adult medical care. While we were unable to adjust for case mix or quantify radiation exposure, paediatricians' diagnostic strategies to minimize radiation exposure may have clinical relevance for adult physicians, and hence enable reductions in ionizing radiation to patients. Advances in knowledge: A large increase in rates of CT scans occurs during adolescence, and considering paediatricians' strategies to minimize radiation exposure may enable reductions to all patients.

Diagnostic and clinical benefit of combined coronary calcium and perfusion assessment in patients undergoing PET/CT myocardial perfusion stress imaging.

PubMed

Bybee, Kevin A; Lee, John; Markiewicz, Richard; Longmore, Ryan; McGhie, A Iain; O'Keefe, James H; Hsu, Bai-Ling; Kennedy, Kevin; Thompson, Randall C; Bateman, Timothy M

2010-04-01

A limitation of stress myocardial perfusion imaging (MPI) is the inability to detect non-obstructive coronary artery disease (CAD). One advantage of MPI with a hybrid CT device is the ability to obtain same-setting measurement of the coronary artery calcium score (CACS). Utilizing our single-center nuclear database, we identified 760 consecutive patients with: (1) no CAD history; (2) a normal clinically indicated Rb-82 PET/CT stress perfusion study; and (3) a same-setting CAC scan. 487 of 760 patients (64.1%) had subclinical CAD based on an abnormal CACS. Of those with CAC, the CACS was > or =100, > or =400, and > or =1000 in 47.0%, 22.4%, and 8.4% of patients, respectively. Less than half of the patients with CAC were receiving aspirin or statin medications prior to PET/CT imaging. Patients with CAC were more likely to be initiated or optimized on proven medical therapy for CAD immediately following PET/CT MPI compared to those without CAC. Subclinical CAD is common in patients without known CAD and normal myocardial perfusion assessed by hybrid PET/CT imaging. Identification of CAC influences subsequent physician prescribing patterns such that those with CAC are more likely to be treated with proven medical therapy for the treatment of CAD.

Gated CT imaging using a free-breathing respiration signal from flow-volume spirometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

D'Souza, Warren D.; Kwok, Young; Deyoung, Chad

2005-12-15

Respiration-induced tumor motion is known to cause artifacts on free-breathing spiral CT images used in treatment planning. This leads to inaccurate delineation of target volumes on planning CT images. Flow-volume spirometry has been used previously for breath-holds during CT scans and radiation treatments using the active breathing control (ABC) system. We have developed a prototype by extending the flow-volume spirometer device to obtain gated CT scans using a PQ 5000 single-slice CT scanner. To test our prototype, we designed motion phantoms to compare image quality obtained with and without gated CT scan acquisition. Spiral and axial (nongated and gated) CTmore » scans were obtained of phantoms with motion periods of 3-5 s and amplitudes of 0.5-2 cm. Errors observed in the volume estimate of these structures were as much as 30% with moving phantoms during CT simulation. Application of motion-gated CT with active breathing control reduced these errors to within 5%. Motion-gated CT was then implemented in patients and the results are presented for two clinical cases: lung and abdomen. In each case, gated scans were acquired at end-inhalation, end-exhalation in addition to a conventional free-breathing (nongated) scan. The gated CT scans revealed reduced artifacts compared with the conventional free-breathing scan. Differences of up to 20% in the volume of the structures were observed between gated and free-breathing scans. A comparison of the overlap of structures between the gated and free-breathing scans revealed misalignment of the structures. These results demonstrate the ability of flow-volume spirometry to reduce errors in target volumes via gating during CT imaging.« less

MO-E-17A-06: Organ Dose in Abdomen-Pelvis CT: Does TG 111 Equilibrium Dose Concept Better Accounts for KVp Dependence Than Conventional CTDI?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, X; Morgan, A; Davros, W

Purpose: In CT imaging, a desirable quality assurance (QA) dose quantity should account for the dose variability across scan parameters and scanner models. Recently, AAPM TG 111 proposed to use equilibrium dose-pitch product, in place of CT dose index (CTDI100), for scan modes involving table translation. The purpose of this work is to investigate whether this new concept better accounts for the kVp dependence of organ dose than the conventional CTDI concept. Methods: The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A Monte Carlo program developed and validated for a 128-slice CT system (Definition Flash,more » Siemens Healthcare) was used to simulate organ dose for abdomenpelvis scans at five tube voltages (70, 80, 100, 120, 140 kVp) with a pitch of 0.8 and a detector configuration of 2x64x0.6 mm. The same Monte Carlo program was used to simulate CTDI100 and equilibrium dose-pitch product. For both metrics, the central and peripheral values were used together with helical pitch to calculate a volume-weighted average, i.e., CTDIvol and (Deq)vol, respectively. Results: While other scan parameters were kept constant, organ dose depended strongly on kVp; the coefficient of variation (COV) across the five kVp values ranged between 70–75% for liver, spleen, stomach, pancreas, kidneys, colon, small intestine, bladder, and ovaries, all of which were inside the primary radiation beam. One-way analysis of variance (ANOVA) for the effect of kVp was highly significant (p=3e−30). When organ dose was normalized by CTDIvol, the COV across the five kVp values reduced to 7–16%. The effect of kVp was still highly significant (p=4e−4). When organ dose was normalized by (Deq)vol, the COV further reduced to 4−12%. The effect of kVp was borderline significant (p=0.04). Conclusion: In abdomen-pelvis CT, TG 111 equilibrium dose concept better accounts for kVp dependence than the conventional CTDI. This work is supported by a faculty startup fund from the Cleveland State University.« less

A prototype piecewise-linear dynamic attenuator

NASA Astrophysics Data System (ADS)

Hsieh, Scott S.; Peng, Mark V.; May, Christopher A.; Shunhavanich, Picha; Fleischmann, Dominik; Pelc, Norbert J.

2016-07-01

The piecewise-linear dynamic attenuator has been proposed as a mechanism in CT scanning for personalizing the x-ray illumination on a patient- and application-specific basis. Previous simulations have shown benefits in image quality, scatter, and dose objectives. We report on the first prototype implementation. This prototype is reduced in scale and speed and is integrated into a tabletop CT system with a smaller field of view (25 cm) and longer scan time (42 s) compared to a clinical system. Stainless steel wedges were machined and affixed to linear actuators, which were in turn held secure by a frame built using rapid prototyping technologies. The actuators were computer-controlled, with characteristic noise of about 100 microns. Simulations suggest that in a clinical setting, the impact of actuator noise could lead to artifacts of only 1 HU. Ring artifacts were minimized by careful design of the wedges. A water beam hardening correction was applied and the scan was collimated to reduce scatter. We scanned a 16 cm water cylinder phantom as well as an anthropomorphic pediatric phantom. The artifacts present in reconstructed images are comparable to artifacts normally seen with this tabletop system. Compared to a flat-field reference scan, increased detectability at reduced dose is shown and streaking is reduced. Artifacts are modest in our images and further refinement is possible. Issues of mechanical speed and stability in the challenging clinical CT environment will be addressed in a future design.

[A case of lung cancer producing granulocyte colony-stimulating factor with a significantly high uptake in the bones observed by a FDG-PET scan].

PubMed

Hidaka, Dai; Koshizuka, Hiroaki; Hiyama, Junichiro; Nakatsubo, Seita; Ikeda, Koutarou; Hayashi, Akihiro; Fujii, Akiko; Sawamoto, Ryouko; Misumi, Yukihiro; Miyagawa, Yousuke

2009-03-01

A 57-year-old man complaining of right shoulder pain was admitted. Chest enhanced CT scanning showed a mass shadow in the right upper lobe with chest wall invasion. The laboratory data on admission showed marked leukocytosis. A CT-guided lung biopsy was performed, and a histological examination of the biopsy specimen showed a spindle cell type pleomorphic carcinoma. Immunohistochemistry staining using an anti-granulocyte colony-stimulating factor (G-CSF) monoclonal antibody demonstrated many tumor cells containing G-CSF as well as an increased level of serum G-CSF. The diagnosis was determined to be lung cancer producing G-CSF. FDG-PET scanning showed a significantly high uptake in the right upper field and the bones throughout the body. After chemoradiation therapy, the patient underwent a right upper lobectomy with a chest wall resection. Since then, the leukocytosis and the high level of serum G-CSF normalized and the high uptake in the bones disappeared in the FDG-PET scan.

Integration of Medical Imaging Including Ultrasound into a New Clinical Anatomy Curriculum

ERIC Educational Resources Information Center

Moscova, Michelle; Bryce, Deborah A.; Sindhusake, Doungkamol; Young, Noel

2015-01-01

In 2008 a new clinical anatomy curriculum with integrated medical imaging component was introduced into the University of Sydney Medical Program. Medical imaging used for teaching the new curriculum included normal radiography, MRI, CT scans, and ultrasound imaging. These techniques were incorporated into teaching over the first two years of the…

Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

NASA Astrophysics Data System (ADS)

Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

2009-02-01

Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

New prospective 4D-CT for mitigating the effects of irregular respiratory motion

NASA Astrophysics Data System (ADS)

Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

2017-08-01

Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

Acute hexogen poisoning after occupational exposure.

PubMed

Testud, F; Glanclaude, J M; Descotes, J

1996-01-01

Hexogen (cyclonite, RDX) nitrate explosive is an infrequent cause of poisoning. A 42-year-old man with no prior history of epilepsy experienced grand mal seizures after sieving fine hexogen (RDX) powder for four hours in an ammunition plant. Physical examination was normal on arrival at the emergency room but recurrent seizures occurred six hour after admission. EEG, CT scan and MRI were normal and the patient recovered uneventfully. The available toxicological data on this rare occupational poisoning are reviewed.

Is triple contrast computed tomographic scanning useful in the selective management of stab wounds to the back?

PubMed

McAllister, E; Perez, M; Albrink, M H; Olsen, S M; Rosemurgy, A S

1994-09-01

We devised a protocol to prospectively manage stab wounds to the back with the hypothesis that the triple contrast computed tomographic (CT) scan is an effective means of detecting occult injury in these patients. All wounds to the back in hemodynamically stable adults were locally explored. All patients with muscular fascial penetration underwent triple contrast CT scanning utilizing oral, rectal, and IV contrast. Patients did not undergo surgical exploration if their CT scan was interpreted as negative or if the CT scan demonstrated injuries not requiring surgical intervention. Fifty-three patients were entered into the protocol. The time to complete the triple contrast CT scan ranged from 3 to 6 hours at a cost of $1050 for each scan. In 51 patients (96%), the CT scan either had negative findings (n = 31) or showed injuries not requiring exploration (n = 20). These patients did well with nonsurgical management. Two CT scans documented significant injury and led to surgical exploration and therapeutic celiotomies. Although triple contrast CT scanning was able to detect occult injury in patients with stab wounds to the back it did so at considerable cost and the results rarely altered clinical care. Therefore, its routine use in these patients is not recommended.

Quantifying the impact of respiratory-gated 4D CT acquisition on thoracic image quality: A digital phantom study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernatowicz, K., E-mail: kingab@student.ethz.ch; Knopf, A.; Lomax, A.

Purpose: Prospective respiratory-gated 4D CT has been shown to reduce tumor image artifacts by up to 50% compared to conventional 4D CT. However, to date no studies have quantified the impact of gated 4D CT on normal lung tissue imaging, which is important in performing dose calculations based on accurate estimates of lung volume and structure. To determine the impact of gated 4D CT on thoracic image quality, the authors developed a novel simulation framework incorporating a realistic deformable digital phantom driven by patient tumor motion patterns. Based on this framework, the authors test the hypothesis that respiratory-gated 4D CTmore » can significantly reduce lung imaging artifacts. Methods: Our simulation framework synchronizes the 4D extended cardiac torso (XCAT) phantom with tumor motion data in a quasi real-time fashion, allowing simulation of three 4D CT acquisition modes featuring different levels of respiratory feedback: (i) “conventional” 4D CT that uses a constant imaging and couch-shift frequency, (ii) “beam paused” 4D CT that interrupts imaging to avoid oversampling at a given couch position and respiratory phase, and (iii) “respiratory-gated” 4D CT that triggers acquisition only when the respiratory motion fulfills phase-specific displacement gating windows based on prescan breathing data. Our framework generates a set of ground truth comparators, representing the average XCAT anatomy during beam-on for each of ten respiratory phase bins. Based on this framework, the authors simulated conventional, beam-paused, and respiratory-gated 4D CT images using tumor motion patterns from seven lung cancer patients across 13 treatment fractions, with a simulated 5.5 cm{sup 3} spherical lesion. Normal lung tissue image quality was quantified by comparing simulated and ground truth images in terms of overall mean square error (MSE) intensity difference, threshold-based lung volume error, and fractional false positive/false negative rates. Results: Averaged across all simulations and phase bins, respiratory-gating reduced overall thoracic MSE by 46% compared to conventional 4D CT (p ∼ 10{sup −19}). Gating leads to small but significant (p < 0.02) reductions in lung volume errors (1.8%–1.4%), false positives (4.0%–2.6%), and false negatives (2.7%–1.3%). These percentage reductions correspond to gating reducing image artifacts by 24–90 cm{sup 3} of lung tissue. Similar to earlier studies, gating reduced patient image dose by up to 22%, but with scan time increased by up to 135%. Beam paused 4D CT did not significantly impact normal lung tissue image quality, but did yield similar dose reductions as for respiratory-gating, without the added cost in scanning time. Conclusions: For a typical 6 L lung, respiratory-gated 4D CT can reduce image artifacts affecting up to 90 cm{sup 3} of normal lung tissue compared to conventional acquisition. This image improvement could have important implications for dose calculations based on 4D CT. Where image quality is less critical, beam paused 4D CT is a simple strategy to reduce imaging dose without sacrificing acquisition time.« less

Optimising μCT imaging of the middle and inner cat ear.

PubMed

Seifert, H; Röher, U; Staszyk, C; Angrisani, N; Dziuba, D; Meyer-Lindenberg, A

2012-04-01

This study's aim was to determine the optimal scan parameters for imaging the middle and inner ear of the cat with micro-computertomography (μCT). Besides, the study set out to assess whether adequate image quality can be obtained to use μCT in diagnostics and research on cat ears. For optimisation, μCT imaging of two cat skull preparations was performed using 36 different scanning protocols. The μCT-scans were evaluated by four experienced experts with regard to the image quality and detail detectability. By compiling a ranking of the results, the best possible scan parameters could be determined. From a third cat's skull, a μCT-scan, using these optimised scan parameters, and a comparative clinical CT-scan were acquired. Afterwards, histological specimens of the ears were produced which were compared to the μCT-images. The comparison shows that the osseous structures are depicted in detail. Although soft tissues cannot be differentiated, the osseous structures serve as valuable spatial orientation of relevant nerves and muscles. Clinical CT can depict many anatomical structures which can also be seen on μCT-images, but these appear a lot less sharp and also less detailed than with μCT. © 2011 Blackwell Verlag GmbH.

Quantitative CT scans of lung parenchymal pathology in premature infants ages 0-6 years.

PubMed

Spielberg, David R; Walkup, Laura L; Stein, Jill M; Crotty, Eric J; Rattan, Mantosh S; Hossain, Md Monir; Brody, Alan S; Woods, Jason C

2018-03-01

Bronchopulmonary dysplasia (BPD) is a common, heterogeneous disease in premature infants. We hypothesized that quantitative CT techniques could assess lung parenchymal heterogeneity in BPD patients across a broad age range and demonstrate how pathologies change over time. A cross-sectional, retrospective study of children age 0-6 years with non-contrast chest CT scans was conducted. BPD subjects met NICHD/NHLBI diagnostic criteria for BPD and were excluded for congenital lung/airway abnormalities or other known/suspected pulmonary diagnoses; control subjects were not premature and had normal CT scan findings. Radiologic opacities, lucencies, and spatial heterogeneity were quantified via: 1) thresholding using CT-attenuation (HU); 2) manual segmentation; and 3) Ochiai reader-scoring system. Clinical outcomes included BPD severity by NICHD/NHLBI criteria, respiratory support at NICU discharge, wheezing, and respiratory exacerbations. Heterogeneity (standard deviation) of lung attenuation in BPD was significantly greater than in controls (difference 36.4 HU [26.1-46.7 HU], P < 0.001); the difference between the groups decreased 0.58 HU per month of age (0.08-1.07 HU per month, P = 0.02). BPD patients had greater amounts of opacities and lucencies than controls except with automated quantification of lucencies. Cross-sectionally, lucencies per Ochiai score and opacities per manual segmentation decreased with time. No approach measured a statistically significant relationship to BPD clinical severity. Opacities, lucencies, and overall heterogeneity of lungs via quantitative CT can distinguish BPD patients from healthy controls, and these abnormalities decrease with age across BPD patients. Defining BPD severity by clinical outcomes such as respiratory support at several time points (vs a single time point, per current guidelines) may be meaningful. © 2017 Wiley Periodicals, Inc.

Quantitative Image Quality and Histogram-Based Evaluations of an Iterative Reconstruction Algorithm at Low-to-Ultralow Radiation Dose Levels: A Phantom Study in Chest CT

PubMed Central

Lee, Ki Baek

2018-01-01

Objective To describe the quantitative image quality and histogram-based evaluation of an iterative reconstruction (IR) algorithm in chest computed tomography (CT) scans at low-to-ultralow CT radiation dose levels. Materials and Methods In an adult anthropomorphic phantom, chest CT scans were performed with 128-section dual-source CT at 70, 80, 100, 120, and 140 kVp, and the reference (3.4 mGy in volume CT Dose Index [CTDIvol]), 30%-, 60%-, and 90%-reduced radiation dose levels (2.4, 1.4, and 0.3 mGy). The CT images were reconstructed by using filtered back projection (FBP) algorithms and IR algorithm with strengths 1, 3, and 5. Image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were statistically compared between different dose levels, tube voltages, and reconstruction algorithms. Moreover, histograms of subtraction images before and after standardization in x- and y-axes were visually compared. Results Compared with FBP images, IR images with strengths 1, 3, and 5 demonstrated image noise reduction up to 49.1%, SNR increase up to 100.7%, and CNR increase up to 67.3%. Noteworthy image quality degradations on IR images including a 184.9% increase in image noise, 63.0% decrease in SNR, and 51.3% decrease in CNR, and were shown between 60% and 90% reduced levels of radiation dose (p < 0.0001). Subtraction histograms between FBP and IR images showed progressively increased dispersion with increased IR strength and increased dose reduction. After standardization, the histograms appeared deviated and ragged between FBP images and IR images with strength 3 or 5, but almost normally-distributed between FBP images and IR images with strength 1. Conclusion The IR algorithm may be used to save radiation doses without substantial image quality degradation in chest CT scanning of the adult anthropomorphic phantom, down to approximately 1.4 mGy in CTDIvol (60% reduced dose). PMID:29354008

CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

NASA Astrophysics Data System (ADS)

Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

2015-09-01

This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

Radiation exposure from Chest CT: Issues and Strategies

PubMed Central

Maher, Michael M.; Rizzo, Stefania; Kanarek, David; Shephard, Jo-Anne O.

2004-01-01

Concerns have been raised over alleged overuse of CT scanning and inappropriate selection of scanning methods, all of which expose patients to unnecessary radiation. Thus, it is important to identify clinical situations in which techniques with lower radiation dose such as plain radiography or no radiation such as MRI and occasionally ultrasonography can be chosen over CT scanning. This article proposes the arguments for radiation dose reduction in CT scanning of the chest and discusses recommended practices and studies that address means of reducing radiation exposure associated with CT scanning of the chest. PMID:15082885

Experimental validation of an OSEM-type iterative reconstruction algorithm for inverse geometry computed tomography

NASA Astrophysics Data System (ADS)

David, Sabrina; Burion, Steve; Tepe, Alan; Wilfley, Brian; Menig, Daniel; Funk, Tobias

2012-03-01

Iterative reconstruction methods have emerged as a promising avenue to reduce dose in CT imaging. Another, perhaps less well-known, advance has been the development of inverse geometry CT (IGCT) imaging systems, which can significantly reduce the radiation dose delivered to a patient during a CT scan compared to conventional CT systems. Here we show that IGCT data can be reconstructed using iterative methods, thereby combining two novel methods for CT dose reduction. A prototype IGCT scanner was developed using a scanning beam digital X-ray system - an inverse geometry fluoroscopy system with a 9,000 focal spot x-ray source and small photon counting detector. 90 fluoroscopic projections or "superviews" spanning an angle of 360 degrees were acquired of an anthropomorphic phantom mimicking a 1 year-old boy. The superviews were reconstructed with a custom iterative reconstruction algorithm, based on the maximum-likelihood algorithm for transmission tomography (ML-TR). The normalization term was calculated based on flat-field data acquired without a phantom. 15 subsets were used, and a total of 10 complete iterations were performed. Initial reconstructed images showed faithful reconstruction of anatomical details. Good edge resolution and good contrast-to-noise properties were observed. Overall, ML-TR reconstruction of IGCT data collected by a bench-top prototype was shown to be viable, which may be an important milestone in the further development of inverse geometry CT.

Registration-based assessment of regional lung function via volumetric CT images of normal subjects vs. severe asthmatics

PubMed Central

Choi, Sanghun; Hoffman, Eric A.; Wenzel, Sally E.; Tawhai, Merryn H.; Yin, Youbing; Castro, Mario

2013-01-01

The purpose of this work was to explore the use of image registration-derived variables associated with computed tomographic (CT) imaging of the lung acquired at multiple volumes. As an evaluation of the utility of such an imaging approach, we explored two groups at the extremes of population ranging from normal subjects to severe asthmatics. A mass-preserving image registration technique was employed to match CT images at total lung capacity (TLC) and functional residual capacity (FRC) for assessment of regional air volume change and lung deformation between the two states. Fourteen normal subjects and thirty severe asthmatics were analyzed via image registration-derived metrics together with their pulmonary function test (PFT) and CT-based air-trapping. Relative to the normal group, the severely asthmatic group demonstrated reduced air volume change (consistent with air trapping) and more isotropic deformation in the basal lung regions while demonstrating increased air volume change associated with increased anisotropic deformation in the apical lung regions. These differences were found despite the fact that both PFT-derived TLC and FRC in the two groups were nearly 100% of predicted values. Data suggest that reduced basal-lung air volume change in severe asthmatics was compensated by increased apical-lung air volume change and that relative increase in apical-lung air volume change in severe asthmatics was accompanied by enhanced anisotropic deformation. These data suggest that CT-based deformation, assessed via inspiration vs. expiration scans, provides a tool for distinguishing differences in lung mechanics when applied to the extreme ends of a population range. PMID:23743399

A 3-Year Study of Predictive Factors for Positive and Negative Appendicectomies.

PubMed

Chang, Dwayne T S; Maluda, Melissa; Lee, Lisa; Premaratne, Chandrasiri; Khamhing, Srisongham

2018-03-06

Early and accurate identification or exclusion of acute appendicitis is the key to avoid the morbidity of delayed treatment for true appendicitis or unnecessary appendicectomy, respectively. We aim (i) to identify potential predictive factors for positive and negative appendicectomies; and (ii) to analyse the use of ultrasound scans (US) and computed tomography (CT) scans for acute appendicitis. All appendicectomies that took place at our hospital from the 1st of January 2013 to the 31st of December 2015 were retrospectively recorded. Test results of potential predictive factors of acute appendicitis were recorded. Statistical analysis was performed using Fisher exact test, logistic regression analysis, sensitivity, specificity, and positive and negative predictive values calculation. 208 patients were included in this study. 184 patients had histologically proven acute appendicitis. The other 24 patients had either nonappendicitis pathology or normal appendix. Logistic regression analysis showed statistically significant associations between appendicitis and white cell count, neutrophil count, C-reactive protein, and bilirubin. Neutrophil count was the test with the highest sensitivity and negative predictive values, whereas bilirubin was the test with the highest specificity and positive predictive values (PPV). US and CT scans had high sensitivity and PPV for diagnosing appendicitis. No single test was sufficient to diagnose or exclude acute appendicitis by itself. Combining tests with high sensitivity (abnormal neutrophil count, and US and CT scans) and high specificity (raised bilirubin) may predict acute appendicitis more accurately.

TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardy, A; Bostani, M; McMillan, K

Purpose: The purpose of this work is to estimate effective and lung doses from a low-dose lung cancer screening CT protocol using Tube Current Modulation (TCM) across patient models of different sizes. Methods: Monte Carlo simulation methods were used to estimate effective and lung doses from a low-dose lung cancer screening protocol for a 64-slice CT (Sensation 64, Siemens Healthcare) that used TCM. Scanning parameters were from the AAPM protocols. Ten GSF voxelized patient models were used and had all radiosensitive organs identified to facilitate estimating both organ and effective doses. Predicted TCM schemes for each patient model were generatedmore » using a validated method wherein tissue attenuation characteristics and scanner limitations were used to determine the TCM output as a function of table position and source angle. The water equivalent diameter (WED) was determined by estimating the attenuation at the center of the scan volume for each patient model. Monte Carlo simulations were performed using the unique TCM scheme for each patient model. Lung doses were tallied and effective doses were estimated using ICRP 103 tissue weighting factors. Effective and lung dose values were normalized by scanspecific 32 cm CTDIvol values based upon the average tube current across the entire simulated scan. Absolute and normalized doses were reported as a function of WED for each patient. Results: For all ten patients modeled, the effective dose using TCM protocols was below 1.5 mSv. Smaller sized patient models experienced lower absolute doses compared to larger sized patients. Normalized effective and lung doses showed some dependence on patient size (R2 = 0.77 and 0.78, respectively). Conclusion: Effective doses for a low-dose lung screening protocol using TCM were below 1.5 mSv for all patient models used in this study. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical Systems; Consultant, Samsung Electronics.« less

The relationship between organ dose and patient size in tube current modulated adult thoracic CT scans

NASA Astrophysics Data System (ADS)

Khatonabadi, Maryam; Zhang, Di; Yang, Jeffrey; DeMarco, John J.; Cagnon, Chris C.; McNitt-Gray, Michael F.

2012-03-01

Recently published AAPM Task Group 204 developed conversion coefficients that use scanner reported CTDIvol to estimate dose to the center of patient undergoing fixed tube current body exam. However, most performed CT exams use TCM to reduce dose to patients. Therefore, the purpose of this study was to investigate the correlation between organ dose and a variety of patient size metrics in adult chest CT scans that use tube current modulation (TCM). Monte Carlo simulations were performed for 32 voxelized models with contoured lungs and glandular breasts tissue, consisting of females and males. These simulations made use of patient's actual TCM data to estimate organ dose. Using image data, different size metrics were calculated, these measurements were all performed on one slice, at the level of patient's nipple. Estimated doses were normalized by scanner-reported CTDIvol and plotted versus different metrics. CTDIvol values were plotted versus different metrics to look at scanner's output versus size. The metrics performed similarly in terms of correlating with organ dose. Looking at each gender separately, for male models normalized lung dose showed a better linear correlation (r2=0.91) with effective diameter, while female models showed higher correlation (r2=0.59) with the anterior-posterior measurement. There was essentially no correlation observed between size and CTDIvol-normalized breast dose. However, a linear relationship was observed between absolute breast dose and size. Dose to lungs and breasts were consistently higher in females with similar size as males which could be due to shape and composition differences between genders in the thoracic region.

Computed tomography scan to detect traumatic arthrotomies and identify periarticular wounds not requiring surgical intervention: an improvement over the saline load test.

PubMed

Konda, Sanjit R; Davidovitch, Roy I; Egol, Kenneth A

2013-09-01

To report our experience with computed tomography (CT) scans to detect traumatic arthrotomies of the knee (TAK) joint based on the presence of intra-articular air. Retrospective review. Level I trauma center. Sixty-two consecutive patients (63 knees) underwent a CT scan of the knee in the emergency department and had a minimum of 14 days follow-up. Cohort of 37 patients (37 knees) from the original 62 patients who underwent a saline load test (SLT). CT scan and SLT. Positive traumatic arthrotomy of the knee (+TAK) was defined as operating room (OR) confirmation of an arthrotomy or no intra-articular air on CT scan (-iaCT) (and -SLT if performed) with follow-up revealing a septic knee. Periarticular wound equivalent to no traumatic arthrotomy (pw = (-TAK)) was defined as OR evaluation revealing no arthrotomy or -iaCT (and -SLT if performed) with follow-up revealing no septic knee. All 32 knees with intra-articular air on CT scan (+iaCT) had OR confirmation of a TAK and none of these patients had a knee infection at a mean follow-up of 140.0 ± 279.6 days. None of the 31 patients with -iaCT had a knee infection at a mean follow-up of 291.0 ± 548.1 days. Based on these results, the sensitivity and specificity of the CT scan to detect +TAK and pw = (-TAK) was 100%. In a subgroup of 37 patients that received both a CT scan and the conventional SLT, the sensitivity and specificity of the CT scan was 100% compared with 92% for the SLT (P < 0.001). CT scan performs better than the conventional SLT to detect traumatic knee arthrotomies and identify periarticular knee wounds that do not require surgical intervention and should be considered a valid diagnostic test in the appropriate clinical setting. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

320-Row wide volume CT significantly reduces density heterogeneity observed in the descending aorta: comparisons with 64-row helical CT.

PubMed

Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

2014-01-01

The aim of this study was to compare density heterogeneity on wide volume (WV) scans with that on helical CT scans. 22 subjects underwent chest CT using 320-WV and 64-helical modes. Density heterogeneity of the descending aorta was evaluated quantitatively and qualitatively. At qualitative assessment, the heterogeneity was judged to be smaller on WV scans than on helical scans (p<0.0001). Mean changes in aortic density between two contiguous slices were 1.64 HU (3.40%) on WV scans and 2.29 HU (5.19%) on helical scans (p<0.0001). CT density of thoracic organs is more homogeneous and reliable on WV scans than on helical scans. Copyright © 2013 Elsevier Ltd. All rights reserved.

CT scanning in stroke patients: meeting the challenge in the remote and rural district general hospital.

PubMed

Todd, A W; Anderson, E M

2009-05-01

National audit data allow crude comparison between centres and indicate that most Scottish hospitals fail to meet current guidelines for CT scanning of the brain in stroke patients. This study identifies some of the reasons for delay in performing CT scans in a largely rural population. This audit study assesses the delays from onset of symptoms, time of admission and request received to CT scan in stroke patients for three different in-patient groups as well as those managed in the community. The reasons for delay in CT scanning varied between different patient groups but for one group of in-patients, changes in booking procedure and introduction of a second CT scanner increased the proportion scanned within 48 hours of request from 65% to 96%. Further developments including the introduction of Saturday and Sunday routine CT scanning, radiologist reporting from home and additional CT scanners placed in remote hospitals may be expected to improve these figures further. Target times of three hours from onset of symptoms to scan to allow thrombolysis may however be impossible to meet for all stroke patients in rural areas.

CT of Anatomic Variants of the Paranasal Sinuses and Nasal Cavity: Poor Correlation With Radiologically Significant Rhinosinusitis but Importance in Surgical Planning.

PubMed

Shpilberg, Katya A; Daniel, Simon C; Doshi, Amish H; Lawson, William; Som, Peter M

2015-06-01

The purpose of this study was to determine the incidence of sinonasal anatomic variants and to assess their relation to sinonasal mucosal disease. A retrospective evaluation of 192 sinus CT examinations of patients with a clinical history of rhinosinusitis was conducted. The CT scans were evaluated for the presence of several anatomic variants of the sinonasal cavities, and the prevalence of each variant was calculated. Prevalences of all sinonasal anatomic variants were compared between patients who had minimal to no apparent imaging evidence of rhinosinusitis and those who had radiologic evidence of clinically significant rhinosinusitis. The most common normal variants were nasal septal deviation, Agger nasi cells, and extension of the sphenoid sinuses into the posterior nasal septum. We found no statistically significant difference in the prevalence of any of the studied anatomic variants between patients with minimal and those with clinically significant paranasal sinus or nasal cavity disease. Analysis of every routine CT scan of the paranasal sinuses obtained for sinusitis or rhinitis for the presence of different anatomic variants is of questionable value unless surgery is planned.

SU-F-T-235: Optical Scan Based Collision Avoidance Using Multiple Stereotactic Cameras During Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardan, R; Popple, R; Dobelbower, M

Purpose: To demonstrate the ability to quickly generate an accurate collision avoidance map using multiple stereotactic cameras during simulation. Methods: Three Kinect stereotactic cameras were placed in the CT simulation room and optically calibrated to the DICOM isocenter. Immediately before scanning, the patient was optically imaged to generate a 3D polygon mesh, which was used to calculate the collision avoidance area using our previously developed framework. The mesh was visually compared to the CT scan body contour to ensure accurate coordinate alignment. To test the accuracy of the collision calculation, the patient and machine were physically maneuvered in the treatmentmore » room to calculated collision boundaries. Results: The optical scan and collision calculation took 38.0 seconds and 2.5 seconds to complete respectively. The collision prediction accuracy was determined using a receiver operating curve (ROC) analysis, where the true positive, true negative, false positive and false negative values were 837, 821, 43, and 79 points respectively. The ROC accuracy was 93.1% over the sampled collision space. Conclusion: We have demonstrated a framework which is fast and accurate for predicting collision avoidance for treatment which can be determined during the normal simulation process. Because of the speed, the system could be used to add a layer of safety with a negligible impact on the normal patient simulation experience. This information could be used during treatment planning to explore the feasible geometries when optimizing plans. Research supported by Varian Medical Systems.« less

Trends and patterns in the use of computed tomography in children and young adults in Catalonia - results from the EPI-CT study.

PubMed

Bosch de Basea, Magda; Salotti, Jane A; Pearce, Mark S; Muchart, Jordi; Riera, Luis; Barber, Ignasi; Pedraza, Salvador; Pardina, Marina; Capdevila, Antoni; Espinosa, Ana; Cardis, Elisabeth

2016-01-01

Although there are undeniable diagnostic benefits of CT scanning, its increasing use in paediatric radiology has become a topic of concern regarding patient radioprotection. To assess the rate of CT scanning in Catalonia, Spain, among patients younger than 21 years old at the scan time. This is a sub-study of a larger international cohort study (EPI-CT, the International pediatric CT scan study). Data were retrieved from the radiological information systems (RIS) of eight hospitals in Catalonia since the implementation of digital registration (between 1991 and 2010) until 2013. The absolute number of CT scans annually increased 4.5% between 1991 and 2013, which was less accentuated when RIS was implemented in most hospitals. Because the population attending the hospitals also increased, however, the rate of scanned patients changed little (8.3 to 9.4 per 1,000 population). The proportions of patients with more than one CT and more than three CTs showed a 1.51- and 2.7-fold increase, respectively, over the 23 years. Gradual increases in numbers of examinations and scanned patients were observed in Catalonia, potentially explained by new CT scanning indications and increases in the availability of scanners, the number of scans per patient and the size of the attended population.

CT scan

MedlinePlus

... this page: //medlineplus.gov/ency/article/003330.htm CT scan To use the sharing features on this page, please enable JavaScript. A computed tomography (CT) scan is an imaging method that uses x- ...

Computed Tomography (CT) - Spine

MedlinePlus

... Resources Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is ... of CT Scanning of the Spine? What is CT Scanning of the Spine? Computed tomography, more commonly ...

Scope for energy improvement for hospital imaging services in the USA.

PubMed

Esmaeili, Amin; Twomey, Janet M; Overcash, Michael R; Soltani, Seyed A; McGuire, Charles; Ali, Kamran

2015-04-01

To aid radiologists by measuring the carbon footprint of CT scans by quantifying in-hospital and out-of-hospital energy use and to assess public health impacts. The study followed a standard life cycle assessment protocol to measure energy from a CT scan then expanding to all hospital electrical energy related to CT usage. In addition, all the fuel energy used to generate electricity and to manufacture the CT consumables was measured. The study was conducted at two hospitals. The entire life cycle energy for a CT scan was 24-34 kWh of natural resource energy per scan. The actual active patient scan energy that produces the images is only about 1.6% of this total life cycle energy. This large multiplier to get total CT energy is a previously undocumented environmental response to the direct radiology order for a patient CT scan. The CT in-hospital energy related to idle periods, where the machine is on but no patients are being scanned and is 14-30-fold higher than the energy used for the CT image. The in-hospital electrical energy of a CT scan makes up only about 25% of the total energy footprint. The rest is generated outside the hospital: 54-62% for generation and transmission of the electricity, while 13-22% is for all the energy to make the consumables. Different CT scanners have some influences on the results and could help guide purchase of CT equipment. The transparent, detailed life cycle approach allows the data from this study to be used by radiologists to examine details of both direct and of unseen energy impacts of CT scans. The public health (outside-the-hospital) impact (including the patients receiving a CT) needs to be measured and included. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

A systematic review of the need for MRI for the clearance of cervical spine injury in obtunded blunt trauma patients after normal cervical spine CT.

PubMed

James, Iyore Ao; Moukalled, Ahmad; Yu, Elizabeth; Tulman, David B; Bergese, Sergio D; Jones, Christian D; Stawicki, Stanislaw Pa; Evans, David C

2014-10-01

Clearance of cervical spine injury (CSI) in the obtunded or comatose blunt trauma patient remains controversial. In patients with unreliable physical examination and no evidence of CSI on computed tomography (CT), magnetic resonance imaging of the cervical spine (CS-MRI) is the typical follow-up study. There is a growing body of evidence suggesting that CS-MRI is unnecessary with negative findings on a multi-detector CT (MDCT) scan. This review article systematically analyzes current literature to address the controversies surrounding clearance of CSI in obtunded blunt trauma patients. A literature search through MEDLINE database was conducted using all databases on the National Center for Biotechnology Information (NCBI) website (www.ncbi.nlm.nih.gov) for keywords: "cervical spine injury," "obtunded," and "MRI." The search was limited to studies published within the last 10 years and with populations of patients older than 18 years old. Eleven studies were included in the analysis yielding data on 1535 patients. CS-MRI detected abnormalities in 256 patients (16.6%). The abnormalities reported on CS-MRI resulted in prolonged rigid c-collar immobilization in 74 patients (4.9%). Eleven patients (0.7%) had unstable injury detected on CS-MRI alone that required surgical intervention. In the obtunded blunt trauma patient with unreliable clinical examination and a normal CT scan, there is still a role for CS-MRI in detecting clinically significant injuries when MRI resources are available. However, when a reliable clinical exam reveals intact gross motor function, CS-MRI may be unnecessary.

Heart CT scan

MedlinePlus

... Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston ... table that slides into the center of the CT scanner. You will lie on your back with ...

Should contrast CT urography replace non-contrast CT as an investigation for ureteric colic in the emergency department in those aged 65 and over?

PubMed

Batura, Deepak; Hashemzehi, Tumaj; Gayed, Wade

2018-06-27

Elderly patients with upper tract urothelial cancer (UTUC) may present with colic and microscopic haematuria, mimicking urolithiasis. Patients presenting to emergency departments with acute ureteric colic are investigated with a CT KUB. CT urography (CTU) identifies UTUC better than a CT KUB. Thus, there is a possibility that a CT KUB may miss UTUC. We studied patients aged 65 years or over presenting to the emergency department with ureteric colic and microscopic haematuria who had a CT KUB between January 2014 and October 2016. Patients who had both CT KUB and CTU were then compared to determine if CT KUB had missed a UTUC and if the diagnoses were concordant by the two tests. A radiologist independent from the reporting radiologists reviewed images as well as their reports. According to the Health Research Authority, England regulations, we did not obtain an ethical review on a voluntary basis for this retrospective study. Four hundred eighty-five patients [228 (47.01%) male and 257 (52.99%) female] had a CT KUB scan over the 34-month period. Their mean age was 74 (SD 6.97) [males 73 (SD 6.42), females 75 (SD 7.42)] years. One hundred eighty-seven scans were normal. Ureteric calculi (167), renal calculi (58) and renal cysts (28) were most frequent diagnoses. The diagnosis was uncertain in 33 patients (6.8%) [16 (48.49%) males and 17 (51.51%) females]. The mean age of this group of patients was 74 (SD 6.64) [males 73 (SD4.43), females 74 (SD7.64)] years. These patients had a CTU for clarity. CTU identified one UTUC not identified by CT KUB (0.2%), corroborated the diagnosis of a ureteric tumour in one patient and excluded UTUC in two others. CTU diagnosed two new bladder tumours and an endometrial tumour. Diagnoses were concordant between CT KUB and CTU in 17 of 33 patients (51.5%). CT KUB scans for patients 65 years and over presenting with ureteric colic is justified. Only a small proportion of patients will subsequently require the higher radiation dose CTU as the probability of missing UTUC is low.

Improved quantitation and reproducibility in multi-PET/CT lung studies by combining CT information.

PubMed

Holman, Beverley F; Cuplov, Vesna; Millner, Lynn; Endozo, Raymond; Maher, Toby M; Groves, Ashley M; Hutton, Brian F; Thielemans, Kris

2018-06-05

Matched attenuation maps are vital for obtaining accurate and reproducible kinetic and static parameter estimates from PET data. With increased interest in PET/CT imaging of diffuse lung diseases for assessing disease progression and treatment effectiveness, understanding the extent of the effect of respiratory motion and establishing methods for correction are becoming more important. In a previous study, we have shown that using the wrong attenuation map leads to large errors due to density mismatches in the lung, especially in dynamic PET scans. Here, we extend this work to the case where the study is sub-divided into several scans, e.g. for patient comfort, each with its own CT (cine-CT and 'snap shot' CT). A method to combine multi-CT information into a combined-CT has then been developed, which averages the CT information from each study section to produce composite CT images with the lung density more representative of that in the PET data. This combined-CT was applied to nine patients with idiopathic pulmonary fibrosis, imaged with dynamic 18 F-FDG PET/CT to determine the improvement in the precision of the parameter estimates. Using XCAT simulations, errors in the influx rate constant were found to be as high as 60% in multi-PET/CT studies. Analysis of patient data identified displacements between study sections in the time activity curves, which led to an average standard error in the estimates of the influx rate constant of 53% with conventional methods. This reduced to within 5% after use of combined-CTs for attenuation correction of the study sections. Use of combined-CTs to reconstruct the sections of a multi-PET/CT study, as opposed to using the individually acquired CTs at each study stage, produces more precise parameter estimates and may improve discrimination between diseased and normal lung.

CT Scans

MedlinePlus

... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

[Preoperative CT Scan in middle ear cholesteatoma].

PubMed

Sethom, Anissa; Akkari, Khemaies; Dridi, Inès; Tmimi, S; Mardassi, Ali; Benzarti, Sonia; Miled, Imed; Chebbi, Mohamed Kamel

2011-03-01

To compare preoperative CT scan finding and per-operative lesions in patients operated for middle ear cholesteatoma, A retrospective study including 60 patients with cholesteatoma otitis diagnosed and treated within a period of 5 years, from 2001 to 2005, at ENT department of Military Hospital of Tunis. All patients had computed tomography of the middle and inner ear. High resolution CT scan imaging was performed using millimetric incidences (3 to 5 millimetres). All patients had surgical removal of their cholesteatoma using down wall technic. We evaluated sensitivity, specificity and predictive value of CT-scan comparing otitic damages and CT finding, in order to examine the real contribution of computed tomography in cholesteatoma otitis. CT scan analysis of middle ear bone structures shows satisfaction (with 83% of sensibility). The rate of sensibility decrease (63%) for the tympanic raff. Predictive value of CT scan for the diagnosis of cholesteatoma was low. However, we have noticed an excellent sensibility in the analysis of ossicular damages (90%). Comparative frontal incidence seems to be less sensible for the detection of facial nerve lesions (42%). But when evident on CT scan findings, lesions of facial nerve were usually observed preoperatively (spécificity 78%). Predictive value of computed tomography for the diagnosis of perilymphatic fistulae (FL) was low. In fact, CT scan imaging have showed FL only for four patients among eight. Best results can be obtained if using inframillimetric incidences with performed high resolution computed tomography. Preoperative computed tomography is necessary for the diagnosis and the evaluation of chronic middle ear cholesteatoma in order to show extending lesion and to detect complications. This CT analysis and surgical correlation have showed that sensibility, specificity and predictive value of CT-scan depend on the anatomic structure implicated in cholesteatoma damages.

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alva-Sánchez, Héctor, E-mail: halva@ciencias.unam.mx; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guidemore » provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.« less

Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

NASA Astrophysics Data System (ADS)

Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

2014-11-01

In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

With "big data" comes big responsibility: outreach to North Carolina Medicaid patients with 10 or more computed tomography scans in 12 months.

PubMed

Biola, Holly; Best, Randall M; Lahlou, Rita M; Burke, Lauren M; Dewar, Charles; Jackson, Carlos T; Broder, Joshua; Grey, Linda; Semelka, Richard C; Dobson, Allen

2014-01-01

Patients are being exposed to increasing levels of ionizing radiation, much of it from computed tomography (CT) scans. Adults without a cancer diagnosis who received 10 or more CT scans in 2010 were identified from North Carolina Medicaid claims data and were sent a letter in July 2011 informing them of their radiation exposure; those who had undergone 20 or more CT scans in 2010 were also telephoned. The CT scan exposure of these high-exposure patients during the 12 months following these interventions was compared with that of adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. The average number of CT scans per month for the high-exposure population decreased over time, but most of that reduction occurred 6-9 months before our interventions took place. At about the same time, the number of CT scans per month also decreased in adult Medicaid patients without cancer who had at least 1 CT scan but were not in the intervention population. Our data do not include information about CT scans that may have been performed during times when patients were not covered by Medicaid. Some of our letters may not have been received or understood. Some high-exposure patients were unintentionally excluded from our study because organization of data on Medicaid claims varies by setting of care. Our patient education intervention was not temporally associated with significant decreases in subsequent CT exposure. Effecting behavior change to reduce exposure to ionizing radiation requires more than an educational letter or telephone call.

Computer-aided detection of acute pulmonary embolism with 64-slice multi-detector row computed tomography: impact of the scanning conditions and overall image quality in the detection of peripheral clots.

PubMed

Dewailly, Marion; Rémy-Jardin, Martine; Duhamel, Alain; Faivre, Jean-Baptiste; Pontana, François; Deken, Valérie; Bakai, Anne-Marie; Remy, Jacques

2010-01-01

To evaluate the performance of a computer-aided detection (CAD) system for diagnosing peripheral acute pulmonary embolism (PE) with a 64-slice multi-detector row computed tomography (CT). Two radiologists investigated the accuracy of a software aimed at detecting peripheral clots (PECAD prototype, version 7; Siemens Medical Systems, Forchheim, Germany) by applying this tool for the analysis of the pulmonary arterial bed of 74 CT angiograms obtained with 64-slice dual-source CT (Definition; Siemens Medical Systems). These cases were retrospectively selected from a database of CT studies performed on the same CT unit, with a similar collimation (64 x 0.6 mm) and similar injection protocols. Patient selection was based on a variety of (1) scanning conditions, namely, nongated (n = 30), electrocardiography-gated (n = 30), and dual-energy CT angiograms (n = 14), and (2) image quality (IQ), namely, scans of excellent IQ (n = 53) and lower IQ due to lower levels of arterial enhancement and/or presence of noise (n = 21). The standard of truth was based on the 2 radiologists' consensus reading and the results of CAD. The software detected 80 of 93 peripheral clots present in the 21 patients (42 segmental and 38 subsegmental clots). The overall sensitivity (95% confidence interval) of the CAD tool was 86% (77%-92%) for detecting peripheral clots, 78% (64.5%-88%) at the segmental level and 97% (85.5%-99.9%) at the subsegmental level. Assuming normal vascular anatomy with 20 segmental and 40 subsegmental arteries, overall specificity and positive and negative predictive values (95% confidence interval) of the software were 91.8% (91%-92.6%), 18.4% (15%-22.4%), and 99.7% (99.5%-99.8%), respectively. A mean of 5.4 false positives was found per patient (total, 354 false positives), mainly linked to the presence of perivascular connective tissue (n = 119; 34%) and perivascular airspace consolidation (n = 97; 27%). The sensitivities (95% confidence interval) for the CAD tool were 91% (69.8%-99.3%) for dual-energy, 87% (59.3%-93.2%) for electrocardiography-gated, and 87% (73.5%-95.3%) for nongated scans (P > 0.05). No significant difference was found in the sensitivity of the CAD software when comparing the scans according to the scanning conditions and image quality. The evaluated CAD software has a good sensitivity in detecting peripheral PE, which is not influenced by the scanning conditions or the overall image quality.

Aortic valve calcification - a commonly observed but frequently ignored finding during CT scanning of the chest.

PubMed

Raju, Prashanth; Sallomi, David; George, Bindu; Patel, Hitesh; Patel, Nikhil; Lloyd, Guy

2012-06-01

To describe the frequency and severity of Aortic valve calcification (AVC) in an unselected cohort of patients undergoing chest CT scanning and to assess the frequency with which AVC was being reported in the radiology reports. Consecutive CT scan images of the chest and the radiological reports (December 2009 to May 2010) were reviewed at the district general hospital (DGH). AVC on CT scan was visually graded on a scale ranging from 0 to IV (0 = no calcification, IV = severe calcification). Total of 416 (232 male; 184 female) CT chest scans [Contrast enhanced 302 (72%), unenhanced 114 (28%)] were reviewed. Mean age was 70.55 ± 11.48 years. AVC in CT scans was identified in 95 of the 416 patients (22.83%). AVC classification was as follows: Grade I: 60 (63.15%), Grade II: 22 (23.15%), Grade III: 9 (9.47%), Grade IV: 4 (4.21%). Only one CT report mentioned AVC. Only 31 of 95 AVC had Transthoracic echocardiogram (TTE). The interval time between CT scan and TTE was variable.   Aortic valve calcification in CT chest scans is a common finding and studies have shown that it is strongly related to the presence and severity of aortic valve disease. As CT scans are considered as a valuable additional screening tool for detection of aortic stenosis, AVC should always be commented upon in the radiology reports. Furthermore, patients with at least Grade III and IV AVC should be sent for TTE. © 2012 Blackwell Publishing Ltd.

Comparison of the diagnostic quality of computed tomography images of normal ocular and orbital structures acquired with and without the use of general anesthesia in the cat.

PubMed

Collins, Sean P; Matheson, Jodi S; Hamor, Ralph E; Mitchell, Mark A; Labelle, Amber L; O'Brien, Robert T

2013-09-01

To compare the diagnostic quality of computed tomography (CT) images of normal ocular and orbital structures acquired with and without the use of general anesthesia in the cat. Eleven privately owned cats with nasal disease presenting to a single referral hospital. All cats received a complete ophthalmic examination. A 16 multislice helical CT system was utilized to acquire images of the skull and neck with and without the use of general anesthesia. Images were acquired before and after the administration of intravenous iodinated contrast. Images of normal ocular and orbital structures were evaluated via consensus by two board-certified radiologists. Visibility of ocular and orbital structures, degree of motion, and streak artifact were assessed and scored for each image set in the transverse, dorsal, and sagittal planes. The use of general anesthesia did not significantly affect the diagnostic quality of images. No motion artifact was observed in any CT image. Streak artifact was significantly increased in scans performed in the transverse orientation but not in the dorsal orientation or sagittal orientation and did not affect the diagnostic quality of the images. Contrast enhancement did not significantly enhance the visibility of any ocular or orbital structures. Diagnostic CT images of normal ocular and orbital structures can be acquired without the use of general anesthesia in the cat. © 2012 American College of Veterinary Ophthalmologists.

Combined use of rapid-prototyping model and surgical guide in correction of mandibular asymmetry malformation patients with normal occlusal relationship.

PubMed

Xu, Haisong; Zhang, Ce; Shim, Yoong Hoon; Li, Hongliang; Cao, Dejun

2015-03-01

The aim of this study is to discuss the application of rapid-prototyping model and surgical guide in the treatment of mandibular asymmetry malformation with normal occlusal relationship. Twenty-four mandibular asymmetry malformation patients with relatively normal occlusal relationship were included in this study. Surgical 3-dimensional rapid-prototyping mandibular models were made for all patients from the computed tomography (CT) DICOM data. The presurgical plan was designed on the model, and the surgical guiders for the osteotomy lines were manufactured. Genioplasty and/or mandibular osteotomy based on the presurgical plan were performed on these patients with the combined use of the rapid-prototyping model and surgical guides. All patients underwent postoperative CT scan and had at least 3-month follow-up. All patients were satisfied with the final results. According to the postoperative CT images and 3-month follow-up, all patients' mandibular asymmetry malformation was significantly improved, and the operation time was distinctly shortened relative to the conventional method. Rapid-prototyping model and surgical guide are viable auxiliary devices for the treatment of mandibular asymmetry malformation with relatively normal occlusal relationship. Combined use of them can make precise preoperative design, improve effects of operation, and shorten operating time.

Value of repeat CT scans in low back pain and radiculopathy.

PubMed

Schroeder, Josh E; Barzilay, Yair; Kaplan, Leon; Itshayek, Eyal; Hiller, Nurith

2016-02-01

We assessed the clinical value of repeat spine CT scan in 108 patients aged 18-60 years who underwent repeat lumbar spine CT scan for low back pain or radiculopathy from January 2008 to December 2010. Patients with a neoplasm or symptoms suggesting underlying disease were excluded from the study. Clinical data was retrospectively reviewed. Index examinations and repeat CT scan performed at a mean of 24.3 ± 11.3 months later were compared by a senior musculoskeletal radiologist. Disc abnormalities (herniation, sequestration, bulge), spinal stenosis, disc space narrowing, and bony changes (osteophytes, fractures, other changes) were documented. Indications for CT scan were low back pain (60 patients, 55%), radiculopathy (46 patients, 43%), or nonspecific back pain (two patients, 2%). A total of 292 spine pathologies were identified in 98 patients (90.7%); in 10 patients (9.3%) no spine pathology was seen on index or repeat CT scan. At repeat CT scan, 269/292 pathologies were unchanged (92.1%); 10/292 improved (3.4%), 8/292 worsened (2.8%, disc herniation or spinal stenosis), and five new pathologies were identified. No substantial therapeutic change was required in patients with worsened or new pathology. Added diagnostic value from repeat CT scan performed within 2-3 years was rare in patients suffering chronic or recurrent low back pain or radiculopathy, suggesting that repeat CT scan should be considered only in patients with progressive neurologic deficits, new neurologic complaints, or signs implying serious underlying conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of helical and cine acquisitions for 4D-CT imaging with multislice CT.

PubMed

Pan, Tinsu

2005-02-01

We proposed a data sufficiency condition (DSC) for four-dimensional-CT (4D-CT) imaging on a multislice CT scanner, designed a pitch factor for a helical 4D-CT, and compared the acquisition time, slice sensitivity profile (SSP), effective dose, ability to cope with an irregular breathing cycle, and gating technique (retrospective or prospective) of the helical 4D-CT and the cine 4D-CT on the General Electric (GE) LightSpeed RT (4-slice), Plus (4-slice), Ultra (8-slice) and 16 (16-slice) multislice CT scanners. To satisfy the DSC, a helical or cine 4D-CT acquisition has to collect data at each location for the duration of a breathing cycle plus the duration of data acquisition for an image reconstruction. The conditions for the comparison were 20 cm coverage in the cranial-caudal direction, a 4 s breathing cycle, and half-scan reconstruction. We found that the helical 4D-CT has the advantage of a shorter scan time that is 10% shorter than that of the cine 4D-CT, and the disadvantages of 1.8 times broadening of SSP and requires an additional breathing cycle of scanning to ensure an adequate sampling at the start and end locations. The cine 4D-CT has the advantages of maintaining the same SSP as slice collimation (e.g., 8 x 2.5 mm slice collimation generates 2.5 mm SSP in the cine 4D-CT as opposed to 4.5 mm in the helical 4D-CT) and a lower dose by 4% on the 8- and 16-slice systems, and 8% on the 4-slice system. The advantage of faster scanning in the helical 4D-CT will diminish if a repeat scan at the location of a breathing irregularity becomes necessary. The cine 4D-CT performs better than the helical 4D-CT in the repeat scan because it can scan faster and is more dose efficient.

Malignant external otitis: CT evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtin, H.D.; Wolfe, P.; May, M.

1982-11-01

Malignant external otitis is an aggressive infection caused by Pseudomonas aeruginosa that most often occurs in elderly diabetics. Malignant external otitis often spreads inferiorly from the external canal to involve the subtemporal area and progresses medially towards the petrous apex leading to multiple cranial nerve palsies. The computed tomographic (CT) findings in malignant external otitis include obliteration of the normal fat planes in the subtemporal area as well as patchy destruction of the bony cortex of the mastoid. The point of exit of the various cranial nerves can be identified on CT scans, and the extent of the inflammatory massmore » correlates well with the clinical findings. Four cases of malignant external otitis are presented. In each case CT provided a good demonstration of involvement of the soft tissues at the base of the skull.« less

Anatomic characteristics of ruptured abdominal aortic aneurysm on conventional CT scans: Implications for rupture risk.

PubMed

Fillinger, Mark F; Racusin, Jessica; Baker, Robert K; Cronenwett, Jack L; Teutelink, Arno; Schermerhorn, Marc L; Zwolak, Robert M; Powell, Richard J; Walsh, Daniel B; Rzucidlo, Eva M

2004-06-01

The purpose of this study was to analyze anatomic characteristics of patients with ruptured abdominal aortic aneurysms (AAAs), with conventional two-dimensional computed tomography (CT), including comparison with control subjects matched for age, gender, and size. Records were reviewed to identify all CT scans obtained at Dartmouth-Hitchcock Medical Center or referring hospitals before emergency AAA repair performed because of rupture or acute severe pain (RUP group). CT scans obtained before elective AAA repair (ELEC group) were reviewed for age and gender match with patients in the RUP group. More than 40 variables were measured on each CT scan. Aneurysm diameter matching was achieved by consecutively deleting the largest RUP scan and the smallest ELEC scan to prevent bias. CT scans were analyzed for 259 patients with AAAs: 122 RUP and 137 ELEC. Patients were well matched for age, gender, and other demographic variables or risk factors. Maximum AAA diameter was significantly different in comparisons of all patients (RUP, 6.5 +/- 2 cm vs ELEC, 5.6 +/- 1 cm; P <.0001), and mean diameter of ruptured AAAs was 5 mm smaller in female patients (6.1 +/- 2 cm vs 6.6 +/- 2 cm; P =.007). Two hundred patients were matched for diameter, gender, and age (100 from each group; maximum AAA diameter, 6.0 +/- 1 cm vs 6.0 +/- 1 cm). Analysis of diameter-matched AAAs indicated that most variables were statistically similar in the two groups, including infrarenal neck length (17 +/- 1 mm vs 19 +/- 1 mm; P =.3), maximum thrombus thickness (25 +/- 1 mm vs 23 +/- 1 mm, P =.4), and indices of body habitus, such as [(maximum AAA diameter)/(normal suprarenal aorta diameter)] or [(maximum AAA diameter)/(L3 transverse diameter)]. Multivariate analysis controlling for gender indicated that the most significant variables for rupture were aortic tortuosity (odds ratio [OR] 3.3, indicating greater risk with no or mild tortuosity), diameter asymmetry (OR, 3.2 for a 1-cm difference in major-minor axis), and current smoking (OR, 2.7, with the greater risk in current smokers). When matched for age, gender, and diameter, ruptured AAAs tend to be less tortuous, yet have greater cross-sectional diameter asymmetry. On conventional two-dimensional CT axial sections, it appears that when diameter asymmetry is associated with low aortic tortuosity, the larger diameter on axial sections more accurately reflects rupture risk, and when diameter asymmetry is associated with moderate or severe aortic tortuosity, the smaller diameter on axial sections more accurately reflects rupture risk. Current smoking is significantly associated with rupture, even when controlling for gender and AAA anatomy.

Reduction in radiation doses from paediatric CT scans in Great Britain.

PubMed

Lee, Choonsik; Pearce, Mark S; Salotti, Jane A; Harbron, Richard W; Little, Mark P; McHugh, Kieran; Chapple, Claire-Louise; Berrington de Gonzalez, Amy

2016-01-01

Although CT scans provide great medical benefits, concerns have been raised about the magnitude of possible associated cancer risk, particularly in children who are more sensitive to radiation than adults. Unnecessary high doses during CT examinations can also be delivered to children, if the scan parameters are not adjusted for patient age and size. We conducted the first survey to directly assess the trends in CT scan parameters and doses for paediatric CT scans performed in Great Britain between 1978 and 2008. We retrieved 1073 CT film sets from 36 hospitals. The patients were 0-19 years old, and CT scans were conducted between 1978 and 2008. We extracted scan parameters from each film including tube current-time product [milliampere seconds (mAs)], tube potential [peak kilovoltage (kVp)] and manufacturer and model of the CT scanner. We estimated the mean mAs for head and trunk (chest and abdomen/pelvis) scans, according to patient age (0-4, 5-9, 10-14 and 15-19 years) and scan year (<1990, 1990-1994, 1995-1999 and ≥2000), and then derived the volumetric CT dose index and estimated organ doses. For head CT scans, mean mAs decreased by about 47% on average from before 1990 to after 2000, with the decrease starting around 1990. The mean mAs for head CTs did not vary with age before 1990, whereas slightly lower mAs values were used for younger patients after 1990. Similar declines in mAs were observed for trunk CTs: a 46% decline on an average from before 1990 to after 2000. Although mean mAs for trunk CTs did not vary with age before 1990, the value varied markedly by age, from 63 mAs for age 0-4 years compared with 315 mAs for those aged >15 years after 2000. No material changes in kVp were found. Estimated brain-absorbed dose from head CT scans decreased from 62 mGy before 1990 to approximately 30 mGy after 2000. For chest CT scans, the lung dose to children aged 0-4 years decreased from 28 mGy before 1990 to 4 mGy after 2000. We found that mAs for head and trunk CTs was approximately halved starting around 1990, and age-specific mAs was generally used for paediatric scans after this date. These changes will have substantially reduced the radiation exposure to children from CT scans in Great Britain. The study shows that mAs and major organ doses for paediatric CT scans in Great Britain began to decrease around 1990.

Reduction in radiation doses from paediatric CT scans in Great Britain

PubMed Central

Pearce, Mark S; Salotti, Jane A; Harbron, Richard W; Little, Mark P; McHugh, Kieran; Chapple, Claire-Louise; Berrington de Gonzalez, Amy

2016-01-01

Objective: Although CT scans provide great medical benefits, concerns have been raised about the magnitude of possible associated cancer risk, particularly in children who are more sensitive to radiation than adults. Unnecessary high doses during CT examinations can also be delivered to children, if the scan parameters are not adjusted for patient age and size. We conducted the first survey to directly assess the trends in CT scan parameters and doses for paediatric CT scans performed in Great Britain between 1978 and 2008. Methods: We retrieved 1073 CT film sets from 36 hospitals. The patients were 0–19 years old, and CT scans were conducted between 1978 and 2008. We extracted scan parameters from each film including tube current–time product [milliampere seconds (mAs)], tube potential [peak kilovoltage (kVp)] and manufacturer and model of the CT scanner. We estimated the mean mAs for head and trunk (chest and abdomen/pelvis) scans, according to patient age (0–4, 5–9, 10–14 and 15–19 years) and scan year (<1990, 1990–1994, 1995–1999 and ≥2000), and then derived the volumetric CT dose index and estimated organ doses. Results: For head CT scans, mean mAs decreased by about 47% on average from before 1990 to after 2000, with the decrease starting around 1990. The mean mAs for head CTs did not vary with age before 1990, whereas slightly lower mAs values were used for younger patients after 1990. Similar declines in mAs were observed for trunk CTs: a 46% decline on an average from before 1990 to after 2000. Although mean mAs for trunk CTs did not vary with age before 1990, the value varied markedly by age, from 63 mAs for age 0–4 years compared with 315 mAs for those aged >15 years after 2000. No material changes in kVp were found. Estimated brain-absorbed dose from head CT scans decreased from 62 mGy before 1990 to approximately 30 mGy after 2000. For chest CT scans, the lung dose to children aged 0–4 years decreased from 28 mGy before 1990 to 4 mGy after 2000. Conclusion: We found that mAs for head and trunk CTs was approximately halved starting around 1990, and age-specific mAs was generally used for paediatric scans after this date. These changes will have substantially reduced the radiation exposure to children from CT scans in Great Britain. Advances in knowledge: The study shows that mAs and major organ doses for paediatric CT scans in Great Britain began to decrease around 1990. PMID:26864156

Role of fluorine-18 fluoride PET-CT scan in the assessment of unilateral condylar hyperplasia in faciomandibular asymmetry patients: a preliminary study.

PubMed

Ahmed, Rais; Singh, Satinder P; Mittal, Bhagwant R; Rattan, Vidya; Parghane, Rahul; Utreja, Ashok

2016-03-01

This prospective study was aimed to determine and quantify the change in mandibular condylar hyperactivity over a period of time by using a fluorine-18 (18F) fluoride PET-computed tomography (CT) scan. Sixteen patients (age 19.50 ± 2.58 years) with noticeable faciomandibular asymmetry caused by unilateral condylar hyperplasia (UCH) were included in the test group and underwent an 18F-fluoride PET-CT scan at the beginning of the study (T0); these patients were then followed up for a minimum of 12 months, after which the 18F-fluoride PET-CT scan was repeated at first follow-up (T1). An age-matched control group consisted of 10 patients with apparently symmetrical faces whose PET-CT scans were acquired for some other medical conditions. Statistical analysis of maximum standardized uptake values (SUV max) obtained through 18F-fluoride PET-CT was performed using the paired t-test. Mean SUV max of the affected condyle at T0 and T1 was 9.18 ± 4.07 and 9.18 ± 3.88, respectively. The mean SUV max of the contralateral condyle at T0 and T1 was 6.21 ± 2.30 and 6.66 ± 2.64, respectively. The mean right-left difference in tracer uptake between the test and control groups both at T0 and T1 was statistically significant. Right-left percentage difference of isotope uptake of the test group was 16.87 ± 15.75% at T0 and 14.97 ± 12.72% at T1. Right-left percentage difference of isotope uptake of the control group was 5.51 ± 5.72%. Although these differences were statistically significant, their clinical relevance was insignificant. SUV max of the higher uptake side and the lower uptake side of the control group was 5.63 ± 1.85 and 5.09 ± 1.83, respectively. Great diversity exists in the clinical presentation of UCH. The growth trend of UCH is highly variable because of the age and sex of patients. The results of the present study show that the 18F-fluoride PET-CT scan may guide us in determining the right time and in making the right choice of surgico-orthodontic intervention in UCH patients. The clinical presentation and SUV max of PET-CT of UCH patients were in agreement with each other. The baseline values of the control group indicated that these could also be used to differentiate normal from abnormal condylar growth in potential class III skeletal pattern cases - that is, patients having sagittal skeletal dysplasia resulting from either maxillary deficiency or mandibular protrusion, or both in combination, thus resulting in a concave facial profile.

A new technique for the diagnosis of acute appendicitis: abdominal CT with compression to the right lower quadrant.

PubMed

Kılınçer, Abidin; Akpınar, Erhan; Erbil, Bülent; Ünal, Emre; Karaosmanoğlu, Ali Devrim; Kaynaroğlu, Volkan; Akata, Deniz; Özmen, Mustafa

2017-08-01

To determine the diagnostic accuracy of abdominal CT with compression to the right lower quadrant (RLQ) in adults with acute appendicitis. 168 patients (age range, 18-78 years) were included who underwent contrast-enhanced CT for suspected appendicitis performed either using compression to the RLQ (n = 71) or a standard protocol (n = 97). Outer diameter of the appendix, appendiceal wall thickening, luminal content and associated findings were evaluated in each patient. Kruskal-Wallis, Fisher's and Pearson's chi-squared tests were used for statistical analysis. There was no significant difference in the mean outer diameter (MOD) between compression CT scans (10.6 ± 1.9 mm) and standard protocol (11.2 ± 2.3 mm) in patients with acute appendicitis (P = 1). MOD was significantly lower in the compression group (5.2 ± 0.8 mm) compared to the standard protocol (6.5 ± 1.1 mm) (P < 0.01) in patients without appendicitis. A cut-off value of 6.75 mm for the outer diameter of the appendix was found to be 100% sensitive in the diagnosis of acute appendicitis for both groups. The specificity was higher for compression CT technique (67.7 vs. 94.9%). Normal appendix diameter was significantly smaller in the compression-CT group compared to standard-CT group, increasing diagnostic accuracy of abdominal compression CT. • Normal appendix diameter is significantly smaller in compression CT. • Compression could force contrast material to flow through the appendiceal lumen. • Compression CT may be a CT counterpart of graded compression US.

Reproducibility and Prognosis of Quantitative Features Extracted from CT Images12

PubMed Central

Balagurunathan, Yoganand; Gu, Yuhua; Wang, Hua; Kumar, Virendra; Grove, Olya; Hawkins, Sam; Kim, Jongphil; Goldgof, Dmitry B; Hall, Lawrence O; Gatenby, Robert A; Gillies, Robert J

2014-01-01

We study the reproducibility of quantitative imaging features that are used to describe tumor shape, size, and texture from computed tomography (CT) scans of non-small cell lung cancer (NSCLC). CT images are dependent on various scanning factors. We focus on characterizing image features that are reproducible in the presence of variations due to patient factors and segmentation methods. Thirty-two NSCLC nonenhanced lung CT scans were obtained from the Reference Image Database to Evaluate Response data set. The tumors were segmented using both manual (radiologist expert) and ensemble (software-automated) methods. A set of features (219 three-dimensional and 110 two-dimensional) was computed, and quantitative image features were statistically filtered to identify a subset of reproducible and nonredundant features. The variability in the repeated experiment was measured by the test-retest concordance correlation coefficient (CCCTreT). The natural range in the features, normalized to variance, was measured by the dynamic range (DR). In this study, there were 29 features across segmentation methods found with CCCTreT and DR ≥ 0.9 and R2Bet ≥ 0.95. These reproducible features were tested for predicting radiologist prognostic score; some texture features (run-length and Laws kernels) had an area under the curve of 0.9. The representative features were tested for their prognostic capabilities using an independent NSCLC data set (59 lung adenocarcinomas), where one of the texture features, run-length gray-level nonuniformity, was statistically significant in separating the samples into survival groups (P ≤ .046). PMID:24772210

Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

PubMed Central

Kim, Bum-Joon; Hong, Ki-Sun; Park, Kyung-Jae; Park, Dong-Hyuk; Chung, Yong-Gu

2012-01-01

Objective The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. Methods A total of 16 patients with large skull defects (>100 cm2) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. Results The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Conclusion Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects. PMID:23346326

The anatomy of the sacrococcygeal cornual region and its clinical relevance.

PubMed

Woon, Jason T K; Stringer, Mark D

2014-09-01

There has been no systematic study of the anatomy of the region between the sacral and coccygeal cornua. Reference texts describe an intercornual ligament connecting these structures. The aim of this study was to investigate the anatomy of this region, which may be relevant to unexplained cases of coccygeal pain (coccydynia) and local nerve blocks. The bony anatomy of the sacrococcygeal (SC) cornual region was analyzed in 33 CT scans obtained from supine adults of mostly European origin with no known SC pathology, 7 μCT scans of cadaver SC specimens, and 105 Asian Indian adult skeletons. A further five cadaver SC specimens were examined histologically. SC cornual fusion was seen in 45% of CT/μCT scans (mean age 67 years, 20 males) and in 20% of adult skeletons (78 males); there was no association with age or sex. In the absence of SC fusion, the mean intersacrococcygeal cornual gap was 7.1 ± 2.4 mm; this was bridged by an intercornual ligament composed of parallel vertical collagen fibers reinforced by elastin fibers on its anterior surface. Small nerve branches were observed adjacent to the ventral aspect of the intercornual ligament and, in one case, traversing the ligament. Ipsilateral sacral and coccygeal cornua are therefore normally bridged by an intercornual ligament that is probably innervated. The cornua are fused on one or both sides in 20-45% of adults. These findings may have implications for some cases of coccydynia and for anesthetists performing local nerve blocks.

Identification of early-stage usual interstitial pneumonia from low-dose chest CT scans using fractional high-density lung distribution

NASA Astrophysics Data System (ADS)

Xie, Yiting; Salvatore, Mary; Liu, Shuang; Jirapatnakul, Artit; Yankelevitz, David F.; Henschke, Claudia I.; Reeves, Anthony P.

2017-03-01

A fully-automated computer algorithm has been developed to identify early-stage Usual Interstitial Pneumonia (UIP) using features computed from low-dose CT scans. In each scan, the pre-segmented lung region is divided into N subsections (N = 1, 8, 27, 64) by separating the lung from anterior/posterior, left/right and superior/inferior in 3D space. Each subsection has approximately the same volume. In each subsection, a classic density measurement (fractional high-density volume h) is evaluated to characterize the disease severity in that subsection, resulting in a feature vector of length N for each lung. Features are then combined in two different ways: concatenation (2*N features) and taking the maximum in each of the two corresponding subsections in the two lungs (N features). The algorithm was evaluated on a dataset consisting of 51 UIP and 56 normal cases, a combined feature vector was computed for each case and an SVM classifier (RBF kernel) was used to classify them into UIP or normal using ten-fold cross validation. A receiver operating characteristic (ROC) area under the curve (AUC) was used for evaluation. The highest AUC of 0.95 was achieved by using concatenated features and an N of 27. Using lung partition (N = 27, 64) with concatenated features had significantly better result over not using partitions (N = 1) (p-value < 0.05). Therefore this equal-volume partition fractional high-density volume method is useful in distinguishing early-stage UIP from normal cases.

Full-Body CT Scans - What You Need to Know

MedlinePlus

... Medical Imaging Medical X-ray Imaging Full-Body CT Scans - What You Need to Know Share Tweet ... new service for health-conscious people: "Whole-body CT screening." This typically involves scanning the body from ...

A multicenter, randomized controlled trial of immediate total-body CT scanning in trauma patients (REACT-2)

PubMed Central

2012-01-01

Background Computed tomography (CT) scanning has become essential in the early diagnostic phase of trauma care because of its high diagnostic accuracy. The introduction of multi-slice CT scanners and infrastructural improvements made total-body CT scanning technically feasible and its usage is currently becoming common practice in several trauma centers. However, literature provides limited evidence whether immediate total-body CT leads to better clinical outcome then conventional radiographic imaging supplemented with selective CT scanning in trauma patients. The aim of the REACT-2 trial is to determine the value of immediate total-body CT scanning in trauma patients. Methods/design The REACT-2 trial is an international, multicenter randomized clinical trial. All participating trauma centers have a multi-slice CT scanner located in the trauma room or at the Emergency Department (ED). All adult, non-pregnant, severely injured trauma patients according to predefined criteria will be included. Patients in whom direct scanning will hamper necessary cardiopulmonary resuscitation or who require an immediate operation because of imminent death (both as judged by the trauma team leader) are excluded. Randomization will be computer assisted. The intervention group will receive a contrast-enhanced total-body CT scan (head to pelvis) during the primary survey. The control group will be evaluated according to local conventional trauma imaging protocols (based on ATLS guidelines) supplemented with selective CT scanning. Primary outcome will be in-hospital mortality. Secondary outcomes are differences in mortality and morbidity during the first year post trauma, several trauma work-up time intervals, radiation exposure, general health and quality of life at 6 and 12 months post trauma and cost-effectiveness. Discussion The REACT-2 trial is a multicenter randomized clinical trial that will provide evidence on the value of immediate total-body CT scanning during the primary survey of severely injured trauma patients. If immediate total-body CT scanning is found to be the best imaging strategy in severely injured trauma patients it could replace conventional imaging supplemented with CT in this specific group. Trial Registration ClinicalTrials.gov: (NCT01523626). PMID:22458247

Relative location prediction in CT scan images using convolutional neural networks.

PubMed

Guo, Jiajia; Du, Hongwei; Zhu, Jianyue; Yan, Ting; Qiu, Bensheng

2018-07-01

Relative location prediction in computed tomography (CT) scan images is a challenging problem. Many traditional machine learning methods have been applied in attempts to alleviate this problem. However, the accuracy and speed of these methods cannot meet the requirement of medical scenario. In this paper, we propose a regression model based on one-dimensional convolutional neural networks (CNN) to determine the relative location of a CT scan image both quickly and precisely. In contrast to other common CNN models that use a two-dimensional image as an input, the input of this CNN model is a feature vector extracted by a shape context algorithm with spatial correlation. Normalization via z-score is first applied as a pre-processing step. Then, in order to prevent overfitting and improve model's performance, 20% of the elements of the feature vectors are randomly set to zero. This CNN model consists primarily of three one-dimensional convolutional layers, three dropout layers and two fully-connected layers with appropriate loss functions. A public dataset is employed to validate the performance of the proposed model using a 5-fold cross validation. Experimental results demonstrate an excellent performance of the proposed model when compared with contemporary techniques, achieving a median absolute error of 1.04 cm and mean absolute error of 1.69 cm. The time taken for each relative location prediction is approximately 2 ms. Results indicate that the proposed CNN method can contribute to a quick and accurate relative location prediction in CT scan images, which can improve efficiency of the medical picture archiving and communication system in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

Clinical evaluation of the reproducibility of volume measurements of pulmonary nodules

NASA Astrophysics Data System (ADS)

Wormanns, Dag; Kohl, Gerhard; Klotz, Ernst; Heindel, Walter; Diederich, Stefan

2002-05-01

High reproducibility of volumetric measurements is an important prerequisite for follow-up of small lung nodules in order to differentiate malignant from benign lesions in a lung cancer screening setting. This study was aimed to evaluate the measurement reproducibility of a new software tool for pulmonary nodule volumetry. In an ongoing study, 147 pulmonary nodules (size 1.6-17.5 mm) were examined with low-dose multidetector CT (Siemens Somatom Volume Zoom, 120 kVp, 20 mAs, detector collimation 4x1 mm, normalized pitch 1.75, slice thickness 1.25 mm, reconstruction increment 0.8 mm). Two consecutive low-dose scans covering the whole lung volume were performed within a few minutes. Between both scans, patients were asked to leave the CT scanner, and the second scan was planned independently from the first one. For all visually detected pulmonary nodules with a diameter <20 mm nodule volume was determined on both scans using a software prototype containing segmentation and volumetry algorithms. Results from both scans were compared. Nodule volume differences were determined as difference between the first and second measurement and ranged from 169 to 87%. The performance of the diagnostic test was measured using ROC analysis. For the detection of a volume doubling the area under curve (Az) was 0.98, for a growth of 50% the Az was 0.89. Further refinement of the segmentation algorithm should lead to more consistent measurements in ill-defined nodules. In conclusion, volumetric measurement of pulmonary nodules in multislice CT data sets is a reliable tool for the detection of growth in small pulmonary nodules.

A CT scan protocol for the detection of radiographic loosening of the glenoid component after total shoulder arthroplasty

PubMed Central

2014-01-01

Background and purpose It is difficult to evaluate glenoid component periprosthetic radiolucencies in total shoulder arthroplasties (TSAs) using plain radiographs. This study was performed to evaluate whether computed tomography (CT) using a specific patient position in the CT scanner provides a better method for assessing radiolucencies in TSA. Methods Following TSA, 11 patients were CT scanned in a lateral decubitus position with maximum forward flexion, which aligns the glenoid orientation with the axis of the CT scanner. Follow-up CT scanning is part of our routine patient care. Glenoid component periprosthetic lucency was assessed according to the Molé score and it was compared to routine plain radiographs by 5 observers. Results The protocol almost completely eliminated metal artifacts in the CT images and allowed accurate assessment of periprosthetic lucency of the glenoid fixation. Positioning of the patient within the CT scanner as described was possible for all 11 patients. A radiolucent line was identified in 54 of the 55 observed CT scans and osteolysis was identified in 25 observations. The average radiolucent line Molé score was 3.4 (SD 2.7) points with plain radiographs and 9.5 (SD 0.8) points with CT scans (p = 0.001). The mean intra-observer variance was lower in the CT scan group than in the plain radiograph group (p = 0.001). Interpretation The CT scan protocol we used is of clinical value in routine assessment of glenoid periprosthetic lucency after TSA. The technique improves the ability to detect and monitor radiolucent lines and, therefore, possibly implant loosening also. PMID:24286563

Chest CT in children: anesthesia and atelectasis.

PubMed

Newman, Beverley; Krane, Elliot J; Gawande, Rakhee; Holmes, Tyson H; Robinson, Terry E

2014-02-01

There has been an increasing tendency for anesthesiologists to be responsible for providing sedation or anesthesia during chest CT imaging in young children. Anesthesia-related atelectasis noted on chest CT imaging has proven to be a common and troublesome problem, affecting image quality and diagnostic sensitivity. To evaluate the safety and effectiveness of a standardized anesthesia, lung recruitment, controlled-ventilation technique developed at our institution to prevent atelectasis for chest CT imaging in young children. Fifty-six chest CT scans were obtained in 42 children using a research-based intubation, lung recruitment and controlled-ventilation CT scanning protocol. These studies were compared with 70 non-protocolized chest CT scans under anesthesia taken from 18 of the same children, who were tested at different times, without the specific lung recruitment and controlled-ventilation technique. Two radiology readers scored all inspiratory chest CT scans for overall CT quality and atelectasis. Detailed cardiorespiratory parameters were evaluated at baseline, and during recruitment and inspiratory imaging on 21 controlled-ventilation cases and 8 control cases. Significant differences were noted between groups for both quality and atelectasis scores with optimal scoring demonstrated in the controlled-ventilation cases where 70% were rated very good to excellent quality scans compared with only 24% of non-protocol cases. There was no or minimal atelectasis in 48% of the controlled ventilation cases compared to 51% of non-protocol cases with segmental, multisegmental or lobar atelectasis present. No significant difference in cardiorespiratory parameters was found between controlled ventilation and other chest CT cases and no procedure-related adverse events occurred. Controlled-ventilation infant CT scanning under general anesthesia, utilizing intubation and recruitment maneuvers followed by chest CT scans, appears to be a safe and effective method to obtain reliable and reproducible high-quality, motion-free chest CT images in children.

H-FABP: A new biomarker to differentiate between CT-positive and CT-negative patients with mild traumatic brain injury

PubMed Central

Lagerstedt, Linnéa; Egea-Guerrero, Juan José; Bustamante, Alejandro; Montaner, Joan; Rodríguez-Rodríguez, Ana; El Rahal, Amir; Turck, Natacha; Quintana, Manuel; García-Armengol, Roser; Prica, Carmen Melinda; Andereggen, Elisabeth; Rinaldi, Lara; Sarrafzadeh, Asita; Schaller, Karl; Sanchez, Jean-Charles

2017-01-01

The majority of patients with mild traumatic brain injury (mTBI) will have normal Glasgow coma scale (GCS) of 15. Furthermore, only 5%–8% of them will be CT-positive for an mTBI. Having a useful biomarker would help clinicians evaluate a patient’s risk of developing intracranial lesions. The S100B protein is currently the most studied and promising biomarker for this purpose. Heart fatty-acid binding protein (H-FABP) has been highlighted in brain injury models and investigated as a biomarker for stroke and severe TBI, for example. Here, we evaluate the performances of S100B and H-FABP for differentiating between CT-positive and CT-negative patients. A total of 261 patients with a GCS score of 15 and at least one clinical symptom of mTBI were recruited at three different European sites. Blood samples from 172 of them were collected ≤ 6 h after trauma. Patients underwent a CT scan and were dichotomised into CT-positive and CT-negative groups for statistical analyses. H-FABP and S100B levels were measured using commercial kits, and their capacities to detect all CT-positive scans were evaluated, with sensitivity set to 100%. For patients recruited ≤ 6 h after trauma, the CT-positive group demonstrated significantly higher levels of both H-FABP (p = 0.004) and S100B (p = 0.003) than the CT-negative group. At 100% sensitivity, specificity reached 6% (95% CI 2.8–10.7) for S100B and 29% (95% CI 21.4–37.1) for H-FABP. Similar results were obtained when including all the patients recruited, i.e. hospital arrival within 24 h of trauma onset. H-FABP out-performed S100B and thus seems to be an interesting protein for detecting all CT-positive mTBI patients with a GCS score of 15 and at least one clinical symptom. PMID:28419114

H-FABP: A new biomarker to differentiate between CT-positive and CT-negative patients with mild traumatic brain injury.

PubMed

Lagerstedt, Linnéa; Egea-Guerrero, Juan José; Bustamante, Alejandro; Montaner, Joan; Rodríguez-Rodríguez, Ana; El Rahal, Amir; Turck, Natacha; Quintana, Manuel; García-Armengol, Roser; Prica, Carmen Melinda; Andereggen, Elisabeth; Rinaldi, Lara; Sarrafzadeh, Asita; Schaller, Karl; Sanchez, Jean-Charles

2017-01-01

The majority of patients with mild traumatic brain injury (mTBI) will have normal Glasgow coma scale (GCS) of 15. Furthermore, only 5%-8% of them will be CT-positive for an mTBI. Having a useful biomarker would help clinicians evaluate a patient's risk of developing intracranial lesions. The S100B protein is currently the most studied and promising biomarker for this purpose. Heart fatty-acid binding protein (H-FABP) has been highlighted in brain injury models and investigated as a biomarker for stroke and severe TBI, for example. Here, we evaluate the performances of S100B and H-FABP for differentiating between CT-positive and CT-negative patients. A total of 261 patients with a GCS score of 15 and at least one clinical symptom of mTBI were recruited at three different European sites. Blood samples from 172 of them were collected ≤ 6 h after trauma. Patients underwent a CT scan and were dichotomised into CT-positive and CT-negative groups for statistical analyses. H-FABP and S100B levels were measured using commercial kits, and their capacities to detect all CT-positive scans were evaluated, with sensitivity set to 100%. For patients recruited ≤ 6 h after trauma, the CT-positive group demonstrated significantly higher levels of both H-FABP (p = 0.004) and S100B (p = 0.003) than the CT-negative group. At 100% sensitivity, specificity reached 6% (95% CI 2.8-10.7) for S100B and 29% (95% CI 21.4-37.1) for H-FABP. Similar results were obtained when including all the patients recruited, i.e. hospital arrival within 24 h of trauma onset. H-FABP out-performed S100B and thus seems to be an interesting protein for detecting all CT-positive mTBI patients with a GCS score of 15 and at least one clinical symptom.

Hyoid bone development: An assessment of optimal CT scanner parameters and 3D volume rendering techniques

PubMed Central

Cotter, Meghan M.; Whyms, Brian J.; Kelly, Michael P.; Doherty, Benjamin M.; Gentry, Lindell R.; Bersu, Edward T.; Vorperian, Houri K.

2015-01-01

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared to corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques. PMID:25810349

Hyoid Bone Development: An Assessment Of Optimal CT Scanner Parameters and Three-Dimensional Volume Rendering Techniques.

PubMed

Cotter, Meghan M; Whyms, Brian J; Kelly, Michael P; Doherty, Benjamin M; Gentry, Lindell R; Bersu, Edward T; Vorperian, Houri K

2015-08-01

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared with corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques. © 2015 Wiley Periodicals, Inc.

How Is Testicular Cancer Diagnosed?

MedlinePlus

... patients with non-seminoma. Many centers have special machines that can do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET with the more detailed images of the CT. Bone scan A bone scan can help show if a ... Information, ...

Assessment of the effects of CT dose in averaged x-ray CT images of a dose-sensitive polymer gel

NASA Astrophysics Data System (ADS)

Kairn, T.; Kakakhel, M. B.; Johnston, H.; Jirasek, A.; Trapp, J. V.

2015-01-01

The signal-to-noise ratio achievable in x-ray computed tomography (CT) images of polymer gels can be increased by averaging over multiple scans of each sample. However, repeated scanning delivers a small additional dose to the gel which may compromise the accuracy of the dose measurement. In this study, a NIPAM-based polymer gel was irradiated and then CT scanned 25 times, with the resulting data used to derive an averaged image and a "zero-scan" image of the gel. Comparison between these two results and the first scan of the gel showed that the averaged and zero-scan images provided better contrast, higher contrast-to- noise and higher signal-to-noise than the initial scan. The pixel values (Hounsfield units, HU) in the averaged image were not noticeably elevated, compared to the zero-scan result and the gradients used in the linear extrapolation of the zero-scan images were small and symmetrically distributed around zero. These results indicate that the averaged image was not artificially lightened by the small, additional dose delivered during CT scanning. This work demonstrates the broader usefulness of the zero-scan method as a means to verify the dosimetric accuracy of gel images derived from averaged x-ray CT data.

Improved aortic enhancement in CT angiography using slope-based triggering with table speed optimization: a pilot study.

PubMed

Bashir, Mustafa R; Weber, Paul W; Husarik, Daniela B; Howle, Laurens E; Nelson, Rendon C

2012-08-01

To assess whether a scan triggering technique based on the slope of the time-attenuation curve combined with table speed optimization may improve arterial enhancement in aortic CT angiography compared to conventional threshold-based triggering techniques. Measurements of arterial enhancement were performed in a physiologic flow phantom over a range of simulated cardiac outputs (2.2-8.1 L/min) using contrast media boluses of 80 and 150 mL injected at 4 mL/s. These measurements were used to construct computer models of aortic attenuation in CT angiography, using cardiac output, aortic diameter, and CT table speed as input parameters. In-plane enhancement was calculated for normal and aneurysmal aortic diameters. Calculated arterial enhancement was poor (<150 HU) along most of the scan length using the threshold-based triggering technique for low cardiac outputs and the aneurysmal aorta model. Implementation of the slope-based triggering technique with table speed optimization improved enhancement in all scenarios and yielded good- (>200 HU; 13/16 scenarios) to excellent-quality (>300 HU; 3/16 scenarios) enhancement in all cases. Slope-based triggering with table speed optimization may improve the technical quality of aortic CT angiography over conventional threshold-based techniques, and may reduce technical failures related to low cardiac output and slow flow through an aneurysmal aorta.

CT-detected intracranial hemorrhage among patients with head injury in Lagos, Nigeria.

PubMed

Eze, Cletus Uche; Abonyi, Livinus Chibuzo; Olowoyeye, Omodele; Njoku, Jerome; Ohagwu, Christopher; Babalola, Sherifat

2013-01-01

To evaluate the computed tomography (CT) findings of intracranial hemorrhage among patients with head trauma in Lagos, Nigeria. In this retrospective, cross-sectional study, a convenience sample of 500 patients with head trauma who had diagnostic cranial CT scans was selected. All the radiological reports and CT scans of patients with head trauma were retrieved in the hospitals selected as study sites. The reports were sorted into 2 groups - normal findings and intracranial bleeding. The reports of intracranial bleeding were sorted again into different classes of intracranial bleeding as identified by the radiologist who reported it. All data were analyzed using the Epi Info public domain software package. The chi-square test was used to measure the statistical significance of study results at P < .05. Most of the study subjects (68%) were men. Traffic accidents accounted for 44% of all the head traumas found in the study, and 58% of the head traumas resulted in intracranial bleeding. Among the hemorrhages found, 37% were intracerebral, 25% were subdural, 16% were intraventricular, 15% were subarachnoid, and 7% were epidural. Intracranial hemorrhage was a common consequence of acute head trauma sustained from traffic accidents in the population studied, with intracerebral hemorrhage being the most prevalent type. Traffic accidents are the main cause of acute head trauma in Lagos, Nigeria. The use of CT for early diagnosis of intracranial hemorrhage appears justifiable.

Study of CT image texture using deep learning techniques

NASA Astrophysics Data System (ADS)

Dutta, Sandeep; Fan, Jiahua; Chevalier, David

2018-03-01

For CT imaging, reduction of radiation dose while improving or maintaining image quality (IQ) is currently a very active research and development topic. Iterative Reconstruction (IR) approaches have been suggested to be able to offer better IQ to dose ratio compared to the conventional Filtered Back Projection (FBP) reconstruction. However, it has been widely reported that often CT image texture from IR is different compared to that from FBP. Researchers have proposed different figure of metrics to quantitate the texture from different reconstruction methods. But there is still a lack of practical and robust method in the field for texture description. This work applied deep learning method for CT image texture study. Multiple dose scans of a 20cm diameter cylindrical water phantom was performed on Revolution CT scanner (GE Healthcare, Waukesha) and the images were reconstructed with FBP and four different IR reconstruction settings. The training images generated were randomly allotted (80:20) to a training and validation set. An independent test set of 256-512 images/class were collected with the same scan and reconstruction settings. Multiple deep learning (DL) networks with Convolution, RELU activation, max-pooling, fully-connected, global average pooling and softmax activation layers were investigated. Impact of different image patch size for training was investigated. Original pixel data as well as normalized image data were evaluated. DL models were reliably able to classify CT image texture with accuracy up to 99%. Results show that the deep learning techniques suggest that CT IR techniques may help lower the radiation dose compared to FBP.

Pulmonary intersegmental planes: imaging appearance and possible reasons leading to their visualization.

PubMed

Zuo, Yi-Zhi; Liu, Chao; Liu, Shu-Wei

2013-04-01

To describe the normal imaging appearance of pulmonary intersegmental planes on thoracic computed tomographic (CT) scans and determine the possible reasons related to their visualization in terms of aging and anatomy. The study was approved by the internal ethics review board. Informed consent was obtained. A retrospective review was undertaken of 104 thoracic multidetector CT scans of an older group (>65 years) and younger group (<55 years). The number, location, and appearance rate of intersegmental planes were assessed. Group comparisons were made, and linear regression analysis was used to assess relationships between age and visualization of intersegmental planes. Thirty lung samples (10 × 10 × 10 mm(3)) from autopsy were scanned by using micro-CT. Thicknesses of intersegmental planes were measured. Significant differences of the thickness between visible and invisible intersegmental planes were assessed with the independent t test. In five fetal specimens (17-21 weeks in gestational age), 7.0-T magnetic resonance (MR) imaging was performed to determine the congenital difference of thickness of intersegmental planes. Within the right lung, appearance rates of visible intersegmental planes were 71.2% at S1-S3, 54.8% at S4-S5, and 70.2% at S7-S10. Within the left lung, appearance rates of visible intersegmental planes were 39.4% at S1+2 to S3, 64.4% at S4-S5, 18.3% at S7-S8, and 89.4% at S7-S10. Appearance rates of visible intersegmental planes on thoracic CT scans were not significantly different (P ≥ .38) between younger and older groups. Mean thicknesses of visible and invisible intersegmental planes were 681.3 μm ± 75.3 (standard deviation) and 221.7 μm ± 54.1, respectively. Visible intersegmental planes were significantly thicker than invisible intersegmental planes (P < .05). Visible intersegmental planes were also seen on fetal lung 7.0-T MR images. The thickness of pulmonary intersegmental planes and variation of intersegmental veins were closely related to visualization of intersegmental planes on thoracic CT scans. Aging was excluded as the possible reason. RSNA, 2013

Quantification of image contrast of infarcts on computed tomography scans.

PubMed

Gomolka, R S; Chrzan, R M; Urbanik, A; Kazmierski, R; Grzanka, A D; Nowinski, W L

2017-02-01

Introduction Accurate identification of infarcts in non-contrast computed tomography (NC-CT) scans of the brain is fundamental in the diagnosis and management of patients with stroke. Quantification of image contrast properties at the boundaries of ischemic infarct regions in NC-CT can contribute to a more precise manual or automatic delineation of these regions. Here we explore these properties quantitatively. Methods We retrospectively investigated 519 NC-CT studies of 425 patients with clinically confirmed ischemic strokes. The average and standard deviation (SD) of patients' age was 67.5 ± 12.4 years and the average(median)±SD time from symptoms onset to NC-CT examination was 27.4(12)±35.7 h. For every scan with an ischemic lesion identified by experts, the image contrast of the lesion vs. normal surrounding parenchyma was calculated as a difference of mean Hounsfield Unit (HU) of 1-5 consecutive voxels (the contrast window width) belonging to the lesion and to the parenchyma. This contrast was calculated at each single voxel of ischemic lesion boundaries (previously delineated by the experts) in horizontal and vertical directions in each image. The distributions of obtained horizontal, vertical and both contrasts combined were calculated among all 519 NC-CTs. Results The highest applicative contrast window width was identified as 5 voxels. The ischemic infarcts were found to be characterized by 6.60 HU, 8.28 HU and 7.55 HU mean values for distributions of horizontal, vertical and combined contrasts. Approximately 40-50% of the infarct boundary voxels were found to refer to the image contrast below 5 HU. Conclusion Low image contrast of ischemic lesions prevents accurate delineation of the infarcts in NC-CT.

Semi-automated method to measure pneumonia severity in mice through computed tomography (CT) scan analysis

NASA Astrophysics Data System (ADS)

Johri, Ansh; Schimel, Daniel; Noguchi, Audrey; Hsu, Lewis L.

2010-03-01

Imaging is a crucial clinical tool for diagnosis and assessment of pneumonia, but quantitative methods are lacking. Micro-computed tomography (micro CT), designed for lab animals, provides opportunities for non-invasive radiographic endpoints for pneumonia studies. HYPOTHESIS: In vivo micro CT scans of mice with early bacterial pneumonia can be scored quantitatively by semiautomated imaging methods, with good reproducibility and correlation with bacterial dose inoculated, pneumonia survival outcome, and radiologists' scores. METHODS: Healthy mice had intratracheal inoculation of E. coli bacteria (n=24) or saline control (n=11). In vivo micro CT scans were performed 24 hours later with microCAT II (Siemens). Two independent radiologists scored the extent of airspace abnormality, on a scale of 0 (normal) to 24 (completely abnormal). Using the Amira 5.2 software (Mercury Computer Systems), a histogram distribution of voxel counts between the Hounsfield range of -510 to 0 was created and analyzed, and a segmentation procedure was devised. RESULTS: A t-test was performed to determine whether there was a significant difference in the mean voxel value of each mouse in the three experimental groups: Saline Survivors, Pneumonia Survivors, and Pneumonia Non-survivors. It was found that the voxel count method was able to statistically tell apart the Saline Survivors from the Pneumonia Survivors, the Saline Survivors from the Pneumonia Non-survivors, but not the Pneumonia Survivors vs. Pneumonia Non-survivors. The segmentation method, however, was successfully able to distinguish the two Pneumonia groups. CONCLUSION: We have pilot-tested an evaluation of early pneumonia in mice using micro CT and a semi-automated method for lung segmentation and scoring system. Statistical analysis indicates that the system is reliable and merits further evaluation.

Individualized Physical 3-dimensional Kidney Tumor Models Constructed From 3-dimensional Printers Result in Improved Trainee Anatomic Understanding.

PubMed

Knoedler, Margaret; Feibus, Allison H; Lange, Andrew; Maddox, Michael M; Ledet, Elisa; Thomas, Raju; Silberstein, Jonathan L

2015-06-01

To evaluate the effect of 3-dimensionally (3D) printed physical renal models with enhancing masses on medical trainee characterization, localization, and understanding of renal malignancy. Proprietary software was used to import standard computed tomography (CT) cross-sectional imaging into 3D printers to create physical models of renal units with enhancing renal lesions in situ. Six different models were printed from a transparent plastic resin; the normal parenchyma was printed in a clear, translucent plastic, with a red hue delineating the suspicious renal lesion. Medical students, who had completed their first year of training, were given an overview and tasked with completion of RENAL nephrometry scores, separately using CT imaging and 3D models. Trainees were also asked to complete a questionnaire about their experience. Variability between trainees was assessed by intraclass correlation coefficients (ICCs), and kappa statistics were used to compare the trainee to experts. Overall trainee nephrometry score accuracy was significantly improved with the 3D model vs CT scan (P <.01). Furthermore, 3 of the 4 components of the nephrometry score (radius, nearness to collecting system, and location) showed significant improvement (P <.001) using the models. There was also more consistent agreement among trainees when using the 3D models compared with CT scans to assess the nephrometry score (intraclass correlation coefficient, 0.28 for CT scan vs 0.72 for 3D models). Qualitative evaluation with questionnaires filled out by the trainees further confirmed that the 3D models improved their ability to understand and conceptualize the renal mass. Physical 3D models using readily available printing techniques improve trainees' understanding and characterization of individual patients' enhancing renal lesions. Published by Elsevier Inc.

Multicenter study of pectus excavatum, final report: complications, static/exercise pulmonary function, and anatomic outcomes.

PubMed

Kelly, Robert E; Mellins, Robert B; Shamberger, Robert C; Mitchell, Karen K; Lawson, M Louise; Oldham, Keith T; Azizkhan, Richard G; Hebra, Andre V; Nuss, Donald; Goretsky, Michael J; Sharp, Ronald J; Holcomb, George W; Shim, Walton K T; Megison, Stephen M; Moss, R Lawrence; Fecteau, Annie H; Colombani, Paul M; Cooper, Dan; Bagley, Traci; Quinn, Amy; Moskowitz, Alan B; Paulson, James F

2013-12-01

A multicenter study of pectus excavatum was described previously. This report presents our final results. Patients treated surgically at 11 centers were followed prospectively. Each underwent a preoperative evaluation with CT scan, pulmonary function tests, and body image survey. Data were collected about associated conditions, complications, and perioperative pain. One year after treatment, patients underwent repeat chest CT scan, pulmonary function tests, and body image survey. A subset of 50 underwent exercise pulmonary function testing. Of 327 patients, 284 underwent Nuss procedure and 43 underwent open procedure without mortality. Of 182 patients with complete follow-up (56%), 18% had late complications, similarly distributed, including substernal bar displacement in 7% and wound infection in 2%. Mean initial CT scan index of 4.4 improved to 3.0 post operation (severe >3.2, normal = 2.5). Computed tomography index improved at the deepest point (xiphoid) and also upper and middle sternum. Pulmonary function tests improved (forced vital capacity from 88% to 93%, forced expiratory volume in 1 second from 87% to 90%, and total lung capacity from 94% to 100% of predicted (p < 0.001 for each). VO2 max during peak exercise increased by 10.1% (p = 0.015) and O2 pulse by 19% (p = 0.007) in 20 subjects who completed both pre- and postoperative exercise tests. There is significant improvement in lung function at rest and in VO2 max and O2 pulse after surgical correction of pectus excavatum, with CT index >3.2. Operative correction significantly reduces CT index and markedly improves the shape of the entire chest, and can be performed safely in a variety of centers. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

PubMed

Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

2009-10-01

To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

SU-F-I-32: Organ Doses from Pediatric Head CT Scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, H; Liu, Q; Qiu, J

Purpose: To evaluate the organ doses of pediatric patients who undergoing head CT scan using Monte Carlo (MC) simulation and compare it with measurements in anthropomorphic child phantom.. Methods: A ten years old children voxel phantom was developed from CT images, the voxel size of the phantom was 2mm*2mm*2mm. Organ doses from head CT scan were simulated using MCNPX software, 180 detectors were placed in the voxel phantom to tally the doses of the represented tissues or organs. When performing the simulation, 120 kVp and 88 mA were selected as the scan parameters. The scan range covered from the topmore » of the head to the end of the chain, this protocol was used at CT simulator for radiotherapy. To validate the simulated results, organ doses were measured with radiophotoluminescence (RPL) detectors, placed in the 28 organs of the 10 years old CIRS ATOM phantom. Results: The organ doses results matched well between MC simulation and phantom measurements. The eyes dose was showed to be as expected the highest organ dose: 28.11 mGy by simulation and 27.34 mGy by measurement respectively. Doses for organs not included in the scan volume were much lower than those included in the scan volume, thymus doses were observed more than 10 mGy due the CT protocol for radiotherapy covered more body part than routine head CT scan. Conclusion: As the eyes are superficial organs, they may receive the highest radiation dose during the CT scan. Considering the relatively high radio sensitivity, using shielding material or organ based tube current modulation technique should be encouraged to reduce the eye radiation risks. Scan range was one of the most important factors that affects the organ doses during the CT scan. Use as short as reasonably possible scan range should be helpful to reduce the patient radiation dose. This work was supported by the National Natural Science Foundation of China(11475047)« less

Impact of adaptive statistical iterative reconstruction on radiation dose in evaluation of trauma patients.

PubMed

Maxfield, Mark W; Schuster, Kevin M; McGillicuddy, Edward A; Young, Calvin J; Ghita, Monica; Bokhari, S A Jamal; Oliva, Isabel B; Brink, James A; Davis, Kimberly A

2012-12-01

A recent study showed that computed tomographic (CT) scans contributed 93% of radiation exposure of 177 patients admitted to our Level I trauma center. Adaptive statistical iterative reconstruction (ASIR) is an algorithm that reduces the noise level in reconstructed images and therefore allows the use of less ionizing radiation during CT scans without significantly affecting image quality. ASIR was instituted on all CT scans performed on trauma patients in June 2009. Our objective was to determine if implementation of ASIR reduced radiation dose without compromising patient outcomes. We identified 300 patients activating the trauma system before and after the implementation of ASIR imaging. After applying inclusion criteria, 245 charts were reviewed. Baseline demographics, presenting characteristics, number of delayed diagnoses, and missed injuries were recorded. The postexamination volume CT dose index (CTDIvol) and dose-length product (DLP) reported by the scanner for CT scans of the chest, abdomen, and pelvis and CT scans of the brain and cervical spine were recorded. Subjective image quality was compared between the two groups. For CT scans of the chest, abdomen, and pelvis, the mean CTDIvol (17.1 mGy vs. 14.2 mGy; p < 0.001) and DLP (1,165 mGy·cm vs. 1,004 mGy·cm; p < 0.001) was lower for studies performed with ASIR. For CT scans of the brain and cervical spine, the mean CTDIvol (61.7 mGy vs. 49.6 mGy; p < 0.001) and DLP (1,327 mGy·cm vs. 1,067 mGy·cm; p < 0.001) was lower for studies performed with ASIR. There was no subjective difference in image quality between ASIR and non-ASIR scans. All CT scans were deemed of good or excellent image quality. There were no delayed diagnoses or missed injuries related to CT scanning identified in either group. Implementation of ASIR imaging for CT scans performed on trauma patients led to a nearly 20% reduction in ionizing radiation without compromising outcomes or image quality. Therapeutic study, level IV.

Impact of adaptive statistical iterative reconstruction on radiation dose in evaluation of trauma patients

PubMed Central

Maxfield, Mark W.; Schuster, Kevin M.; McGillicuddy, Edward A.; Young, Calvin J.; Ghita, Monica; Bokhari, S.A. Jamal; Oliva, Isabel B.; Brink, James A.; Davis, Kimberly A.

2013-01-01

BACKGROUND A recent study showed that computed tomographic (CT) scans contributed 93% of radiation exposure of 177 patients admitted to our Level I trauma center. Adaptive statistical iterative reconstruction (ASIR) is an algorithm that reduces the noise level in reconstructed images and therefore allows the use of less ionizing radiation during CT scans without significantly affecting image quality. ASIR was instituted on all CT scans performed on trauma patients in June 2009. Our objective was to determine if implementation of ASIR reduced radiation dose without compromising patient outcomes. METHODS We identified 300 patients activating the trauma system before and after the implementation of ASIR imaging. After applying inclusion criteria, 245 charts were reviewed. Baseline demographics, presenting characteristics, number of delayed diagnoses, and missed injuries were recorded. The postexamination volume CT dose index (CTDIvol) and dose-length product (DLP)reported by the scanner for CT scans of the chest, abdomen, and pelvis and CT scans of the brain and cervical spine were recorded. Subjective image quality was compared between the two groups. RESULTS For CT scans of the chest, abdomen, and pelvis, the mean CTDIvol(17.1 mGy vs. 14.2 mGy; p < 0.001) and DLP (1,165 mGy·cm vs. 1,004 mGy·cm; p < 0.001) was lower for studies performed with ASIR. For CT scans of the brain and cervical spine, the mean CTDIvol(61.7 mGy vs. 49.6 mGy; p < 0.001) and DLP (1,327 mGy·cm vs. 1,067 mGy·cm; p < 0.001) was lower for studies performed with ASIR. There was no subjective difference in image quality between ASIR and non-ASIR scans. All CT scans were deemed of good or excellent image quality. There were no delayed diagnoses or missed injuries related to CT scanning identified in either group. CONCLUSION Implementation of ASIR imaging for CT scans performed on trauma patients led to a nearly 20% reduction in ionizing radiation without compromising outcomes or image quality. PMID:23147183

Neurocognitive assessment in patients with a minor traumatic brain injury and an abnormal initial CT scan: Can cognitive evaluation assist in identifying patients who require surveillance CT brain imaging?

PubMed

Clements, Thomas W; Dunham, Michael; Kirkpatrick, Andrew; Rajakumar, Ruphus; Gratton, Carolyn; Lall, Rohan; McBeth, Paul; Ball, Chad G

2018-05-01

Evidence for repeat computed tomography (CT) in minor traumatic brain injury (mTBI) patients with intracranial pathology is scarce. The aim of this study was to investigate the utility of clinical cognitive assessment (COG) in defining the need for repeat imaging. COG performance was compared with findings on subsequent CT, and need for neurosurgery in mTBI patients (GCS 13-15 and positive CT findings). Of 152 patients, 65.8% received a COG (53.0% passed). Patients with passed COG underwent fewer repeat CT (43.4% vs. 78.7%; p = .001) and had shorter LOS (8.7 vs. 19.5; p < .05). Only 1 patient required neurosurgery after a passed COG. The negative predictive value of a normal COG was 90.6% (95%CI = 81.8%-95.4%). mTBI patients with an abnormal index CT who pass COG are less likely to undergo repeat CT head, and rarely require neurosurgery. The COG warrants further investigation to determine its role in omitting repeat head CT. Copyright © 2018 Elsevier Inc. All rights reserved.

The scab-like sign: A CT finding indicative of haemoptysis in patients with chronic pulmonary aspergillosis?

PubMed

Sato, Haruka; Okada, Fumito; Matsumoto, Shunro; Mori, Hiromu; Kashiwagi, Junji; Komatsu, Eiji; Maeda, Toru; Nishida, Haruto; Daa, Tsutomu; Ohtani, Satoshi; Umeki, Kenji; Ando, Masaru; Kadota, Junichi

2018-05-03

The aim of this study was to assess the CT findings that characterise haemoptysis in patients with chronic pulmonary aspergillosis (CPA). We retrospectively identified 120 consecutive patients with CPA (84 men and 36 women, 17-89 years of age, mean age 68.4 years) who had undergone a total of 829 CT examinations between January 2007 and February 2017. In the 11 patients who underwent surgical resection, CT images were compared with the pathological results. The scab-like sign was seen on 142 of the 829 CT scans, specifically, in 87 of the 90 CT scans for haemoptysis and in 55 of the 739 CT scans obtained during therapy evaluation. In 48 of those 55 patients, haemoptysis occurred within 55 days (mean 12.0 days) after the CT scan. In the 687 CT scans with no scab-like sign, there were only three instances of subsequent haemoptysis in the respective patients over the following 6 months. Patients with and without scab-like sign differed significantly in the frequency of haemoptysis occurring after a CT scan (p<0.0001). Pathologically, the scab-like sign corresponded to a fibrinopurulent mass or blood crust. The scab-like sign should be considered as a CT finding indicative of haemoptysis. • Haemoptysis is commonly found in patients with CPA. • A CT finding indicative of haemoptysis in CPA patients is described. • Scab-like sign may identify CPA patients at higher risk of haemoptysis.

Optimization of dose and image quality in adult and pediatric computed tomography scans

NASA Astrophysics Data System (ADS)

Chang, Kwo-Ping; Hsu, Tzu-Kun; Lin, Wei-Ting; Hsu, Wen-Lin

2017-11-01

Exploration to maximize CT image and reduce radiation dose was conducted while controlling for multiple factors. The kVp, mAs, and iteration reconstruction (IR), affect the CT image quality and radiation dose absorbed. The optimal protocols (kVp, mAs, IR) are derived by figure of merit (FOM) based on CT image quality (CNR) and CT dose index (CTDIvol). CT image quality metrics such as CT number accuracy, SNR, low contrast materials' CNR and line pair resolution were also analyzed as auxiliary assessments. CT protocols were carried out with an ACR accreditation phantom and a five-year-old pediatric head phantom. The threshold values of the adult CT scan parameters, 100 kVp and 150 mAs, were determined from the CT number test and line pairs in ACR phantom module 1and module 4 respectively. The findings of this study suggest that the optimal scanning parameters for adults be set at 100 kVp and 150-250 mAs. However, for improved low- contrast resolution, 120 kVp and 150-250 mAs are optimal. Optimal settings for pediatric head CT scan were 80 kVp/50 mAs, for maxillary sinus and brain stem, while 80 kVp /300 mAs for temporal bone. SNR is not reliable as the independent image parameter nor the metric for determining optimal CT scan parameters. The iteration reconstruction (IR) approach is strongly recommended for both adult and pediatric CT scanning as it markedly improves image quality without affecting radiation dose.

[Mesenteric volvulus associated with mesenteric lipoma: about a case].

PubMed

Dème, Hamidou; Badji, Nfally; Akpo, Léra Géraud; Touré, Mouhamed Hamine; Draha, Ronald; Niang, Fallou Gallas; Diop, Abdoulaye Dione; Niang, El Hadj

2016-01-01

We report the case of a 7-year old patient presenting for acute paroxysmal abdominal pain at the level of epigastrium associated with vomiting without involving blockage of materials and gas. Clinical examination and laboratory tests were unremarkable. Abdominal ultrasound was requested as a first line investigationa and showed a right echogenic homogeneous flank and iliac fossa mass with regular contours without vascular Doppler signal and associated with "whirl sign" of mesenteric vessels. On CT scan this mass was seen as a well-defined lipoma formation, exerting a mass effect on the cecum, which was in direct contact with mesenteric volvulus. Arrangement of the mesenteric vessels at their origin was normal. The diagnosis of mesenteric volvulus associated with lipoma was retained. Surgical management and histological analysis of the surgical specimen confirmed the diagnosis. This clinical case aims to highlight the contribution of ultrasound and CT scan in the diagnosis of midgut volvulus.

Multicystic mesothelioma--a rare case of ascites: case report.

PubMed

Manuc, M; Lamatic, C; Pop, C; Dobrea, C; Becheanu, G; Grasu, M; Iosif, D; Diculescu, M

2007-01-01

We present the case of a 37-year-old male, admitted to our clinic with abdominal tenderness, right supraclavicular tumour, and ascites. The presence of ascites was incidentally reported 6 years before, but no other evaluation was done at that moment or during this period. Abdominal ultrasound and CT scan revealed moderate ascites, perivascular adenopathies, and multiple abdominal cystic lesions, while thoracic CT scan revealed the same lesions in mediastinum. Laboratory data were within normal limits, including the tumoral markers, and the tests for hydatid cysts. A biopsy from the right supraclavicular nodule was performed, and based on usual and immunohistochemical stains (calretinin, mesotheline, CK 5/6, CK 7, CK18 diffusely positive in mesothelial cells, and CEA -M, bcl-2 and vimentin negative), suggested the diagnosis of mesothelioma. Based on these results, the diagnosis of "multicystic mesothelioma" was made. The patient was referred for surgery.

Extracorporeal circuit for Panton-Valentine leukocidin-producing Staphylococcus aureus necrotizing pneumonia.

PubMed

Lavoue, S; Le Gac, G; Gacouin, A; Revest, M; Sohier, L; Mouline, J; Jouneau, S; Flecher, E; Tattevin, P; Tadié, J-M

2016-09-01

To describe two cases of Panton-Valentine leukocidin-producing Staphylococcus aureus (PVL-SA) necrotizing pneumonia treated with ECMO, and complete pulmonary evaluation at six months. Retrospective analysis of two patients presenting with severe PVL-SA pneumonia who both underwent complete respiratory function testing and chest CT scan six months after hospital discharge. Indications for ECMO were refractory hypoxia and left ventricular dysfunction associated with right ventricular dilatation. Patients were weaned off ECMO after 52 and 5 days. No ECMO-related hemorrhagic complication was observed. Pulmonary function tests performed at six months were normal and the CT scan showed complete regression of pulmonary injuries. PVL-SA pneumonia is characterized by extensive parenchymal injuries, including necrotic and hemorrhagic complications. ECMO may be used as a salvage treatment without any associated hemorrhagic complication, provided anticoagulant therapy is carefully monitored, and may lead to complete pulmonary recovery at six months. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

SU-E-J-55: End-To-End Effectiveness Analysis of 3D Surface Image Guided Voluntary Breath-Holding Radiotherapy for Left Breast

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, M; Feigenberg, S

Purpose To evaluate the effectiveness of using 3D-surface-image to guide breath-holding (BH) left-side breast treatment. Methods Two 3D surface image guided BH procedures were implemented and evaluated: normal-BH, taking BH at a comfortable level, and deep-inspiration-breath-holding (DIBH). A total of 20 patients (10 Normal-BH and 10 DIBH) were recruited. Patients received a BH evaluation using a commercialized 3D-surface- tracking-system (VisionRT, London, UK) to quantify the reproducibility of BH positions prior to CT scan. Tangential 3D/IMRT plans were conducted. Patients were initially setup under free-breathing (FB) condition using the FB surface obtained from the untaged CT to ensure a correct patientmore » position. Patients were then guided to reach the planned BH position using the BH surface obtained from the BH CT. Action-levels were set at each phase of treatment process based on the information provided by the 3D-surface-tracking-system for proper interventions (eliminate/re-setup/ re-coaching). We reviewed the frequency of interventions to evaluate its effectiveness. The FB-CBCT and port-film were utilized to evaluate the accuracy of 3D-surface-guided setups. Results 25% of BH candidates with BH positioning uncertainty > 2mm are eliminated prior to CT scan. For >90% of fractions, based on the setup deltas from3D-surface-trackingsystem, adjustments of patient setup are needed after the initial-setup using laser. 3D-surface-guided-setup accuracy is comparable as CBCT. For the BH guidance, frequency of interventions (a re-coaching/re-setup) is 40%(Normal-BH)/91%(DIBH) of treatments for the first 5-fractions and then drops to 16%(Normal-BH)/46%(DIBH). The necessity of re-setup is highly patient-specific for Normal-BH but highly random among patients for DIBH. Overall, a −0.8±2.4 mm accuracy of the anterior pericardial shadow position was achieved. Conclusion 3D-surface-image technology provides effective intervention to the treatment process and ensures favorable day-to-day setup accuracy. DIBH setup appears to be more uncertain and this would be the patient group who will definitely benefit from the extra information of 3D surface setup.« less

Phantom-less bone mineral density (BMD) measurement using dual energy computed tomography-based 3-material decomposition

NASA Astrophysics Data System (ADS)

Hofmann, Philipp; Sedlmair, Martin; Krauss, Bernhard; Wichmann, Julian L.; Bauer, Ralf W.; Flohr, Thomas G.; Mahnken, Andreas H.

2016-03-01

Osteoporosis is a degenerative bone disease usually diagnosed at the manifestation of fragility fractures, which severely endanger the health of especially the elderly. To ensure timely therapeutic countermeasures, noninvasive and widely applicable diagnostic methods are required. Currently the primary quantifiable indicator for bone stability, bone mineral density (BMD), is obtained either by DEXA (Dual-energy X-ray absorptiometry) or qCT (quantitative CT). Both have respective advantages and disadvantages, with DEXA being considered as gold standard. For timely diagnosis of osteoporosis, another CT-based method is presented. A Dual Energy CT reconstruction workflow is being developed to evaluate BMD by evaluating lumbar spine (L1-L4) DE-CT images. The workflow is ROI-based and automated for practical use. A dual energy 3-material decomposition algorithm is used to differentiate bone from soft tissue and fat attenuation. The algorithm uses material attenuation coefficients on different beam energy levels. The bone fraction of the three different tissues is used to calculate the amount of hydroxylapatite in the trabecular bone of the corpus vertebrae inside a predefined ROI. Calibrations have been performed to obtain volumetric bone mineral density (vBMD) without having to add a calibration phantom or to use special scan protocols or hardware. Accuracy and precision are dependent on image noise and comparable to qCT images. Clinical indications are in accordance with the DEXA gold standard. The decomposition-based workflow shows bone degradation effects normally not visible on standard CT images which would induce errors in normal qCT results.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation.

PubMed

Kim, Sangroh; Yoshizumi, Terry T; Yin, Fang-Fang; Chetty, Indrin J

2013-04-21

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan-scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the 'ISource = 8: Phase-Space Source Incident from Multiple Directions' in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

Medical thoracoscopy vs CT scan-guided Abrams pleural needle biopsy for diagnosis of patients with pleural effusions: a randomized, controlled trial.

PubMed

Metintas, Muzaffer; Ak, Guntulu; Dundar, Emine; Yildirim, Huseyin; Ozkan, Ragip; Kurt, Emel; Erginel, Sinan; Alatas, Fusun; Metintas, Selma

2010-06-01

In cases of pleural effusion, tissue samples can be obtained through Abrams needle pleural biopsy (ANPB), thoracoscopy, or cutting-needle pleural biopsy under the guidance of CT scan (CT-CNPB) for histopathologic analysis. This study aimed to compare the diagnostic efficiency and reliability of ANPB under CT scan guidance (CT-ANPB) with that of medical thoracoscopy in patients with pleural effusion. Between January 2006 and January 2008, 124 patients with exudative pleural effusion that could not be diagnosed by cytologic analysis were included in the study. All patients were randomized after the CT scan was performed. Patients either underwent CT-ANPB or thoracoscopy. The two groups were compared in terms of diagnostic sensitivity and complications associated with the methods used. Of the 124 patients, malignant mesothelioma was diagnosed in 33, metastatic pleural disease in 47, benign pleural disease in 42, and two were of indeterminate origin. In the CT-ANPB group, the diagnostic sensitivity was 87.5%, as compared with 94.1% in the thoracoscopy group; the difference was not statistically significant (P = .252). No difference was identified between the sensitivities of the two methods based on the cause, the CT scan findings, and the degree of pleural thickening. Complication rates were low and acceptable. We recommend the use of CT-ANPB as the primary method of diagnosis in patients with pleural thickening or lesions observed by CT scan. In patients with only pleural fluid appearance on CT scan and in those who may have benign pleural pathologies other than TB, the primary method of diagnosis should be medical thoracoscopy. clinicaltrials.gov; Identifier: NCT00720954.

Developing patient-specific dose protocols for a CT scanner and exam using diagnostic reference levels.

PubMed

Strauss, Keith J

2014-10-01

The management of image quality and radiation dose during pediatric CT scanning is dependent on how well one manages the radiographic techniques as a function of the type of exam, type of CT scanner, and patient size. The CT scanner's display of expected CT dose index volume (CTDIvol) after the projection scan provides the operator with a powerful tool prior to the patient scan to identify and manage appropriate CT techniques, provided the department has established appropriate diagnostic reference levels (DRLs). This paper provides a step-by-step process that allows the development of DRLs as a function of type of exam, of actual patient size and of the individual radiation output of each CT scanner in a department. Abdomen, pelvis, thorax and head scans are addressed. Patient sizes from newborns to large adults are discussed. The method addresses every CT scanner regardless of vendor, model or vintage. We cover adjustments to techniques to manage the impact of iterative reconstruction and provide a method to handle all available voltages other than 120 kV. This level of management of CT techniques is necessary to properly monitor radiation dose and image quality during pediatric CT scans.

Noise spatial nonuniformity and the impact of statistical image reconstruction in CT myocardial perfusion imaging.

PubMed

Lauzier, Pascal Theriault; Tang, Jie; Speidel, Michael A; Chen, Guang-Hong

2012-07-01

To achieve high temporal resolution in CT myocardial perfusion imaging (MPI), images are often reconstructed using filtered backprojection (FBP) algorithms from data acquired within a short-scan angular range. However, the variation in the central angle from one time frame to the next in gated short scans has been shown to create detrimental partial scan artifacts when performing quantitative MPI measurements. This study has two main purposes. (1) To demonstrate the existence of a distinct detrimental effect in short-scan FBP, i.e., the introduction of a nonuniform spatial image noise distribution; this nonuniformity can lead to unexpectedly high image noise and streaking artifacts, which may affect CT MPI quantification. (2) To demonstrate that statistical image reconstruction (SIR) algorithms can be a potential solution to address the nonuniform spatial noise distribution problem and can also lead to radiation dose reduction in the context of CT MPI. Projection datasets from a numerically simulated perfusion phantom and an in vivo animal myocardial perfusion CT scan were used in this study. In the numerical phantom, multiple realizations of Poisson noise were added to projection data at each time frame to investigate the spatial distribution of noise. Images from all datasets were reconstructed using both FBP and SIR reconstruction algorithms. To quantify the spatial distribution of noise, the mean and standard deviation were measured in several regions of interest (ROIs) and analyzed across time frames. In the in vivo study, two low-dose scans at tube currents of 25 and 50 mA were reconstructed using FBP and SIR. Quantitative perfusion metrics, namely, the normalized upslope (NUS), myocardial blood volume (MBV), and first moment transit time (FMT), were measured for two ROIs and compared to reference values obtained from a high-dose scan performed at 500 mA. Images reconstructed using FBP showed a highly nonuniform spatial distribution of noise. This spatial nonuniformity led to large fluctuations in the temporal direction. In the numerical phantom study, the level of noise was shown to vary by as much as 87% within a given image, and as much as 110% between different time frames for a ROI far from isocenter. The spatially nonuniform noise pattern was shown to correlate with the source trajectory and the object structure. In contrast, images reconstructed using SIR showed a highly uniform spatial distribution of noise, leading to smaller unexpected noise fluctuations in the temporal direction when a short scan angular range was used. In the numerical phantom study, the noise varied by less than 37% within a given image, and by less than 20% between different time frames. Also, the noise standard deviation in SIR images was on average half of that of FBP images. In the in vivo studies, the deviation observed between quantitative perfusion metrics measured from low-dose scans and high-dose scans was mitigated when SIR was used instead of FBP to reconstruct images. (1) Images reconstructed using FBP suffered from nonuniform spatial noise levels. This nonuniformity is another manifestation of the detrimental effects caused by short-scan reconstruction in CT MPI. (2) Images reconstructed using SIR had a much lower and more uniform noise level and thus can be used as a potential solution to address the FBP nonuniformity. (3) Given the improvement in the accuracy of the perfusion metrics when using SIR, it may be desirable to use a statistical reconstruction framework to perform low-dose dynamic CT MPI.

Noise spatial nonuniformity and the impact of statistical image reconstruction in CT myocardial perfusion imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lauzier, Pascal Theriault; Tang Jie; Speidel, Michael A.

Purpose: To achieve high temporal resolution in CT myocardial perfusion imaging (MPI), images are often reconstructed using filtered backprojection (FBP) algorithms from data acquired within a short-scan angular range. However, the variation in the central angle from one time frame to the next in gated short scans has been shown to create detrimental partial scan artifacts when performing quantitative MPI measurements. This study has two main purposes. (1) To demonstrate the existence of a distinct detrimental effect in short-scan FBP, i.e., the introduction of a nonuniform spatial image noise distribution; this nonuniformity can lead to unexpectedly high image noise andmore » streaking artifacts, which may affect CT MPI quantification. (2) To demonstrate that statistical image reconstruction (SIR) algorithms can be a potential solution to address the nonuniform spatial noise distribution problem and can also lead to radiation dose reduction in the context of CT MPI. Methods: Projection datasets from a numerically simulated perfusion phantom and an in vivo animal myocardial perfusion CT scan were used in this study. In the numerical phantom, multiple realizations of Poisson noise were added to projection data at each time frame to investigate the spatial distribution of noise. Images from all datasets were reconstructed using both FBP and SIR reconstruction algorithms. To quantify the spatial distribution of noise, the mean and standard deviation were measured in several regions of interest (ROIs) and analyzed across time frames. In the in vivo study, two low-dose scans at tube currents of 25 and 50 mA were reconstructed using FBP and SIR. Quantitative perfusion metrics, namely, the normalized upslope (NUS), myocardial blood volume (MBV), and first moment transit time (FMT), were measured for two ROIs and compared to reference values obtained from a high-dose scan performed at 500 mA. Results: Images reconstructed using FBP showed a highly nonuniform spatial distribution of noise. This spatial nonuniformity led to large fluctuations in the temporal direction. In the numerical phantom study, the level of noise was shown to vary by as much as 87% within a given image, and as much as 110% between different time frames for a ROI far from isocenter. The spatially nonuniform noise pattern was shown to correlate with the source trajectory and the object structure. In contrast, images reconstructed using SIR showed a highly uniform spatial distribution of noise, leading to smaller unexpected noise fluctuations in the temporal direction when a short scan angular range was used. In the numerical phantom study, the noise varied by less than 37% within a given image, and by less than 20% between different time frames. Also, the noise standard deviation in SIR images was on average half of that of FBP images. In the in vivo studies, the deviation observed between quantitative perfusion metrics measured from low-dose scans and high-dose scans was mitigated when SIR was used instead of FBP to reconstruct images. Conclusions: (1) Images reconstructed using FBP suffered from nonuniform spatial noise levels. This nonuniformity is another manifestation of the detrimental effects caused by short-scan reconstruction in CT MPI. (2) Images reconstructed using SIR had a much lower and more uniform noise level and thus can be used as a potential solution to address the FBP nonuniformity. (3) Given the improvement in the accuracy of the perfusion metrics when using SIR, it may be desirable to use a statistical reconstruction framework to perform low-dose dynamic CT MPI.« less

Noise spatial nonuniformity and the impact of statistical image reconstruction in CT myocardial perfusion imaging

PubMed Central

Lauzier, Pascal Thériault; Tang, Jie; Speidel, Michael A.; Chen, Guang-Hong

2012-01-01

Purpose: To achieve high temporal resolution in CT myocardial perfusion imaging (MPI), images are often reconstructed using filtered backprojection (FBP) algorithms from data acquired within a short-scan angular range. However, the variation in the central angle from one time frame to the next in gated short scans has been shown to create detrimental partial scan artifacts when performing quantitative MPI measurements. This study has two main purposes. (1) To demonstrate the existence of a distinct detrimental effect in short-scan FBP, i.e., the introduction of a nonuniform spatial image noise distribution; this nonuniformity can lead to unexpectedly high image noise and streaking artifacts, which may affect CT MPI quantification. (2) To demonstrate that statistical image reconstruction (SIR) algorithms can be a potential solution to address the nonuniform spatial noise distribution problem and can also lead to radiation dose reduction in the context of CT MPI. Methods: Projection datasets from a numerically simulated perfusion phantom and an in vivo animal myocardial perfusion CT scan were used in this study. In the numerical phantom, multiple realizations of Poisson noise were added to projection data at each time frame to investigate the spatial distribution of noise. Images from all datasets were reconstructed using both FBP and SIR reconstruction algorithms. To quantify the spatial distribution of noise, the mean and standard deviation were measured in several regions of interest (ROIs) and analyzed across time frames. In the in vivo study, two low-dose scans at tube currents of 25 and 50 mA were reconstructed using FBP and SIR. Quantitative perfusion metrics, namely, the normalized upslope (NUS), myocardial blood volume (MBV), and first moment transit time (FMT), were measured for two ROIs and compared to reference values obtained from a high-dose scan performed at 500 mA. Results: Images reconstructed using FBP showed a highly nonuniform spatial distribution of noise. This spatial nonuniformity led to large fluctuations in the temporal direction. In the numerical phantom study, the level of noise was shown to vary by as much as 87% within a given image, and as much as 110% between different time frames for a ROI far from isocenter. The spatially nonuniform noise pattern was shown to correlate with the source trajectory and the object structure. In contrast, images reconstructed using SIR showed a highly uniform spatial distribution of noise, leading to smaller unexpected noise fluctuations in the temporal direction when a short scan angular range was used. In the numerical phantom study, the noise varied by less than 37% within a given image, and by less than 20% between different time frames. Also, the noise standard deviation in SIR images was on average half of that of FBP images. In the in vivo studies, the deviation observed between quantitative perfusion metrics measured from low-dose scans and high-dose scans was mitigated when SIR was used instead of FBP to reconstruct images. Conclusions: (1) Images reconstructed using FBP suffered from nonuniform spatial noise levels. This nonuniformity is another manifestation of the detrimental effects caused by short-scan reconstruction in CT MPI. (2) Images reconstructed using SIR had a much lower and more uniform noise level and thus can be used as a potential solution to address the FBP nonuniformity. (3) Given the improvement in the accuracy of the perfusion metrics when using SIR, it may be desirable to use a statistical reconstruction framework to perform low-dose dynamic CT MPI. PMID:22830741

Increased therapeutic ratio by 18FDG-PET CT planning in patients with clinical CT stage N2-N3M0 non-small-cell lung cancer: a modeling study.

PubMed

van Der Wel, Antoinet; Nijsten, Sebastiaan; Hochstenbag, Monique; Lamers, Rob; Boersma, Liesbeth; Wanders, Rinus; Lutgens, Ludy; Zimny, Michael; Bentzen, Søren M; Wouters, Brad; Lambin, Philippe; De Ruysscher, Dirk

2005-03-01

With this modeling study, we wanted to estimate the potential gain from incorporating fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning in the radiotherapy treatment planning of CT Stage N2-N3M0 non-small-cell lung cancer (NSCLC) patients. Twenty-one consecutive patients with clinical CT Stage N2-N3M0 NSCLC were studied. For each patient, two three-dimensional conformal treatment plans were made: one with a CT-based planning target volume (PTV) and one with a PET-CT-based PTV, both to deliver 60 Gy in 30 fractions. From the dose-volume histograms and dose distributions on each plan, the dosimetric factors predicting esophageal and lung toxicity were analyzed and compared. For each patient, the maximal tolerable prescribed radiation dose for the CT PTV vs. PET-CT PTV was calculated according to the constraints for the lung, esophagus, and spinal cord. From these results, the tumor control probability (TCP) was estimated, assuming a clinical dose-response curve with a median toxic dose of 84.5 Gy and a gamma(50) of 2.0. Dose-response curves were modeled, taking into account geographic misses according to the accuracy of CT and PET in our institutions. The gross tumor volume of the nodes decreased from 13.7 +/- 3.8 cm(3) on the CT scan to 9.9 +/- 4.0 cm(3) on the PET-CT scan (p = 0.011). All dose-volume characteristics for the esophagus and lungs decreased in favor of PET-CT. The esophageal V(45) (the volume of the esophagus receiving 45 Gy) decreased from 45.2% +/- 4.9% to 34.0% +/- 5.8% (p = 0.003), esophageal V(55) (the volume of the esophagus receiving 55 Gy) from 30.6% +/- 3.2% to 21.9% +/- 3.8% (p = 0.004), mean esophageal dose from 29.8 +/- 2.5 Gy to 23.7 +/- 3.1 Gy (p = 0.004), lung V(20) (the volume of the lungs minus the PTV receiving 20 Gy) from 24.9% +/- 2.3% to 22.3% +/- 2.2% (p = 0.012), and mean lung dose from 14.7 +/- 1.3 Gy to 13.6 +/- 1.3 Gy (p = 0.004). For the same toxicity levels of the lung, esophagus, and spinal cord, the dose could be increased from 56.0 +/- 5.4 Gy with CT planning to 71.0 +/- 13.7 Gy with PET planning (p = 0.038). The TCP corresponding to these doses was estimated to be 14.2% +/- 5.6% for CT and 22.8% +/- 7.1% for PET-CT planning (p = 0.026). Adjusting for geographic misses by PET-CT vs. CT planning yielded TCP estimates of 12.5% and 18.3% (p = 0.009) for CT and PET-CT planning, respectively. In this group of clinical CT Stage N2-N3 NSCLC patients, use of FDG-PET scanning information in radiotherapy planning reduced the radiation exposure of the esophagus and lung, and thus allowed significant radiation dose escalation while respecting all relevant normal tissue constraints. This, together with a reduced risk of geographic misses using PET-CT, led to an estimated increase in TCP from 13% to 18%. The results of this modeling study support clinical trials investigating incorporation of FDG-PET information in CT-based radiotherapy planning.

Accuracy of Canadian CT head rule in predicting positive findings on CT of the head of patients after mild head injury in a large trauma centre in Saudi Arabia

PubMed Central

Arab, Ala Faisal; Ahmed, Anwar E; Hussein, Mohamed Ahmed; Khankan, Azzam A; Alokaili, Riyadh Nasser

2015-01-01

Background Investigation of unjustified computed tomography (CT) scan in patients with minor head injury is lacking in Saudi Arabia. The purpose of the study was to evaluate the compliance and effectiveness of the Canadian computed tomography head rule (CCHR) in our emergency department (ED) and trauma centre and also to reduce the number of unjustified CT studies of the head in the centre. Methods A retrospective study of 368 ED patients with minor head injury was conducted. Patients who underwent CT scan between July 2010 and June 2011were selected from the ED head trauma registry by systematic randomisation. The CCHR was retrospectively applied on the patients’ charts to calculate the prevalence of unjustified head CT scans. A separate survey was conducted to evaluate three emergency physicians’ level of awareness about the CCHR and their ability to determine the necessity of CT scans with various clinical scenarios of head injury. Results The prevalence of unjustified CT scans as per the CCHR was 61.8% (95% confidence interval (CI) 56.5–66.9%). Approximately 5% of the sample had positive CT findings with 95% CI 2.9–7.6%. The CCHR correctly identified 12 cases with positive CT findings with 66.67% sensitivity. Only 24 (6.7%) had Glasgow coma scale scores less than 15 (13/14). The Glasgow coma scale correctly identified only two cases with positive CT findings with 11.11% sensitivity. The percentage of skull fracture (0.9% vs 5%, P = 0.030) was significantly lower in patients with unjustified CT scans than in patients with clinically justified CT scans. There was fair to substantial agreement between the ED physicians and the CCHR (κ = 35–61%). Two ED physicians identified all cases of justified CT scan with 100% sensitivity (95% CI 71.51–100%). Conclusion The level of education regarding the CCHR was found to be optimal among emergency physicians using a case-based scenario survey. The CCHR was found to have a poor compliance potential in the busy ED of our trauma centre and the prevalence of unjustified cranial CT scans remained high. PMID:26471399

Cholesteatomas of the temporal bone: role of computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, D.W.; Voorhees, R.L.; Lufkin, R.B.

1983-09-01

Computed tomography (CT) of the temporal bone was performed in 64 patients thought to have a cholesteatoma of the middle ear. Twenty had not had surgery before, while 44 had been operated on; special consideration was given to 21 patients who were scanned immediately before a second operation and had confirmation of the CT findings. Inflammatory disease without cholesteatoma was characterized by absence of erosion of the otic capsule or ossicular chain. Sharply circumscribed cholesteatomas were easily diagnosed by CT. When they were combined with scarring, granulation tissue, or postsurgical changes, the resulting soft-tissue masses were indistinguishable, although cholesteatoma maymore » be suspected if there is evidence of progressive bone erosion about the middle ear. CT can play a major role in postoperative follow-up by confirming that the ear is normal and demonstrating displacement of ossicular grafts or prostheses.« less

A case of pheochromocytoma with negative MIBG scintigraphy, PET-CT and genetic tests (VHL included) and a rare case of post-operative erectile dysfunction.

PubMed

Defeudis, Giuseppe; Fioriti, Elvira; Palermo, Andrea; Tuccinardi, Dario; Minucci, Angelo; Capoluongo, Ettore; Pozzilli, Paolo; Manfrini, Silvia

2018-06-02

Pheochromocytoma (Ph) is a rare catecholamine-secreting neuroendocrine tumour that arises from the chromaffin cells of the adrenal medulla. Ph usually presents with symptoms including paroxysmal headache, sweating, palpitations, and hypertension. During a computed tomography (CT) scan in a normotensive 49-year-old man, an incidentaloma of 4.5 cm was detected. Hypercortisolism was excluded after the dexamethasone suppression test, levels of DHEAS all falling within the normal range. After a 24-h urine collection, normal urinary metanephrines and a 4-fold higher level compared to the normal range of urinary normetanephrines were observed. Cortisoluria levels were within the normal range. Multiple endocrine neoplasia type 2 (MEN 2) was also excluded. Before the adrenalectomy, 123 I meta-iodobenzylguanidine scintigraphy (MIBG) and 18F-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG PET)/CT were performed and were both negative. Histological examination confirmed the laboratory diagnosis of Ph. Genetic screening to evaluate the SDHB, SDHD, RET, CDKN1B, and VHL genes was requested in order to test for Von Hippel Lindau disease, but unexpectedly all of these were negative. On follow-up after surgery, the patient presented normal urinary catecholamines. However, after Ph removal, he reported frequent episodes of erectile dysfunction (ED) despite non-use of any antihypertensive medications and in the absence of any other precipitating factors, such as hormonal imbalance. This is a case report in which, in a normotensive patient with Ph, both MIBG and FDG PET-CT were negative, as were also genetic exams, including VHL, this underlining the difficulties in diagnosing this condition; furthermore, a rare case of ED occurred after surgery.

Computed tomographic imaging in the pediatric patient with a seatbelt sign: still not good enough.

PubMed

Kopelman, Tammy R; Jamshidi, Ramin; Pieri, Paola G; Davis, Karole; Bogert, James; Vail, Sydney J; Gridley, Daniel; Singer Pressman, Melissa A

2018-02-01

Considering the improvements in CT over the past decade, this study aimed to determine whether CT can diagnose HVI in pediatric trauma patients with seatbelt signs (SBS). We retrospectively identified pediatric patients with SBS who had abdominopelvic CT performed on initial evaluation over 5 1/2years. Abnormal CT was defined by identification of any intra-abdominal abnormality possibly related to trauma. One hundred twenty patients met inclusion criteria. CT was abnormal in 38/120 (32%) patients: 34 scans had evidence of HVI and 6 showed solid organ injury (SOI). Of the 34 with suspicion for HVI, 15 (44%) had small amounts of isolated pelvic free fluid as the only abnormal CT finding; none required intervention. Ultimately, 16/120 (13%) patients suffered HVI and underwent celiotomy. Three patients initially had a normal CT but required celiotomy for clinical deterioration within 20h of presentation. False negative CT rate was 3.6%. The sensitivity, specificity and accuracy of CT to diagnose significant HVI in the presence of SBS were 81%, 80%, and 80%, respectively. Despite improvements in CT, pediatric patients with SBS may have HVI not evident on initial CT confirming the need to observation for delayed manifestation of HVI. Level II Study of a Diagnostic Test. Copyright © 2017 Elsevier Inc. All rights reserved.

Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations.

PubMed

Montes, Carlos; Tamayo, Pilar; Hernandez, Jorge; Gomez-Caminero, Felipe; García, Sofia; Martín, Carlos; Rosero, Angela

2013-08-01

Hybrid imaging, such as SPECT/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose.

Automated measurement of uptake in cerebellum, liver, and aortic arch in full-body FDG PET/CT scans.

PubMed

Bauer, Christian; Sun, Shanhui; Sun, Wenqing; Otis, Justin; Wallace, Audrey; Smith, Brian J; Sunderland, John J; Graham, Michael M; Sonka, Milan; Buatti, John M; Beichel, Reinhard R

2012-06-01

The purpose of this work was to develop and validate fully automated methods for uptake measurement of cerebellum, liver, and aortic arch in full-body PET/CT scans. Such measurements are of interest in the context of uptake normalization for quantitative assessment of metabolic activity and/or automated image quality control. Cerebellum, liver, and aortic arch regions were segmented with different automated approaches. Cerebella were segmented in PET volumes by means of a robust active shape model (ASM) based method. For liver segmentation, a largest possible hyperellipsoid was fitted to the liver in PET scans. The aortic arch was first segmented in CT images of a PET/CT scan by a tubular structure analysis approach, and the segmented result was then mapped to the corresponding PET scan. For each of the segmented structures, the average standardized uptake value (SUV) was calculated. To generate an independent reference standard for method validation, expert image analysts were asked to segment several cross sections of each of the three structures in 134 F-18 fluorodeoxyglucose (FDG) PET/CT scans. For each case, the true average SUV was estimated by utilizing statistical models and served as the independent reference standard. For automated aorta and liver SUV measurements, no statistically significant scale or shift differences were observed between automated results and the independent standard. In the case of the cerebellum, the scale and shift were not significantly different, if measured in the same cross sections that were utilized for generating the reference. In contrast, automated results were scaled 5% lower on average although not shifted, if FDG uptake was calculated from the whole segmented cerebellum volume. The estimated reduction in total SUV measurement error ranged between 54.7% and 99.2%, and the reduction was found to be statistically significant for cerebellum and aortic arch. With the proposed methods, the authors have demonstrated that automated SUV uptake measurements in cerebellum, liver, and aortic arch agree with expert-defined independent standards. The proposed methods were found to be accurate and showed less intra- and interobserver variability, compared to manual analysis. The approach provides an alternative to manual uptake quantification, which is time-consuming. Such an approach will be important for application of quantitative PET imaging to large scale clinical trials. © 2012 American Association of Physicists in Medicine.

Deformable anatomical templates for brachytherapy treatment planning in radiotherapy of cervical cancer

NASA Astrophysics Data System (ADS)

Christensen, Gary E.; Williamson, Jeffrey F.; Chao, K. S. C.; Miller, Michael I.; So, F. B.; Vannier, Michael W.

1997-10-01

This paper describes a new method to register serial, volumetric x-ray computed tomography (CT) data sets for tracking soft-tissue deformation caused by insertion of intracavity brachytherapy applicators to treat cervical cancer. 3D CT scans collected from the same patient with and without a brachytherapy applicator are registered to aid in computation of the radiation dose to tumor and normal tissue. The 3D CT image volume of pelvic anatomy with the applicator. Initial registration is accomplished by rigid alignment of the pelvic bones and non-rigid alignment of gray scale CT data and hand segmentations of the vagina, cervix, bladder, and rectum. A viscous fluid transformation model is used for non-rigid registration to allow for local, non-linear registration of the vagina, cervix, bladder, and rectum without disturbing the rigid registration of the bony pelvis and adjacent structures. Results are presented in which two 3D CT data sets of the same patient - imaged with and without a brachytherapy applicator - are registered.

First Clinical Investigation of Cone Beam Computed Tomography and Deformable Registration for Adaptive Proton Therapy for Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veiga, Catarina; Janssens, Guillaume; Teng, Ching-Ling

2016-05-01

Purpose: An adaptive proton therapy workflow using cone beam computed tomography (CBCT) is proposed. It consists of an online evaluation of a fast range-corrected dose distribution based on a virtual CT (vCT) scan. This can be followed by more accurate offline dose recalculation on the vCT scan, which can trigger a rescan CT (rCT) for replanning. Methods and Materials: The workflow was tested retrospectively for 20 consecutive lung cancer patients. A diffeomorphic Morphon algorithm was used to generate the lung vCT by deforming the average planning CT onto the CBCT scan. An additional correction step was applied to account formore » anatomic modifications that cannot be modeled by deformation alone. A set of clinical indicators for replanning were generated according to the water equivalent thickness (WET) and dose statistics and compared with those obtained on the rCT scan. The fast dose approximation consisted of warping the initial planned dose onto the vCT scan according to the changes in WET. The potential under- and over-ranges were assessed as a variation in WET at the target's distal surface. Results: The range-corrected dose from the vCT scan reproduced clinical indicators similar to those of the rCT scan. The workflow performed well under different clinical scenarios, including atelectasis, lung reinflation, and different types of tumor response. Between the vCT and rCT scans, we found a difference in the measured 95% percentile of the over-range distribution of 3.4 ± 2.7 mm. The limitations of the technique consisted of inherent uncertainties in deformable registration and the drawbacks of CBCT imaging. The correction step was adequate when gross errors occurred but could not recover subtle anatomic or density changes in tumors with complex topology. Conclusions: A proton therapy workflow based on CBCT provided clinical indicators similar to those using rCT for patients with lung cancer with considerable anatomic changes.« less

Arthroscopic and 3D CT Scan Evaluation of Femoral Footprint of the Anterior Cruciate Ligament in Chronic ACL Deficient Knees.

PubMed

Das, Anupam; Yadav, C S; Gamanagatti, Shivanand; Pandey, R M; Mittal, Ravi

2018-06-13

The outcome of single-bundle anterior cruciate ligament (ACL) reconstruction depends largely on the anatomic placement of bone tunnel. The lateral intercondylar ridge (LIR) and bifurcate ridge (BR) are useful bony landmarks for femoral tunnel placement. The purpose of our study was to compare the bony landmarks of ACL footprint on femur by three-dimensional computed tomography (3D CT) scan and arthroscopy in chronic ACL-deficient knees. Fifty patients above 18 years of age who were diagnosed of having ACL tear were selected for the study. All the cases were more than 6 months old since the injury. Preoperative 3D CT scan of the affected knee was obtained for each of them. They underwent single-bundle anatomic ACL reconstruction. Measurements were done on the preoperative 3D CT and arthroscopy to quantify the position of the LIR and BR. The proximodistal distance of lateral femoral condyle was 21.41+/-2.5 mm on CT scan and 22.02+/-2.02 mm on arthroscopy. On preoperative 3D CT scan, the midpoint of the LIR was found to be located at a mean distance of 11.17±2.11 mm from the proximal margin of the lateral femoral condyle. On arthroscopy, it was at 10.18+/-1.52 mm from the proximal margin the lateral femoral condyle. The "bifurcate ridge"(BR) was not visible in any of the cases during arthroscopy or CT scan. We concluded that LIR is an easily identifiable bony landmark on arthroscopy in all cases. It can also be identified on CT scans. BR is not identified both on arthroscopy and CT scans in chronic ACL tears. The arthroscopic measurements of bony landmarks are quite close to those of CT scan. Midpoint of LIR is at 52.185% of the proximodistal distance on CT scan evaluation and it is at 46.21% on arthroscopic evaluation. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

PET Index of Bone Glucose Metabolism (PIBGM) Classification of PET/CT Data for Fever of Unknown Origin Diagnosis

PubMed Central

Yang, Jian; Liu, Xinxin; Ai, Danni; Fan, Jingfan; Zheng, Youjing; Li, Fang; Huo, Li; Wang, Yongtian

2015-01-01

Objectives Fever of unknown origin (FUO) remains a challenge in clinical practice. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is helpful in diagnosing the etiology of FUO. This paper aims to develop a completely automatic classification method based on PET/CT data for the computer-assisted diagnosis of FUO. Methods We retrospectively analyzed the FDG PET/CT scan of 175 FUO patients, 79 males and 96 females. The final diagnosis of all FUO patients was achieved through pathology or clinical evaluation, including 108 normal patients and 67 FUO patients. CT anatomic information was used to acquire bone functional information from PET images. The skeletal system of FUO patients was classified by analyzing the standardized uptake value (SUV) and the PET index of bone glucose metabolism (PIBGM). The SUV distributions in the bone marrow and the bone cortex were also studied in detail. Results The SUV and PIBGM of the bone marrow only slightly differed between the FUO patients and normal people, whereas the SUV of whole bone structures and the PIBGM of the bone cortex significantly differed between the normal people and FUO patients. The method detected 43 patients from 67 FUO patients, with sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 64.18%, 95%, 93.48%, 72.73%, and 83.33%, respectively. Conclusion The experimental results demonstrate that the study can achieve automatic classification of FUO patients by the proposed novel biomarker of PIBGM, which has the potential to be utilized in clinical practice. PMID:26076139

Computed tomographic features of apical infection of equine maxillary cheek teeth: a retrospective study of 49 horses.

PubMed

Bühler, M; Fürst, A; Lewis, F I; Kummer, M; Ohlerth, S

2014-07-01

Computed tomographic (CT) studies evaluating the relevance of individual CT features of apical infection in maxillary cheek teeth are lacking. To study the prevalence and relationship of single CT features in horses with and without clinical evidence of apical infection in maxillary cheek teeth. Retrospective case-control study. Multislice CT scans of the head of 49 horses were evaluated retrospectively. Changes of the infundibulum, pulp, root, lamina dura, periodontal space and alveolar bone in maxillary cheek teeth were recorded. Single CT changes were much more prevalent in the 28 horses with clinical signs. However, infundibular changes and a nondetectable lamina dura were also common in the 21 horses without clinical evidence of apical infection. Computed tomographic abnormalities of the pulp, root, periapical bone and periodontal space and the presence of a tooth fracture were significantly related. Infundibular changes were not associated with other CT signs of apical infection. Although nondetectable lamina dura was the most frequent CT change in all teeth in both studied groups, it was most commonly a solitary feature in otherwise normal teeth. Apical infections, defined as ≥3 CT changes, occurred mainly in the 108/208, 109/209 and 110/210 (Triadan numbers) and were found only in horses with clinical evidence of apical infection, except in one horse without clinical signs that had one affected root. Combined CT changes of the pulp, root, lamina dura, periapical bone and periodontal space and the presence of a tooth fracture appear to be reliable features to diagnose apical infection in maxillary cheek teeth. As a solitary feature, a nondetectable lamina dura should be interpreted cautiously and may even be considered normal due to its minor thickness and/or too low resolution of the imaging modality. © 2013 EVJ Ltd.

Comparison of Conventional Versus Spiral Computed Tomography with Three Dimensional Reconstruction in Chronic Otitis Media with Ossicular Chain Destruction.

PubMed

Naghibi, Saeed; Seifirad, Sirous; Adami Dehkordi, Mahboobeh; Einolghozati, Sasan; Ghaffarian Eidgahi Moghadam, Nafiseh; Akhavan Rezayat, Amir; Seifirad, Soroush

2016-01-01

Chronic otitis media (COM) can be treated with tympanoplasty with or without mastoidectomy. In patients who have undergone middle ear surgery, three-dimensional spiral computed tomography (CT) scan plays an important role in optimizing surgical planning. This study was performed to compare the findings of three-dimensional reconstructed spiral and conventional CT scan of ossicular chain study in patients with COM. Fifty patients enrolled in the study underwent plane and three dimensional CT scan (PHILIPS-MX 8000). Ossicles changes, mastoid cavity, tympanic cavity, and presence of cholesteatoma were evaluated. Results of the two methods were then compared and interpreted by a radiologist, recorded in questionnaires, and analyzed. Logistic regression test and Kappa coefficient of agreement were used for statistical analyses. Sixty two ears with COM were found in physical examination. A significant difference was observed between the findings of the two methods in ossicle erosion (11.3% in conventional CT vs. 37.1% in spiral CT, P = 0.0001), decrease of mastoid air cells (82.3% in conventional CT vs. 93.5% in spiral CT, P = 0.001), and tympanic cavity opacity (12.9% in conventional CT vs. 40.3% in spiral CT, P=0.0001). No significant difference was observed between the findings of the two methods in ossicle destruction (6.5% conventional CT vs. 56.4% in spiral CT, P = 0.125), and presence of cholesteatoma (3.2% in conventional CT vs. 42% in spiral CT, P = 0.172). In this study, spiral CT scan demonstrated ossicle dislocation in 9.6%, decrease of mastoid air cells in 4.8%, and decrease of volume in the tympanic cavity in 1.6%; whereas, none of these findings were reported in the patients' conventional CT scans. Spiral-CT scan is superior to conventional CT in the diagnosis of lesions in COM before operation. It can be used for detailed evaluation of ossicular chain in such patients.

Interpretation of Brain CT Scans in the Field by Critical Care Physicians in a Mobile Stroke Unit

PubMed Central

Zakariassen, Erik; Lindner, Thomas; Nome, Terje; Bache, Kristi G.; Røislien, Jo; Gleditsch, Jostein; Solyga, Volker; Russell, David; Lund, Christian G.

2017-01-01

ABSTRACT BACKGROUND AND PURPOSE In acute stroke, thromboembolism or spontaneous hemorrhage abruptly reduces blood flow to a part of the brain. To limit necrosis, rapid radiological identification of the pathological mechanism must be conducted to allow the initiation of targeted treatment. The aim of the Norwegian Acute Stroke Prehospital Project is to determine if anesthesiologists, trained in prehospital critical care, may accurately assess cerebral computed tomography (CT) scans in a mobile stroke unit (MSU). METHODS In this pilot study, 13 anesthesiologists assessed unselected acute stroke patients with a cerebral CT scan in an MSU. The scans were simultaneously available by teleradiology at the receiving hospital and the on‐call radiologist. CT scan interpretation was focused on the radiological diagnosis of acute stroke and contraindications for thrombolysis. The aim of this study was to find inter‐rater agreement between the pre‐ and in‐hospital radiological assessments. A neuroradiologist evaluated all CT scans retrospectively. Statistical analysis of inter‐rater agreement was analyzed with Cohen's kappa. RESULTS Fifty‐one cerebral CT scans from the MSU were included. Inter‐rater agreement between prehospital anesthesiologists and the in‐hospital on‐call radiologists was excellent in finding radiological selection for thrombolysis (kappa .87). Prehospital CT scans were conducted in median 10 minutes (7 and 14 minutes) in the MSU, and median 39 minutes (31 and 48 minutes) before arrival at the receiving hospital. CONCLUSION This pilot study shows that anesthesiologists trained in prehospital critical care may effectively assess cerebral CT scans in an MSU, and determine if there are radiological contraindications for thrombolysis. PMID:28766306

SU-G-IeP1-06: Estimating Relative Tissue Density From Quantitative MR Images: A Novel Perspective for MRI-Only Heterogeneity Corrected Dose Calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soliman, A; Hashemi, M; Safigholi, H

Purpose: To explore the feasibility of extracting the relative density from quantitative MRI measurements as well as estimate a correlation between the extracted measures and CT Hounsfield units. Methods: MRI has the ability to separate water and fat signals, producing two separate images for each component. By performing appropriate corrections on the separated images, quantitative measurement of water and fat mass density can be estimated. This work aims to test this hypothesis on 1.5T.Peanut oil was used as fat-representative, while agar as water-representative. Gadolinium Chloride III and Sodium Chloride were added to the agar solution to adjust the relaxation timesmore » and the medium conductivity, respectively. Peanut oil was added to the agar solution with different percentages: 0%, 3%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%. The phantom was scanned on 1.5T GE Optima 450W with the body coil using a multigradient echo sequences. Water/fat separation were performed while correcting for main field (B0) inhomogeneity and T{sub 2}* relaxation time. B1+ inhomogeneities were ignored. The phantom was subsequently scanned on a Philips Brilliance CT Big Bore. MR-corrected fat signal from all vials were normalized to 100% fat signal. CT Hounsfield values were then compared to those obtained from the normalized MR-corrected fat values as well as to the phantom for validation. Results: Good agreement were found between CT HU and the MR-extracted fat values (R{sup 2} = 0.98). CT HU also showed excellent agreement with the prepared fat fractions (R{sup 2}=0.99). Vials with 70%, 80%, and 90% fat percentages showed inhomogeneous distributions, however their results were included for completion. Conclusion: Quantitative MRI water/fat imaging can be potentially used to extract the relative tissue density. Further in-vivo validation are required.« less

Lecithin-coated gold nanoflowers (GNFs) for CT scan imaging applications and biochemical parameters; in vitro and in vivo studies.

PubMed

Aziz, Farooq; Bano, Khizra; Siddique, Ahmad Hassan; Bajwa, Sadia Zafar; Nazir, Aalia; Munawar, Anam; Shaheen, Ayesha; Saeed, Madiha; Afzal, Muhammad; Iqbal, M Zubair; Wu, Aiguo; Khan, Waheed S

2018-01-09

We report a novel strategy for the fabrication of lecithin-coated gold nanoflowers (GNFs) via single-step design for CT imaging application. Field-emission electron microscope confirmed flowers like morphology of the as-synthesized nanostructures. Furthermore, these show absorption peak in near-infrared (NIR) region at λ max 690 nm Different concentrations of GNFs are tested as a contrast agent in CT scans at tube voltage 135 kV and tube current 350 mA. These results are compared with same amount of iodine at same CT scan parameters. The results of in vitro CT scan study show that GNFs have good contrast enhancement properties, whereas in vivo study of rabbits CT scan shows that GNFs enhance the CT image clearly at 135 kV as compared to that of iodine. Cytotoxicity was studied and blood profile show minor increase of white blood cells and haemoglobin, whereas decrease of red blood cells and platelets.

Leukemia and brain tumors among children after radiation exposure from CT scans: design and methodological opportunities of the Dutch Pediatric CT Study.

PubMed

Meulepas, Johanna M; Ronckers, Cécile M; Smets, Anne M J B; Nievelstein, Rutger A J; Jahnen, Andreas; Lee, Choonsik; Kieft, Mariëtte; Laméris, Johan S; van Herk, Marcel; Greuter, Marcel J W; Jeukens, Cécile R L P N; van Straten, Marcel; Visser, Otto; van Leeuwen, Flora E; Hauptmann, Michael

2014-04-01

Computed tomography (CT) scans are indispensable in modern medicine; however, the spectacular rise in global use coupled with relatively high doses of ionizing radiation per examination have raised radiation protection concerns. Children are of particular concern because they are more sensitive to radiation-induced cancer compared with adults and have a long lifespan to express harmful effects which may offset clinical benefits of performing a scan. This paper describes the design and methodology of a nationwide study, the Dutch Pediatric CT Study, regarding risk of leukemia and brain tumors in children after radiation exposure from CT scans. It is a retrospective record-linkage cohort study with an expected number of 100,000 children who received at least one electronically archived CT scan covering the calendar period since the introduction of digital archiving until 2012. Information on all archived CT scans of these children will be obtained, including date of examination, scanned body part and radiologist's report, as well as the machine settings required for organ dose estimation. We will obtain cancer incidence by record linkage with external databases. In this article, we describe several approaches to the collection of data on archived CT scans, the estimation of radiation doses and the assessment of confounding. The proposed approaches provide useful strategies for data collection and confounder assessment for general retrospective record-linkage studies, particular those using hospital databases on radiological procedures for the assessment of exposure to ionizing or non-ionizing radiation.

Pre-operative predictive factors for gallbladder cholesterol polyps using conventional diagnostic imaging

PubMed Central

Choi, Ji-Hoon; Yun, Jung-Won; Kim, Yong-Sung; Lee, Eun-A; Hwang, Sang-Tae; Cho, Yong-Kyun; Kim, Hong-Joo; Park, Jung-Ho; Park, Dong-Il; Sohn, Chong-Il; Jeon, Woo-Kyu; Kim, Byung-Ik; Kim, Hyoung-Ook; Shin, Jun-Ho

2008-01-01

AIM: To determine the clinical data that might be useful for differentiating benign from malignant gallbladder (GB) polyps by comparing radiological methods, including abdominal ultrasonography (US) and computed tomography (CT) scanning, with postoperative pathology findings. METHODS: Fifty-nine patients underwent laparoscopic cholecystectomy for a GB polyp of around 10 mm. They were divided into two groups, one with cholesterol polyps and the other with non-cholesterol polyps. Clinical features such as gender, age, symptoms, size and number of polyps, the presence of a GB stone, the radiologically measured maximum diameter of the polyp by US and CT scanning, and the measurements of diameter from postoperative pathology were recorded for comparative analysis. RESULTS: Fifteen of the 41 cases with cholesterol polyps (36.6%) were detected with US but not CT scanning, whereas all 18 non-cholesterol polyps were observed using both methods. In the cholesterol polyp group, the maximum measured diameter of the polyp was smaller by CT scan than by US. Consequently, the discrepancy between those two scanning measurements was greater than for the non-cholesterol polyp group. CONCLUSION: The clinical signs indicative of a cholesterol polyp include: (1) a polyp observed by US but not observable by CT scanning, (2) a smaller diameter on the CT scan compared to US, and (3) a discrepancy in its maximum diameter between US and CT measurements. In addition, US and the CT scan had low accuracy in predicting the polyp diameter compared to that determined by postoperative pathology. PMID:19058309

Pre-operative predictive factors for gallbladder cholesterol polyps using conventional diagnostic imaging.

PubMed

Choi, Ji-Hoon; Yun, Jung-Won; Kim, Yong-Sung; Lee, Eun-A; Hwang, Sang-Tae; Cho, Yong-Kyun; Kim, Hong-Joo; Park, Jung-Ho; Park, Dong-Il; Sohn, Chong-Il; Jeon, Woo-Kyu; Kim, Byung-Ik; Kim, Hyoung-Ook; Shin, Jun-Ho

2008-11-28

To determine the clinical data that might be useful for differentiating benign from malignant gallbladder (GB) polyps by comparing radiological methods, including abdominal ultrasonography (US) and computed tomography (CT) scanning, with postoperative pathology findings. Fifty-nine patients underwent laparoscopic cholecystectomy for a GB polyp of around 10 mm. They were divided into two groups, one with cholesterol polyps and the other with non-cholesterol polyps. Clinical features such as gender, age, symptoms, size and number of polyps, the presence of a GB stone, the radiologically measured maximum diameter of the polyp by US and CT scanning, and the measurements of diameter from postoperative pathology were recorded for comparative analysis. Fifteen of the 41 cases with cholesterol polyps (36.6%) were detected with US but not CT scanning, whereas all 18 non-cholesterol polyps were observed using both methods. In the cholesterol polyp group, the maximum measured diameter of the polyp was smaller by CT scan than by US. Consequently, the discrepancy between those two scanning measurements was greater than for the non-cholesterol polyp group. The clinical signs indicative of a cholesterol polyp include: (1) a polyp observed by US but not observable by CT scanning, (2) a smaller diameter on the CT scan compared to US, and (3) a discrepancy in its maximum diameter between US and CT measurements. In addition, US and the CT scan had low accuracy in predicting the polyp diameter compared to that determined by postoperative pathology.

18F-Choline PET/CT scan in staging and biochemical recurrence in prostate cancer patients: Changes in classification and radiotherapy planning.

PubMed

Cardona Arboniés, J; Rodríguez Alfonso, B; Mucientes Rasilla, J; Martínez Ballesteros, C; Zapata Paz, I; Prieto Soriano, A; Carballido Rodriguez, J; Mitjavila Casanovas, M

To evaluate the role of the 18 F-Choline PET/CT in prostate cancer management when detecting distant disease in planning radiotherapy and staging and to evaluate the therapy changes guided by PET/TC results. A retrospective evaluation was performed on 18 F-Choline PET/CT scans of patients with prostate cancer. Staging and planning radiotherapy scans were selected in patients with at least 9 months follow up. There was a total of 56 studies, 33 (58.93%) for staging, and 23 (41.07%) for planning radiotherapy. All scans were obtained using a hybrid PET/CT scanner. The PET/CT acquisition protocol consisted of a dual-phase procedure after the administration of an intravenous injection of 296-370MBq of 18 F-Choline. There were 43 out of 56 (76.8%) scans considered as positive, and 13 (23.2%) were negative. The TNM staging was changed in 13 (23.2%) scans. The PET/CT findings ruled out distant disease in 4 out of 13 scans, and unknown distant disease was detected in 9 (69.3%) scans. 18 F-Choline PET/CT is a useful technique for detecting unknown distant disease in prostate cancer when staging and planning radiotherapy. The inclusion of 18 F-choline PET/CT should be considered in prostate cancer management protocols. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

A comparison of sequential and spiral scanning techniques in brain CT.

PubMed

Pace, Ivana; Zarb, Francis

2015-01-01

To evaluate and compare image quality and radiation dose of sequential computed tomography (CT) examinations of the brain and spiral CT examinations of the brain imaged on a GE HiSpeed NX/I Dual Slice 2CT scanner. A random sample of 40 patients referred for CT examination of the brain was selected and divided into 2 groups. Half of the patients were scanned using the sequential technique; the other half were scanned using the spiral technique. Radiation dose data—both the computed tomography dose index (CTDI) and the dose length product (DLP)—were recorded on a checklist at the end of each examination. Using the European Guidelines on Quality Criteria for Computed Tomography, 4 radiologists conducted a visual grading analysis and rated the level of visibility of 6 anatomical structures considered necessary to produce images of high quality. The mean CTDI(vol) and DLP values were statistically significantly higher (P <.05) with the sequential scans (CTDI(vol): 22.06 mGy; DLP: 304.60 mGy • cm) than with the spiral scans (CTDI(vol): 14.94 mGy; DLP: 229.10 mGy • cm). The mean image quality rating scores for all criteria of the sequential scanning technique were statistically significantly higher (P <.05) in the visual grading analysis than those of the spiral scanning technique. In this local study, the sequential technique was preferred over the spiral technique for both overall image quality and differentiation between gray and white matter in brain CT scans. Other similar studies counter this finding. The radiation dose seen with the sequential CT scanning technique was significantly higher than that seen with the spiral CT scanning technique. However, image quality with the sequential technique was statistically significantly superior (P <.05).

CT scan exposure in Spanish children and young adults by socioeconomic status: Cross-sectional analysis of cohort data.

PubMed

Bosch de Basea, Magda; Espinosa, Ana; Gil, Mariona; Figuerola, Jordi; Pardina, Marina; Vilar, José; Cardis, Elisabeth

2018-01-01

Recent publications reported that children in disadvantaged areas undergo more CT scanning than others. The present study is aimed to assess the potential differences in CT imaging by socioeconomic status (SES) in Spanish young scanned subjects and if such differences vary with different indicators or different time point SES measurements. The associations between CT scanning and SES, and between the CT scan rate per patient and SES were investigated in the Spanish EPI-CT subcohort. Various SES indicators were studied to determine whether particular SES dimensions were more closely related to the probability of undergoing one or multiple CTs. Comparisons were made with indices based on 2001 and 2011 censuses. We found evidence of socio-economic variation among young people, mainly related to autonomous communities of residence. A slightly higher rate of scans per patient of multiple body parts in the less affluent categories was observed, possibly reflecting a higher rate of accidents and violence in these groups. The number of CT scans per patient was higher both in the most affluent and the most deprived categories and somewhat lower in the intermediate groups. This relation varied with the SES indicator used, with lower CT scans per patients in categories of high unemployment and temporary work, but not depending on categories of unskilled work or illiteracy. The relationship between these indicators and number of CTs in 2011 was different than that seen with the 2001 census, with the number of CTs increasing with higher unemployment. Overall we observed some differences in the SES distribution of scanned patients by Autonomous Community in Spain. There was, however, no major differences in the frequency of CT scans per patient by SES overall, based on the 2001 census. The use of different indicators and of SES data collected at different time points led to different relations between SES and frequency of CT scans, outlining the difficulty of adequately capturing the social and economic dimensions which may affect health and health service utilisation.

CT scan exposure in Spanish children and young adults by socioeconomic status: Cross-sectional analysis of cohort data

PubMed Central

Espinosa, Ana; Gil, Mariona; Figuerola, Jordi; Pardina, Marina; Vilar, José; Cardis, Elisabeth

2018-01-01

Recent publications reported that children in disadvantaged areas undergo more CT scanning than others. The present study is aimed to assess the potential differences in CT imaging by socioeconomic status (SES) in Spanish young scanned subjects and if such differences vary with different indicators or different time point SES measurements. The associations between CT scanning and SES, and between the CT scan rate per patient and SES were investigated in the Spanish EPI-CT subcohort. Various SES indicators were studied to determine whether particular SES dimensions were more closely related to the probability of undergoing one or multiple CTs. Comparisons were made with indices based on 2001 and 2011 censuses. We found evidence of socio-economic variation among young people, mainly related to autonomous communities of residence. A slightly higher rate of scans per patient of multiple body parts in the less affluent categories was observed, possibly reflecting a higher rate of accidents and violence in these groups. The number of CT scans per patient was higher both in the most affluent and the most deprived categories and somewhat lower in the intermediate groups. This relation varied with the SES indicator used, with lower CT scans per patients in categories of high unemployment and temporary work, but not depending on categories of unskilled work or illiteracy. The relationship between these indicators and number of CTs in 2011 was different than that seen with the 2001 census, with the number of CTs increasing with higher unemployment. Overall we observed some differences in the SES distribution of scanned patients by Autonomous Community in Spain. There was, however, no major differences in the frequency of CT scans per patient by SES overall, based on the 2001 census. The use of different indicators and of SES data collected at different time points led to different relations between SES and frequency of CT scans, outlining the difficulty of adequately capturing the social and economic dimensions which may affect health and health service utilisation. PMID:29723272

An electron beam linear scanning mode for industrial limited-angle nano-computed tomography.

PubMed

Wang, Chengxiang; Zeng, Li; Yu, Wei; Zhang, Lingli; Guo, Yumeng; Gong, Changcheng

2018-01-01

Nano-computed tomography (nano-CT), which utilizes X-rays to research the inner structure of some small objects and has been widely utilized in biomedical research, electronic technology, geology, material sciences, etc., is a high spatial resolution and non-destructive research technique. A traditional nano-CT scanning model with a very high mechanical precision and stability of object manipulator, which is difficult to reach when the scanned object is continuously rotated, is required for high resolution imaging. To reduce the scanning time and attain a stable and high resolution imaging in industrial non-destructive testing, we study an electron beam linear scanning mode of nano-CT system that can avoid mechanical vibration and object movement caused by the continuously rotated object. Furthermore, to further save the scanning time and study how small the scanning range could be considered with acceptable spatial resolution, an alternating iterative algorithm based on ℓ 0 minimization is utilized to limited-angle nano-CT reconstruction problem with the electron beam linear scanning mode. The experimental results confirm the feasibility of the electron beam linear scanning mode of nano-CT system.

An electron beam linear scanning mode for industrial limited-angle nano-computed tomography

NASA Astrophysics Data System (ADS)

Wang, Chengxiang; Zeng, Li; Yu, Wei; Zhang, Lingli; Guo, Yumeng; Gong, Changcheng

2018-01-01

Nano-computed tomography (nano-CT), which utilizes X-rays to research the inner structure of some small objects and has been widely utilized in biomedical research, electronic technology, geology, material sciences, etc., is a high spatial resolution and non-destructive research technique. A traditional nano-CT scanning model with a very high mechanical precision and stability of object manipulator, which is difficult to reach when the scanned object is continuously rotated, is required for high resolution imaging. To reduce the scanning time and attain a stable and high resolution imaging in industrial non-destructive testing, we study an electron beam linear scanning mode of nano-CT system that can avoid mechanical vibration and object movement caused by the continuously rotated object. Furthermore, to further save the scanning time and study how small the scanning range could be considered with acceptable spatial resolution, an alternating iterative algorithm based on ℓ0 minimization is utilized to limited-angle nano-CT reconstruction problem with the electron beam linear scanning mode. The experimental results confirm the feasibility of the electron beam linear scanning mode of nano-CT system.

Dual energy micro CT SkyScan 1173 for the characterization of urinary stone

NASA Astrophysics Data System (ADS)

Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

2016-03-01

Knowledge of the composition of urinary stones is an essential part to determine suitable treatments for patients. The aim of this research is to characterize the urinary stones by using dual energy micro CT SkyScan 11173. This technique combines high-energy and low- energy scanning during a single acquisition. Six human urinary stones were scanned in vitro using 80 kV and 120 kV micro CT SkyScan 1173. Projected images were produced by micro CT SkyScan 1173 and then reconstructed using NRecon (in-house software from SkyScan) to obtain a complete 3D image. The urinary stone images were analysed using CT analyser to obtain information of internal structure and Hounsfield Unit (HU) values to determine the information regarding the composition of the urinary stones, respectively. HU values obtained from some regions of interest in the same slice are compared to a reference HU. The analysis shows information of the composition of the six scanned stones obtained. The six stones consist of stone number 1 (calcium+cystine), number 2 (calcium+struvite), number 3 (calcium+cystine+struvite), number 4 (calcium), number 5 (calcium+cystine+struvite), and number 6 (calcium+uric acid). This shows that dual energy micro CT SkyScan 1173 was able to characterize the composition of the urinary stone.

Involved-node radiotherapy in early-stage Hodgkin's lymphoma. Definition and guidelines of the German Hodgkin Study Group (GHSG).

PubMed

Eich, Hans Theodor; Müller, Rolf-Peter; Engenhart-Cabillic, Rita; Lukas, Peter; Schmidberger, Heinz; Staar, Susanne; Willich, Normann

2008-08-01

Radiotherapy of Hodgkin's Lymphoma has evolved from extended-field to involved-field (IF) radiotherapy reducing toxicity whilst maintaining high cure rates. Recent publications recommend further reduction in the radiation field to involved-node (IN) radiotherapy; however, this concept has never been tested in a randomized trial. The German Hodgkin Study Group aims to compare it with standard IF radiotherapy in their future HD17 trial. ALL patients must be examined by the radiation oncologist before the start of chemotherapy. At that time, patients must have complete staging CT scans. For patients with IN radiotherapy, a radiation planning CT before and after chemotherapy with patients in the treatment position is recommended. Fusion techniques, allowing the overlapping of the pre- and postchemotherapy CT scans, should be used. Usage of PET-CT scans with patients in the treatment position is recommended, whenever possible. The clinical target volume encompasses the initial volume of the Lymph node(s) before chemotherapy and incorporates the initial Location and extent of the disease taking the displacement of the normal tissues into account. The margin of the planning target volume should be 2 cm in axial and 3 cm in craniocaudal direction. If necessary, it can be reduced to 1-1.5 cm. To minimize Lung and cardiac toxicity, the target definition in the mediastinum is different. The concept of IN radiotherapy has been proposed as a means to further improve the therapeutic ratio by reducing the risk of radiation-induced toxicity, including second malignancies. Field sizes wiLL further decrease compared to IF radiotherapy.

Age- and gender-related characteristics of the pubic symphysis and triradiate cartilage in pediatric computed tomography.

PubMed

Bayer, Jörg; Neubauer, Jakob; Saueressig, Ulrich; Südkamp, Norbert P; Reising, Kilian

2016-11-01

There is little information on the pubic symphysis' normal CT appearance in children. We sought to generate age-, gender- and maturity-related symphyseal width appearances in CT scans. Pelvic CT scans performed for any reason during a 6-year period in patients younger than 18 years were retrospectively analyzed. The symphysis width was measured in the axial plane and the triradiate cartilage was classified as open or closed. Four hundred twenty-seven CT scans were evaluated and 350 remained for analysis. Age- and gender-related measurements of the symphysis width are illustrated on various centile graphs. When grouping children by age in years 0-6, 7-11, 12-15 and 16-17, mean (standard deviation) symphysis width was 5.4 mm (0.9), 5.3 mm (1.1), 4.1 mm (1.1) and 3.5 mm (1.0), respectively, in girls and 5.9 mm (1.3), 5.4 mm (1.2), 5.2 mm (1.1) and 4.0 mm (1.0), respectively, in boys. Boys and girls were significantly different in the age groups 12-15 years (P<0.001) and 16-17 years (P=0.04). In the mature pelvis, the symphyseal gap is significantly (P<0.001) shorter in both genders, and in girls compared to boys (P=0.04). The pubic symphysis width in children differs according to age, gender and maturity. The reference values published herein may help detect symphyseal injury.

Utility of 68Ga-PSMA-11 PET/CT in Imaging of Glioma-A Pilot Study.

PubMed

Sasikumar, Arun; Kashyap, Raghava; Joy, Ajith; Charan Patro, Kanhu; Bhattacharya, Parthasarathy; Reddy Pilaka, Venkata Krishna; Oommen, Karuna Elza; Pillai, Maroor Raghavan Ambikalmajan

2018-06-22

Imaging of gliomas remains challenging. The aim of the study was to assess the feasibility of using Ga-PSMA-11 PET/CT for imaging gliomas. Fifteen patients with glioma from 2 centers were included in the study. Ten patients were treated cases of glioblastoma with suspected recurrence. Two patients were sent for assessing the nature (primary lesion/metastasis) of space-occupying lesion in the brain; 3 patients were imaged immediately after surgery and before radiotherapy. Target-to-background ratios (TBR) for the brain lesions were calculated using contralateral cerebellar uptake as background. Among the 10 cases with suspected recurrence, scan was positive in 9, subsequent surgery was done, and histopathology proved it to be true recurrence. In the scan-negative case on follow-up, no evidence of disease could be made clinically or radiologically. Among the other cases the presence or absence of disease could be unequivocally identified on the Ga-PSMA-11 brain scan and correlated with the histopathology or other imaging. Apart from the visual assessment quantitative assessment of the lesions with TBR also showed a significantly high TBR value for those with true disease compared with those with no disease. In the evaluation of gliomas, Ga-PSMA-11 PET/CT brain imaging is a potentially useful imaging tool. The use of Ga-PSMA-11 brain PET/CT in evaluation of recurrent glioma seems promising. Absence of physiological uptake of Ga-PSMA-11 in the normal brain parenchyma results in high TBR values and consequently better visualization of glioma lesions.

TU-A-12A-08: Computing Longitudinal Material Changes in Bone Metastases Using Dual Energy Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidtlein, CR; Hwang, S; Veeraraghavan, H

Purpose: This study demonstrates a methodology for tracking changes in metastatic bone disease using trajectories in material basis space in serial dual energy computed tomography (DECT) studies. Methods: This study includes patients with bone metastases from breast cancer that had clinical surveillance CT scans using a General Electric CT750HD in dual energy mode. A radiologist defined regions-of-interested (ROI) for bone metastasis, normal bone, and marrow across the serial DECT scans. Our approach employs a Radon transform to forward-projection the basis images, namely, water and iodine, into sinogram space. This data is then repartitioned into fat/bone and effective density/Z image pairsmore » using assumed energy spectrums for the x-ray energies. This approach both helps remove negative material densities and avoids adding spectrum-hardening artifacts. These new basis data sets were then reconstructed via filtered back-projection to create new material basis pair images. The trajectories of these pairs were then plotted in the new basis space providing a means to both visualize and quantitatively measure changes in the material properties of the tumors. Results: ROI containing radiologist defined metastatic bone disease showed well-defined trajectories in both fat/bone and effective density/Z space. ROI that contained radiologist defined normal bone and marrow did not exhibit any discernible trajectories and were stable from scan to scan. Conclusions: The preliminary results show that changes in material composition and effective density/Z image pairs were seen primarily in metastasis and not in normal tissue. This study indicates that by using routine clinical DECT it may be possible to monitor therapy response of bone metastases because healing or worsening bone metastases change material composition of bone. Additional studies are needed to further validate these results and to test for their correlation with outcome.« less

[The imaging diagnosis of hepatic focal nodular hyperplasia].

PubMed

Bazzocchi, M; Macorig, D; Cecconi, P; Gozzi, G

1991-12-01

Focal nodular hyperplasia (FNH) is a rare benign hepatocellular tumor occurring in noncirrhotic patients, mostly females, 20-50 years of age. It is usually asymptomatic. The authors took the lead from 5 cases of FNH studied over last year to analyze the different patterns exhibited by the condition on the various imaging techniques currently available. At scintigraphy with 99mTc DISIDA or with TcSC, FNH can be hyper, normal, or hypocaptating. On US scans, the lesion is often homogeneous and isoechoic, but it can also be hyper/hypoechoic. With Doppler US, high-flow signals can be observed. On unenhanced CT scans the lesion is solid, well-demarcated, isodense or slightly hyperdense; sometimes it shows a central hypodense area corresponding to fibrovascular scar. On postcontrast scans it appears hyper/isodense. At dynamic CT the lesion density, which is high during the arterial phase, decreases quickly in the parenchymal and the venous phases and reaches equal/inferior values to surrounding liver parenchyma. On liver angio-CT it is sometimes possible to visualize the bile ducts in the central scar. At angiography, FNH is hypervascular and homogeneous. On MR scans, in T1-weighted SE sequences, the condition is isointense or slightly hypointense, whereas on T2-weighted pulse sequences it is slightly hyperintense; the central scar is hypointense on T1, and hyperintense on T2, weighted scans. As we have no pathognomonic patterns but only orientative ones, a reliable differential diagnosis with hepatocellular adenoma (HA) and fibrolamellar hepatocellular carcinoma (FL-HCC) must be based on biopsy or cytology or, even better, histology. The differential diagnosis is nevertheless necessary because, while FNH does not usually require a surgical approach but only a radiological follow-up, both HA (due to possible bleeding and degeneration) and FL-HCC require surgery.

SU-E-J-270: Repeated 18F-FDG PET/CTs Based Feature Analysis for the Predication of Anal Cancer Recurrence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J; Chuong, M; Choi, W

Purpose: To identify PET/CT based imaging predictors of anal cancer recurrence and evaluate baseline vs. mid-treatment vs. post-treatment PET/CT scans in the tumor recurrence prediction. Methods: FDG-PET/CT scans were obtained at baseline, during chemoradiotherapy (CRT, midtreatment), and after CRT (post-treatment) in 17 patients of anal cancer. Four patients had tumor recurrence. For each patient, the mid-treatment and post-treatment scans were respectively aligned to the baseline scan by a rigid registration followed by a deformable registration. PET/CT image features were computed within the manually delineated tumor volume of each scan to characterize the intensity histogram, spatial patterns (texture), and shape ofmore » the tumors, as well as the changes of these features resulting from CRT. A total of 335 image features were extracted. An Exact Logistic Regression model was employed to analyze these PET/CT image features in order to identify potential predictors for tumor recurrence. Results: Eleven potential predictors of cancer recurrence were identified with p < 0.10, including five shape features, five statistical texture features, and one CT intensity histogram feature. Six features were indentified from posttreatment scans, 3 from mid-treatment scans, and 2 from baseline scans. These features indicated that there were differences in shape, intensity, and spatial pattern between tumors with and without recurrence. Recurrent tumors tended to have more compact shape (higher roundness and lower elongation) and larger intensity difference between baseline and follow-up scans, compared to non-recurrent tumors. Conclusion: PET/CT based anal cancer recurrence predictors were identified. The post-CRT PET/CT is the most important scan for the prediction of cancer recurrence. The baseline and mid-CRT PET/CT also showed value in the prediction and would be more useful for the predication of tumor recurrence in early stage of CRT. This work was supported in part by the National Cancer Institute Grant R01CA172638.« less

SedCT: MATLAB™ tools for standardized and quantitative processing of sediment core computed tomography (CT) data collected using a medical CT scanner

NASA Astrophysics Data System (ADS)

Reilly, B. T.; Stoner, J. S.; Wiest, J.

2017-08-01

Computed tomography (CT) of sediment cores allows for high-resolution images, three-dimensional volumes, and down core profiles. These quantitative data are generated through the attenuation of X-rays, which are sensitive to sediment density and atomic number, and are stored in pixels as relative gray scale values or Hounsfield units (HU). We present a suite of MATLAB™ tools specifically designed for routine sediment core analysis as a means to standardize and better quantify the products of CT data collected on medical CT scanners. SedCT uses a graphical interface to process Digital Imaging and Communications in Medicine (DICOM) files, stitch overlapping scanned intervals, and create down core HU profiles in a manner robust to normal coring imperfections. Utilizing a random sampling technique, SedCT reduces data size and allows for quick processing on typical laptop computers. SedCTimage uses a graphical interface to create quality tiff files of CT slices that are scaled to a user-defined HU range, preserving the quantitative nature of CT images and easily allowing for comparison between sediment cores with different HU means and variance. These tools are presented along with examples from lacustrine and marine sediment cores to highlight the robustness and quantitative nature of this method.

Spiral computed tomography phase-space source model in the BEAMnrc/EGSnrc Monte Carlo system: implementation and validation

NASA Astrophysics Data System (ADS)

Kim, Sangroh; Yoshizumi, Terry T.; Yin, Fang-Fang; Chetty, Indrin J.

2013-04-01

Currently, the BEAMnrc/EGSnrc Monte Carlo (MC) system does not provide a spiral CT source model for the simulation of spiral CT scanning. We developed and validated a spiral CT phase-space source model in the BEAMnrc/EGSnrc system. The spiral phase-space source model was implemented in the DOSXYZnrc user code of the BEAMnrc/EGSnrc system by analyzing the geometry of spiral CT scan—scan range, initial angle, rotational direction, pitch, slice thickness, etc. Table movement was simulated by changing the coordinates of the isocenter as a function of beam angles. Some parameters such as pitch, slice thickness and translation per rotation were also incorporated into the model to make the new phase-space source model, designed specifically for spiral CT scan simulations. The source model was hard-coded by modifying the ‘ISource = 8: Phase-Space Source Incident from Multiple Directions’ in the srcxyznrc.mortran and dosxyznrc.mortran files in the DOSXYZnrc user code. In order to verify the implementation, spiral CT scans were simulated in a CT dose index phantom using the validated x-ray tube model of a commercial CT simulator for both the original multi-direction source (ISOURCE = 8) and the new phase-space source model in the DOSXYZnrc system. Then the acquired 2D and 3D dose distributions were analyzed with respect to the input parameters for various pitch values. In addition, surface-dose profiles were also measured for a patient CT scan protocol using radiochromic film and were compared with the MC simulations. The new phase-space source model was found to simulate the spiral CT scanning in a single simulation run accurately. It also produced the equivalent dose distribution of the ISOURCE = 8 model for the same CT scan parameters. The MC-simulated surface profiles were well matched to the film measurement overall within 10%. The new spiral CT phase-space source model was implemented in the BEAMnrc/EGSnrc system. This work will be beneficial in estimating the spiral CT scan dose in the BEAMnrc/EGSnrc system.

SU-C-206-07: A Practical Sparse View Ultra-Low Dose CT Acquisition Scheme for PET Attenuation Correction in the Extended Scan Field-Of-View

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, J; Fan, J; Gopinatha Pillai, A

Purpose: To further reduce CT dose, a practical sparse-view acquisition scheme is proposed to provide the same attenuation estimation as higher dose for PET imaging in the extended scan field-of-view. Methods: CT scans are often used for PET attenuation correction and can be acquired at very low CT radiation dose. Low dose techniques often employ low tube voltage/current accompanied with a smooth filter before backprojection to reduce CT image noise. These techniques can introduce bias in the conversion from HU to attenuation values, especially in the extended CT scan field-of-view (FOV). In this work, we propose an ultra-low dose CTmore » technique for PET attenuation correction based on sparse-view acquisition. That is, instead of an acquisition of full amount of views, only a fraction of views are acquired. We tested this technique on a 64-slice GE CT scanner using multiple phantoms. CT scan FOV truncation completion was performed based on the published water-cylinder extrapolation algorithm. A number of continuous views per rotation: 984 (full), 246, 123, 82 and 62 have been tested, corresponding to a CT dose reduction of none, 4x, 8x, 12x and 16x. We also simulated sparse-view acquisition by skipping views from the fully-acquired view data. Results: FBP reconstruction with Q. AC filter on reduced views in the full extended scan field-of-view possesses similar image quality to the reconstruction on acquired full view data. The results showed a further potential for dose reduction compared to the full acquisition, without sacrificing any significant attenuation support to the PET. Conclusion: With the proposed sparse-view method, one can potential achieve at least 2x more CT dose reduction compared to the current Ultra-Low Dose (ULD) PET/CT protocol. A pre-scan based dose modulation scheme can be combined with the above sparse-view approaches, which can even further reduce the CT scan dose during a PET/CT exam.« less

Use of PET/CT scanning in cancer patients: technical and practical considerations

PubMed Central

2005-01-01

This overview of the oncologic applications of positron emission tomography (PET) focuses on the technical aspects and clinical applications of a newer technique: the combination of a PET scanner and a computed tomography (CT) scanner in a single (PET/CT) device. Examples illustrate how PET/CT contributes to patient care and improves upon the previous state-of-the-art method of comparing a PET scan with a separate CT scan. Finally, the author presents some of the results from studies of PET/CT imaging that are beginning to appear in the literature. PMID:16252023

Potential for adult-based epidemiological studies to characterize overall cancer risks associated with a lifetime of CT scans.

PubMed

Shuryak, Igor; Lubin, Jay H; Brenner, David J

2014-06-01

Recent epidemiological studies have suggested that radiation exposure from pediatric CT scanning is associated with small excess cancer risks. However, the majority of CT scans are performed on adults, and most radiation-induced cancers appear during middle or old age, in the same age range as background cancers. Consequently, a logical next step is to investigate the effects of CT scanning in adulthood on lifetime cancer risks by conducting adult-based, appropriately designed epidemiological studies. Here we estimate the sample size required for such studies to detect CT-associated risks. This was achieved by incorporating different age-, sex-, time- and cancer type-dependent models of radiation carcinogenesis into an in silico simulation of a population-based cohort study. This approach simulated individual histories of chest and abdominal CT exposures, deaths and cancer diagnoses. The resultant sample sizes suggest that epidemiological studies of realistically sized cohorts can detect excess lifetime cancer risks from adult CT exposures. For example, retrospective analysis of CT exposure and cancer incidence data from a population-based cohort of 0.4 to 1.3 million (depending on the carcinogenic model) CT-exposed UK adults, aged 25-65 in 1980 and followed until 2015, provides 80% power for detecting cancer risks from chest and abdominal CT scans.

CT cardiac imaging: evolution from 2D to 3D backprojection

NASA Astrophysics Data System (ADS)

Tang, Xiangyang; Pan, Tinsu; Sasaki, Kosuke

2004-04-01

The state-of-the-art multiple detector-row CT, which usually employs fan beam reconstruction algorithms by approximating a cone beam geometry into a fan beam geometry, has been well recognized as an important modality for cardiac imaging. At present, the multiple detector-row CT is evolving into volumetric CT, in which cone beam reconstruction algorithms are needed to combat cone beam artifacts caused by large cone angle. An ECG-gated cardiac cone beam reconstruction algorithm based upon the so-called semi-CB geometry is implemented in this study. To get the highest temporal resolution, only the projection data corresponding to 180° plus the cone angle are row-wise rebinned into the semi-CB geometry for three-dimensional reconstruction. Data extrapolation is utilized to extend the z-coverage of the ECG-gated cardiac cone beam reconstruction algorithm approaching the edge of a CT detector. A helical body phantom is used to evaluate the ECG-gated cone beam reconstruction algorithm"s z-coverage and capability of suppressing cone beam artifacts. Furthermore, two sets of cardiac data scanned by a multiple detector-row CT scanner at 16 x 1.25 (mm) and normalized pitch 0.275 and 0.3 respectively are used to evaluate the ECG-gated CB reconstruction algorithm"s imaging performance. As a reference, the images reconstructed by a fan beam reconstruction algorithm for multiple detector-row CT are also presented. The qualitative evaluation shows that, the ECG-gated cone beam reconstruction algorithm outperforms its fan beam counterpart from the perspective of cone beam artifact suppression and z-coverage while the temporal resolution is well maintained. Consequently, the scan speed can be increased to reduce the contrast agent amount and injection time, improve the patient comfort and x-ray dose efficiency. Based up on the comparison, it is believed that, with the transition of multiple detector-row CT into volumetric CT, ECG-gated cone beam reconstruction algorithms will provide better image quality for CT cardiac applications.

Texture classification of lung computed tomography images

NASA Astrophysics Data System (ADS)

Pheng, Hang See; Shamsuddin, Siti M.

2013-03-01

Current development of algorithms in computer-aided diagnosis (CAD) scheme is growing rapidly to assist the radiologist in medical image interpretation. Texture analysis of computed tomography (CT) scans is one of important preliminary stage in the computerized detection system and classification for lung cancer. Among different types of images features analysis, Haralick texture with variety of statistical measures has been used widely in image texture description. The extraction of texture feature values is essential to be used by a CAD especially in classification of the normal and abnormal tissue on the cross sectional CT images. This paper aims to compare experimental results using texture extraction and different machine leaning methods in the classification normal and abnormal tissues through lung CT images. The machine learning methods involve in this assessment are Artificial Immune Recognition System (AIRS), Naive Bayes, Decision Tree (J48) and Backpropagation Neural Network. AIRS is found to provide high accuracy (99.2%) and sensitivity (98.0%) in the assessment. For experiments and testing purpose, publicly available datasets in the Reference Image Database to Evaluate Therapy Response (RIDER) are used as study cases.

The Beatles, the Nobel Prize, and CT scanning of the chest.

PubMed

Goodman, Lawrence R

2010-01-01

From its first test scan on a mouse, in 1967, to current medical practice, the CT scanner has become a core imaging tool in thoracic diagnosis. Initially financed by money from Beatles' record sales, the first patient scan was performed in 1971. Only 8 years later, a Nobel Prize in Physics and Medicine was awarded to Hounsfield and Cormack for their discovery. This article traces the history of CT scanner development and how each technical advance expanded chest diagnostic frontiers. Chest imaging now accounts for 30% of all CT scanning.

Trends and patterns of computed tomography scan use among children in The Netherlands: 1990-2012.

PubMed

Meulepas, Johanna M; Smets, Anne M J B; Nievelstein, Rutger A J; Gradowska, Patrycja; Verbeke, Jonathan; Holscher, Herma C; Rutten, Matthieu J C M; Kieft, Mariëtte; Ronckers, Cécile M; Hauptmann, Michael

2017-06-01

To evaluate trends and patterns in CT usage among children (aged 0-17 years) in The Netherlands during the period 1990-2012. Lists of electronically archived paediatric CT scans were requested from the Radiology Information Systems (RIS) of Dutch hospitals which reported >10 paediatric CT scans annually in a survey conducted in 2010. Data included patient identification, birth date, gender, scan date and body part scanned. For non-participating hospitals and for years prior to electronic archiving in some participating hospitals, data were imputed by calendar year and hospital type (academic, general with <500 beds, general with ≥ 500 beds). Based on 236,066 CT scans among 146,368 patients performed between 1990 and 2012, estimated annual numbers of paediatric CT scans in The Netherlands increased from 7,731 in 1990 to 26,023 in 2012. More than 70 % of all scans were of the head and neck. During the last decade, substantial increases of more than 5 % per year were observed in general hospitals with fewer than 500 beds and among children aged 10 years or older. The estimated number of paediatric CT scans has more than tripled in The Netherlands during the last two decades. • Paediatric CT in The Netherlands has tripled during the last two decades. • The number of paediatric CTs increased through 2012 in general hospitals. • Paediatric CTs continued to increase among children aged 10 years or older.

Are CT scans obtained at referring institutions justified prior to transfer to a pediatric trauma center?

PubMed

Benedict, Leo Andrew; Paulus, Jessica K; Rideout, Leslie; Chwals, Walter J

2014-01-01

To assess whether pediatric trauma patients initially evaluated at referring institutions met Massachusetts statewide trauma field triage criteria for stabilization and immediate transfer to a Pediatric Trauma Center (PTC) without pre-transfer CT imaging. A 3-year retrospective cohort study was completed at our level 1 PTC. Patients with CT imaging at referring institutions were classified according to a triage scheme based on Massachusetts statewide trauma field triage criteria. Demographic data and injury profile characteristics were abstracted from patient medical records and our pediatric trauma registry. A total of 262 patients with 413 CT scans were reviewed from 2008 to 2011. 172 patients scanned (66%, 95% CI: 60%, 71%) met criteria for immediate transfer to a pediatric trauma center. Notably, 110 scans (27% of the total performed at referring institutions) were duplicated within four hours upon arrival to our PTC. GCS score <14 (45%) was the most common requirement for transfer, and CT scan of the head was the most frequent scan obtained (53%). The majority of pediatric trauma patients were subjected to CT scans at referring institutions despite meeting Massachusetts trauma triage guidelines that call for stabilization and immediate transfer to a pediatric trauma center without any CT imaging. © 2014.

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves.

PubMed

Aladmawi, Mohamed A; Pragliola, Claudio; Vriz, Olga; Galzerano, Domenico

2017-04-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus.

Outcome of Blunt Abdominal Traumas with Stable Hemodynamic and Positive FAST Findings.

PubMed

Behboodi, Firooz; Mohtasham-Amiri, Zahra; Masjedi, Navid; Shojaie, Reza; Sadri, Peyman

2016-01-01

Focused assessment with sonography for trauma (FAST) is a highly effective first screening tool for initial classification of abdominal trauma patients. The present study was designed to evaluate the outcome of patients with blunt abdominal trauma and positive FAST findings. The present prospective cross-sectional study was done on patients over 7 years old with normal abdominal examination, positive FAST findings, and available abdominopelvic computed tomography (CT) scan findings. The frequency of need for laparotomy as well as its probable risk factors were calculated. 180 patients were enrolled (mean age: 28.0 ± 11.5 years; 76.7% male). FAST findings were confirmed by abdominopelvic CT scan in only 124 (68.9%) cases. Finally, 12 (6.6%) patients needed laparotomy. Mean age of those in need of laparotomy was significantly higher than others (36.75 ± 11.37 versus 27.34 ± 11.37, p = 0.006). Higher grading of spleen (p = 0.001) and hepatic (p = 0.038) ruptures increased the probability of need for laparotomy. 68.9% of the positive FAST findings in patients with blunt abdominal trauma and stable hemodynamics was confirmed by abdominopelvic CT scan and only 6.6% needed laparotomy. Simultaneous presence of free fluid and air in the abdominal area, old age, and higher grading o solid organ injuries were factors that had a significant correlation with need for laparotomy.

Atypical manifestation of cat-scratch disease: isolated epigastric pain in an immunocompetent, 12-year-old child.

PubMed

Kayemba-Kay's, Simon; Kovács, Tamas; Rakotoharinandrasana, Iarolalao; Benosman, Sidi Mohamed

2015-07-01

We present a 12-year-old immunocompetent girl with hepato splenic cat-scratch disease (CSD). Her sole inaugural complaint was isolated epigastric pain. She fully recovered, with normalized abdominal CT scan following 2 weeks course of Azythromycin®. CSD should be included in differential diagnosis in children with epigastric pain, especially in those with domestic pets.

Is It Better to Enter a Volume CT Dose Index Value before or after Scan Range Adjustment for Radiation Dose Optimization of Pediatric Cardiothoracic CT with Tube Current Modulation?

PubMed Central

2018-01-01

Objective To determine whether the body size-adapted volume computed tomography (CT) dose index (CTDvol) in pediatric cardiothoracic CT with tube current modulation is better to be entered before or after scan range adjustment for radiation dose optimization. Materials and Methods In 83 patients, cardiothoracic CT with tube current modulation was performed with the body size-adapted CTDIvol entered after (group 1, n = 42) or before (group 2, n = 41) scan range adjustment. Patient-related, radiation dose, and image quality parameters were compared and correlated between the two groups. Results The CTDIvol after the CT scan in group 1 was significantly higher than that in group 2 (1.7 ± 0.1 mGy vs. 1.4 ± 0.3 mGy; p < 0.0001). Image noise (4.6 ± 0.5 Hounsfield units [HU] vs. 4.5 ± 0.7 HU) and image quality (1.5 ± 0.6 vs. 1.5 ± 0.6) showed no significant differences between the two (p > 0.05). In both groups, all patient-related parameters, except body density, showed positive correlations (r = 0.49–0.94; p < 0.01) with the CTDIvol before and after the CT scan. The CTDIvol after CT scan showed modest positive correlation (r = 0.49; p ≤ 0.001) with image noise in group 1 but no significant correlation (p > 0.05) in group 2. Conclusion In pediatric cardiothoracic CT with tube current modulation, the CTDIvol entered before scan range adjustment provides a significant dose reduction (18%) with comparable image quality compared with that entered after scan range adjustment.

Is there a trend in CT scanning scaphoid nonunions for deformity assessment?-A systematic review.

PubMed

Ten Berg, Paul W L; de Roo, Marieke G A; Maas, Mario; Strackee, Simon D

2017-06-01

The effect of scaphoid nonunion deformity on wrist function is uncertain due to the lack of reliable imaging tools. Advanced three-dimensional (3-D) computed tomography (CT)-based imaging techniques may improve deformity assessment by using a mirrored image of the contralateral intact wrist as anatomic reference. The implementation of such techniques depends on the extent to which conventional CT is currently used in standard practice. The purpose of this systematic review of medical literature was to analyze the trend in CT scanning scaphoid nonunions, either unilaterally or bilaterally. Using Medline and Embase databases, two independent reviewers searched for original full-length clinical articles describing series with at least five patients focusing on reconstructive surgery of scaphoid nonunions with bone grafting and/or fixation, from the years 2000-2015. We excluded reports focusing on only nonunions suspected for avascular necrosis and/or treated with vascularized bone grafting, as their workup often includes magnetic resonance imaging. For data analysis, we evaluated the use of CT scans and distinguished between uni- and bilateral, and pre- and postoperative scans. Seventy-seven articles were included of which 16 were published between 2000 and 2005, 19 between 2006 and 2010, and 42 between 2011 and 2015. For these consecutive intervals, the rates of articles describing the use of pre- and postoperative CT scans increased from 13%, to 16%, to 31%, and from 25%, to 32%, to 52%, respectively. Hereof, only two (3%) articles described the use of bilateral CT scans. There is an evident trend in performing unilateral CT scans before and after reconstructive surgery of a scaphoid nonunion. To improve assessment of scaphoid nonunion deformity using 3-D CT-based imaging techniques, we recommend scanning the contralateral wrist as well. Copyright © 2017 Elsevier B.V. All rights reserved.

Automated estimation of abdominal effective diameter for body size normalization of CT dose.

PubMed

Cheng, Phillip M

2013-06-01

Most CT dose data aggregation methods do not currently adjust dose values for patient size. This work proposes a simple heuristic for reliably computing an effective diameter of a patient from an abdominal CT image. Evaluation of this method on 106 patients scanned on Philips Brilliance 64 and Brilliance Big Bore scanners demonstrates close correspondence between computed and manually measured patient effective diameters, with a mean absolute error of 1.0 cm (error range +2.2 to -0.4 cm). This level of correspondence was also demonstrated for 60 patients on Siemens, General Electric, and Toshiba scanners. A calculated effective diameter in the middle slice of an abdominal CT study was found to be a close approximation of the mean calculated effective diameter for the study, with a mean absolute error of approximately 1.0 cm (error range +3.5 to -2.2 cm). Furthermore, the mean absolute error for an adjusted mean volume computed tomography dose index (CTDIvol) using a mid-study calculated effective diameter, versus a mean per-slice adjusted CTDIvol based on the calculated effective diameter of each slice, was 0.59 mGy (error range 1.64 to -3.12 mGy). These results are used to calculate approximate normalized dose length product values in an abdominal CT dose database of 12,506 studies.

MO-DE-207A-09: Low-Dose CT Image Reconstruction Via Learning From Different Patient Normal-Dose Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, H; Xing, L; Liang, Z

Purpose: To investigate a novel low-dose CT (LdCT) image reconstruction strategy for lung CT imaging in radiation therapy. Methods: The proposed approach consists of four steps: (1) use the traditional filtered back-projection (FBP) method to reconstruct the LdCT image; (2) calculate structure similarity (SSIM) index between the FBP-reconstructed LdCT image and a set of normal-dose CT (NdCT) images, and select the NdCT image with the highest SSIM as the learning source; (3) segment the NdCT source image into lung and outside tissue regions via simple thresholding, and adopt multiple linear regression to learn high-order Markov random field (MRF) pattern formore » each tissue region in the NdCT source image; (4) segment the FBP-reconstructed LdCT image into lung and outside regions as well, and apply the learnt MRF prior in each tissue region for statistical iterative reconstruction of the LdCT image following the penalized weighted least squares (PWLS) framework. Quantitative evaluation of the reconstructed images was based on the signal-to-noise ratio (SNR), local binary pattern (LBP) and histogram of oriented gradients (HOG) metrics. Results: It was observed that lung and outside tissue regions have different MRF patterns predicted from the NdCT. Visual inspection showed that our method obviously outperformed the traditional FBP method. Comparing with the region-smoothing PWLS method, our method has, in average, 13% increase in SNR, 15% decrease in LBP difference, and 12% decrease in HOG difference from reference standard for all regions of interest, which indicated the superior performance of the proposed method in terms of image resolution and texture preservation. Conclusion: We proposed a novel LdCT image reconstruction method by learning similar image characteristics from a set of NdCT images, and the to-be-learnt NdCT image does not need to be scans from the same subject. This approach is particularly important for enhancing image quality in radiation therapy.« less

The Effect of the Presence of EEG Leads on Image Quality in Cerebral Perfusion SPECT and FDG PET/CT.

PubMed

Zhang, Lulu; Yen, Stephanie P; Seltzer, Marc A; Thomas, George P; Willis, Kristen; Siegel, Alan

2018-06-08

Rationale: Cerebral perfusion SPECT and 18 F-FDG PET/CT are commonly performed diagnostic procedures for patients suffering from epilepsy. Individuals receiving these tests are often in-patients undergoing examinations with EEG leads. We have routinely removed these leads before these tests due to concerns that they would lead to imaging artifacts. The leads would then be replaced at the conclusion of the scan. The goal of our study was to determine if the EEG leads actually do cause artifacts that could lead to erroneous scan interpretation or make the scan uninterpretable. Methods: PET/CT with 18 F-FDG and SPECT with technetium-99m ECD were performed on a two dimensional brain phantom. The phantom was scanned with standard leads, CT/MR compatible leads and with no leads. The scans were interpreted by three experienced nuclear medicine physicians who were asked to rank the images by quality and then to determine if they could differentiate each of the scans from a scan in which it was indicated that no leads were present. Results: No differences could be detected between SPECT or PET scans performed without leads or with either set of leads. The standard EEG leads did create an artifact in the CT portion of the PET/CT while the CT/MR compatible leads did not. Conclusion: This phantom study suggest that EEG leads, standard or CT/MR compatible do not need to be removed for SPECT or for PET. Further study evaluating the effect on patients scan would be of value to support this conclusion. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Radiation Dose Reduction by Indication-Directed Focused z-Direction Coverage for Neck CT.

PubMed

Parikh, A K; Shah, C C

2016-06-01

The American College of Radiology-American Society of Neuroradiology-Society for Pediatric Radiology Practice Parameter for a neck CT suggests that coverage should be from the sella to the aortic arch. It also recommends using CT scans judiciously to achieve the clinical objective. Our purpose was to analyze the potential dose reduction by decreasing the scan length of a neck CT and to assess for any clinically relevant information that might be missed from this modified approach. This retrospective study included 126 children who underwent a neck CT between August 1, 2013, and September 30, 2014. Alteration of the scan length for the modified CT was suggested on the topographic image on the basis of the indication of the study, with the reader blinded to the images and the report. The CT dose index volume of the original scan was multiplied by the new scan length to calculate the dose-length product of the modified study. The effective dose was calculated for the original and modified studies by using age-based conversion factors from the American Association of Physicists in Medicine Report No. 96. Decreasing the scan length resulted in an average estimated dose reduction of 47%. The average reduction in scan length was 10.4 cm, decreasing the overall coverage by 48%. The change in scan length did not result in any missed findings that altered management. Of the 27 abscesses in this study, none extended to the mediastinum. All of the lesions in question were completely covered. Decreasing the scan length of a neck CT according to the indication provides a significant savings in radiation dose, while not altering diagnostic ability or management. © 2016 by American Journal of Neuroradiology.

[A case of sphenoid sinusitis which could be diagnosed by orbital computed tomography after detected Strepotococcus pneumoniae from blood culture].

PubMed

Kimura, Takuma; Aoki, Makoto; Aoki, Yasuko; Tonhyo, Chong

2005-03-01

We report a case of sphenoid sinusitis which could be diagnosed by orbital CT after detecting Strepotococcus pneumoniae from blood culture. A previously healthy 47 year-old Japanese male was admitted to our hospital with severe left-sided headache of 2 days duration. From 9 days before hospitalization (1st day), the patient complained of cough and sputum. On physical examination, his neck was supple and his temperature was 38.3 degrees C. The rest of the examination was normal. A chest radiograph, sinus radiograph, and head computed tomographic (CT) scan without contrast material disclosed no abnormalities. Lumbar puncture was done and cerebrospinal fluid was clear and cell counts and the levels of glucose and protein were normal. The peripheral white blood cell count was 14,400/fl, and the C-reactive protein level was 9.6 mg/dl. After blood, urine, pharyngeal mucus and cerebrospinal fluid cultures were obtained, empirical antibiotic therapy with 2 gms of piperacillin twice daily was begun. He complained sever left-sided retro-orbital headahe on the next day too. The lumbar puncture and head CT scan with contrast material was done again but gave no diagnostic clues. The examinations by the otolaryngologist, ophthalmologist and dentist found no abnormal findings. On the 3rd hospitalized day, Strepotococcus pneumoniae was detected from the blood culture taken on the 1st hospitalized day. A CT scan focused on orbita was done and revealed a low density area of the left sphenoid sinus. The dose of piperacillin was increased to 4 gms twice daily and continued for 24 days. The patient's headache improved and piperacillin was changed to oral levofloxacin 100 mg, three times daily on the 26th day. The medication was stopped on the 73th day. Isolated sphenoid sinusitis is rare, but crtitical complications such as cranial nerve involvement, brain abscess, and bacterial meningitis may happen. It is necessary to also think of sphenoid sinusitis in practices of patients with severe headache.

SU-F-I-40: Impact of Scan Length On Patient Dose in Abdomen/pelvis CT Diagnosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, I; Song, J; Kim, K

Purpose: To analysis the impact of scan length on patient doses in abdomen/pelvis CT diagnosis of each hospital. Methods: Scan length of 7 hospitals from abdomen/pelvis CT diagnosis was surveyed in Korea. Surveyed scan lengths were additional distance above diaphragm and distance below pubic symphysis except for standard scan range between diaphragm and pubic symphysis. Patient dose was estimated for adult male and female according to scan length of each hospital. CT-Expo was used to estimate the patient dose under identical equipment settings (120 kVp, 100 mAs, 10 mm collimation width, etc.) except scan length. Effective dose was calculated bymore » using tissue weighting factor of ICRP 103 recommendation. Increase rate of effective dose was calculated comparing with effective dose of standard scan range Results: Scan lengths of abdomen/pelvis CT diagnosis of each hospital were different. Also effective dose was increased with increasing the scan length. Generally increasing the distance above diaphragm caused increase of effective dose of male and female, but increasing the distance below pubic symphysis caused increase of effective dose of male. Conclusion: We estimated the patient dose according to scan length of each hospital in abdomen/pelvis CT diagnosis. Effective dose was increased by increasing the scan length because dose of organs with high tissue weighting factor such as lung, breast, testis were increased. Scan length is important factor on patient dose in CT diagnosis. If radiologic technologist interested in patient dose, decreasing the unnecessary scan length will decrease the risk of patients from radiation. This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI13C0004).« less

Three-dimensional surface reconstruction for industrial computed tomography

NASA Technical Reports Server (NTRS)

Vannier, M. W.; Knapp, R. H.; Gayou, D. E.; Sammon, N. P.; Butterfield, R. L.; Larson, J. W.

1985-01-01

Modern high resolution medical computed tomography (CT) scanners can produce geometrically accurate sectional images of many types of industrial objects. Computer software has been developed to convert serial CT scans into a three-dimensional surface form, suitable for display on the scanner itself. This software, originally developed for imaging the skull, has been adapted for application to industrial CT scanning, where serial CT scans thrrough an object of interest may be reconstructed to demonstrate spatial relationships in three dimensions that cannot be easily understood using the original slices. The methods of three-dimensional reconstruction and solid modeling are reviewed, and reconstruction in three dimensions from CT scans through familiar objects is demonstrated.

SU-E-P-41: Imaging Coordination of Cone Beam CT, On-Board Image Conjunction with Optical Image Guidance for SBRT Treatment with Respiratory Motion Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y; Campbell, J

2015-06-15

Purpose: To spare normal tissue for SBRT lung/liver patients, especially for patients with significant tumor motion, image guided respiratory motion management has been widely implemented in clinical practice. The purpose of this study was to evaluate imaging coordination of cone beam CT, on-board X-ray image conjunction with optical image guidance for SBRT treatment with motion management. Methods: Currently in our clinic a Varian Novlis Tx was utilized for treating SBRT patients implementing CBCT. A BrainLAB X-ray ExacTrac imaging system in conjunction with optical guidance was primarily used for SRS patients. CBCT and X-ray imaging system were independently calibrated with 1.0more » mm tolerance. For SBRT lung/liver patients, the magnitude of tumor motion was measured based-on 4DCT and the measurement was analyzed to determine if patients would be beneficial with respiratory motion management. For patients eligible for motion management, an additional CT with breath holding would be scanned and used as primary planning CT and as reference images for Cone beam CT. During the SBRT treatment, a CBCT with pause and continuing technology would be performed with patients holding breath, which may require 3–4 partially scanned CBCT to combine as a whole CBCT depending on how long patients capable of holding breath. After patients being setup by CBCT images, the ExactTrac X-ray imaging system was implemented with patients’ on-board X-ray images compared to breath holding CT-based DRR. Results: For breath holding patients SBRT treatment, after initially localizing patients with CBCT, we then position patients with ExacTrac X-ray and optical imaging system. The observed deviations of real-time optical guided position average at 3.0, 2.5 and 1.5 mm in longitudinal, vertical and lateral respectively based on 35 treatments. Conclusion: The respiratory motion management clinical practice improved our physician confidence level to give tighter tumor margin for sparing normal tissue for SBRT lung/liver patients.« less

CT scan (image)

MedlinePlus

CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

Blend Sign on Computed Tomography: Novel and Reliable Predictor for Early Hematoma Growth in Patients With Intracerebral Hemorrhage.

PubMed

Li, Qi; Zhang, Gang; Huang, Yuan-Jun; Dong, Mei-Xue; Lv, Fa-Jin; Wei, Xiao; Chen, Jian-Jun; Zhang, Li-Juan; Qin, Xin-Yue; Xie, Peng

2015-08-01

Early hematoma growth is not uncommon in patients with intracerebral hemorrhage and is an independent predictor of poor functional outcome. The purpose of our study was to report and validate the use of our newly identified computed tomographic (CT) blend sign in predicting early hematoma growth. Patients with intracerebral hemorrhage who underwent baseline CT scan within 6 hours after onset of symptoms were included. The follow-up CT scan was performed within 24 hours after the baseline CT scan. Significant hematoma growth was defined as an increase in hematoma volume of >33% or an absolute increase of hematoma volume of >12.5 mL. The blend sign on admission nonenhanced CT was defined as blending of hypoattenuating area and hyperattenuating region with a well-defined margin. Univariate and multivariable logistic regression analyses were performed to assess the relationship between the presence of the blend sign on nonenhanced admission CT and early hematoma growth. A total of 172 patients were included in our study. Blend sign was observed in 29 of 172 (16.9%) patients with intracerebral hemorrhage on baseline nonenhanced CT scan. Of the 61 patients with hematoma growth, 24 (39.3%) had blend sign on admission CT scan. Interobserver agreement for identifying blend sign was excellent between the 2 readers (κ=0.957). The multivariate logistic regression analysis demonstrated that the time to baseline CT scan, initial hematoma volume, and presence of blend sign on baseline CT scan to be independent predictors of early hematoma growth. The sensitivity, specificity, positive and negative predictive values of blend sign for predicting hematoma growth were 39.3%, 95.5%, 82.7%, and 74.1%, respectively. The CT blend sign could be easily identified on regular nonenhanced CT and is highly specific for predicting hematoma growth. © 2015 American Heart Association, Inc.

A comparative study of cranial, blunt trauma fractures as seen at medicolegal autopsy and by Computed Tomography

PubMed Central

2009-01-01

Background Computed Tomography (CT) has become a widely used supplement to medico legal autopsies at several forensic institutes. Amongst other things, it has proven to be very valuable in visualising fractures of the cranium. Also CT scan data are being used to create head models for biomechanical trauma analysis by Finite Element Analysis. If CT scan data are to be used for creating individual head models for retrograde trauma analysis in the future we need to ascertain how well cranial fractures are captured by CT scan. The purpose of this study was to compare the diagnostic agreement between CT and autopsy regarding cranial fractures and especially the precision with which cranial fractures are recorded. Methods The autopsy fracture diagnosis was compared to the diagnosis of two CT readings (reconstructed with Multiplanar and Maximum Intensity Projection reconstructions) by registering the fractures on schematic drawings. The extent of the fractures was quantified by merging 3-dimensional datasets from both the autopsy as input by 3D digitizer tracing and CT scan. Results The results showed a good diagnostic agreement regarding fractures localised in the posterior fossa, while the fracture diagnosis in the medial and anterior fossa was difficult at the first CT scan reading. The fracture diagnosis improved during the second CT scan reading. Thus using two different CT reconstructions improved diagnosis in the medial fossa and at the impact points in the cranial vault. However, fracture diagnosis in the anterior and medial fossa and of hairline fractures in general still remained difficult. Conclusion The study showed that the forensically important fracture systems to a large extent were diagnosed on CT images using Multiplanar and Maximum Intensity Projection reconstructions. Difficulties remained in the minute diagnosis of hairline fractures. These inconsistencies need to be resolved in order to use CT scan data of victims for individual head modelling and trauma analysis. PMID:19835570

Delayed splenic vascular injury after nonoperative management of blunt splenic trauma.

PubMed

Furlan, Alessandro; Tublin, Mitchell E; Rees, Mitchell A; Nicholas, Dederia H; Sperry, Jason L; Alarcon, Louis H

2017-05-01

Delayed splenic vascular injury (DSVI) is traditionally considered a rare, often clinically occult, harbinger of splenic rupture in patients with splenic trauma that are managed conservatively. The purpose of our study was to assess the incidence of DSVI and associated features in patients admitted with blunt splenic trauma and managed nonoperatively. A retrospective analysis was conducted over a 4-y time. Patients admitted with blunt splenic trauma, managed no-operatively and with a follow-up contrast-enhanced computed tomography (CT) scan study during admission were included. The CT scans were reviewed for American Association for the Surgery of Trauma splenic injury score, amount of hemoperitoneum, and presence of DSVI. Logistic regression models were used to investigate the risk factors associated with DSVI. A total of 100 patients (60 men and 40 women) constituted the study group. Follow-up CT scan demonstrated a 23% incidence of DSVI. Splenic artery angiography validated DSVI in 15% of the total patient population. Most DSVIs were detected only on arterial phase CT scan imaging. The American Association for the Surgery of Trauma splenic injury score (odds ratio = 1.73; P = 0.045) and the amount of hemoperitoneum (odds ratio = 1.90; P = 0.023) on admission CT scan were associated with the development of DSVI on follow-up CT scan. DSVI on follow-up CT scan imaging of patients managed nonoperatively after splenic injury is common and associated with splenic injury score assessed on admission CT scan. Copyright © 2016 Elsevier Inc. All rights reserved.

Advantages and limitations of computed tomography scans for treatment planning of lung cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mira, J.G.; Potter, J.L.; Fullerton, G.D.

1982-09-01

Forty-five Chest computed tomography (CT) scans performed on patients with lung carcinoma (LC) were evaluated in an attempt to understand the pattern of intrathoracic tumor spread and the advantages and limitations this technique offers for treatment planning when compared to planning done by conventional X rays. The following findings can help treatment planning. (1) When regular X rays do not show location (i.e., hemithorax opacification), CT scan will show it in 68% of patients. If regular X rays show a well localized mass, unsuspected tumor extensions were disclosed in 78% of these patients. Hence, CT scans should be done inmore » all LC patients prior to treatment planning; (2) Mediastinal masses frequently spread anteriorly toward the sternum and posteriorly around the vertebral bodies toward the cord and costal pleura. This should be considered for radiotherapy boost techniques; (3) Lung masses spread in one third of cases toward the lateral costal pleura. Thus, the usual 1-2cm of safety margin around the LC are not sufficient in some cases; (4) Tumor size can appear much smaller in regular X rays than in CT scans. Hence, CT scans are necessary for accurate staging and evaluation of tumor response. Some CT scan limitations are: (1) Atelectasis blends with tumor in approximately half of the patients, thus obscuring tumor boundaries; (2) CT numbers and contrast enhancement did not help to differentiate between these two structures; and (3) Limited definition of CT scan prevents investigation of suspected microscopic spread around tumor masses.« less

Patient characteristics associated with differences in radiation exposure from pediatric abdomen-pelvis CT scans: a quantile regression analysis.

PubMed

Cooper, Jennifer N; Lodwick, Daniel L; Adler, Brent; Lee, Choonsik; Minneci, Peter C; Deans, Katherine J

2017-06-01

Computed tomography (CT) is a widely used diagnostic tool in pediatric medicine. However, due to concerns regarding radiation exposure, it is essential to identify patient characteristics associated with higher radiation burden from CT imaging, in order to more effectively target efforts towards dose reduction. Our objective was to identify the effects of various demographic and clinical patient characteristics on radiation exposure from single abdomen/pelvis CT scans in children. CT scans performed at our institution between January 2013 and August 2015 in patients under 16 years of age were processed using a software tool that estimates patient-specific organ and effective doses and merges these estimates with data from the electronic health record and billing record. Quantile regression models at the 50th, 75th, and 90th percentiles were used to estimate the effects of patients' demographic and clinical characteristics on effective dose. 2390 abdomen/pelvis CT scans (median effective dose 1.52mSv) were included. Of all characteristics examined, only older age, female gender, higher BMI, and whether the scan was a multiphase exam or an exam that required repeating for movement were significant predictors of higher effective dose at each quantile examined (all p<0.05). The effects of obesity and multiphase or repeat scanning on effective dose were magnified in higher dose scans. Older age, female gender, obesity, and multiphase or repeat scanning are all associated with increased effective dose from abdomen/pelvis CT. Targeted efforts to reduce dose from abdominal CT in these groups should be undertaken. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessing stapes piston position using computed tomography: a cadaveric study.

PubMed

Hahn, Yoav; Diaz, Rodney; Hartman, Jonathan; Bobinski, Matthew; Brodie, Hilary

2009-02-01

Temporal bone computed tomographic (CT) scanning in the postoperative stapedotomy patient is inaccurate in assessing stapes piston position within the vestibule. Poststapedotomy patients that have persistent vertigo may undergo CT scanning to assess the position of the stapes piston within the vestibule to rule out overly deep insertion. Vertigo is a recognized complication of the deep piston, and CT evaluation is often recommended. The accuracy of CT scan in this setting is unestablished. Stapedotomy was performed on 12 cadaver ears, and stainless steel McGee pistons were placed. The cadaver heads were then scanned using a fine-cut temporal bone protocol. Temporal bone dissection was performed with microscopic measurement of the piston depth in the vestibule. These values were compared with depth of intravestibular penetration measured on CT scan by 4 independent measurements. The intravestibular penetration as assessed by computed tomography was consistently greater than the value found on cadaveric anatomic dissection. The radiographic bias was greater when piston location within the vestibule was shallower. The axial CT scan measurement was 0.53 mm greater, on average, than the anatomic measurement. On average, the coronal CT measurement was 0.68 mm greater than the anatomic measurement. The degree of overestimation of penetration, however, was highly inconsistent. Standard temporal bone CT scan is neither an accurate nor precise examination of stapes piston depth within the vestibule. We found that CT measurement consistently overstated intravestibular piston depth. Computed tomography is not a useful study in the evaluation of piston depth for poststapedectomy vertigo and is of limited value in this setting.

Neural network and its application to CT imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikravesh, M.; Kovscek, A.R.; Patzek, T.W.

We present an integrated approach to imaging the progress of air displacement by spontaneous imbibition of oil into sandstone. We combine Computerized Tomography (CT) scanning and neural network image processing. The main aspects of our approach are (I) visualization of the distribution of oil and air saturation by CT, (II) interpretation of CT scans using neural networks, and (III) reconstruction of 3-D images of oil saturation from the CT scans with a neural network model. Excellent agreement between the actual images and the neural network predictions is found.

Everolimus induces rapid plasma glucose normalization in insulinoma patients by effects on tumor as well as normal tissues.

PubMed

Fiebrich, Helle-Brit; Siemerink, Ester J M; Brouwers, Adrienne H; Links, Thera P; Remkes, Wouter S; Hospers, Geke A P; de Vries, Elisabeth G E

2011-01-01

Mammalian target of rapamycin inhibitor everolimus administered to four insulinoma patients rapidly controlled hypoglycemia (Kulke et al., N Engl J Med 2009;360:195-197). We wanted to identify the kinetics of everolimus effects on controlling hypoglycemia and understand underlying mechanisms. Three consecutive patients with a metastasized symptomatic insulinoma were started on 100 μg of octreotide subcutaneously three times daily. Because of persisting hypoglycemias, treatment with daily 10 mg of oral everolimus was initiated. Serial plasma glucose levels and serum insulin levels were measured. Computer tomography (CT) scans were performed before and after 2 and 5 months of treatment. [¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography (¹⁸F-FDG-PET) scans, to visualize glucose metabolism, were made before and after 2 weeks, 5 weeks, and 5 months of treatment. The ¹⁸F-FDG uptake was quantified as the maximum standardized uptake value. All patients achieved control of hypoglycemia on everolimus within 14 days. Insulin levels were 2.5- to 6.3-fold elevated before start of treatment and declined 14%-64% after 4 weeks of treatment. CT scans showed stable disease at 2 months in all patients, with progressive disease after 5 months in one. Before treatment, both the tumor lesions and the muscles and myocardium showed high ¹⁸F-FDG uptake. Everolimus reduced tumor and muscle ¹⁸F-FDG uptake after 2 weeks by 26% ± 14% and 19% ± 41%, and after 5 months by 31% ± 13% and 27% ± 41%. Everolimus normalizes plasma glucose levels in metastatic insulinoma within 14 days, coinciding with a lower glucose uptake in tumor and muscles and declining (pro)insulin levels. This effect on tumor as well as normal tissues explains the rapid controlling of hypoglycemia.

Evaluation of a semiautomated lung mass calculation technique for internal dosimetry applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busse, Nathan; Erwin, William; Pan, Tinsu

2013-12-15

Purpose: The authors sought to evaluate a simple, semiautomated lung mass estimation method using computed tomography (CT) scans obtained using a variety of acquisition techniques and reconstruction parameters for mass correction of medical internal radiation dose-based internal radionuclide radiation absorbed dose estimates.Methods: CT scans of 27 patients with lung cancer undergoing stereotactic body radiation therapy treatment planning with PET/CT were analyzed retrospectively. For each patient, free-breathing (FB) and respiratory-gated 4DCT scans were acquired. The 4DCT scans were sorted into ten respiratory phases, representing one complete respiratory cycle. An average CT reconstruction was derived from the ten-phase reconstructions. Mid expiration breath-holdmore » CT scans were acquired in the same session for many patients. Deep inspiration breath-hold diagnostic CT scans of many of the patients were obtained from different scanning sessions at similar time points to evaluate the effect of contrast administration and maximum inspiration breath-hold. Lung mass estimates were obtained using all CT scan types, and intercomparisons made to assess lung mass variation according to scan type. Lung mass estimates using the FB CT scans from PET/CT examinations of another group of ten male and ten female patients who were 21–30 years old and did not have lung disease were calculated and compared with reference lung mass values. To evaluate the effect of varying CT acquisition and reconstruction parameters on lung mass estimation, an anthropomorphic chest phantom was scanned and reconstructed with different CT parameters. CT images of the lungs were segmented using the OsiriX MD software program with a seed point of about −850 HU and an interval of 1000. Lung volume, and mean lung, tissue, and air HUs were recorded for each scan. Lung mass was calculated by assuming each voxel was a linear combination of only air and tissue. The specific gravity of lung volume was calculated using the formula (lung HU − air HU)/(tissue HU − air HU), and mass = specific gravity × total volume × 1.04 g/cm{sup 3}.Results: The range of calculated lung masses was 0.51–1.29 kg. The average male and female lung masses during FB CT were 0.80 and 0.71 kg, respectively. The calculated lung mass varied across the respiratory cycle but changed to a lesser degree than did lung volume measurements (7.3% versus 15.4%). Lung masses calculated using deep inspiration breath-hold and average CT were significantly larger (p < 0.05) than were some masses calculated using respiratory-phase and FB CT. Increased voxel size and smooth reconstruction kernels led to high lung mass estimates owing to partial volume effects.Conclusions: Organ mass correction is an important component of patient-specific internal radionuclide dosimetry. Lung mass calculation necessitates scan-based density correction to account for volume changes owing to respiration. The range of lung masses in the authors’ patient population represents lung doses for the same absorbed energy differing from 25% below to 64% above the dose found using reference phantom organ masses. With proper management of acquisition parameters and selection of FB or midexpiration breath hold scans, lung mass estimates with about 10% population precision may be achieved.« less

Lung PET scan

MedlinePlus

... PET - chest; PET - lung; PET - tumor imaging; PET/CT - lung; Solitary pulmonary nodule - PET ... minutes. PET scans are performed along with a CT scan. This is because the combined information from ...

Rationale and Application of Tangential Scanning to Industrial Inspection of Hardwood Logs

Treesearch

Nand K. Gupta; Daniel L. Schmoldt; Bruce Isaacson

1998-01-01

Industrial computed tomography (CT) inspection of hardwood logs has some unique requirements not found in other CT applications. Sawmill operations demand that large volumes of wood be scanned quickly at high spatial resolution for extended duty cycles. Current CT scanning geometries and commercial systems have both technical and economic [imitations. Tangential...

Automatic CT simulation optimization for radiation therapy: A general strategy.

PubMed

Li, Hua; Yu, Lifeng; Anastasio, Mark A; Chen, Hsin-Chen; Tan, Jun; Gay, Hiram; Michalski, Jeff M; Low, Daniel A; Mutic, Sasa

2014-03-01

In radiation therapy, x-ray computed tomography (CT) simulation protocol specifications should be driven by the treatment planning requirements in lieu of duplicating diagnostic CT screening protocols. The purpose of this study was to develop a general strategy that allows for automatically, prospectively, and objectively determining the optimal patient-specific CT simulation protocols based on radiation-therapy goals, namely, maintenance of contouring quality and integrity while minimizing patient CT simulation dose. The authors proposed a general prediction strategy that provides automatic optimal CT simulation protocol selection as a function of patient size and treatment planning task. The optimal protocol is the one that delivers the minimum dose required to provide a CT simulation scan that yields accurate contours. Accurate treatment plans depend on accurate contours in order to conform the dose to actual tumor and normal organ positions. An image quality index, defined to characterize how simulation scan quality affects contour delineation, was developed and used to benchmark the contouring accuracy and treatment plan quality within the predication strategy. A clinical workflow was developed to select the optimal CT simulation protocols incorporating patient size, target delineation, and radiation dose efficiency. An experimental study using an anthropomorphic pelvis phantom with added-bolus layers was used to demonstrate how the proposed prediction strategy could be implemented and how the optimal CT simulation protocols could be selected for prostate cancer patients based on patient size and treatment planning task. Clinical IMRT prostate treatment plans for seven CT scans with varied image quality indices were separately optimized and compared to verify the trace of target and organ dosimetry coverage. Based on the phantom study, the optimal image quality index for accurate manual prostate contouring was 4.4. The optimal tube potentials for patient sizes of 38, 43, 48, 53, and 58 cm were 120, 140, 140, 140, and 140 kVp, respectively, and the corresponding minimum CTDIvol for achieving the optimal image quality index 4.4 were 9.8, 32.2, 100.9, 241.4, and 274.1 mGy, respectively. For patients with lateral sizes of 43-58 cm, 120-kVp scan protocols yielded up to 165% greater radiation dose relative to 140-kVp protocols, and 140-kVp protocols always yielded a greater image quality index compared to the same dose-level 120-kVp protocols. The trace of target and organ dosimetry coverage and the γ passing rates of seven IMRT dose distribution pairs indicated the feasibility of the proposed image quality index for the predication strategy. A general strategy to predict the optimal CT simulation protocols in a flexible and quantitative way was developed that takes into account patient size, treatment planning task, and radiation dose. The experimental study indicated that the optimal CT simulation protocol and the corresponding radiation dose varied significantly for different patient sizes, contouring accuracy, and radiation treatment planning tasks.

Radiation exposure - how do CT scans for appendicitis compare between a free standing children's hospital and non-dedicated pediatric facilities?

PubMed

Sharp, Nicole E; Raghavan, Maneesha U; Svetanoff, Wendy J; Thomas, Priscilla T; Sharp, Susan W; Brown, James C; Rivard, Douglas C; St Peter, Shawn D; Holcomb, George W

2014-06-01

We compare the amount of radiation children receive from CT scans performed at non-dedicated pediatric facilities (OH) versus those at a dedicated children's hospital (CH). Using a retrospective chart review, all children undergoing CT scanning for appendicitis at an OH were compared to children undergoing CT imaging for appendicitis at a CH between January 2011 and November 2012. One hundred sixty-three children underwent CT scans at 42 different OH. Body mass index was similar between the two groups (21.00±6.49kg/m(2), 19.58±5.18kg/m(2), P=0.07). Dose length product (DLP) was 620±540.3 at OH and 253.78±211.08 at CH (P < 0.001). OH CT scans accurately diagnosed appendicitis in 81%, while CT scans at CH were accurate in 95% (P=0.026). CTDIvol was recorded in 65 patients with subset analysis showing CTDIvol of 16.98±15.58 and 4.89±2.64, a DLP of 586.25±521.59 and 143.54±41.19, and size-specific dose estimate (SSDE) of 26.71±23.1 and 3.81±2.02 at OH and CH, respectively (P<0.001). Using SSDE as a marker for radiation exposure, children received 86% less radiation and had improved diagnostic accuracy when CT scans are performed at a CH. Copyright © 2014 Elsevier Inc. All rights reserved.

Postoperative PET/CT and target delineation before adjuvant radiotherapy in patients with oral cavity squamous cell carcinoma.

PubMed

Dutta, Pinaki R; Riaz, Nadeem; McBride, Sean; Morris, Luc G; Patel, Snehal; Ganly, Ian; Wong, Richard J; Palmer, Frank; Schöder, Heiko; Lee, Nancy

2016-04-01

The purpose of this study was for us to present our evaluation of the effectiveness of positron emission tomography (PET)/CT imaging in postoperative patients with oral cavity squamous cell carcinoma (SCC) before initiating adjuvant radiation therapy. Treatment planning PET/CT scans were obtained in 44 patients with oral cavity SCC receiving adjuvant radiation. We identified target areas harboring macroscopic disease requiring higher radiation doses or additional surgery. Fourteen PET/CT scans were abnormal. Thirteen patients underwent surgery and/or biopsy, increased radiation dose, and/or addition of chemotherapy. Eleven patients received higher radiation doses. Patients undergoing imaging >8 weeks were more likely to have abnormal results (p = .01). One-year distant metastases-free survival was significantly worse in patients with positive PET/CT scans (61.5% vs 92.7%; p = .01). The estimated positive predictive value (PPV) was 38% for postoperative PET/CT scanning. We demonstrated that 32% of patients have abnormal PET/CT scans resulting in management changes. Patients may benefit from postoperative PET/CT imaging to optimize adjuvant radiation treatment planning. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1285-E1293, 2016. © 2015 Wiley Periodicals, Inc.

SU-E-I-13: Evaluation of Metal Artifact Reduction (MAR) Software On Computed Tomography (CT) Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, V; Kohli, K

2015-06-15

Purpose: A new commercially available metal artifact reduction (MAR) software in computed tomography (CT) imaging was evaluated with phantoms in the presence of metals. The goal was to assess the ability of the software to restore the CT number in the vicinity of the metals without impacting the image quality. Methods: A Catphan 504 was scanned with a GE Optima RT 580 CT scanner (GE Healthcare, Milwaukee, WI) and the images were reconstructed with and without the MAR software. Both datasets were analyzed with Image Owl QA software (Image Owl Inc, Greenwich, NY). CT number sensitometry, MTF, low contrast, uniformity,more » noise and spatial accuracy were compared for scans with and without MAR software. In addition, an in-house made phantom was scanned with and without a stainless steel insert at three different locations. The accuracy of the CT number and metal insert dimension were investigated as well. Results: Comparisons between scans with and without MAR algorithm on the Catphan phantom demonstrate similar results for image quality. However, noise was slightly higher for the MAR algorithm. Evaluation of the CT number at various locations of the in-house made phantom was also performed. The baseline HU, obtained from the scan without metal insert, was compared to scans with the stainless steel insert at 3 different locations. The HU difference between the baseline scan versus metal scan was improved when the MAR algorithm was applied. In addition, the physical diameter of the stainless steel rod was over-estimated by the MAR algorithm by 0.9 mm. Conclusion: This work indicates with the presence of metal in CT scans, the MAR algorithm is capable of providing a more accurate CT number without compromising the overall image quality. Future work will include the dosimetric impact on the MAR algorithm.« less

Predictors of positive 18F-FDG PET/CT-scan for large vessel vasculitis in patients with persistent polymyalgia rheumatica.

PubMed

Prieto-Peña, Diana; Martínez-Rodríguez, Isabel; Loricera, Javier; Banzo, Ignacio; Calderón-Goercke, Mónica; Calvo-Río, Vanesa; González-Vela, Carmen; Corrales, Alfonso; Castañeda, Santos; Blanco, Ricardo; Hernández, José L; González-Gay, Miguel Á

2018-05-18

Polymyalgia rheumatica (PMR) is often the presenting manifestation of giant cell arteritis (GCA). Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan often discloses the presence of large vessel vasculitis (LVV) in PMR patients. We aimed to identify predictive factors of a positive PET/CT scan for LVV in patients classified as having isolated PMR according to well-established criteria. A set of consecutive patients with PMR from a single hospital were assessed. All of them underwent PET/CT scan between January 2010 and February 2018 based on clinical considerations. Patients with PMR associated to other diseases, including those with cranial features of GCA, were excluded. The remaining patients were categorized in classic PMR (if fulfilled the 2012 EULAR/ACR classification criteria at disease diagnosis; n = 84) or atypical PMR (who did not fulfill these criteria; n = 16). Only information on patients with classic PMR was assessed. The mean age of the 84 patients (51 women) with classic PMR was 71.4 ± 9.2 years. A PET/CT scan was positive in 51 (60.7%). Persistence of classic PMR symptoms was the most common reason to perform a PET/CT scan. Nevertheless, patients with positive PET/CT scan often had unusual symptoms. The best set of predictors of a positive PET/CT scan were bilateral diffuse lower limb pain (OR = 8.8, 95% CI: 1.7-46.3; p = 0.01), pelvic girdle pain (OR = 4.9, 95% CI: 1.50-16.53; p = 0.01) and inflammatory low back pain (OR = 4.7, 95% CI: 1.03-21.5; p = 0.04). Inflammatory low back pain, pelvic girdle and diffuse lower limb pain are predictors of positive PET/CT scan for LVV in PMR. Copyright © 2018 Elsevier Inc. All rights reserved.

WE-EF-207-09: Single-Scan Dual-Energy CT Using Primary Modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrongolo, M; Zhu, L

Purpose: Compared with conventional CT, dual energy CT (DECT) provides better material differentiation but requires projection data with two different effective x-ray spectra. Current DECT scanners use either a two-scan setting or costly imaging components, which are not feasible or available on open-gantry cone-beam CT systems. We propose a hardware-based method which utilizes primary modulation to enable single-scan DECT on a conventional CT scanner. The CT imaging geometry of primary modulation is identical to that used in our previous method for scatter removal, making it possible for future combination with effective scatter correction on the same CT scanner. Methods: Wemore » insert an attenuation sheet with a spatially-varying pattern - primary modulator-between the x-ray source and the imaged object. During the CT scan, the modulator selectively hardens the x-ray beam at specific detector locations. Thus, the proposed method simultaneously acquires high and low energy data. High and low energy CT images are then reconstructed from projections with missing data via an iterative CT reconstruction algorithm with gradient weighting. Proof-of-concept studies are performed using a copper modulator on a cone-beam CT system. Results: Our preliminary results on the Catphan(c) 600 phantom indicate that the proposed method for single-scan DECT is able to successfully generate high-quality high and low energy CT images and distinguish different materials through basis material decomposition. By applying correction algorithms and using all of the acquired projection data, we can reconstruct a single CT image of comparable image quality to conventional CT images, i.e., without primary modulation. Conclusion: This work shows great promise in using a primary modulator to perform high-quality single-scan DECT imaging. Future studies will test method performance on anthropomorphic phantoms and perform quantitative analyses on image qualities and DECT decomposition accuracy. We will use simulations to optimize the modulator material and geometry parameters.« less

Computerized method for automatic evaluation of lean body mass from PET/CT: comparison with predictive equations.

PubMed

Chan, Tao

2012-01-01

CT has become an established method for calculating body composition, but it requires data from the whole body, which are not typically obtained in routine PET/CT examinations. A computerized scheme that evaluates whole-body lean body mass (LBM) based on CT data from limited-whole-body coverage was developed. The LBM so obtained was compared with results from conventional predictive equations. LBM can be obtained automatically from limited-whole-body CT data by 3 means: quantification of body composition from CT images in the limited-whole-body scan, based on thresholding of CT attenuation; determination of the range of coverage based on a characteristic trend of changing composition across different levels and pattern recognition of specific features at strategic positions; and estimation of the LBM of the whole body on the basis of a predetermined relationship between proportion of fat mass and extent of coverage. This scheme was validated using 18 whole-body PET/CT examinations truncated at different lengths to emulate limited-whole-body data. LBM was also calculated using predictive equations that had been reported for use in SUV normalization. LBM derived from limited-whole-body data using the proposed method correlated strongly with LBM derived from whole-body CT data, with correlation coefficients ranging from 0.991 (shorter coverage) to 0.998 (longer coverage) and SEMs of LBM ranging from 0.14 to 0.33 kg. These were more accurate than results from different predictive equations, which ranged in correlation coefficient from 0.635 to 0.970 and in SEM from 0.64 to 2.40 kg. LBM of the whole body could be automatically estimated from CT data of limited-whole-body coverage typically acquired in PET/CT examinations. This estimation allows more accurate and consistent quantification of metabolic activity of tumors based on LBM-normalized standardized uptake value.

Chest x-ray as a screening tool for blunt thoracic trauma in children.

PubMed

Yanchar, Natalie L; Woo, Kenneth; Brennan, Maureen; Palmer, Cameron S; Zs Ee, Michael; Sweeney, Brian; Crameri, Joe

2013-10-01

With the increasing use of thoracic computed tomography (CT) to screen for injuries in pediatric blunt thoracic trauma (BTT), we determined whether chest x-ray (CXR) and other clinical and epidemiologic variables could be used to predict significant thoracic injuries, to inform the selective use of CT in pediatric BTT. We further queried if these were discrepant from factors associated with the decision to obtain a thoracic CT. This retrospective cohort study included cases of BTT from three Level I pediatric trauma centers between April 1999 and March 2008. Pre-CT epidemiologic, clinical, and radiologic variables associated with CT findings of any thoracic injury or a significant thoracic injury as well as the decision to obtain a thoracic CT were determined using logistic regression. Of 425 patients, 40% patients had a significant thoracic injury, 49% had nonsignificant thoracic injury, and 11% had no thoracic injury at all. Presence of hydrothorax and/or pneumothorax on CXR significantly increased the likelihood of significant chest injury visualized by CT (adjusted odds ratio 10.8; 95% confidence interval, 6.5-18), as did the presence of isolated subcutaneous emphysema (adjusted odds ratio, 19.8; 95% confidence interval, 2.3-168). Although a normal CXR finding was not statistically associated with a reduced risk of significant thoracic injury, 8 of the 9 cases with normal CXR findings and significant injuries involved occult pneumothoraces or hemothoraces not requiring intervention. Converse to features suggesting increased risk of significant injury, the decision to obtain a thoracic CT was only associated with later period in the study and obtaining a CT scan of another body region. CXR can be used to screen for significant thoracic injuries and direct the selective use of thoracic CT in pediatric BTT. Prospective studies are needed to validate these findings and develop guidelines that include CXR to define indications for thoracic CT in pediatric BTT. Prognostic study, level III.

TH-E-BRF-04: Characterizing the Response of Texture-Based CT Image Features for Quantification of Radiation-Induced Normal Lung Damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krafft, S; Court, L; Briere, T

2014-06-15

Purpose: Radiation induced lung damage (RILD) is an important dose-limiting toxicity for patients treated with radiation therapy. Scoring systems for RILD are subjective and limit our ability to find robust predictors of toxicity. We investigate the dose and time-related response for texture-based lung CT image features that serve as potential quantitative measures of RILD. Methods: Pre- and post-RT diagnostic imaging studies were collected for retrospective analysis of 21 patients treated with photon or proton radiotherapy for NSCLC. Total lung and selected isodose contours (0–5, 5–15, 15–25Gy, etc.) were deformably registered from the treatment planning scan to the pre-RT and availablemore » follow-up CT studies for each patient. A CT image analysis framework was utilized to extract 3698 unique texture-based features (including co-occurrence and run length matrices) for each region of interest defined by the isodose contours and the total lung volume. Linear mixed models were fit to determine the relationship between feature change (relative to pre-RT), planned dose and time post-RT. Results: Seventy-three follow-up CT scans from 21 patients (median: 3 scans/patient) were analyzed to describe CT image feature change. At the p=0.05 level, dose affected feature change in 2706 (73.1%) of the available features. Similarly, time affected feature change in 408 (11.0%) of the available features. Both dose and time were significant predictors of feature change in a total of 231 (6.2%) of the extracted image features. Conclusion: Characterizing the dose and time-related response of a large number of texture-based CT image features is the first step toward identifying objective measures of lung toxicity necessary for assessment and prediction of RILD. There is evidence that numerous features are sensitive to both the radiation dose and time after RT. Beyond characterizing feature response, further investigation is warranted to determine the utility of these features as surrogates of clinically significant lung injury.« less

Estimating the lifetime risk of cancer associated with multiple CT scans.

PubMed

Ivanov, V K; Kashcheev, V V; Chekin, S Yu; Menyaylo, A N; Pryakhin, E A; Tsyb, A F; Mettler, F A

2014-12-01

Multiple CT scans are often done on the same patient resulting in an increased risk of cancer. Prior publications have estimated risks on a population basis and often using an effective dose. Simply adding up the risks from single scans does not correctly account for the survival function. A methodology for estimating personal radiation risks attributed to multiple CT imaging using organ doses is presented in this article. The estimated magnitude of the attributable risk fraction for the possible development of radiation-induced cancer indicates the necessity for strong clinical justification when ordering multiple CT scans.

[Non-operation management of 12 cases with brain abscess demonstrated by CT scan].

PubMed

Long, J

1990-12-01

This paper reported 12 cases with brain abscess demonstrated by CT scan. Using antibiotic management without surgical intervention, in 10 cases the curative effects were satisfactory. The paper indicated that CT scan was very useful in prompt and correct diagnosis of brain abscess and with sequential CT scan medical therapy was feasible. It is significant in treatment of brain abscess especially for the patients who have a poor general condition, have the brain abscess located in important functional area or have multiple abscesses so that the operation is difficult for them.

Normal uptake of 68Ga-DOTA-TOC by the pancreas uncinate process mimicking malignancy at somatostatin receptor PET.

PubMed

Jacobsson, Hans; Larsson, Patricia; Jonsson, Cathrine; Jussing, Emma; Grybäck, Per

2012-04-01

To characterize a commonly occurring increased uptake by the uncinate process of the pancreas at PET/CT using 68Ga-DOTA-d-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC). This tracer has replaced In pentetreotide (OctreoScan®) for somatostatin receptor scintigraphy at our laboratory. Fifty of our first 74 PET/CT examinations with 68Ga-DOTA-TOC could be evaluated in retrospect. None of these patients had surgery or showed any pathology in the pancreas head at the concomitant CT. Thirty-five of the 50 examinations (70%) showed an uptake by the uncinate process sufficiently intense to be interpreted as pathologic and simulating a tumor. Mean SUVmax was 9.2. Mean SUVmean using an isoactivity cut-off of >75% and >50% was 7.8 and 6.0, respectively. Volume calculations of the uncinate process activity using these definitions gave 0.9 mL and 4.2 mL, respectively. There is a frequent physiological uptake of 68Ga-DOTA-TOC by the pancreas uncinate process. This may be caused by an accumulation of pancreatic polypeptide-containing cells expressing somatostatin receptors. If there is a normal finding at concomitant diagnostic CT, this uptake should be regarded as physiological.

Diagnostic value of chest radiographs in bedridden patients suspected of having pneumonia.

PubMed

Esayag, Yaacov; Nikitin, Irina; Bar-Ziv, Jacob; Cytter, Ruth; Hadas-Halpern, Irith; Zalut, Todd; Yinnon, Amos M

2010-01-01

To assess the diagnostic value of the chest radiograph for the diagnosis of pneumonia in bedridden patients, using non-contrast-enhanced high-resolution chest computed tomography (CT) as the gold standard. We prospectively evaluated bedridden patients hospitalized with moderate to high clinical probability of pneumonia. Chest radiographs were interpreted in a blinded fashion by 3 observers and classified as definite, normal, or uncertain for pneumonia. Chest CT was obtained within 12 hours of chest radiograph. We applied Bayesian analysis to assess the accuracy of chest radiograph in the diagnosis of pneumonia. In a 5-month period, 58 patients were evaluated, 31 (53%) were female. Their chest radiographs were interpreted as negative, uncertain, or positive for pneumonia in 31 (53%), 15 (26%), and 12 (21%) patients, respectively, while CT confirmed pneumonia in 11 (35%), 10 (67%), and in 10 (83%). The sensitivity of the chest radiograph to diagnose pneumonia was 65%, the specificity was 93%, the positive and negative predictive values were, respectively, 83% and 65%, while the overall accuracy was 69% (95% confidence interval, 50%-79%). In bedridden patients with suspected pneumonia, a normal chest radiograph does not rule out the diagnosis, hence, a chest CT scan might provide valuable diagnostic information. Copyright 2010 Elsevier Inc. All rights reserved.

Vomiting--is this a good indication for CT head scans in patients with minor head injury?

PubMed

Bainbridge, J; Khirwadkar, H; Hourihan, M D

2012-02-01

The National Institute for Health and Clinical Excellence head injury guidelines advise CT imaging within 1 h if there is more than one episode of vomiting post-head injury in adults and three or more episodes in children. Since the guideline publication, studies have found that, following head injury, vomiting alone is associated with an abnormal CT head scan in 13-45% of cases. CT head scan requests referred from the emergency department between 1 May 2009 and 30 April 2010 were retrospectively reviewed. Patients with vomiting as the sole indication for an "immediate" CT head scan performed within 1 h were included in the study. Reports produced by experienced neuroradiologists were reviewed and the detection of significant head injury was noted. There were 1264 CT head scans performed during our study period. 151 (124 adults, 27 children) were indicated owing to vomiting following head injury. 5 of the 124 adult scans and 1 of the 27 paediatric scans showed an abnormal finding, giving positive predictive values (PPV) of 4% and 3.7%, respectively. None of these patients required either acute or delayed neurosurgical intervention. In our experience, vomiting alone has a PPV of 4% for significant head injury in adults. However, none of these injuries were serious enough to warrant acute or delayed intervention. Given these findings, vomiting following head injury is a reasonable indication for a CT head scan; however, as none of the patients required acute intervention, we suggest that these scans do not usually need to be performed within 1 h of request.

Hybrid detection of lung nodules on CT scan images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Lin; Tan, Yongqiang; Schwartz, Lawrence H.

Purpose: The diversity of lung nodules poses difficulty for the current computer-aided diagnostic (CAD) schemes for lung nodule detection on computed tomography (CT) scan images, especially in large-scale CT screening studies. We proposed a novel CAD scheme based on a hybrid method to address the challenges of detection in diverse lung nodules. Methods: The hybrid method proposed in this paper integrates several existing and widely used algorithms in the field of nodule detection, including morphological operation, dot-enhancement based on Hessian matrix, fuzzy connectedness segmentation, local density maximum algorithm, geodesic distance map, and regression tree classification. All of the adopted algorithmsmore » were organized into tree structures with multi-nodes. Each node in the tree structure aimed to deal with one type of lung nodule. Results: The method has been evaluated on 294 CT scans from the Lung Image Database Consortium (LIDC) dataset. The CT scans were randomly divided into two independent subsets: a training set (196 scans) and a test set (98 scans). In total, the 294 CT scans contained 631 lung nodules, which were annotated by at least two radiologists participating in the LIDC project. The sensitivity and false positive per scan for the training set were 87% and 2.61%. The sensitivity and false positive per scan for the testing set were 85.2% and 3.13%. Conclusions: The proposed hybrid method yielded high performance on the evaluation dataset and exhibits advantages over existing CAD schemes. We believe that the present method would be useful for a wide variety of CT imaging protocols used in both routine diagnosis and screening studies.« less

18F-FDG SPECT/CT in the diagnosis of differentiated thyroid carcinoma with elevated thyroglobulin and negative iodine-131 scans.

PubMed

Ma, C; Wang, X; Shao, M; Zhao, L; Jiawei, X; Wu, Z; Wang, H

2015-06-01

Aim of the present study was to investigate the usefulness of 18F-FDG SPECT/CT in differentiated thyroid cancer (DTC) with elevated serum thyroglobulin (Tg) but negative iodine-131 scan. This retrospective review of patients with DTC recurrence who had 18F-FDG SPECT/CT and 18F-FDG PET/CT for elevated serum Tg but negative iodine-131 scan (March 2007-October 2012). After total thyroidectomy followed by radioiodine ablation, 86 consecutive patients with elevated Tg levels underwent 18F-FDG SPECT/CT or 18F-FDG PET/CT. Of these, 45 patients had 18F-FDG SPECT/CT, the other 41 patients had 18F-FDG PET/CT 3-4weeks after thyroid hormone withdrawal. The results of 18F-FDG PET/CT and SPECT/CT were correlated with patient follow-up information, which included the results from subsequent imaging modalities such as neck ultrasound, MRI and CT, Tg levels, and histologic examination of surgical specimens. The diagnostic accuracy of the two imaging modalities was evaluated. In 18F-FDG SPECT/CT scans, 24 (24/45) patients had positive findings, 22 true positive in 24 patients, false positive in 2 patients, true-negative and false-negative in 6, 15 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG SPECT/CT were 59.5%, 75% and 62.2%, respectively. Twenty six patients had positive findings on 18F-FDG PET/CT scans, 23 true positive in 26 (26/41) patients, false positive in 3 patients, true-negative and false-negative in 9, 6 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 79.3%, 81.8% and 78.1%, respectively. Clinical management changed for 13 (29%) of 45 patients by 18F-FDG SPECT/CT, 14 (34%) of 41 patients by 18F-FDG PET/CT including surgery, radiation therapy, or multikinase inhibitor. Based on the retrospective analysis of 86 patients, 18F-FDG SPECT/CT has lower sensitivity in the diagnosis of DTC recurrence with elevated Tg and negative iodine-131scan to 18F-FDG PET/CT. The clinical application of FDG SPECT/CT is then limited and cannot replace PET/CT.

SU-E-J-97: Evaluation of Multi-Modality (CT/MR/PET) Image Registration Accuracy in Radiotherapy Planning.

PubMed

Sethi, A; Rusu, I; Surucu, M; Halama, J

2012-06-01

Evaluate accuracy of multi-modality image registration in radiotherapy planning process. A water-filled anthropomorphic head phantom containing eight 'donut-shaped' fiducial markers (3 internal + 5 external) was selected for this study. Seven image sets (3CTs, 3MRs and PET) of phantom were acquired and fused in a commercial treatment planning system. First, a narrow slice (0.75mm) baseline CT scan was acquired (CT1). Subsequently, the phantom was re-scanned with a coarse slice width = 1.5mm (CT2) and after subjecting phantom to rotation/displacement (CT3). Next, the phantom was scanned in a 1.5 Tesla MR scanner and three MR image sets (axial T1, axial T2, coronal T1) were acquired at 2mm slice width. Finally, the phantom and center of fiducials were doped with 18F and a PET scan was performed with 2mm cubic voxels. All image scans (CT/MR/PET) were fused to the baseline (CT1) data using automated mutual-information based fusion algorithm. Difference between centroids of fiducial markers in various image modalities was used to assess image registration accuracy. CT/CT image registration was superior to CT/MR and CT/PET: average CT/CT fusion error was found to be 0.64 ± 0.14 mm. Corresponding values for CT/MR and CT/PET fusion were 1.33 ± 0.71mm and 1.11 ± 0.37mm. Internal markers near the center of phantom fused better than external markers placed on the phantom surface. This was particularly true for the CT/MR and CT/PET. The inferior quality of external marker fusion indicates possible distortion effects toward the edges of MR image. Peripheral targets in the PET scan may be subject to parallax error caused by depth of interaction of photons in detectors. Current widespread use of multimodality imaging in radiotherapy planning calls for periodic quality assurance of image registration process. Such studies may help improve safety and accuracy in treatment planning. © 2012 American Association of Physicists in Medicine.

TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, D; Neylon, J; Dou, T

Purpose: A recently proposed 4D-CT protocol uses deformable registration of free-breathing fast-helical CT scans to generate a breathing motion model. In order to allow accurate registration, free-breathing images are required to be free of doubling-artifacts, which arise when tissue motion is greater than scan speed. This work identifies the minimum scanner parameters required to successfully generate free-breathing fast-helical scans without doubling-artifacts. Methods: 10 patients were imaged under free breathing conditions 25 times in alternating directions with a 64-slice CT scanner using a low dose fast helical protocol. A high temporal resolution (0.1s) 4D-CT was generated using a patient specific motionmore » model and patient breathing waveforms, and used as the input for a scanner simulation. Forward projections were calculated using helical cone-beam geometry (800 projections per rotation) and a GPU accelerated reconstruction algorithm was implemented. Various CT scanner detector widths and rotation times were simulated, and verified using a motion phantom. Doubling-artifacts were quantified in patient images using structural similarity maps to determine the similarity between axial slices. Results: Increasing amounts of doubling-artifacts were observed with increasing rotation times > 0.2s for 16×1mm slice scan geometry. No significant increase in doubling artifacts was observed for 64×1mm slice scan geometry up to 1.0s rotation time although blurring artifacts were observed >0.6s. Using a 16×1mm slice scan geometry, a rotation time of less than 0.3s (53mm/s scan speed) would be required to produce images of similar quality to a 64×1mm slice scan geometry. Conclusion: The current generation of 16 slice CT scanners, which are present in most Radiation Oncology departments, are not capable of generating free-breathing sorting-artifact-free images in the majority of patients. The next generation of CT scanners should be capable of at least 53mm/s scan speed in order to use a fast-helical 4D-CT protocol to generate a motion-artifact free 4D-CT. NIH R01CA096679.« less

The utility of computed tomography in the management of fever and neutropenia in pediatric oncology.

PubMed

Rao, Avani D; Sugar, Elizabeth A; Barrett, Neil; Mahesh, Mahadevappa; Arceci, Robert J

2015-10-01

Despite the frequent use and radiation exposure of computed tomography (CT) scans, there is little information on patterns of CT use and their utility in the management of pediatric patients with fever and neutropenia (FN). We examined the contribution of either the commonly employed pan-CT (multiple anatomical locations) or targeted CT (single location) scanning to identify possible infectious etiologies in this challenging clinical scenario. Procedure Pediatric patients with an underlying malignancy admitted for fever (temperature ≥ 38.3 °C) and an absolute neutrophil count <500 cells/μL from 2003-2009 were included. Risk factors associated with utilization, results, and effects on clinical management of CT scans were identified. Results Charts for 635 admissions for FN from 263 patients were reviewed. Overall, 139 (22%) admissions (93 individuals) had at least one scan. Of 188 scans, 103 (55%) were pan-scans. Changes in management were most strongly associated with the identification of evidence consistent with infection (OR = 12.64, 95% CI: 5.05-31.60, P < 0.001). Seventy-eight (41%) of all CT scans led to a change in clinical management, most commonly relating to use of antibiotic (N = 41, 53%) or antifungal/antiviral medications (N = 33, 42%). The odds of a change in clinical management did not differ for those receiving a pan-scan compared to those receiving a targeted scan (OR = 1.23; 95% CI, 0.61-2.46; P = 0.57). Conclusions When CT is clinically indicated, it is important for clinicians to strongly consider utilizing a targeted scan to reduce radiation exposure to patients as well as to decrease costs without compromising care. © 2015 Wiley Periodicals, Inc.

CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro.

PubMed

Zarse, Chad A; Hameed, Tariq A; Jackson, Molly E; Pishchalnikov, Yuri A; Lingeman, James E; McAteer, James A; Williams, James C

2007-08-01

Calcium oxalate monohydrate (COM) stones are often resistant to breakage using shock wave (SW) lithotripsy. It would be useful to identify by computed tomography (CT) those COM stones that are susceptible to SW's. For this study, 47 COM stones (4-10 mm in diameter) were scanned with micro CT to verify composition and also for assessment of heterogeneity (presence of pronounced lobulation, voids, or apatite inclusions) by blinded observers. Stones were then placed in water and scanned using 64-channel helical CT. As with micro CT, heterogeneity was assessed by blinded observers, using high-bone viewing windows. Then stones were broken in a lithotripter (Dornier Doli-50) over 2 mm mesh, and SW's counted. Results showed that classification of stones using micro CT was highly repeatable among observers (kappa = 0.81), and also predictive of stone fragility. Stones graded as homogeneous required 1,874 +/- 821 SW/g for comminution, while stones with visible structure required half as many SW/g, 912 +/- 678. Similarly, when stones were graded by appearance on helical CT, classification was repeatable (kappa = 0.40), and homogeneous stones required more SW's for comminution than did heterogeneous stones (1,702 +/- 993 SW/g, compared to 907 +/- 773). Stone fragility normalized to stone size did not correlate with Hounsfield units (P = 0.85). In conclusion, COM stones of homogeneous structure require almost twice as many SW's to comminute than stones of similar mineral composition that exhibit internal structural features that are visible by CT. This suggests that stone fragility in patients could be predicted using pre-treatment CT imaging. The findings also show that Hounsfield unit values of COM stones did not correlate with stone fragility. Thus, it is stone morphology, rather than X-ray attenuation, which correlates with fragility to SW's in this common stone type.

Verification of computed tomographic estimates of cochlear implant array position: a micro-CT and histologic analysis.

PubMed

Teymouri, Jessica; Hullar, Timothy E; Holden, Timothy A; Chole, Richard A

2011-08-01

To determine the efficacy of clinical computed tomographic (CT) imaging to verify postoperative electrode array placement in cochlear implant (CI) patients. Nine fresh cadaver heads underwent clinical CT scanning, followed by bilateral CI insertion and postoperative clinical CT scanning. Temporal bones were removed, trimmed, and scanned using micro-CT. Specimens were then dehydrated, embedded in either methyl methacrylate or LR White resin, and sectioned with a diamond wafering saw. Histology sections were examined by 3 blinded observers to determine the position of individual electrodes relative to soft tissue structures within the cochlea. Electrodes were judged to be within the scala tympani, scala vestibuli, or in an intermediate position between scalae. The position of the array could be estimated accurately from clinical CT scans in all specimens using micro-CT and histology as a criterion standard. Verification using micro-CT yielded 97% agreement, and histologic analysis revealed 95% agreement with clinical CT results. A composite, 3-dimensional image derived from a patient's preoperative and postoperative CT images using a clinical scanner accurately estimates the position of the electrode array as determined by micro-CT imaging and histologic analyses. Information obtained using the CT method provides valuable insight into numerous variables of interest to patient performance such as surgical technique, array design, and processor programming and troubleshooting.

Reducing Head CT Use for Children With Head Injuries in a Community Emergency Department.

PubMed

Jennings, Rebecca M; Burtner, Jennifer J; Pellicer, Joseph F; Nair, Deepthi K; Bradford, Miranda C; Shaffer, Michele; Uspal, Neil G; Tieder, Joel S

2017-04-01

Clinical decision rules have reduced use of computed tomography (CT) to evaluate minor pediatric head injury in pediatric emergency departments (EDs). CT use remains high in community EDs, where the majority of children seek medical care. We sought to reduce the rate of CT scans used to evaluate pediatric head injury from 29% to 20% in a community ED. We evaluated a quality improvement (QI) project in a community ED aimed at decreasing the use of head CT scans in children by implementing a validated head trauma prediction rule for traumatic brain injury. A multidisciplinary team identified key drivers of CT use and implemented decision aids to improve the use of prediction rules. The team identified and mitigated barriers. An affiliated children's hospital offered Maintenance of Certification credit and QI coaching to participants. We used statistical process control charts to evaluate the effect of the intervention on monthly CT scan rates and performed a Wald test of equivalence to compare preintervention and postintervention CT scan proportions. The baseline period (February 2013-July 2014) included 695 patients with a CT scan rate of 29.2% (95% confidence interval, 25.8%-32.6%). The postintervention period (August 2014-October 2015) included 651 patients with a CT scan rate of 17.4% (95% confidence interval, 14.5%-20.2%, P < .01). Barriers included targeting providers with variable pediatric experience and parental imaging expectations. We demonstrate that a Maintenance of Certification QI project sponsored by a children's hospital can facilitate evidence-based pediatric care and decrease the rate of unnecessary CT use in a community setting. Copyright © 2017 by the American Academy of Pediatrics.

18 F-FDG PET/CT for planning external beam radiotherapy alters therapy in 11% of 581 patients.

PubMed

Birk Christensen, Charlotte; Loft-Jakobsen, Annika; Munck Af Rosenschöld, Per; Højgaard, Liselotte; Roed, Henrik; Berthelsen, Anne K

2018-03-01

18 F-FDG PET/CT (FDG PET/CT) used in radiotherapy planning for extra-cerebral malignancy may reveal metastases to distant sites that may affect the choice of therapy. To investigate the role of FDG PET/CT on treatment strategy changes induced by the use of PET/CT as part of the radiotherapy planning. 'A major change of treatment strategy' was defined as either including more lesions in the gross tumour volume (GTV) distant from the primary tumour or a change in treatment modalities. The study includes 581 consecutive patients who underwent an FDG PET/CT scan for radiotherapy planning in our institution in the year 2008. All PET/CT scans were performed with the patient in treatment position with the use of immobilization devices according to the intended radiotherapy treatment. All scans were evaluated by a nuclear medicine physician together with a radiologist to delineate PET-positive GTV (GTV-PET). For 63 of the patients (11%), the PET/CT simulation scans resulted in a major change in treatment strategy because of the additional diagnostic information. Changes were most frequently observed in patients with lung cancer (20%) or upper gastrointestinal cancer (12%). In 65% of the patients for whom the PET/CT simulation scan revealed unexpected dissemination, radiotherapy was given - changed (n = 38) or unchanged (n = 13) according to the findings on the FDG PET/CT. Unexpected dissemination on the FDG PET/CT scanning performed for radiotherapy planning caused a change in treatment strategy in 11% of 581 patients. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

SU-G-JeP2-06: Dosimetric and Workflow Evaluation of First Commercial Synthetic CT Software for Clinical Use in Pelvis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyagi, N; Zhang, J; Happersett, L

2016-06-15

Purpose: evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy Methods: Twenty prostate patients underwent CT and MR simulation scans in treatment position on a 3T Philips scanner. The MR protocol consisted of a T2w turbo spin-echo for soft tissue contrast, a 2D balanced-fast field echo (b-FFE) for fiducial identification, a dual-echo 3D FFE B0 map for distortion analysis and a 3D mDIXON FFE sequence to generate syn-CT. Two echoes are acquired during mDIXON scan, allowing water, fat, and in-phase images to be derived using the frequency shift of the fat and water protons. Tissues were classifiedmore » as: air, adipose, water, trabecular/spongy bone and compact/cortical bone and assigned specific bulk HU values. Bone structures are segmented based on a pelvis bone atlas. Accuracy of syn-CT for patient treatment planning was analyzed by transferring the original plan and structures from the CT to syn-CT via rigid registration and recalculating dose. In addition, new IMRT plans were generated on the syn-CT using structures contoured on MR and transferred to the syn-CT. Accuracy of fiducial-based localization at the treatment machine performed using syn-CT or DRRs generated from syn-CT was assessed by comparing to orthogonal kV radiographs or CBCT. Results: Dosimetric comparison between CT and syn-CT was within 0.5% for all structures. The de-novo optimized plans generated on the syn-CT met our institutional clinical objectives for target and normal structures. Patient-induced susceptibility distortion based on B0 maps was within 1mm and 0.4 mm in the body and prostate. The rectal and bladder outlines on the syn-CT were deemed sufficient for assessing rectal and bladder filling on the CBCT at the time of treatment. CBCT localization showed a median error of < ±1 mm in LR, AP and SI direction. Conclusion: MRI derived syn-CT can be used clinically in MR-alone planning and treatment process for prostate. Drs. Deasy, Hunt and Tyagi have Master research agreement with Philips healthcare.« less

Very low-dose (0.15 mGy) chest CT protocols using the COPDGene 2 test object and a third-generation dual-source CT scanner with corresponding third-generation iterative reconstruction software.

PubMed

Newell, John D; Fuld, Matthew K; Allmendinger, Thomas; Sieren, Jered P; Chan, Kung-Sik; Guo, Junfeng; Hoffman, Eric A

2015-01-01

The purpose of this study was to evaluate the impact of ultralow radiation dose single-energy computed tomographic (CT) acquisitions with Sn prefiltration and third-generation iterative reconstruction on density-based quantitative measures of growing interest in phenotyping pulmonary disease. The effects of both decreasing dose and different body habitus on the accuracy of the mean CT attenuation measurements and the level of image noise (SD) were evaluated using the COPDGene 2 test object, containing 8 different materials of interest ranging from air to acrylic and including various density foams. A third-generation dual-source multidetector CT scanner (Siemens SOMATOM FORCE; Siemens Healthcare AG, Erlangen, Germany) running advanced modeled iterative reconstruction (ADMIRE) software (Siemens Healthcare AG) was used.We used normal and very large body habitus rings at dose levels varying from 1.5 to 0.15 mGy using a spectral-shaped (0.6-mm Sn) tube output of 100 kV(p). Three CT scans were obtained at each dose level using both rings. Regions of interest for each material in the test object scans were automatically extracted. The Hounsfield unit values of each material using weighted filtered back projection (WFBP) at 1.5 mGy was used as the reference value to evaluate shifts in CT attenuation at lower dose levels using either WFBP or ADMIRE. Statistical analysis included basic statistics, Welch t tests, multivariable covariant model using the F test to assess the significance of the explanatory (independent) variables on the response (dependent) variable, and CT mean attenuation, in the multivariable covariant model including reconstruction method. Multivariable regression analysis of the mean CT attenuation values showed a significant difference with decreasing dose between ADMIRE and WFBP. The ADMIRE has reduced noise and more stable CT attenuation compared with WFBP. There was a strong effect on the mean CT attenuation values of the scanned materials for ring size (P < 0.0001) and dose level (P < 0.0001). The number of voxels in the region of interest for the particular material studied did not demonstrate a significant effect (P > 0.05). The SD was lower with ADMIRE compared with WFBP at all dose levels and ring sizes (P < 0.05). The third-generation dual-source CT scanners using third-generation iterative reconstruction methods can acquire accurate quantitative CT images with acceptable image noise at very low-dose levels (0.15 mGy). This opens up new diagnostic and research opportunities in CT phenotyping of the lung for developing new treatments and increased understanding of pulmonary disease.

Effects of megavoltage computed tomographic scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy.

PubMed

Zhu, Jian; Bai, Tong; Gu, Jiabing; Sun, Ziwen; Wei, Yumei; Li, Baosheng; Yin, Yong

2018-04-27

To evaluate the effect of pretreatment megavoltage computed tomographic (MVCT) scan methodology on setup verification and adaptive dose calculation in helical TomoTherapy. Both anthropomorphic heterogeneous chest and pelvic phantoms were planned with virtual targets by TomoTherapy Physicist Station and were scanned with TomoTherapy megavoltage image-guided radiotherapy (IGRT) system consisted of six groups of options: three different acquisition pitches (APs) of 'fine', 'normal' and 'coarse' were implemented by multiplying 2 different corresponding reconstruction intervals (RIs). In order to mimic patient setup variations, each phantom was shifted 5 mm away manually in three orthogonal directions respectively. The effect of MVCT scan options was analyzed in image quality (CT number and noise), adaptive dose calculation deviations and positional correction variations. MVCT scanning time with pitch of 'fine' was approximately twice of 'normal' and 3 times more than 'coarse' setting, all which will not be affected by different RIs. MVCT with different APs delivered almost identical CT numbers and image noise inside 7 selected regions with various densities. DVH curves from adaptive dose calculation with serial MVCT images acquired by varied pitches overlapped together, where as there are no significant difference in all p values of intercept & slope of emulational spinal cord (p = 0.761 & 0.277), heart (p = 0.984 & 0.978), lungs (p = 0.992 & 0.980), soft tissue (p = 0.319 & 0.951) and bony structures (p = 0.960 & 0.929) between the most elaborated and the roughest serials of MVCT. Furthermore, gamma index analysis shown that, compared to the dose distribution calculated on MVCT of 'fine', only 0.2% or 1.1% of the points analyzed on MVCT of 'normal' or 'coarse' do not meet the defined gamma criterion. On chest phantom, all registration errors larger than 1 mm appeared at superior-inferior axis, which cannot be avoided with the smallest AP and RI. On pelvic phantom, craniocaudal errors are much smaller than chest, however, AP of 'coarse' presents larger registration errors which can be reduced from 2.90 mm to 0.22 mm by registration technique of 'full image'. AP of 'coarse' with RI of 6 mm is recommended in adaptive radiotherapy (ART) planning to provide craniocaudal longer and faster MVCT scan, while registration technique of 'full image' should be used to avoid large residual error. Considering the trade-off between IGRT and ART, AP of 'normal' with RI of 2 mm was highly recommended in daily practice.

Age- and gender-specific estimates of cumulative CT dose over 5 years using real radiation dose tracking data in children.

PubMed

Lee, Eunsol; Goo, Hyun Woo; Lee, Jae-Yeong

2015-08-01

It is necessary to develop a mechanism to estimate and analyze cumulative radiation risks from multiple CT exams in various clinical scenarios in children. To identify major contributors to high cumulative CT dose estimates using actual dose-length product values collected for 5 years in children. Between August 2006 and July 2011 we reviewed 26,937 CT exams in 13,803 children. Among them, we included 931 children (median age 3.5 years, age range 0 days-15 years; M:F = 533:398) who had 5,339 CT exams. Each child underwent at least three CT scans and had accessible radiation dose reports. Dose-length product values were automatically extracted from DICOM files and we used recently updated conversion factors for age, gender, anatomical region and tube voltage to estimate CT radiation dose. We tracked the calculated CT dose estimates to obtain a 5-year cumulative value for each child. The study population was divided into three groups according to the cumulative CT dose estimates: high, ≥30 mSv; moderate, 10-30 mSv; and low, <10 mSv. We reviewed clinical data and CT protocols to identify major contributors to high and moderate cumulative CT dose estimates. Median cumulative CT dose estimate was 5.4 mSv (range 0.5-71.1 mSv), and median number of CT scans was 4 (range 3-36). High cumulative CT dose estimates were most common in children with malignant tumors (57.9%, 11/19). High frequency of CT scans was attributed to high cumulative CT dose estimates in children with ventriculoperitoneal shunt (35 in 1 child) and malignant tumors (range 18-49). Moreover, high-dose CT protocols, such as multiphase abdomen CT (median 4.7 mSv) contributed to high cumulative CT dose estimates even in children with a low number of CT scans. Disease group, number of CT scans, and high-dose CT protocols are major contributors to higher cumulative CT dose estimates in children.

Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France.

PubMed

Journy, N; Rehel, J-L; Ducou Le Pointe, H; Lee, C; Brisse, H; Chateil, J-F; Caer-Lorho, S; Laurier, D; Bernier, M-O

2015-01-06

Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. The cohort included 67,274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans.

Detecting Regional Myocardial Abnormalities in Patients With Wolff-Parkinson-White Syndrome With the Use of ECG-Gated Cardiac MDCT.

PubMed

Lee, Hye-Jeong; Uhm, Jae-Sun; Joung, Boyoung; Hong, Yoo Jin; Hur, Jin; Choi, Byoung Wook; Kim, Young Jin

2016-04-01

Myocardial dyskinesia caused by the accessory pathway and related reversible heart failure have been well documented in echocardiographic studies of pediatric patients with Wolff-Parkinson-White (WPW) syndrome. However, the long-term effects of dyskinesia on the myocardium of adult patients have not been studied in depth. The goal of the present study was to evaluate regional myocardial abnormalities on cardiac CT examinations of adult patients with WPW syndrome. Of 74 patients with WPW syndrome who underwent cardiac CT from January 2006 through December 2013, 58 patients (mean [± SD] age, 52.2 ± 12.7 years), 36 (62.1%) of whom were men, were included in the study after the presence of combined cardiac disease was excluded. Two observers blindly evaluated myocardial thickness and attenuation on cardiac CT scans. On the basis of CT findings, patients were classified as having either normal or abnormal findings. We compared the two groups for other clinical findings, including observations from ECG, echocardiography, and electrophysiologic study. Of the 58 patients studied, 16 patients (27.6%) were found to have myocardial abnormalities (i.e., abnormal wall thinning with or without low attenuation). All abnormal findings corresponded with the location of the accessory pathway. Patients with abnormal findings had statistically significantly decreased left ventricular function, compared with patients with normal findings (p < 0.001). The frequency of regional wall motion abnormality was statistically significantly higher in patients with abnormal findings (p = 0.043). However, echocardiography documented structurally normal hearts in all patients. A relatively high frequency (27.6%) of regional myocardial abnormalities was observed on the cardiac CT examinations of adult patients with WPW syndrome. These abnormal findings might reflect the long-term effects of dyskinesia, suggesting irreversible myocardial injury that ultimately causes left ventricular dysfunction.

Unit Cost Analysis of PET-CT at an Apex Public Sector Health Care Institute in India.

PubMed

Gajuryal, S H; Daga, A; Siddharth, V; Bal, C S; Satpathy, S

2017-01-01

PET/CT scan service is one of the capital intensive and revenue-generating centres of a tertiary care hospital. The cost associated with the provisioning of PET services is dependent upon the unit costs of the resources consumed. The study aims to determine the cost of providing PET/CT Scan services in a hospital. This descriptive and observational study was conducted in the Department of Nuclear Medicine at a tertiary apex teaching hospital in New Delhi, India in the year 2014-15. Traditional costing methodology was used for calculating the unit cost of PET/CT scan service. The cost was calculated under two heads that is capital and operating cost. Annualized cost of capital assets was calculated using methodology prescribed by WHO and operating costs was taken on an actual basis. Average number of PET/CT scan performed in a day is 30. The annual cost of providing PET/CT scan services was calculated to be 65,311,719 Indian Rupees (INR) (US$ 1,020,496), while the unit cost of PET scan was calculated to be 9625.92 INR (US$ 150). 3/4th cost was spent on machinery and equipment (75.3%) followed by healthcare personnel (11.37%), electricity (5%), consumables and supplies (4%) engineering maintenance (3.24%), building, furniture and HVAC capital cost (0.76%), and manifold cost (0.05%). Of the total cost, 76% was capital cost while the remaining was operating cost. Total cost for establishing PET/CT scan facility with cyclotron and chemistry module and PET/CT scan without cyclotron and chemistry module was calculated to be INR 610,873,517 (US$9944899) and 226,745,158 (US$3542893), respectively. (US$ 1=INR 64).

Radiation from CT scans in paediatric trauma patients: Indications, effective dose, and impact on surgical decisions.

PubMed

Livingston, Michael H; Igric, Ana; Vogt, Kelly; Parry, Neil; Merritt, Neil H

2014-01-01

The purpose of this study was to determine the effective dose of radiation due to computed tomography (CT) scans in paediatric trauma patients at a level 1 Canadian paediatric trauma centre. We also explored the indications and actions taken as a result of these scans. We performed a retrospective review of paediatric trauma patients presenting to our centre from January 1, 2007 to December 31, 2008. All CT scans performed during the initial trauma resuscitation, hospital stay, and 6 months afterwards were included. Effective dose was calculated using the reported dose length product for each scan and conversion factors specific for body region and age of the patient. 157 paediatric trauma patients were identified during the 2-year study period. Mean Injury Severity Score was 22.5 (range 12-75). 133 patients received at least one CT scan. The mean number of scans per patient was 2.6 (range 0-16). Most scans resulted in no further action (56%) or additional imaging (32%). A decision to perform a procedure (2%), surgery (8%), or withdrawal of life support (2%) was less common. The average dose per patient was 13.5mSv, which is 4.5 times the background radiation compared to the general population. CT head was the most commonly performed type of scan and was most likely to be repeated. CT body, defined as a scan of the chest, abdomen, and/or pelvis, was associated with the highest effective dose. CT is a significant source of radiation in paediatric trauma patients. Clinicians should carefully consider the indications for each scan, especially when performing non-resuscitation scans. There is a need for evidence-based treatment algorithms to assist clinicians in selecting appropriate imaging for patients with severe multisystem trauma. Copyright © 2013 Elsevier Ltd. All rights reserved.

Clinical importance of [18F]fluorodeoxyglucose positron emission tomography/computed tomography in the management of patients with bronchoalveolar carcinoma: Role in the detection of recurrence.

PubMed

Skoura, Evangelia; Datseris, Ioannis E; Exarhos, Dimitrios; Chatziioannou, Sophia; Oikonomopoulos, Georgios; Samartzis, Alexandros; Giannopoulou, Chariklia; Syrigos, Konstantinos N

2013-05-01

[ 18 F]fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been reported to have a low sensitivity in the initial diagnosis of bronchoalveolar carcinoma (BAC) due to BAC's low metabolic activity. The aim of this study was to assess the value of [ 18 F]FDG-PET/CT in the detection of BAC recurrence. Between February 2007 and September 2011, the [ 18 F]FDG-PET/CT scans that were performed on patients with known, histologically proven BAC were studied. A total of 24 [ 18 F]FDG-PET/CT scans were performed in 22 patients, including 16 males and 6 females, with a mean age of 65±9 years. Among the scans, 15 were performed to assess for possible recurrence with equivocal findings in conventional imaging methods and 9 for restaging post-therapy. In all cases conventional imaging studies (CT and MRI) were performed 5-30 days prior to PET/CT. Among the 24 [ 18 F]FDG-PET/CT scans, 18 were positive and 6 negative. Among the 15 [ 18 F]FDG-PET/CT scans performed for suspected recurrence, 34 lesions were detected and the mean maximum standardized uptake value (SUVmax) was 6.8±3.26. In nine scans, upstaging was observed, while two were in agreement with the findings of the conventional modalities. A greater number of lesions were detected in two scans and fewer lesions were detected in one, with no change in staging. Only one scan was negative. By contrast, in patients examined for restaging, there were only five lesions with a mean SUVmax of 4.86±3.18. Agreement between the findings of [ 18 F]FDG-PET/CT and the conventional modalities was observed in 8 out of 9 cases. Although [ 18 F]FDG-PET/CT has been reported to have a low sensitivity in the initial diagnosis of BAC, the present results indicate that when there is recurrence, the lesions become [ 18 F]FDG avid. [ 18 F]FDG-PET/CT may provide further information in patients evaluated for recurrence and thus improve patient management.

Dose reduction in 64-row whole-body CT in multiple trauma: an optimized CT protocol with iterative image reconstruction on a gemstone-based scintillator.

PubMed

Geyer, Lucas L; Körner, Markus; Harrieder, Andreas; Mueck, Fabian G; Deak, Zsuzsanna; Wirth, Stefan; Linsenmaier, Ulrich

2016-01-01

Evaluation of potential dose savings by implementing adaptive statistical iterative reconstruction (ASiR) on a gemstone-based scintillator in a clinical 64-row whole-body CT (WBCT) protocol after multiple trauma. Dose reports of 152 WBCT scans were analysed for two 64-row multidetector CT scanners (Scanners A and B); the main scanning parameters were kept constant. ASiR and a gemstone-based scintillator were used in Scanner B, and the noise index was adjusted (head: 5.2 vs 6.0; thorax/abdomen: 29.0 vs 46.0). The scan length, CT dose index (CTDI) and dose-length product (DLP) were analysed. The estimated mean effective dose was calculated using normalized conversion factors. Student's t-test was used for statistics. Both the mean CTDI (mGy) (Scanner A: 53.8 ± 2.0, 10.3 ± 2.5, 14.4 ± 3.7; Scanner B: 48.7 ± 2.2, 7.1 ± 2.3, 9.1 ± 3.6; p < 0.001, respectively) and the mean DLP (mGy cm) (Scanner A: 1318.9 ± 167.8, 509.3 ± 134.7, 848.8 ± 254.0; Scanner B: 1190.6 ± 172.6, 354.6 ± 128.3, 561.0 ± 246.7; p < 0.001, respectively) for the head, thorax and abdomen were significantly reduced with Scanner B. There was no relevant difference in scan length. The total mean effective dose (mSv) was significantly decreased with Scanner B (24.4 ± 6.0, 17.2 ± 5.8; p < 0.001). The implementation of ASiR and a gemstone-based scintillator allows for significant dose savings in a clinical WBCT protocol. Recent technical developments can significantly reduce radiation dose of WBCT in multiple trauma. Dose reductions of 10-34% can be achieved.

Does C₁ fracture displacement correlate with transverse ligament integrity?

PubMed

Radcliff, Kristen E; Sonagli, Marcos A; Rodrigues, Luciano M; Sidhu, Gursukhman S; Albert, Todd J; Vaccaro, Alexander R

2013-05-01

The Rule of Spence states that displacement of the C₁ lateral masses by >6.9-8.1 mm suggests loss of transverse ligament integrity. The purpose of this study was to establish the thresholds of C₁ displacement on CT scans that correspond to transverse ligament disruption. Over four years, consecutive patients with acute C₁ fractures with at least three fracture lines were analyzed. CT measurements and MRI were assessed by blinded observers for bony displacement in the axial (internal and external lateral mass separation), coronal and sagittal planes and transverse ligament integrity. Eighteen patients were studied. Mean CT bony measurements were as follows: internal border lateral mass separation (ILM) 23.3 ± 3.4 mm, external border lateral mass separation (ELM) 50.3 ± 4.3 mm, total C₁ lateral mass overhang over the C₂ superior process (LMO) 5.4 ± 1.3 mm. Twelve patients were identified as having intact transverse ligament and six had transverse ligament disruption. There was no difference in mean normalized ILM, ELM, or LMO between patients with or without transverse ligament integrity (P > 0.05). There was no correlation between bony displacement and transverse ligament integrity. CT scans post-injury may not show the position of maximal displacement. If there is clinical concern about a possible transverse ligament injury, MRI should be performed. © 2013 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

Implementation of material decomposition using an EMCCD and CMOS-based micro-CT system.

PubMed

Podgorsak, Alexander R; Nagesh, Sv Setlur; Bednarek, Daniel R; Rudin, Stephen; Ionita, Ciprian N

2017-02-11

This project assessed the effectiveness of using two different detectors to obtain dual-energy (DE) micro-CT data for the carrying out of material decomposition. A micro-CT coupled to either a complementary metal-oxide semiconductor (CMOS) or an electron multiplying CCD (EMCCD) detector was used to acquire image data of a 3D-printed phantom with channels filled with different materials. At any instance, materials such as iohexol contrast agent, water, and platinum were selected to make up the scanned object. DE micro-CT data was acquired, and slices of the scanned object were differentiated by material makeup. The success of the decomposition was assessed quantitatively through the computation of percentage normalized root-mean-square error (%NRMSE). Our results indicate a successful decomposition of iohexol for both detectors (%NRMSE values of 1.8 for EMCCD, 2.4 for CMOS), as well as platinum (%NRMSE value of 4.7). The CMOS detector performed material decomposition on air and water on average with 7 times more %NRMSE, possibly due to the decreased sensitivity of the CMOS system. Material decomposition showed the potential to differentiate between materials such as the iohexol and platinum, perhaps opening the door for its use in the neurovascular anatomical region. Work supported by Toshiba America Medical Systems, and partially supported by NIH grant 2R01EB002873.

Implementation of material decomposition using an EMCCD and CMOS-based micro-CT system

NASA Astrophysics Data System (ADS)

Podgorsak, Alexander R.; Nagesh, S. V. Setlur; Bednarek, Daniel R.; Rudin, Stephen; Ionita, Ciprian N.

2017-03-01

This project assessed the effectiveness of using two different detectors to obtain dual-energy (DE) micro-CT data for the carrying out of material decomposition. A micro-CT coupled to either a complementary metal-oxide semiconductor (CMOS) or an electron multiplying CCD (EMCCD) detector was used to acquire image data of a 3D-printed phantom with channels filled with different materials. At any instance, materials such as iohexol contrast agent, water, and platinum were selected to make up the scanned object. DE micro-CT data was acquired, and slices of the scanned object were differentiated by material makeup. The success of the decomposition was assessed quantitatively through the computation of percentage normalized root-mean-square error (%NRMSE). Our results indicate a successful decomposition of iohexol for both detectors (%NRMSE values of 1.8 for EMCCD, 2.4 for CMOS), as well as platinum (%NRMSE value of 4.7). The CMOS detector performed material decomposition on air and water on average with 7 times more %NRMSE, possibly due to the decreased sensitivity of the CMOS system. Material decomposition showed the potential to differentiate between materials such as the iohexol and platinum, perhaps opening the door for its use in the neurovascular anatomical region. Work supported by Toshiba America Medical Systems, and partially supported by NIH grant 2R01EB002873.

Facial nerve conduction after sclerotherapy in children with facial lymphatic malformations: report of two cases.

PubMed

Lin, Pei-Jung; Guo, Yuh-Cherng; Lin, Jan-You; Chang, Yu-Tang

2007-04-01

Surgical excision is thought to be the standard treatment of choice for lymphatic malformations. However, when the lesions are limited to the face only, surgical scar and facial nerve injury may impair cosmetics and facial expression. Sclerotherapy, an injection of a sclerosing agent directly through the skin into a lesion, is an alternative method. By evaluating facial nerve conduction, we observed the long-term effect of facial lymphatic malformations after intralesional injection of OK-432 and correlated the findings with anatomic outcomes. One 12-year-old boy with a lesion over the right-side preauricular area adjacent to the main trunk of facial nerve and the other 5-year-old boy with a lesion in the left-sided cheek involving the buccinator muscle were enrolled. The follow-up data of more than one year, including clinical appearance, computed tomography (CT) scan and facial nerve evaluation were collected. The facial nerve conduction study was normal in both cases. Blink reflex in both children revealed normal results as well. Complete resolution was noted on outward appearance and CT scan. The neurophysiologic data were compatible with good anatomic and functional outcomes. Our report suggests that the inflammatory reaction of OK-432 did not interfere with adjacent facial nerve conduction.

The impact on CT dose of the variability in tube current modulation technology: a theoretical investigation

NASA Astrophysics Data System (ADS)

Li, Xiang; Segars, W. Paul; Samei, Ehsan

2014-08-01

Body CT scans are routinely performed using tube-current-modulation (TCM) technology. There is notable variability across CT manufacturers in terms of how TCM technology is implemented. Some manufacturers aim to provide uniform image noise across body regions and patient sizes, whereas others aim to provide lower noise for smaller patients. The purpose of this study was to conduct a theoretical investigation to understand how manufacturer-dependent TCM scheme affects organ dose, and to develop a generic approach for assessing organ dose across TCM schemes. The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A ray-tracing method was developed to calculate the attenuation of the phantom for a given projection angle based on phantom anatomy, CT system geometry, x-ray energy spectrum, and bowtie filter filtration. The tube current (mA) for a given projection angle was then calculated as a log-linear function of the attenuation along that projection. The slope of this function, termed modulation control strength, α, was varied from 0 to 1 to emulate the variability in TCM technology. Using a validated Monte Carlo program, organ dose was simulated for five α values (α = 0, 0.25, 0.5, 0.75, and 1) in the absence and presence of a realistic system mA limit. Organ dose was further normalized by volume-weighted CT dose index (CTDIvol) to obtain conversion factors (h factors) that are relatively independent of system specifics and scan parameters. For both chest and abdomen-pelvis scans and for 24 radiosensitive organs, organ dose conversion factors varied with α, following second-order polynomial equations. This result suggested the need for α-specific organ dose conversion factors (i.e., conversion factors specific to the modulation scheme used). On the other hand, across the full range of α values, organ dose in a TCM scan could be derived from the conversion factors established for a fixed-mA scan (hFIXED). This was possible by multiplying hFIXED by a revised definition of CTDIvol that accounts for two factors: (a) the tube currents at the location of an organ and (b) the variation in organ volume along the longitudinal direction. This α-generic approach represents an approximation. The error associated with this approximation was evaluated using the α-specific organ dose (i.e., the organ dose obtained by using α-specific mA profiles as inputs into the Monte Carlo simulation) as the reference standard. When the mA profiles were constrained by a realistic system limit, this α-generic approach had errors of less than ~20% for the full range of α values. This was the case for 24 radiosensitive organs in both chest and abdomen-pelvis CT scans with the exception of thyroid in the chest scan and bladder in the abdomen-pelvis scan. For these two organs, the errors were less than ~40%. The results of this theoretical study suggested that knowing the mA modulation profile and the fixed-mA conversion factors, organ dose may be estimated for a TCM scan independent of the specific modulation scheme applied.

Natural killer cells activity in a metastatic colorectal cancer patient with complete and long lasting response to therapy.

PubMed

Ottaiano, Alessandro; Napolitano, Maria; Capozzi, Monica; Tafuto, Salvatore; Avallone, Antonio; Scala, Stefania

2017-11-16

Here we report a case of a 70-year-old man who received adjuvant chemotherapy with fluorouracile, folinic acid and oxaliplatin after a left hemicolectomy for a stage IIIb adenocarcinoma in May 2009. During follow-up he de-veloped abdominal lymphnodes metastases evidenced by positron emission tomography- computed tomography (PET-CT) scan and increase of carcinoembryonic antigen (CEA) level. Chemotherapy with capecitabine, oxaliplatin and bevacizumab was started in April 2012. Restaging showed a complete response and normalization of CEA. The patient received maintenance therapy with bevacizumab which was stopped in December 2013 for patient choice. In October 2014, a new increase in CEA was documented and PET-CT scan showed lung metastases. Analysis of RAS status revealed the absence of mutations, then the patient started a second-line chemotherapy with fluorouracile, folinic acid, irinotecan (folfiri) and panitumumab achieving, in January 2015, a complete response and normalization of CEA. Thereafter, folfiri was discontinued for toxicity; furthermore, upon the third occurrence of a grade 3 dermatologic toxicity, panitumumab was continued from June 2015 at 60% of the original dose and it was administered every three weeks. Until presentation of this case, the patient maintains a complete response, has no symptoms of disease and CEA is normal. Interestingly, this patient presented a high proportion of circulating natural killer (NK) cells (35.1%) with high cytotoxic activity against tumor cells. Study on the role of NK in patients with advanced colorectal cancer are ongoing.

Immediate total-body CT scanning versus conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomised controlled trial.

PubMed

Sierink, Joanne C; Treskes, Kaij; Edwards, Michael J R; Beuker, Benn J A; den Hartog, Dennis; Hohmann, Joachim; Dijkgraaf, Marcel G W; Luitse, Jan S K; Beenen, Ludo F M; Hollmann, Markus W; Goslings, J Carel

2016-08-13

Published work suggests a survival benefit for patients with trauma who undergo total-body CT scanning during the initial trauma assessment; however, level 1 evidence is absent. We aimed to assess the effect of total-body CT scanning compared with the standard work-up on in-hospital mortality in patients with trauma. We undertook an international, multicentre, randomised controlled trial at four hospitals in the Netherlands and one in Switzerland. Patients aged 18 years or older with trauma with compromised vital parameters, clinical suspicion of life-threatening injuries, or severe injury were randomly assigned (1:1) by ALEA randomisation to immediate total-body CT scanning or to a standard work-up with conventional imaging supplemented with selective CT scanning. Neither doctors nor patients were masked to treatment allocation. The primary endpoint was in-hospital mortality, analysed in the intention-to-treat population and in subgroups of patients with polytrauma and those with traumatic brain injury. The χ(2) test was used to assess differences in mortality. This trial is registered with ClinicalTrials.gov, number NCT01523626. Between April 22, 2011, and Jan 1, 2014, 5475 patients were assessed for eligibility, 1403 of whom were randomly assigned: 702 to immediate total-body CT scanning and 701 to the standard work-up. 541 patients in the immediate total-body CT scanning group and 542 in the standard work-up group were included in the primary analysis. In-hospital mortality did not differ between groups (total-body CT 86 [16%] of 541 vs standard work-up 85 [16%] of 542; p=0.92). In-hospital mortality also did not differ between groups in subgroup analyses in patients with polytrauma (total-body CT 81 [22%] of 362 vs standard work-up 82 [25%] of 331; p=0.46) and traumatic brain injury (68 [38%] of 178 vs 66 [44%] of 151; p=0.31). Three serious adverse events were reported in patients in the total-body CT group (1%), one in the standard work-up group (<1%), and one in a patient who was excluded after random allocation. All five patients died. Diagnosing patients with an immediate total-body CT scan does not reduce in-hospital mortality compared with the standard radiological work-up. Because of the increased radiation dose, future research should focus on the selection of patients who will benefit from immediate total-body CT. ZonMw, the Netherlands Organisation for Health Research and Development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Processing of CT images for analysis of diffuse lung disease in the lung tissue research consortium

NASA Astrophysics Data System (ADS)

Karwoski, Ronald A.; Bartholmai, Brian; Zavaletta, Vanessa A.; Holmes, David; Robb, Richard A.

2008-03-01

The goal of Lung Tissue Resource Consortium (LTRC) is to improve the management of diffuse lung diseases through a better understanding of the biology of Chronic Obstructive Pulmonary Disease (COPD) and fibrotic interstitial lung disease (ILD) including Idiopathic Pulmonary Fibrosis (IPF). Participants are subjected to a battery of tests including tissue biopsies, physiologic testing, clinical history reporting, and CT scanning of the chest. The LTRC is a repository from which investigators can request tissue specimens and test results as well as semi-quantitative radiology reports, pathology reports, and automated quantitative image analysis results from the CT scan data performed by the LTRC core laboratories. The LTRC Radiology Core Laboratory (RCL), in conjunction with the Biomedical Imaging Resource (BIR), has developed novel processing methods for comprehensive characterization of pulmonary processes on volumetric high-resolution CT scans to quantify how these diseases manifest in radiographic images. Specifically, the RCL has implemented a semi-automated method for segmenting the anatomical regions of the lungs and airways. In these anatomic regions, automated quantification of pathologic features of disease including emphysema volumes and tissue classification are performed using both threshold techniques and advanced texture measures to determine the extent and location of emphysema, ground glass opacities, "honeycombing" (HC) and "irregular linear" or "reticular" pulmonary infiltrates and normal lung. Wall thickness measurements of the trachea, and its branches to the 3 rd and limited 4 th order are also computed. The methods for processing, segmentation and quantification are described. The results are reviewed and verified by an expert radiologist following processing and stored in the public LTRC database for use by pulmonary researchers. To date, over 1200 CT scans have been processed by the RCL and the LTRC project is on target for recruitment of the 2200 patients with 1800 CT scans in the repository for the 5-year effort. Ongoing analysis of the results in the LTRC database by the LTRC participating institutions and outside investigators are underway to look at the clinical and physiological significance of the imaging features of these diseases and correlate these findings with quality of life and other important prognostic indicators of severity. In the future, the quantitative measures of disease may have greater utility by showing correlation with prognosis, disease severity and other physiological parameters. These imaging features may provide non-invasive alternative endpoints or surrogate markers to alleviate the need for tissue biopsy or provide an accurate means to monitor rate of disease progression or response to therapy.

Organ dose conversion coefficients for tube current modulated CT protocols for an adult population

NASA Astrophysics Data System (ADS)

Fu, Wanyi; Tian, Xiaoyu; Sahbaee, Pooyan; Zhang, Yakun; Segars, William Paul; Samei, Ehsan

2016-03-01

In computed tomography (CT), patient-specific organ dose can be estimated using pre-calculated organ dose conversion coefficients (organ dose normalized by CTDIvol, h factor) database, taking into account patient size and scan coverage. The conversion coefficients have been previously estimated for routine body protocol classes, grouped by scan coverage, across an adult population for fixed tube current modulated CT. The coefficients, however, do not include the widely utilized tube current (mA) modulation scheme, which significantly impacts organ dose. This study aims to extend the h factors and the corresponding dose length product (DLP) to create effective dose conversion coefficients (k factor) database incorporating various tube current modulation strengths. Fifty-eight extended cardiac-torso (XCAT) phantoms were included in this study representing population anatomy variation in clinical practice. Four mA profiles, representing weak to strong mA dependency on body attenuation, were generated for each phantom and protocol class. A validated Monte Carlo program was used to simulate the organ dose. The organ dose and effective dose was further normalized by CTDIvol and DLP to derive the h factors and k factors, respectively. The h factors and k factors were summarized in an exponential regression model as a function of body size. Such a population-based mathematical model can provide a comprehensive organ dose estimation given body size and CTDIvol. The model was integrated into an iPhone app XCATdose version 2, enhancing the 1st version based upon fixed tube current modulation. With the organ dose calculator, physicists, physicians, and patients can conveniently estimate organ dose.

Investigating different computed tomography techniques for internal target volume definition.

PubMed

Yoganathan, S A; Maria Das, K J; Subramanian, V Siva; Raj, D Gowtham; Agarwal, Arpita; Kumar, Shaleen

2017-01-01

The aim of this work was to evaluate the various computed tomography (CT) techniques such as fast CT, slow CT, breath-hold (BH) CT, full-fan cone beam CT (FF-CBCT), half-fan CBCT (HF-CBCT), and average CT for delineation of internal target volume (ITV). In addition, these ITVs were compared against four-dimensional CT (4DCT) ITVs. Three-dimensional target motion was simulated using dynamic thorax phantom with target insert of diameter 3 cm for ten respiration data. CT images were acquired using a commercially available multislice CT scanner, and the CBCT images were acquired using On-Board-Imager. Average CT was generated by averaging 10 phases of 4DCT. ITVs were delineated for each CT by contouring the volume of the target ball; 4DCT ITVs were generated by merging all 10 phases target volumes. Incase of BH-CT, ITV was derived by boolean of CT phases 0%, 50%, and fast CT target volumes. ITVs determined by all CT and CBCT scans were significantly smaller (P < 0.05) than the 4DCT ITV, whereas there was no significant difference between average CT and 4DCT ITVs (P = 0.17). Fast CT had the maximum deviation (-46.1% ± 20.9%) followed by slow CT (-34.3% ± 11.0%) and FF-CBCT scans (-26.3% ± 8.7%). However, HF-CBCT scans (-12.9% ± 4.4%) and BH-CT scans (-11.1% ± 8.5%) resulted in almost similar deviation. On the contrary, average CT had the least deviation (-4.7% ± 9.8%). When comparing with 4DCT, all the CT techniques underestimated ITV. In the absence of 4DCT, the HF-CBCT target volumes with appropriate margin may be a reasonable approach for defining the ITV.

Making the diagnosis: metopic ridge versus metopic craniosynostosis.

PubMed

Birgfeld, Craig B; Saltzman, Babette S; Hing, Anne V; Heike, Carrie L; Khanna, Paritosh C; Gruss, Joseph S; Hopper, Richard A

2013-01-01

The metopic suture is the only calvarial suture which normally closes during infancy. Upon closure, a palpable and visible ridge often forms which can be confused with metopic craniosynostosis. Metopic ridging (MR) is treated nonsurgically while metopic craniosynostosis (MCS) is treated surgically. Differentiating between the two is paramount; however, consensus is lacking about where a clear diagnostic threshold lies. The goal of this study is to describe the physical examination and CT scan characteristics which may help to differentiate between physiological closure of the metopic suture with ridging (MR) and MCS. A retrospective chart review of all patients seen at Seattle Children's Hospital between 2004 and 2009 with the diagnosis of either MCS or MR (n = 282) was performed. Physical examination characteristics described by diagnosing practitioners were analyzed. Clinical photos were assessed by 3 expert raters to determine the importance of these characteristics. CT scan findings were abstracted and compared between the two diagnoses. The "classic" triad of narrow forehead, biparietal widening, and hypotelorism was present in only 14% of patients with MCS. Ninety-eight percent of patients in both groups had a palpable metopic ridge. The photographic finding of narrow forehead and pterional constriction was present in all patients with MCS, but only in 11.2% and 2.8% of patients with MR. On CT scan, the presence of 3 or more MCS findings was diagnostic of MCS in 96% of patients. Patients with MCS were more likely to present before 6 months of age (66% vs. 32%). Patients with MCS tend to present earlier than those with MR. Upon physical examination, the relationship between the lateral frontal bone and the lateral orbit is important in distinguishing between the two diagnoses. A CT scan can be helpful in making the diagnosis not to confirm a closed suture but to identify 3 or more MCS characteristics.

Human identification based on cranial computed tomography scan — a case report

PubMed Central

Silva, RF; Botelho, TL; Prado, FB; Kawagushi, JT; Daruge Júnior, E; Bérzin, F

2011-01-01

Today, there is increasing use of CT scanning on a clinical basis, aiding in the diagnosis of diseases or injuries. This exam also provides important information that allows identification of individuals. This paper reports the use of a CT scan on the skull, taken when the victim was alive, for the positive identification of a victim of a traffic accident in which the fingerprint analysis was impossible. The authors emphasize that the CT scan is a tool primarily used in clinical diagnosis and may contribute significantly to forensic purpose, allowing the exploration of virtual corpses before the classic autopsy. The use of CT scans might increase the quantity and quality of information involved in the death of the person examined. PMID:21493883

CT scans in young people in Northern England: trends and patterns 1993–2002

PubMed Central

Pearce, Mark S.; Salotti, Jane A.; McHugh, Kieran; Metcalf, Wenhua; Kim, Kwang P.; Craft, Alan W.; Parker, Louise; Ron, Elaine

2014-01-01

Background Although CT can be greatly beneficial, its relatively high radiation doses have caused public health concerns. Objective To assess patterns in CT usage among patients aged less than 22 years in Northern England during the period 1993–2002. Materials and methods Electronic data were obtained from radiology information systems of all nine National Health Service trusts in the region. Results A total of 38,681 scans had been performed in 20,483 patients aged less than 22 years. The number of CT examinations rose, with the steepest increase between 1997 and 2000. The number of patients scanned per year increased less dramatically, with 2.24/1,000 population aged less than 22 years having one scan or more in 1993 compared to 3.54/1,000 in 2002. This reflects an increase in the median number of scans per patient, which rose from 1 in 1993 to 2 by 1999. More than 70% of CT examinations were of the head, with the number of head examinations varying with time and patient age. Conclusion The frequency of CT scans in this population more than doubled during the study period. This is partly, but not wholly, explained by an increase in the number of scans per patient. PMID:21594548

Positive Enteric Contrast Material for Abdominal and Pelvic CT with Automatic Exposure Control: What Is the Effect On Patient Radiation Exposure?

PubMed Central

Wang, Zhen J.; Chen, Katherine S.; Gould, Robert; Coakley, Fergus V.; Fu, Yanjun; Yeh, Benjamin M.

2014-01-01

Objective To assess the effect of positive enteric contrast administration on automatic exposure control (AEC) CT radiation exposure in 1) a CT phantom, and 2) a retrospective review of patients. Materials and Methods We scanned a CT phantom containing simulated bowel that was sequentially filled with water and positive enteric contrast, and recorded the mean volume CT dose index (CTDIvol). We also identified 17 patients who had undergone 2 technically comparable CT scans of the abdomen and pelvis, one with positive enteric contrast and the other with oral water. Paired student t-tests were used to compare the mean CTDIvol between scans performed with and without positive enteric contrast. Both the phantom and patient CT scans were performed using AEC with a fixed noise index. Results The mean CTDIvol for the phantom with simulated bowel containing water and positive enteric contrast were 8.2 ± 0.2 mGy, and 8.7 ± 0.1 mGy (6.1% higher than water, p=0.02), respectively. The mean CTDIvol for patients scanned with oral water and with positive enteric contrast were 11.8mGy and 13.1mGy, respectively (p=0.003). This corresponded to a mean CTDIvol which was 11.0% higher (range: 0.0–20.7% higher) in scans with positive enteric contrast than those with oral water in patients. Conclusions When automatic exposure control is utilized for abdominopelvic CT, the radiation exposure, as measured by CTDIvol, is higher for scans performed with positive enteric contrast than those with oral water. PMID:21493028

Is appendiceal CT scan overused for evaluating patients with right lower quadrant pain?

PubMed

Safran, D B; Pilati, D; Folz, E; Oller, D

2001-05-01

Reports citing excellent sensitivity, specificity, and predictive accuracy of focused appendiceal computed tomography (CT) and showing an overall reduction in resource use and nontherapeutic laparotomies have led to increasing use of that imaging modality. Diagnostic algorithms have begun to incorporate appendiceal CT for patients presenting to the emergency department with right lower quadrant pain. We present a series of 4 cases in which use of appendiceal CT ultimately led to increased cost, resource use, and complexity in patient care. The results of these cases support an argument against unbridled use of appendiceal CT scanning and reinforce the need for clinical evaluation by the operating surgeon before routine performance of appendiceal CT scan.

Acute onset quadriplegia.

PubMed

Rajasekharan, Chandrasekharan; Deepak, Menon

2012-07-10

A 50-year-old man, with history of chronic alcohol intake was brought in a stuporous state to the emergency services having been found in that condition in his home the same day. Examination revealed the patient in an akinteic mute state with apparently normal cranial nerves, hypotonia and quadriplegia with bilateral extensor plantar reflex. CT scan and MRI of the brain revealed bilateral infarct parasagittally with normal Magnetic resonance venogram suggestive of bilateral anterior cerebral artery infarct. Follow-up magnetic resonance angiogram revealed an azygous anterior cerebral artery thus proving an infarct of unpaired anterior cerebral artery infarct as the cause for quadriplegia in this patient.

Extension of RPI-adult male and female computational phantoms to obese patients and a Monte Carlo study of the effect on CT imaging dose

NASA Astrophysics Data System (ADS)

Ding, Aiping; Mille, Matthew M.; Liu, Tianyu; Caracappa, Peter F.; Xu, X. George

2012-05-01

Although it is known that obesity has a profound effect on x-ray computed tomography (CT) image quality and patient organ dose, quantitative data describing this relationship are not currently available. This study examines the effect of obesity on the calculated radiation dose to organs and tissues from CT using newly developed phantoms representing overweight and obese patients. These phantoms were derived from the previously developed RPI-adult male and female computational phantoms. The result was a set of ten phantoms (five males, five females) with body mass indexes ranging from 23.5 (normal body weight) to 46.4 kg m-2 (morbidly obese). The phantoms were modeled using triangular mesh geometry and include specified amounts of the subcutaneous adipose tissue and visceral adipose tissue. The mesh-based phantoms were then voxelized and defined in the Monte Carlo N-Particle Extended code to calculate organ doses from CT imaging. Chest-abdomen-pelvis scanning protocols for a GE LightSpeed 16 scanner operating at 120 and 140 kVp were considered. It was found that for the same scanner operating parameters, radiation doses to organs deep in the abdomen (e.g., colon) can be up to 59% smaller for obese individuals compared to those of normal body weight. This effect was found to be less significant for shallow organs. On the other hand, increasing the tube potential from 120 to 140 kVp for the same obese individual resulted in increased organ doses by as much as 56% for organs within the scan field (e.g., stomach) and 62% for those out of the scan field (e.g., thyroid), respectively. As higher tube currents are often used for larger patients to maintain image quality, it was of interest to quantify the associated effective dose. It was found from this study that when the mAs was doubled for the obese level-I, obese level-II and morbidly-obese phantoms, the effective dose relative to that of the normal weight phantom increased by 57%, 42% and 23%, respectively. This set of new obese phantoms can be used in the future to study the optimization of image quality and radiation dose for patients of different weight classifications. Our ultimate goal is to compile all the data derived from these phantoms into a comprehensive dosimetry database defined in the VirtualDose software.

Effect of topogram-tube angle combination on CT radiation dose reduction

NASA Astrophysics Data System (ADS)

Shim, J.; Yoon, M.

2017-09-01

This study assessed the ability of various types of topograms, when used with an automatic tube current modulation (ATCM) technique, to reduce radiation dose from computed tomography (CT) scans. Three types of topograms were used with the ATCM technique: (i) anteroposterior (AP) topograms alone, (ii) AP topograms followed by lateral topograms, and (iii) lateral topograms followed by AP topograms. Various regions (chest, abdomen and whole-body) of a humanoid phantom were scanned at several tube voltages (80, 100 and 120 kVp) with the selected topograms. Although the CT dose depended on the order of topograms, the CT dose with respect to patient positioning depended on the number of topograms performed. The magnitude of the difference in CT dose between number and order of topograms was greater for the scans of the abdomen than the chest. These results suggest that, for the Siemens SOMATOM Definition AS CT scanner, choosing the right combination of CT scan conditions with the ATCM technique can minimize radiation dose to a patient.

Cancer risk in 680,000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians.

PubMed

Mathews, John D; Forsythe, Anna V; Brady, Zoe; Butler, Martin W; Goergen, Stacy K; Byrnes, Graham B; Giles, Graham G; Wallace, Anthony B; Anderson, Philip R; Guiver, Tenniel A; McGale, Paul; Cain, Timothy M; Dowty, James G; Bickerstaffe, Adrian C; Darby, Sarah C

2013-05-21

To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. Population based, cohort, data linkage study in Australia. COHORT MEMBERS: 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005; all exposures to CT scans funded by Medicare during 1985-2005 were identified for this cohort. Cancers diagnosed in cohort members up to 31 December 2007 were obtained through linkage to national cancer records. Cancer incidence rates in individuals exposed to a CT scan more than one year before any cancer diagnosis, compared with cancer incidence rates in unexposed individuals. 60,674 cancers were recorded, including 3150 in 680,211 people exposed to a CT scan at least one year before any cancer diagnosis. The mean duration of follow-up after exposure was 9.5 years. Overall cancer incidence was 24% greater for exposed than for unexposed people, after accounting for age, sex, and year of birth (incidence rate ratio (IRR) 1.24 (95% confidence interval 1.20 to 1.29); P<0.001). We saw a dose-response relation, and the IRR increased by 0.16 (0.13 to 0.19) for each additional CT scan. The IRR was greater after exposure at younger ages (P<0.001 for trend). At 1-4, 5-9, 10-14, and 15 or more years since first exposure, IRRs were 1.35 (1.25 to 1.45), 1.25 (1.17 to 1.34), 1.14 (1.06 to 1.22), and 1.24 (1.14 to 1.34), respectively. The IRR increased significantly for many types of solid cancer (digestive organs, melanoma, soft tissue, female genital, urinary tract, brain, and thyroid); leukaemia, myelodysplasia, and some other lymphoid cancers. There was an excess of 608 cancers in people exposed to CT scans (147 brain, 356 other solid, 48 leukaemia or myelodysplasia, and 57 other lymphoid). The absolute excess incidence rate for all cancers combined was 9.38 per 100,000 person years at risk, as of 31 December 2007. The average effective radiation dose per scan was estimated as 4.5 mSv. The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose.

Estimating the effective radiation dose imparted to patients by intraoperative cone-beam computed tomography in thoracolumbar spinal surgery.

PubMed

Lange, Jeffrey; Karellas, Andrew; Street, John; Eck, Jason C; Lapinsky, Anthony; Connolly, Patrick J; Dipaola, Christian P

2013-03-01

Observational. To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases with patient size, and the radiation dose received by larger patients as a result of more than 3 O-arm scans in standard mode may exceed the dose received during standard CT of the abdomen. Understanding radiation imparted to patients by cone-beam CT is important for assessing risks and benefits of this technology, especially when spinal surgical procedures require multiple intraoperative scans.

[Three-dimensional tooth model reconstruction based on fusion of dental computed tomography images and laser-scanned images].

PubMed

Zhang, Dongxia; Gan, Yangzhou; Xiong, Jing; Xia, Zeyang

2017-02-01

Complete three-dimensional(3D) tooth model provides essential information to assist orthodontists for diagnosis and treatment planning. Currently, 3D tooth model is mainly obtained by segmentation and reconstruction from dental computed tomography(CT) images. However, the accuracy of 3D tooth model reconstructed from dental CT images is low and not applicable for invisalign design. And another serious problem also occurs, i.e. frequentative dental CT scan during different intervals of orthodontic treatment often leads to radiation to the patients. Hence, this paper proposed a method to reconstruct tooth model based on fusion of dental CT images and laser-scanned images. A complete3 D tooth model was reconstructed with the registration and fusion between the root reconstructed from dental CT images and the crown reconstructed from laser-scanned images. The crown of the complete 3D tooth model reconstructed with the proposed method has higher accuracy. Moreover, in order to reconstruct complete 3D tooth model of each orthodontic treatment interval, only one pre-treatment CT scan is needed and in the orthodontic treatment process only the laser-scan is required. Therefore, radiation to the patients can be reduced significantly.

Single energy micro CT SkyScan 1173 for the characterization of urinary stone

NASA Astrophysics Data System (ADS)

Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

2016-08-01

A urinary stone is a solid piece of material produced from crystallization of excreted substances in the urine. Knowledge of the composition of urinary stones is essential to determine the suitable treatment for the patient. The aim of this research was to characterize urinary stones using single energy micro CT SkyScan 1173. Six human urinary stones were scanned in vitro using 80 kV in micro CT SkyScan 1173. The produced projection, images, were reconstructed using NRecon (in-house software from SkyScan). The images of urinary stones were analyzed using CT Analyser (CT An) to obtain information of the internal structure and the Hounsfield Unit (HU) value to determine the information regarding the composition of the urinary stones, respectively. The average HU values from certain region of interests in the same slice were compared with spectral curves of known materials from National Institute of Standards and Technology (NIST). From the analysis, the composition of the six scanned stones were obtained. Two stones are composed of cystine, two are composed of struvite, two other stones are composed of struvite+cystine. In conclusion, the single energy micro CT with 80 kV can be used identifying cystine and struvite urinary stone.

SU-G-IeP4-07: Feasibility of Low Dose 18FDG PET in Pediatric Oncology Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, J; Binzel, K; Hall, NC

Purpose: To evaluate and demonstrate the feasibility of low dose FDG PET in pediatric oncology patients using virtual dose reduction as well as true patients PET/CT scans. Methods: Wholebody 18F-FDG PET/CT of 39 clinical pediatric patients (0.16±0.06MBq/kg) were scanned on a Gemini TF 64 system at 75±5 min post FDG injection using 3min/bed. Based on the 180s/bed listmode PET data, subsets of total counts in 120s, 90s, 60s, 30s and 15s per bed position were extracted for PET reconstruction to simulate lower dose PET at 2/3th, 1/2th, 1/3th, 1/6th and 1/12th dose levels. PET/CT scans of Jaszczak PET phantom withmore » 6 hot hollow spheres varying with sizes and contrast ratios were performed (real PET versus simulated PET) to validate the methodology of virtual dose PET simulation. Region of interests (ROIs) were placed on lesions and normal anatomical tissues with quantitative and qualitative assessment performed. Significant lower FDG dose PET/CT of 5 research adolescents were scanned to validate the proposal and low dose PET feasibility. Results: Although all lesions are visible on the 1/12th dose PET, overall PET image quality appears to be influenced in a multi-factorial way. 30%–60% dose reduction from current standard of care FDG PET is recommended to maintain equivalent quality and PET quantification. An optimized BMI-based FDG administration is recommended (from 1.1±0.5 mCi for BMI < 18.5 to 4.8±1.5 mCi for BMI > 30). A linear lowest “Dose-BMI” relationship is given. SUVs from 1/12th to full dose PETs were identified as consistent (R2 = 1.08, 0.99, 1.01, 1.00 and 0.98). No significant variances of count density, SUV and SNR were found across certain dose ranges (p<0.01). Conclusion: Pediatric PET/CT can be performed using current time-of-flight systems at substantially lower PET doses (30–60%) than the standard of care PET/CT without compromising qualitative and quantitative image quality in clinical.« less

Spiral computed tomography evaluation of rabbit VX2 hepatic tumors treated with 20 kHz ultrasound and microbubbles

PubMed Central

Shen, Zhi-Yong; Liu, Chun; Wu, Ming-Feng; Shi, Hai-Feng; Zhou, Yu-Feng; Zhuang, Wei; Xia, Gan-Lin

2017-01-01

The aim of the present study was to explore the therapeutic effect of 20 kHz ultrasound (US) and microbubbles (MBs) on rabbit VX2 liver tumors by spiral computed tomography (CT) scanning. A total of 16 New Zealand rabbits with hepatic VX2 tumors were divided into four groups: Control, MB, low-frequency US and US + MB. The treatment effect was evaluated by spiral CT scanning prior to, during and following treatment (at 0 weeks and the end of 1 and 2 weeks). The tumor growth rate was recorded. The specimens of VX2 tumors were collected for histological examination and transmission electron microscopy (TEM). No significant differences were observed between tumor areas measured by CT and pathology after 2-week treatment (P>0.05). The mean tumor growth rates in the control, MB, US and US + MB groups after 2 weeks of treatment were 385±21, 353±12, 302±14 and 154±9%, respectively (P<0.05, US + MB vs. the other three groups). Hematoxylin and eosin staining in the US + MB group revealed coagulation necrosis, interstitial hemorrhage and intravascular thrombosis. In the control, MB and US groups, tumor cells exhibited clear nuclear hyperchromatism. TEM of US + MB revealed vascular endothelial cell wall rupture, widened endothelial cell gaps, interstitial erythrocyte leakage and microvascular thrombosis, while intact vascular endothelial cells and normal erythrocytes in the tumor vessels were observed in the control, MB and US groups. A combination of 20 kHz US and MBs may effectively inhibit rabbit VX2 tumors. Spiral CT scanning is an ideal method to evaluate the US treatment on rabbit tumors. PMID:28928850

Method for studying gas composition in the human mastoid cavity by use of laser spectroscopy.

PubMed

Lindberg, Sven; Lewander, Märta; Svensson, Tomas; Siemund, Roger; Svanberg, Katarina; Svanberg, Sune

2012-04-01

We evaluated a method for gas monitoring in the mastoid cavity using tunable diode laser spectroscopy by comparing it to simultaneously obtained computed tomographic (CT) scans. The presented optical technique measures free gases, oxygen (O2), and water vapor (H2O) within human tissue by use of low-power diode lasers. Laser light was sent into the tip of the mastoid process, and the emerging light at the level of the antrum was captured with a detector placed on the skin. The absorption of H2O was used to monitor the probed gas volume of the mastoid cavity, and it was compared to the CT scan-measured volume. The ratio between O2 absorption and H2O absorption estimated the O2 content in the mastoid cavity and thus the ventilation. The parameters were compared to the grading of mastoid cavities based on the CT scans (n = 31). The reproducibility of the technique was investigated by measuring each mastoid cavity 4 times. Both O2 and H2O were detected with good reproducibility. The H2O absorption and the CT volume correlated (r = 0.69). The average ratio between the normalized O2 absorption and the H2O absorption signals was 0.7, indicating a lower O2 content than in surrounding air (expected ratio, 1.0), which is consistent with previous findings made by invasive techniques. All mastoid cavities with radiologic signs of disease were detected. Laser spectroscopy monitoring appears to be a usable tool for noninvasive investigations of gas composition in the mastoid cavity, providing important clinical information regarding size and ventilation.

Diagnosis and surgical outcomes of intraparotid facial nerve schwannoma showing normal facial nerve function.

PubMed

Lee, D W; Byeon, H K; Chung, H P; Choi, E C; Kim, S-H; Park, Y M

2013-07-01

The findings of intraparotid facial nerve schwannoma (FNS) using preoperative diagnostic tools, including ultrasonography (US)-guided fine needle aspiration biopsy, computed tomography (CT) scan, and magnetic resonance imaging (MRI), were analyzed to determine if there are any useful findings that might suggest the presence of a lesion. Treatment guidelines are suggested. The medical records of 15 patients who were diagnosed with an intraparotid FNS were retrospectively analyzed. US and CT scans provide clinicians with only limited information; gadolinium enhanced T1-weighted images from MRI provide more specific findings. Tumors could be removed successfully with surgical exploration, preserving facial nerve function at the same time. Gadolinium-enhanced T1-weighted MRI showed more characteristic findings for the diagnosis of intraparotid FNS. Intraparotid FNS without facial palsy can be diagnosed with MRI preoperatively, and surgical exploration is a suitable treatment modality which can remove the tumor and preserve facial nerve function. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Preliminary experiments on pharmacokinetic diffuse fluorescence tomography of CT-scanning mode

NASA Astrophysics Data System (ADS)

Zhang, Yanqi; Wang, Xin; Yin, Guoyan; Li, Jiao; Zhou, Zhongxing; Zhao, Huijuan; Gao, Feng; Zhang, Limin

2016-10-01

In vivo tomographic imaging of the fluorescence pharmacokinetic parameters in tissues can provide additional specific and quantitative physiological and pathological information to that of fluorescence concentration. This modality normally requires a highly-sensitive diffuse fluorescence tomography (DFT) working in dynamic way to finally extract the pharmacokinetic parameters from the measured pharmacokinetics-associated temporally-varying boundary intensity. This paper is devoted to preliminary experimental validation of our proposed direct reconstruction scheme of instantaneous sampling based pharmacokinetic-DFT: A highly-sensitive DFT system of CT-scanning mode working with parallel four photomultiplier-tube photon-counting channels is developed to generate an instantaneous sampling dataset; A direct reconstruction scheme then extracts images of the pharmacokinetic parameters using the adaptive-EKF strategy. We design a dynamic phantom that can simulate the agent metabolism in living tissue. The results of the dynamic phantom experiments verify the validity of the experiment system and reconstruction algorithms, and demonstrate that system provides good resolution, high sensitivity and quantitativeness at different pump speed.

TU-F-18A-06: Dual Energy CT Using One Full Scan and a Second Scan with Very Few Projections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, T; Zhu, L

Purpose: The conventional dual energy CT (DECT) requires two full CT scans at different energy levels, resulting in dose increase as well as imaging errors from patient motion between the two scans. To shorten the scan time of DECT and thus overcome these drawbacks, we propose a new DECT algorithm using one full scan and a second scan with very few projections by preserving structural information. Methods: We first reconstruct a CT image on the full scan using a standard filtered-backprojection (FBP) algorithm. We then use a compressed sensing (CS) based iterative algorithm on the second scan for reconstruction frommore » very few projections. The edges extracted from the first scan are used as weights in the Objectives: function of the CS-based reconstruction to substantially improve the image quality of CT reconstruction. The basis material images are then obtained by an iterative image-domain decomposition method and an electron density map is finally calculated. The proposed method is evaluated on phantoms. Results: On the Catphan 600 phantom, the CT reconstruction mean error using the proposed method on 20 and 5 projections are 4.76% and 5.02%, respectively. Compared with conventional iterative reconstruction, the proposed edge weighting preserves object structures and achieves a better spatial resolution. With basis materials of Iodine and Teflon, our method on 20 projections obtains similar quality of decomposed material images compared with FBP on a full scan and the mean error of electron density in the selected regions of interest is 0.29%. Conclusion: We propose an effective method for reducing projections and therefore scan time in DECT. We show that a full scan plus a 20-projection scan are sufficient to provide DECT images and electron density with similar quality compared with two full scans. Our future work includes more phantom studies to validate the performance of our method.« less

The impact of the introduction of PECARN head CT rules on the utilisation of head CT scans in a private tertiary hospital in Sub-Saharan Africa.

PubMed

Kobe, Isaac O; Qureshi, Mahmoud M; Hassan, Saidi; Oluoch-Olunya, David L

2017-12-01

The decision to order head CT scans to rule out clinically significant traumatic brain injury in mild head injury in children is made on the basis of clinical decision rules of which the Paediatric Emergency Care Applied Research Network (PECARN) CT head rules have been found to be most sensitive. The purpose of this study is to determine the proportion of head CT scans done for children with mild head injury and to determine disposition of patients from casualty after the introduction of PECARN head CT rules compared to the period before. The research question is "will introduction of the PECARN CT head rules reduce the proportion of head CT scans requested for children under 18 years with mild head injury at the AKUHN?" A before and after quasi experimental study with a study population including all children under 18 years presenting to the AKUHN with mild head injury and a Glasgow coma scale of 14 and above on presentation. Sample size was 85. A total of 42 patients files were analysed in the before study while 43 patients were selected for the after study. The median age was 5 years. The proportion of head CT scans reduced from 56% in the before group to 33% in the after group with no missed clinically significant traumatic brain injury. More patients were discharged home after evaluation in the after group (81%) than in the before group (58%). The number of head CT scans ordered reduced without missing any clinically significant traumatic brain injury.

[Exposure to CT scans in childhood and long-term cancer risk: A review of epidemiological studies].

PubMed

Baysson, Hélène; Journy, Neige; Roué, Tristan; Ducou-Lepointe, Hubert; Etard, Cécile; Bernier, Marie-Odile

2016-02-01

Amongst medical exams requiring ionizing radiation, computed tomography (CT) scans are used more frequently, including in children. These CT examinations are associated with absorbed doses that are much higher than those associated with conventional radiology. In comparison to adults, children have a greater sensitivity to radiation and a longer life span with more years at cancer risks. Five epidemiological studies on cancer risks after CT scan exposure during childhood were published between 2012 and 2015. The results of these studies are consistent and show an increase of cancer risks in children who have been exposed to several CT scans. However, methodological limits due to indication bias, retrospective assessment of radiation exposure from CT scans and lack of statistical power are to be taken into consideration. International projects such as EPI-CT (Epidemiological study to quantify risks for pediatric computerized tomography and to optimize dose), with a focus on dosimetric reconstruction and minimization of bias will provide more precise results. In the meantime, available results reinforce the necessity of justification and optimization of doses. Copyright © 2015 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Standardization and quantification in FDG-PET/CT imaging for staging and restaging of malignant disease.

PubMed

Gámez-Cenzano, Cristina; Pino-Sorroche, Francisco

2014-04-01

There is a growing interest in using quantification in FDG-PET/CT in oncology, especially for evaluating response to therapy. Complex full quantitative procedures with blood sampling and dynamic scanning have been clinically replaced by the use of standardized uptake value measurements that provide an index of regional tracer uptake normalized to the administered dose of FDG. Some approaches have been proposed for assessing quantitative metabolic response, such as EORTC and PERCIST criteria in solid tumors. When using standardized uptake value in clinical routine and multicenter trials, standardization of protocols and quality control procedures of instrumentation is required. Copyright © 2014 Elsevier Inc. All rights reserved.

[Fever, atrial fibrillation, and angina pectoris in a 58-year-old man].

PubMed

Groebner, M; Südhoff, T; Doering, M; Kirmayer, M; Nitsch, T; Prügl, L; Römer, W; Wolf, H; Tacke, J; Massoudy, P; Nüsse, T; Elsner, D

2014-05-01

Primary cardiac lymphoma (PCL) respresents a very rare type of cardiac tumour. This report illustrates a case of PCL in an immunocompetent 58-year-old man presenting with atrial fibrillation and febrile syndrome. Comprehensive imaging [computer tomography (CT), cardiac magnetic resonance imaging (cMRI), 3-dimensional transesophageal echocardiography (3D-TEE)] identified a large right atrial tumour, leading to pericardial effusion. Isolated cardiac involvement was confirmed by positron emission tomography (PET)-CT. A diffuse large B-cell lymphoma (DLBCL) was diagnosed based on the results of a TEE-guided biopsy. A normalized PET scan (PETAL study) indicated complete remission following R-CHOP 14 immunochemotherapy. Thus, an interdisciplinary and multimodal approach avoided unnecessary cardiac surgery.

Lung Hot Spot Without Corresponding Computed Tomography Abnormality on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Artifactual or Real, Iatrogenic or Pathologic?

PubMed

Liu, Yiyan

Focal lung uptake without corresponding lesions or abnormalities on computed tomography (CT) scan poses a dilemma in the interpretation of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT). A limited number of case reports have previously suggested an artifactual or iatrogenic nature of the uptake. In the present study, 8 relevant cases were included within a retrospective search of the database. Medical records were reviewed for follow-up radiological and pathologic information. In 7 of 8 cases with focal increased FDG uptake but no corresponding lesions or abnormalities on CT scan, the lung hot spots were artifactual or iatrogenic upon follow-up diagnostic chest CT or repeated PET/CT or both the scans. Microemboli were most likely a potential cause of the pulmonary uptake, with or without partial paravenous injection. One case in the series had a real pulmonary lesion demonstrated on follow-up PET/CT scans and on surgical pathology, although the initial integrated CT and follow-up diagnostic chest CT scans revealed negative findings to demonstrate pulmonary abnormalities corresponding to the hot spot on the PET scan. In conclusion, the finding of a lung hot spot in the absence of anatomical abnormality on FDG PET/CT was most likely artifactual or iatrogenic, but it might also represent a real pulmonary lesion. Nonvisualization of anatomical abnormality could be because of its small size and position directly overlying a segmental vessel. Further image follow-up is necessary and important to clarify the nature of the uptake. Copyright © 2017 Elsevier Inc. All rights reserved.

Journal Club: Head CT scans in the emergency department for syncope and dizziness.

PubMed

Mitsunaga, Myles M; Yoon, Hyo-Chun

2015-01-01

The purpose of this study was to determine the yield of acutely abnormal findings on head CT scans in patients presenting to the emergency department with dizziness, near-syncope, or syncope and to determine the clinical factors that potentially predicted acutely abnormal head CT findings and hospital admission. We retrospectively reviewed the electronic medical records of all patients presenting to an HMO emergency department between July 1, 2012, and December 31, 2012, who underwent head CT for a primary complaint of dizziness, syncope, or near-syncope. The primary outcomes were head CT scans with acutely abnormal findings and hospital admission. Binary logistic regression was used to assess the association between clinical variables and acute head CT findings and between clinical variables and hospital admission. Of the 253 patients who presented with dizziness, 7.1% had head CT scans with acutely abnormal findings, and 18.6% were admitted. Of the 236 patients who presented with syncope or near-syncope, 6.4% had head CT scans with acutely abnormal findings, and 39.8% were admitted. The following three clinical factors were found to be significantly correlated with acutely abnormal head CT findings: a focal neurologic deficit (p = 0.003), age greater than 60 years (p = 0.011), and acute head trauma (p = 0.026). Our results suggest that most patients presenting with syncope or dizziness to the emergency department may not benefit from head CT unless they are older, have a focal neurologic deficit, or have a history of recent head trauma.

The role of 99Tcm-HMPAO brain SPET in paediatric traumatic brain injury.

PubMed

Goshen, E; Zwas, S T; Shahar, E; Tadmor, R

1996-05-01

Twenty-eight paediatric patients suffering from chronic sequelae of traumatic brain injury (TBI) were examined by EEG, radionuclide imaging with 99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO), computed tomography (CT) and, when available, magnetic resonance imaging (MRI), the results of which were evaluated retrospectively. Our findings indicate that neuro-SPET (single photon emission tomography) with 99Tcm-HMPAO is more sensitive than morphological or electrophysiological tests in detecting functional lesions. In our group, 15 of 32 CT scans were normal, compared with 3 of 35 SPET studies. SPET identified approximately 2.5 times more lesions than CT (86 vs 34). SPET was found to be particularly sensitive in detecting organic abnormalities in the basal ganglia and cerebellar regions, with a 3.6:1 detection rate in the basal ganglia and a 5:1 detection rate in the cerebellum compared with CT. In conclusion, neuro-SPET appears to be very useful when evaluating paediatric post-TBI patients in whom other modalities are not successful.

Tomographic image reconstruction using x-ray phase information

NASA Astrophysics Data System (ADS)

Momose, Atsushi; Takeda, Tohoru; Itai, Yuji; Hirano, Keiichi

1996-04-01

We have been developing phase-contrast x-ray computed tomography (CT) to make possible the observation of biological soft tissues without contrast enhancement. Phase-contrast x-ray CT requires for its input data the x-ray phase-shift distributions or phase-mapping images caused by an object. These were measured with newly developed fringe-scanning x-ray interferometry. Phase-mapping images at different projection directions were obtained by rotating the object in an x-ray interferometer, and were processed with a standard CT algorithm. A phase-contrast x-ray CT image of a nonstained cancerous tissue was obtained using 17.7 keV synchrotron x rays with 12 micrometer voxel size, although the size of the observation area was at most 5 mm. The cancerous lesions were readily distinguishable from normal tissues. Moreover, fine structures corresponding to cancerous degeneration and fibrous tissues were clearly depicted. It is estimated that the present system is sensitive down to a density deviation of 4 mg/cm3.

Multi-organ segmentation from multi-phase abdominal CT via 4D graphs using enhancement, shape and location optimization.

PubMed

Linguraru, Marius George; Pura, John A; Chowdhury, Ananda S; Summers, Ronald M

2010-01-01

The interpretation of medical images benefits from anatomical and physiological priors to optimize computer-aided diagnosis (CAD) applications. Diagnosis also relies on the comprehensive analysis of multiple organs and quantitative measures of soft tissue. An automated method optimized for medical image data is presented for the simultaneous segmentation of four abdominal organs from 4D CT data using graph cuts. Contrast-enhanced CT scans were obtained at two phases: non-contrast and portal venous. Intra-patient data were spatially normalized by non-linear registration. Then 4D erosion using population historic information of contrast-enhanced liver, spleen, and kidneys was applied to multi-phase data to initialize the 4D graph and adapt to patient specific data. CT enhancement information and constraints on shape, from Parzen windows, and location, from a probabilistic atlas, were input into a new formulation of a 4D graph. Comparative results demonstrate the effects of appearance and enhancement, and shape and location on organ segmentation.

Pitfalls in 16-detector row CT of the coronary arteries.

PubMed

Nakanishi, Tadashi; Kayashima, Yasuyo; Inoue, Rintaro; Sumii, Kotaro; Gomyo, Yukihiko

2005-01-01

Recently developed 16-detector row computed tomography (CT) has been introduced as a reliable noninvasive imaging modality for evaluating the coronary arteries. In most cases, with appropriate premedication that includes beta-blockers and nitroglycerin, ideal data sets can be acquired from which to obtain excellent-quality coronary CT angiograms, most often with multiplanar reformation, thin-slab maximum intensity projection, and volume rendering. However, various artifacts associated with data creation and reformation, postprocessing methods, and image interpretation can hamper accurate diagnosis. These artifacts can be related to pulsation (nonassessable segments, pseudostenosis) as well as rhythm disorders, respiratory issues, partial volume averaging effect, high-attenuation entities, inappropriate scan pitch, contrast material enhancement, and patient body habitus. Some artifacts have already been resolved with technical advances, whereas others represent partially inherent limitations of coronary CT angiography. Familiarity with the pitfalls of coronary angiography with 16-detector row CT, coupled with the knowledge of both the normal anatomy and anatomic variants of the coronary arteries, can almost always help radiologists avoid interpretive errors in the diagnosis of coronary artery stenosis. (c) RSNA, 2005.

The effect of respiratory motion on pulmonary nodule location during electromagnetic navigation bronchoscopy.

PubMed

Chen, Alexander; Pastis, Nicholas; Furukawa, Brian; Silvestri, Gerard A

2015-05-01

Electromagnetic navigation has improved the diagnostic yield of peripheral bronchoscopy for pulmonary nodules. For these procedures, a thin-slice chest CT scan is performed prior to bronchoscopy at full inspiration and is used to create virtual airway reconstructions that are used as a map during bronchoscopy. Movement of the lung occurs with respiratory variation during bronchoscopy, and the location of pulmonary nodules during procedures may differ significantly from their location on the initial planning full-inspiratory chest CT scan. This study was performed to quantify pulmonary nodule movement from full inspiration to end-exhalation during tidal volume breathing in patients undergoing electromagnetic navigation procedures. A retrospective review of electromagnetic navigation procedures was performed for which two preprocedure CT scans were performed prior to bronchoscopy. One CT scan was performed at full inspiration, and a second CT scan was performed at end-exhalation during tidal volume breathing. Pulmonary lesions were identified on both CT scans, and distances between positions were recorded. Eighty-five pulmonary lesions were identified in 46 patients. Average motion of all pulmonary lesions was 17.6 mm. Pulmonary lesions located in the lower lobes moved significantly more than upper lobe nodules. Size and distance from the pleura did not significantly impact movement. Significant movement of pulmonary lesions occurs between full inspiration and end-exhalation during tidal volume breathing. This movement from full inspiration on planning chest CT scan to tidal volume breathing during bronchoscopy may significantly affect the diagnostic yield of electromagnetic navigation bronchoscopy procedures.

Evaluation of diagnostic value of CT scan, physical examination and ultrasound based on pathological findings in patients with pelvic masses.

PubMed

Firoozabadi, Razieh Dehghani; Karimi Zarchi, Mojgan; Mansurian, Hamid Reza; Moghadam, Bita Rafiei; Teimoori, Soraya; Naseri, Ali

2011-01-01

Because benign and malignant cervical and ovarian masses occur with different percentages in different age groups, the importance of primary diagnosis and selection of a suitable surgical procedure is underlined. Diagnosis of pelvic masses is carried out using ultrasound, physical examination, CT scan and MRI. The objective of this study is to evaluate the diagnostic value of CT scan in pelvic masses in comparison with physical examination-ultrasound based on pathology of the lesion in patients undergoing laparotomic surgery. This analytic-descriptive study focused on age, sonographic findings, physical examinations, CT scan and pathological findings in 139 patients with pelvic mass, gathered with questionnaires and statistically analayzed using the SPSS software programme. Of 139 patients with pelvic mass (patients aged from 17 to 75 years old), 62 (44%) cases were diagnosed as benign and 77 (55.4%) as malignant; among them malignant tratoma serocyst adenocarsinoma with 33 (23.7%) cases and benign myoma with 21 (15.2%) cases comprised the most frequent cases. The sensitivity and specificity of sonography-physical examination were 51.9% and 87.9% respectively and the sensitivity and specificity of CT scan images were 79.2% and 91.6% respectively. It was shown that CT scan images were more consistant with pathological findings in predicting appropriate surgical procedures than do sonography-physical examinations. The sensitivity of CT scan is far higher than that of sonography-physical examination in the diagnosis of pelvic mass malignancy.

Use of multidetector-row computed tomography scan to detect pannus formation in prosthetic mechanical aortic valves

PubMed Central

Aladmawi, Mohamed A.; Vriz, Olga; Galzerano, Domenico

2017-01-01

Obstruction of a mechanical aortic valve by pannus formation at the subvalvular level is a major long-term complication of aortic valve replacement (AVR). In fact, pannus is sometime difficult to differentiate from patient-prosthesis mismatch or valve thrombosis. In most cases cine-angiography and echocardiography, either transthoracic or transesophageal, cannot correctly visualize the complication when the leaflets show a normal mobility. Recent technological refinements made this difficult diagnosis possible by ECG-gated computed tomography (CT) scan which shows adequate images in 90% of the cases and can differentiate pannus from fresh and organized thrombus. PMID:28540078

Choroidal Haller's and Sattler's Layers Thickness in Normal Indian Eyes.

PubMed

Roy, Rupak; Saurabh, Kumar; Vyas, Chinmayi; Deshmukh, Kaustubh; Sharma, Preeti; Chandrasekharan, Dhileesh P; Bansal, Aditya

2018-01-01

This study aims to study normative choroidal thickness (CT) and Haller's and Sattler's layers thickness in normal Indian eyes. The choroidal imaging of 73 eyes of 43 healthy Indian individuals was done using enhanced depth imaging feature of spectralis optical coherence tomography. Rraster scan protocol centered at fovea was used for imaging separately by two observers. CT was defined as the length of the perpendicular line drown from the outer border of hypereflective RPE-Bruch's complex to inner margin of choroidoscleral junction. Choroidal vessel layer thickness was measured after defining a largest choroidal vessel lumen within 750 μ on either side of the subfoveal CT vector. A perpendicular line was drawn to the innermost border of this lumen, and the distance between the perpendicular line and innermost border of choroidoscleral junction gave large choroidal vessel layer thickness (LCVLT, Haller's layer). Medium choroidal vessel layer thickness (MCVLT, Sattler's layer) was measured as the distance between same perpendicular line and outer border of hypereflective RPE-Bruch's complex. The mean age of individuals was 28.23 ± 15.29 years (range 14-59 years). Overall, the mean subfoveal CT was 331.6 ± 63.9 μ. Mean LCVLT was 227.08 ± 51.24 μ and the mean MCVLT was 95.65 ± 23.62 μ. CT was maximum subfoveally with gradual reduction in the thickness as the distance from the fovea increased. This is the first study describing the choroidal sublayer thickness, i.e., Haller's and Sattler's layer thickness along with CT in healthy Indian population.

Choroidal Haller's and Sattler's Layers Thickness in Normal Indian Eyes

PubMed Central

Roy, Rupak; Saurabh, Kumar; Vyas, Chinmayi; Deshmukh, Kaustubh; Sharma, Preeti; Chandrasekharan, Dhileesh P.; Bansal, Aditya

2018-01-01

AIM: This study aims to study normative choroidal thickness (CT) and Haller's and Sattler's layers thickness in normal Indian eyes. MATERIALS AND METHODS: The choroidal imaging of 73 eyes of 43 healthy Indian individuals was done using enhanced depth imaging feature of spectralis optical coherence tomography. Rraster scan protocol centered at fovea was used for imaging separately by two observers. CT was defined as the length of the perpendicular line drown from the outer border of hypereflective RPE-Bruch's complex to inner margin of choroidoscleral junction. Choroidal vessel layer thickness was measured after defining a largest choroidal vessel lumen within 750 μ on either side of the subfoveal CT vector. A perpendicular line was drawn to the innermost border of this lumen, and the distance between the perpendicular line and innermost border of choroidoscleral junction gave large choroidal vessel layer thickness (LCVLT, Haller's layer). Medium choroidal vessel layer thickness (MCVLT, Sattler's layer) was measured as the distance between same perpendicular line and outer border of hypereflective RPE-Bruch's complex. RESULTS: The mean age of individuals was 28.23 ± 15.29 years (range 14–59 years). Overall, the mean subfoveal CT was 331.6 ± 63.9 μ. Mean LCVLT was 227.08 ± 51.24 μ and the mean MCVLT was 95.65 ± 23.62 μ. CT was maximum subfoveally with gradual reduction in the thickness as the distance from the fovea increased. CONCLUSION: This is the first study describing the choroidal sublayer thickness, i.e., Haller's and Sattler's layer thickness along with CT in healthy Indian population. PMID:29899646

Sensitivity and Specificity of Emergency Physicians and Trainees for Identifying Internally Concealed Drug Packages on Abdominal Computed Tomography Scan: Do Lung Windows Improve Accuracy?

PubMed

Asha, Stephen Edward; Cooke, Andrew

2015-09-01

Suspected body packers may be brought to emergency departments (EDs) close to international airports for abdominal computed tomography (CT) scanning. Senior emergency clinicians may be asked to interpret these CT scans. Missing concealed drug packages have important clinical and forensic implications. The accuracy of emergency clinician interpretation of abdominal CT scans for concealed drugs is not known. Limited evidence suggests that accuracy for identification of concealed packages can be increased by viewing CT images on "lung window" settings. To determine the accuracy of senior emergency clinicians in interpreting abdominal CT scans for concealed drugs, and to determine if this accuracy was improved by viewing scans on both abdominal and lung window settings. Emergency clinicians blinded to all patient identifiers and the radiology report interpreted CT scans of suspected body packers using standard abdominal window settings and then with the addition of lung window settings. The reference standard was the radiologist's report. Fifty-five emergency clinicians reported 235 CT scans. The sensitivity, specificity, and accuracy of interpretation using abdominal windows was 89.9% (95% confidence interval [CI] 83.0-94.7), 81.9% (95% CI 73.7-88.4), and 86.0% (95% CI 81.5-90.4), respectively, and with both window settings was 94.1% (95% CI 88.3-97.6), 76.7% (95% CI 68.0-84.1), 85.5% (95% CI 81.0-90.0), respectively. Diagnostic accuracy was similar regardless of the clinician's experience. Interrater reliability was moderate (kappa 0.46). The accuracy of interpretation of abdominal CT scans performed for the purpose of detecting concealed drug packages by emergency clinicians is not high enough to safely discharge these patients from the ED. The use of lung windows improved sensitivity, but at the expense of specificity. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

[Mobile CT: technical aspects of prehospital stroke imaging before intravenous thrombolysis].

PubMed

Gierhake, D; Weber, J E; Villringer, K; Ebinger, M; Audebert, H J; Fiebach, J B

2013-01-01

To reduce the time from symptom onset to treatment with tissue plasminogen activator (tPA) in ischemic stroke, an ambulance was equipped with a CT scanner. We analyzed process and image quality of CT scanning during the pilot study regarding image quality and safety issues. The pilot study of a stroke emergency mobile unit (STEMO) ran over a period of 12 weeks on 5 weekdays from 7a.m. to 6:30 p.m. A teleradiological service for the justifying indication and reporting was established. The radiographer was responsible for the performance of the CT scan on the ambulance. 64 cranial CT scans and 1 intracranial CT angiography were performed. We compared times from ambulance alarm to treatment decision (time of last brain scan) with a cohort of 50 consecutive tPA treatments before implementation of STEMO. 62 (95%) of the 65 scans performed had sufficient quality for reading. Technical quality was not optimal in 45 cases (69%) mainly caused by suboptimal positioning of patient or eye lens protection. Motion artefacts were observed in 8 exams (12%). No safety issues occurred for team or patients. 23 patients were treated with thrombolysis. Time from alarm to last CT scan was 18 minutes shorter than in the tPA cohort before STEMO implementation. A teleradiological support for primary stroke imaging by CT on-site is feasible, quality-wise of diagnostic value and has not raised safety issues. © Georg Thieme Verlag KG Stuttgart · New York.

The prevalence of sarcopenia in patients with respiratory failure classified as normally nourished using computed tomography and subjective global assessment.

PubMed

Sheean, Patricia M; Peterson, Sarah J; Gomez Perez, Sandra; Troy, Karen L; Patel, Ankur; Sclamberg, Joy S; Ajanaku, Folabomi C; Braunschweig, Carol A

2014-09-01

Declines in nutrition status and adverse body composition changes frequently occur in the critically ill. The objective of this cross-sectional study was to examine the prevalence of sarcopenia and its occurrence in patients classified as normal nourished using subjective global assessment (SGA). Exploiting diagnostic CT images, skeletal muscle mass at the L3 region was quantified and used to determine sarcopenia and its association with normal nutrition status in 56 patients with respiratory failure. Sarcopenia was defined as an L3 skeletal muscle index of ≤38.5 cm(2)/m(2) for women and ≤52.4 cm(2)/m(2) for men. CT imaging and SGA classifications completed within 14, 10 and 7 days of each other were analyzed to assess sarcopenia and the influence of time between scans on misclassification (ie, normal nourished and sarcopenic). Descriptive statistics were conducted. The average patient was 59.2 (± 15.6) years old, admitted with sepsis/infection, an APACHE II score of 26 (± 8.0), and BMI of 28.3 (± 5.8). Sarcopenia and sarcopenic obesity were prevalent in a minimum of 56% and 24% of patients, respectively, depending on the number of days between CT imaging and SGA assessment. Misclassified individuals were predominantly male, minority and overweight or obese. Controlling for age, no significant differences were noted for patients classified as normal nourished vs malnourished by SGA for lumbar muscle cross-sectional, whole-body lean mass, or skeletal muscle index. Sarcopenia is highly prevalent among patients with respiratory failure requiring mechanical ventilation (MV) and not readily detected in patients classified as normal nourished using SGA. © 2013 American Society for Parenteral and Enteral Nutrition.

CT biliary cystoscopy of gallbladder polyps

PubMed Central

Lou, Ming-Wu; Hu, Wei-Dong; Fan, Yi; Chen, Jin-Hua; E, Zhan-Sen; Yang, Guang-Fu

2004-01-01

AIM: CT virtual endoscopy has been used in the study of various organs of body including the biliary tract, however, CT virtual endoseopy in diagnosis of gallbladder polyps has not yet been reported. This study was to evaluate the diagnostic value of CT virtual endoscopy in polyps of the gallbladder. METHODS: Thirty-two cases of gallbladder polyps were examined by CT virtual endoscopy, ultrasound, CT scan with oral biliary contrast separately and confirmed by operation and pathology. CT biliary cystoscopic findings were analyzed and compared with those of ultrasound and CT scan with oral biliary contrast, and evaluated in comparison with operative and pathologic findings in all cases. RESULTS: The detection rate of gallbladder polyps was 93.8%(90/96), 96.9%(93/96) and 79.2%(76/96) for CT cystoscopy, ultrasound and CT scan with oral contrast, respectively. CT biliary cystoscopy corresponded well with ultrasound as well as pathology in demonstrating the location, size and configuration of polyps. CT endoscopy was superior to ultrasound in viewing the polyps in a more precise way, 3 dimensionally from any angle in space, and showing the surface in details. CT biliary cystoscopy was also superior to CT scan with oral biliary contrast in terms of observation of the base of polyps for the presence of a pedicle, detection rates as well as image quality. The smallest polyp detected by CT biliary cystoscopy was measured 1.5 mm×2.2 mm×2.5 mm. CONCLUSION: CT biliary cystoscopy is a non-invasive and accurate technique for diagnosis and management of gallbladder polyps. PMID:15069726

Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Claus; Liu Tianxiao; Jennelle, Richard L.

The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her originalmore » kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive dental artifacts.« less

Liver perfusion imaging in patients with primary and metastatic liver malignancy: prospective comparison between 99mTc-MAA spect and dynamic CT perfusion.

PubMed

Reiner, Caecilia S; Goetti, Robert; Burger, Irene A; Fischer, Michael A; Frauenfelder, Thomas; Knuth, Alexander; Pfammatter, Thomas; Schaefer, Niklaus; Alkadhi, Hatem

2012-05-01

To prospectively analyze the correlation between parameters of liver perfusion from technetium99m-macroaggregates of albumin (99mTc-MAA) single photon emission computed tomography (SPECT) with those obtained from dynamic CT perfusion in patients with primary or metastatic liver malignancy. Twenty-five consecutive patients (11 women, 14 men; mean age 60.9 ± 10.8; range: 32-78 years) with primary (n = 5) or metastatic (n = 20) liver malignancy planned to undergo selective internal radiotherapy underwent dynamic contrast-enhanced CT liver perfusion imaging (four-dimensional spiral mode, scan range 14.8 cm, 15 scans, cycle time 3 seconds) and 99m)Tc-MAA SPECT after intraarterial injection of 180 MBq 99mTc-MAA on the same day. Data were evaluated by two blinded and independent readers for the parameters arterial liver perfusion (ALP), portal venous perfusion (PVP), and total liver perfusion (TLP) from CT, and the 99mTc-MAA uptake-ratio of tumors in relation to normal liver parenchyma from SPECT. Interreader agreements for quantitative perfusion parameters were high for dynamic CT (r = 0.90-0.98, each P < .01) and 99mTc -MAA SPECT (r = 0.91, P < .01). Significant correlation was found between 99mTc-MAA uptake ratio and ALP (r = 0.7, P < .01) in liver tumors. No significant correlation was found between 99mTc-MAA uptake ratio, PVP (r = -0.381, P = .081), and TLP (r = 0.039, P = .862). This study indicates that in patients with primary and metastatic liver malignancy, ALP obtained by dynamic CT liver perfusion significantly correlates with the 99mTc-MAA uptake ratio obtained by SPECT. Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.

Bronchoscopy in the investigation of outpatients with hemoptysis at a lung cancer clinic.

PubMed

Arooj, Parniya; Bredin, Emily; Henry, Michael T; Khan, Kashif A; Plant, Barry J; Murphy, Desmond M; Kennedy, Marcus P

2018-06-01

In the investigation of lung cancer, current practice in many healthcare systems would support bronchoscopy regardless of CT findings in patients with hemoptysis. We sought to identify the cause, the diagnostic yield of CT and bronchoscopy and the requirement for bronchoscopy in at risk patients with hemoptysis with a normal CT scan through our rapid access lung cancer clinic (RALC). Initially, a chart review was performed on all patients with hemoptysis (2011-2012) and thereafter a prospective analysis was performed (2013-2016). Our analysis represents the largest study to date in outpatients with hemoptysis. In our retrospective study, 155 patients reported hemoptysis. Causes were lower respiratory tract infections (RTIs) (47%) and lung cancer (16%). Our prospective study included 182 patients. The causes of hemoptysis were RTIs (50%) and lung cancer (18%). There were no false negative CT-scans for lung cancer. 47/57 present with lung cancer underwent bronchoscopy and 43/47 were positive for lung cancer (92%). Patients with hemoptysis and lung cancer have a higher stage of malignancy with a predominance of squamous cell lung carcinoma. Smoking status, the duration of hemoptysis or description of hemoptysis were not predictive of lung cancer however lung cancer was not identified in patients age <50. One sixth of patients presenting with hemoptysis to our lung cancer clinic had lung cancer. No patient identified with cancer related haemoptysis had a CT negative for lung cancer and a combination of bronchoscopy plus endobronchial ultrasound trans-bronchial needle aspiration (EBUS-TBNA) in those patients with a CT suspicious of lung cancer is 92% sensitive for lung cancer causing hemoptysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey.

PubMed

Martin, Matthew J; Bush, Lisa D; Inaba, Kenji; Byerly, Saskya; Schreiber, Martin; Peck, Kimberly A; Barmparas, Galinos; Menaker, Jay; Hazelton, Joshua P; Coimbra, Raul; Zielinski, Martin D; Brown, Carlos V R; Ball, Chad G; Cherry-Bukowiec, Jill R; Burlew, Clay Cothren; Dunn, Julie; Minshall, C Todd; Carrick, Matthew M; Berg, Gina M; Demetriades, Demetrios; Long, William

2017-12-01

Intoxication often prevents clinical clearance of the cervical spine (Csp) after trauma leading to prolonged immobilization even with a normal computed tomography (CT) scan. We evaluated the accuracy of CT at detecting clinically significant Csp injury, and surveyed participants on related opinions and practice. A prospective multicenter study (2013-2015) at 17 centers. All adult blunt trauma patients underwent structured clinical examination and imaging including a Csp CT, with follow-up thru discharge. alcohol- and drug-intoxicated patients (TOX+) were identified by serum and/or urine testing. Primary outcomes included the incidence and type of Csp injuries, the accuracy of CT scan, and the impact of TOX+ on the time to Csp clearance. A 36-item survey querying local protocols, practices, and opinions in the TOX+ population was administered. Ten thousand one hundred ninety-one patients were prospectively enrolled and underwent CT Csp during the initial trauma evaluation. The majority were men (67%), had vehicular trauma or falls (83%), with mean age of 48 years, and mean Injury Severity Score (ISS) of 11. The overall incidence of Csp injury was 10.6%. TOX+ comprised 30% of the cohort (19% EtOH only, 6% drug only, and 5% both). TOX+ were significantly younger (41 years vs. 51 years; p < 0.01) but with similar mean Injury Severity Score (11) and Glasgow Coma Scale score (13). The TOX+ cohort had a lower incidence of Csp injury versus nonintoxicated (8.4% vs. 11.5%; p < 0.01). In the TOX+ group, CT had a sensitivity of 94%, specificity of 99.5%, and negative predictive value (NPV) of 99.5% for all Csp injuries. For clinically significant injuries, the NPV was 99.9%, and there were no unstable Csp injuries missed by CT (NPV, 100%). When CT Csp was negative, TOX+ led to longer immobilization versus sober patients (mean, 8 hours vs. 2 hours; p < 0.01), and prolonged immobilization (>12 hrs) in 25%. The survey showed marked variations in protocols, definitions, and Csp clearance practices among participating centers, although 100% indicated willingness to change practice based on these data. For intoxicated patients undergoing Csp imaging, CT scan was highly accurate and reliable for identifying clinically significant spine injuries, and had a 100% NPV for identifying unstable injuries. CT-based clearance in TOX+ patients appears safe and may avoid unnecessary prolonged immobilization. There was wide disparity in practices, definitions, and opinions among the participating centers. Diagnostic tests or criteria, level II.

Accuracy of iodine quantification using dual energy CT in latest generation dual source and dual layer CT.

PubMed

Pelgrim, Gert Jan; van Hamersvelt, Robbert W; Willemink, Martin J; Schmidt, Bernhard T; Flohr, Thomas; Schilham, Arnold; Milles, Julien; Oudkerk, Matthijs; Leiner, Tim; Vliegenthart, Rozemarijn

2017-09-01

To determine the accuracy of iodine quantification with dual energy computed tomography (DECT) in two high-end CT systems with different spectral imaging techniques. Five tubes with different iodine concentrations (0, 5, 10, 15, 20 mg/ml) were analysed in an anthropomorphic thoracic phantom. Adding two phantom rings simulated increased patient size. For third-generation dual source CT (DSCT), tube voltage combinations of 150Sn and 70, 80, 90, 100 kVp were analysed. For dual layer CT (DLCT), 120 and 140 kVp were used. Scans were repeated three times. Median normalized values and interquartile ranges (IQRs) were calculated for all kVp settings and phantom sizes. Correlation between measured and known iodine concentrations was excellent for both systems (R = 0.999-1.000, p < 0.0001). For DSCT, median measurement errors ranged from -0.5% (IQR -2.0, 2.0%) at 150Sn/70 kVp and -2.3% (IQR -4.0, -0.1%) at 150Sn/80 kVp to -4.0% (IQR -6.0, -2.8%) at 150Sn/90 kVp. For DLCT, median measurement errors ranged from -3.3% (IQR -4.9, -1.5%) at 140 kVp to -4.6% (IQR -6.0, -3.6%) at 120 kVp. Larger phantom sizes increased variability of iodine measurements (p < 0.05). Iodine concentration can be accurately quantified with state-of-the-art DECT systems from two vendors. The lowest absolute errors were found for DSCT using the 150Sn/70 kVp or 150Sn/80 kVp combinations, which was slightly more accurate than 140 kVp in DLCT. • High-end CT scanners allow accurate iodine quantification using different DECT techniques. • Lowest measurement error was found in scans with largest photon energy separation. • Dual-source CT quantified iodine slightly more accurately than dual layer CT.

Development of a diagnostic system for bilirubin detection in cerebral spinal fluid

NASA Astrophysics Data System (ADS)

Bhadri, Prashant R.; Salgaonkar, Vasant A.; Majumdar, Anindya; Morgan, Chad J.; Zuccarello, Mario; Pyne, Gail J.; Dulaney, Elizabeth; Caffery, James, Jr.; Shukla, Rakesh; Beyette, Fred R., Jr.

2004-11-01

A weakened portion of an artery in the brain leads to a medical condition known as a cerebral aneurysm. A subarachnoid hemorrhage (SAH) occurs when an aneurysm ruptures. For those individuals suspected of having a SAH, a computerized tomography (CT) scan of the brain usually demonstrates evidence of the bleeding. However, in a considerable portion of people, the CT scan is unable to detect the blood that has escaped from the blood vessel. Recent studies have indicated nearly 30% of patients with a SAH are initially misdiagnosed. For circumstances when a SAH is suspected despite a normal CT scan, physicians make the diagnosis of SAH by performing a spinal tap. A spinal tap uses a needle to sample the cerebrospinal fluid (CSF) collected from the patient"s lumbar spine. However, it is also possible for blood to be introduced into the CSF as a result of the spinal tap procedure. Therefore, an effective solution is required to help medical personnel differentiate between the blood that results from a tap and that from a ruptured aneurysm. In this paper, the development of a prototype is described which is sensitive and specific for measuring bilirubin in CSF, hemorrhagic-CSF and CSF-like solutions. To develop this instrument a combination of spectrophotometric analysis, custom data analysis software and other hardware interfaces are assembled that lay the foundation for the development of portable and user-friendly equipment suitable for assisting trained medical personnel with the diagnosis of a ruptured cerebral aneurysm.

Relative hypotension increases the probability of the need for angioembolisation in pelvic fracture patients without contrast extravasation on computed tomography scan.

PubMed

Kuo, Ling-Wei; Yang, Shang-Ju; Fu, Chih-Yuan; Liao, Chien-Hung; Wang, Shang-Yu; Wu, Shih-Chi

2016-01-01

In the evaluation of haemorrhage in trauma patients with pelvic fractures, contrast extravasation (CE) on computed tomography (CT) scan often implies active arterial bleeding. However, the absence of CE on CT scan does not always exclude the need for transcatheter arterial embolisation (TAE) to achieve haemostasis. In the current study, we evaluated the factors associated with the need for TAE in patients without CE on CT scan. These factors may be evaluated as adjuncts to CT scanning in the management of patients with pelvic fractures. We retrospectively reviewed our trauma registry and medical records of patients with pelvic fractures. When CE was observed, indicating active haemorrhage, the patients underwent TAE to achieve haemostasis. In contrast, patients without CE were held for observation and treatment of their injuries, and if their condition deteriorated after a delayed interval, they were then also referred for TAE if no other focus of haemorrhage was found. Patients without CE on CT scan but with retroperitoneal haemorrhage requiring TAE were investigated. Their demographic characteristics, associated injuries, fracture patterns, and changes in systolic blood pressure were described and analysed. In total, 201 patients with pelvic fracture underwent CT scan examination; 47 (23.4%) had CE by CT scan, whereas the other 154 (76.6%) did not. Of the 154 patients who did not show CE by CT scan, 124 (80.5%) patients never underwent TAE; however, 30 (19.5%) of these patients did eventually undergo TAE. In comparing the patients who underwent TAE to those who did not undergo TAE among patients without CE on CT scan, the systolic blood pressure (SBP) on arrival (median: 100.0 mmHg vs 136.0 mmHg, p<0.01) and the lowest SBP recorded in the ED (median: 68.0 mmHg vs 129.0 mmHg, p<0.01) were significantly lower in the patients who underwent TAE. The ROC curve analysis revealed that the most appropriate cutoff value of decrement of SBP (SBP on arrival minus the lowest SBP in the ED) was 30 mmHg (AUC=0.89). In the management of pelvic fracture patients, greater attention should be directed toward patients with relative hypotension. The higher likelihood of haemodynamic deterioration and the need for TAE for haemorrhage control should remain under consideration in such cases, despite the absence of CE by CT scan. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thyroglobulin levels and thyroglobulin doubling time independently predict a positive 18F-FDG PET/CT scan in patients with biochemical recurrence of differentiated thyroid carcinoma.

PubMed

Giovanella, Luca; Trimboli, Pierpaolo; Verburg, Frederik A; Treglia, Giorgio; Piccardo, Arnoldo; Foppiani, Luca; Ceriani, Luca

2013-06-01

To assess the relationship between serum thyroglobulin (Tg) levels, Tg doubling time (Tg-DT) and the diagnostic performance of (18)F-FDG PET/CT in detecting recurrences of (131)I-negative differentiated thyroid carcinoma (DTC). Included in the present study were 102 patients with DTC. All patients were treated by thyroid ablation (e.g. thyroidectomy and (131)I), and underwent (18)F-FDG PET/CT due to detectable Tg levels and negative conventional imaging. Consecutive serum Tg measurements performed before the (18)F-FDG PET/CT examination were used for Tg-DT calculation. The (18)F-FDG PET/CT results were assessed as true or false after histological and/or clinical follow-up. Serum Tg levels were higher in patients with a positive (18)F-FDG PET/CT scan (median 6.7 ng/mL, range 0.7-73.6 ng/mL) than in patients with a negative scan (median 1.8 ng/mL, range 0.5-4.9 ng/mL; P < 0.001). In 43 (88 %) of 49 patients with a true-positive (18)F-FDG PET/CT scan, the Tg levels were >5.5 ng/mL, and in 31 (74 %) of 42 patients with a true-negative (18)F-FDG PET/CT scan, the Tg levels were ≤5.5 ng/mL. A Tg-DT of <1 year was found in 46 of 49 patients (94 %) with a true-positive (18)F-FDG PET/CT scan, and 40 of 42 patients (95 %) with a true-negative scan had a stable or increased Tg-DT. Moreover, combining Tg levels and Tg-DT as selection criteria correctly distinguished between patients with a positive and a negative scan (P<0.0001). The accuracy of (18)F-FDG PET/CT significantly improves when the serum Tg level is above 5.5 ng/mL during levothyroxine treatment or when the Tg-DT is less than 1 year, independent of the absolute value.

A survey of emergency physicians' fear of malpractice and its association with the decision to order computed tomography scans for children with minor head trauma.

PubMed

Wong, Andrew C; Kowalenko, Terry; Roahen-Harrison, Stephanie; Smith, Barbara; Maio, Ronald F; Stanley, Rachel M

2011-03-01

The objective of the study was to determine whether fear of malpractice is associated with emergency physicians' decision to order head computed tomography (CT) in 3 age-specific scenarios of pediatric minor head trauma. We hypothesized that physicians with higher fear of malpractice scores will be more likely to order head CT scans. Board-eligible/board-certified members of the Michigan College of Emergency Physicians were sent a 2-part survey consisting of case scenarios and demographic questions. Effect of fear of malpractice on the decision to order a CT scan was evaluated using a cumulative logit model. Two hundred forty-six members (36.5%) completed the surveys. In scenario 1 (infant), being a male and working in a university setting were associated with reduced odds of ordering a CT scan (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.18-0.88; and OR, 0.35; 95% CI, 0.13-0.96, respectively). In scenario 2 (toddler), working for 15 years or more, at multiple hospitals, and for a private group were associated with reduced odds of ordering a CT scan (OR, 0.46; 95% CI, 0.26-0.79; OR, 0.36; 95% CI, 0.16-0.80; and OR, 0.51; 95% CI, 0.27-0.94, respectively). No demographic variables were significantly associated with ordering a CT scan in scenario 3 (teen). Overall, the fear of malpractice was not significantly associated with ordering a CT scan (OR, 1.28; 95% CI, 0.73-2.26; and OR, 1.70; 95% CI, 0.97-3.0). Only in scenario 2 was high fear significantly associated with increased odds of ordering a CT scan (OR, 2.09; 95% CI, 1.08-4.05). Members of Michigan College of Emergency Physicians with a higher fear of malpractice score tended to order more head CT scans in pediatric minor head trauma. However, this trend was shown to be statistically significant only in 1 case and not overall.

High pitch third generation dual-source CT: Coronary and Cardiac Visualization on Routine Chest CT

PubMed Central

Sandfort, Veit; Ahlman, Mark; Jones, Elizabeth; Selwaness, Mariana; Chen, Marcus; Folio, Les; Bluemke, David A.

2016-01-01

Background Chest CT scans are frequently performed in radiology departments but have not previously contained detailed depiction of cardiac structures. Objectives To evaluate myocardial and coronary visualization on high-pitch non-gated CT of the chest using 3rd generation dual-source computed tomography (CT). Methods Cardiac anatomy of patients who had 3rd generation, non-gated high pitch contrast enhanced chest CT and who also had prior conventional (low pitch) chest CT as part of a chest abdomen pelvis exam was evaluated. Cardiac image features were scored by reviewers blinded to diagnosis and pitch. Paired analysis was performed. Results 3862 coronary segments and 2220 cardiac structures were evaluated by two readers in 222 CT scans. Most patients (97.2%) had chest CT for oncologic evaluation. The median pitch was 2.34 (IQR 2.05, 2.65) in high pitch and 0.8 (IQR 0.8, 0.8) in low pitch scans (p<0.001). High pitch CT showed higher image visualization scores for all cardiovascular structures compared with conventional pitch scans (p<0.0001). Coronary arteries were visualized in 9 coronary segments per exam in high pitch scans versus 2 segments for conventional pitch (p<0.0001). Radiation exposure was lower in the high pitch group compared with the conventional pitch group (median CTDIvol 10.83 vs. 12.36 mGy and DLP 790 vs. 827 mGycm respectively, p <0.01 for both) with comparable image noise (p=0.43). Conclusion Myocardial structure and coronary arteries are frequently visualized on non-gated 3rd generation chest CT. These results raise the question of whether the heart and coronary arteries should be routinely interpreted on routine chest CT that is otherwise obtained for non-cardiac indications. PMID:27133589

Utility of CT in the diagnosis and management of small-bowel obstruction in children.

PubMed

Wang, Qiuyan; Chavhan, Govind B; Babyn, Paul S; Tomlinson, George; Langer, Jacob C

2012-12-01

CT is often used in the diagnosis and management of small-bowel obstruction in children. To determine sensitivity of CT in delineating presence, site and cause of small-bowel obstruction in children. We retrospectively reviewed the CT scans of 47 children with surgically proven small-bowel obstruction. We noted any findings of obstruction and the site and cause of obstruction. Presence, absence or equivocal findings of bowel obstruction on abdominal radiographs performed prior to CT were also noted. We reviewed patient charts for clinical details and surgical findings, including bowel resection. Statistical analysis was performed using Fisher exact test to determine which CT findings might predict bowel resection. CT correctly diagnosed small-bowel obstruction in 43/47 (91.5%) cases. CT correctly indicated site of obstruction in 37/47 (78.7%) cases and cause of obstruction in 32/47 (68.1%) cases. Small-bowel feces sign was significantly associated with bowel resection at surgery (P = 0.0091). No other CT finding was predictive of bowel resection. Out of 41 children who had abdominal radiographs before CT, 29 (70.7%) showed unequivocal obstruction, six (14.6%) showed equivocal findings and six (14.6%) were unremarkable. CT is highly sensitive in diagnosing small-bowel obstruction in children and is helpful in determining the presence of small-bowel obstruction in many clinically suspected cases with equivocal or normal plain radiographs. CT also helps to determine the site and cause of the obstruction with good sensitivity.

Are the studies on cancer risk from CT scans biased by indication? Elements of answer from a large-scale cohort study in France

PubMed Central

Journy, N; Rehel, J-L; Ducou Le Pointe, H; Lee, C; Brisse, H; Chateil, J-F; Caer-Lorho, S; Laurier, D; Bernier, M-O

2015-01-01

Background: Recent epidemiological results suggested an increase of cancer risk after receiving computed tomography (CT) scans in childhood or adolescence. Their interpretation is questioned due to the lack of information about the reasons for examination. Our objective was to estimate the cancer risk related to childhood CT scans, and examine how cancer-predisposing factors (PFs) affect assessment of the radiation-related risk. Methods: The cohort included 67 274 children who had a first scan before the age of 10 years from 2000 to 2010 in 23 French departments. Cumulative X-rays doses were estimated from radiology protocols. Cancer incidence was retrieved through the national registry of childhood cancers; PF from discharge diagnoses. Results: During a mean follow-up of 4 years, 27 cases of tumours of the central nervous system, 25 of leukaemia and 21 of lymphoma were diagnosed; 32% of them among children with PF. Specific patterns of CT exposures were observed according to PFs. Adjustment for PF reduced the excess risk estimates related to cumulative doses from CT scans. No significant excess risk was observed in relation to CT exposures. Conclusions: This study suggests that the indication for examinations, whether suspected cancer or PF management, should be considered to avoid overestimation of the cancer risks associated with CT scans. PMID:25314057

The presurgical workup before third molar surgery: how much is enough?

PubMed

Better, Hadar; Abramovitz, Itzhak; Shlomi, Biniamin; Kahn, Adrian; Levy, Yaakov; Shaham, Amit; Chaushu, Gavriel

2004-06-01

We sought to assess the indications for patient referral for computed tomography (CT) scan before third molar extraction. The influence of the data obtained from the CT scans on the surgical outcome and morbidity was also evaluated. There were 189 patients in the study (120 females and 69 males). Sixty-five patients were referred to receive CT and formed the study group. The remaining patients were included in the control group. There were no statistically significant differences between the groups with regard to demographic data and tooth and root angulations. Indications for tooth extraction such as pain, swelling, pericoronitis, caries, endodontic problems, pathology, and prosthetic considerations were similar. The proximity of the tooth root to the inferior alveolar canal was the only statistically significant difference between the 2 groups (P <.001). The treatment plan outcomes for extraction, surgical extraction, and follow-up were comparable. The surgeon changed the initial decision from "surgical extraction" to "follow-up" in only 1 case after CT scan. Within the limits of the present study, it can be concluded that the main reason for CT scan referral is the proximity of the third molar root to the inferior alveolar canal (<1 mm). The data obtained from the CT scan had minimal effect on the final surgical outcome. The routine use of CT scan in cases of third molar extractions cannot be recommended.

Relationship of brain imaging with radionuclides and with x-ray computed tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhl, D.E.

1981-03-03

Because of high sensitivity and specificity for altered local cerebral structure, x-ray computed tomography (CT) is the preferred initial diagnostic imaging study under most circumstances when cerebral disease is suspected. CT has no competitor for detecting fresh intracerebral hemorrhage. Radionuclide imaging (RN) scan is preferred when relative perfusion is to be assessed, in patients allergic to contrast media, and when an adequate CT study is not technically possible. (RN) plays an important complementary role to CT, especially for patients suspected of subacute or chronic subdura hematoma, cerebral infarction, arteriovenous malformations, meningitis, encephalitis, normal pressure hydrocephalus, or when CT findings aremore » inconclusive. When CT is not available, RN serves as a good screening study for suspected cerebral tumor, infection, recent infarction, arteriovenous malformation, and chronic subdural hematoma. Future improvement in radionuclide imaging by means of emission composition potential. The compound plating approacl threshold for all the investigated transistors and fast neutron spectra lies within the raal. The value of the potential slightly changes with the coordinate change in this region, i.e. the charge on a collecting electrode is not practically guided up to a certain moment of time during the movement of nonequilibrium carriers.« less

Mild brain injury and anticoagulants: Less is enough.

PubMed

Campiglio, Laura; Bianchi, Francesca; Cattalini, Claudio; Belvedere, Daniela; Rosci, Chiara Emilia; Casellato, Chiara Livia; Secchi, Manuela; Saetti, Maria Cristina; Baratelli, Elena; Innocenti, Alessandro; Cova, Ilaria; Gambini, Chiara; Romano, Luca; Oggioni, Gaia; Pagani, Rossella; Gardinali, Marco; Priori, Alberto

2017-08-01

Despite the higher theoretical risk of traumatic intracranial hemorrhage (ICH) in anticoagulated patients with mild head injury, the value of sequential head CT scans to identify bleeding remains controversial. This study evaluated the utility of 2 sequential CT scans at a 48-hour interval (CT1 and CT2) in patients with mild head trauma (Glasgow Coma Scale 13-15) taking oral anticoagulants. We retrospectively evaluated the clinical records of all patients on chronic anticoagulation treatment admitted to the emergency department for mild head injury. A total of 344 patients were included, and 337 (97.9%) had a negative CT1. CT2 was performed on 284 of the 337 patients with a negative CT1 and was positive in 4 patients (1.4%), but none of the patients developed concomitant neurologic worsening or required neurosurgery. Systematic routine use of a second CT scan in mild head trauma in patients taking anticoagulants is expensive and clinically unnecessary.

Childhood CT scans linked to leukemia and brain cancer later in life

Cancer.gov

Children and young adults scanned multiple times by computed tomography (CT), a commonly used diagnostic tool, have a small increased risk of leukemia and brain tumors in the decade following their first scan.

Utility of 18 F-FDG PET/CT scan to diagnose the etiology of fever of unknown origin in patients on dialysis.

PubMed

Tek Chand, Kalawat; Chennu, Krishna Kishore; Amancharla Yadagiri, Lakshmi; Manthri Gupta, Ranadheer; Rapur, Ram; Vishnubotla, Siva Kumar

2017-04-01

Studies on fever of unknown origin (FUO) in patients of chronic kidney disease and end stage renal disease patients on dialysis were not many. In this study, we used 18 F-FDG PET/CT scan whole body survey for detection of hidden infection, in patients on dialysis, labelled as FUO. In this retrospective study, 20 patients of end stage renal disease on dialysis were investigated for the cause of FUO using 18F-FDG PET/CT scan. All these patients satisfied the definition of FUO as defined by Petersdorf and Beeson. Any focal abnormal site of increased FDG concentration detected by PET/CT, either a solitary or multiple lesions was documented and at least one of the detected abnormal sites of radio tracer concentration was further examined for histopathology. All patients were on renal replacement therapy. Of these, 18 were on hemodialysis and two were on peritoneal dialysis. 18F-FDG PET/CT scan showed metabolically active lesions in 15 patients and metabolically quiescent in five patients. After 18F-FDG PET/CT scan all, but one patient had a change in treatment for fever. Anti-tuberculous treatment was given in 15 patients, antibiotics in four patients and anti-malaria treatment in one patient. The present study is first study of 18F-FDG PET/CT scan in patients of end stage renal disease on dialysis with FUO. The study showed that the 18 F FDG PET/CT scan may present an opportunity to attain the diagnosis in end stage renal disease patients on dialysis with FUO. © 2016 International Society for Hemodialysis.

Avoiding CT scans in children with single-suture craniosynostosis.

PubMed

Schweitzer, T; Böhm, H; Meyer-Marcotty, P; Collmann, H; Ernestus, R-I; Krauß, J

2012-07-01

During the last decades, computed tomography (CT) has become the predominant imaging technique in the diagnosis of craniosynostosis. In most craniofacial centers, at least one three-dimensional (3D) computed tomographic scan is obtained in every case of suspected craniosynostosis. However, with regard to the risk of radiation exposure particularly in young infants, CT scanning and even plain radiography should be indicated extremely carefully. Our current diagnostic protocol in the management of single-suture craniosynostosis is mainly based on careful clinical examination with regard to severity and degree of the abnormality and on ophthalmoscopic surveillance. Imaging techniques consist of ultrasound examination in young infants while routine plain radiographs are usually postponed to the date of surgery or the end of the first year. CT and magnetic resonance imaging (MRI) are confined to special diagnostic problems rarely encountered in isolated craniosynostosis. The results of this approach were evaluated retrospectively in 137 infants who were referred to our outpatient clinic for evaluation and/or treatment of suspected single suture craniosynostosis or positional deformity during a 2-year period (2008-2009). In 133 (97.1%) of the 137 infants, the diagnosis of single-suture craniosynostosis (n = 110) or positional plagiocephaly (n = 27) was achieved through clinical analysis only. Two further cases were classified by ultrasound, while the remaining two cases needed additional digital radiographs. In no case was CT scanning retrospectively considered necessary for establishing the diagnosis. Yet in 17.6% of cases, a cranial CT scan had already been performed elsewhere (n = 16) or had been definitely scheduled (n = 8). CT scanning is rarely necessary for evaluation of single-suture craniosynostosis. Taking into account that there is a quantifiable risk of developing cancer in further lifetime, every single CT scan should be carefully indicated.

Paediatric blunt abdominal trauma - are we doing too many computed tomography scans?

PubMed

Arnold, M; Moore, S W

2013-02-14

Blunt abdominal trauma in childhood contributes significantly to both morbidity and mortality. Selective non-operative management of blunt abdominal trauma in children depends on both diagnostic and clinical factors. Computed tomography (CT) scanning is widely used to facilitate better management. Increased availability of CT may, however, result in its overuse in the management of blunt abdominal trauma in children, which carries significant radiation exposure risks. To evaluate the use and value of CT scanning in the overall management and outcome of blunt abdominal trauma in children in the Tygerberg Academic Hospital trauma unit, Parow, Cape Town, South Africa, before and after improved access to CT as a result of installation of a new rapid CT scanner in the trauma management area (previously the scanner had been 4 floors away). Patients aged 0 - 13 years who were referred with blunt abdominal trauma due to vehicle-related accidents before the introduction of the new CT scanner (group 1, n=66, November 2003 - March 2009) were compared with those seen in the 1-year period after the scanner was installed (group 2, n=37, April 2009 - April 2010). Details of clinical presentation, imaging results and their influence on management were retrospectively reviewed. A follow-up group was evaluated after stricter criteria for abdominal CT scanning (viz. prior evaluation by paediatric surgical personnel) were introduced (group 3, n=14, November 2011 - May 2012) to evaluate the impact of this clinical screening on the rate of negative scans. There were 66 patients in group 1 and 37 in group 2. An apparent increase in CT use with increased availability was accompanied by a marked increase in negative CT scans (38.9% compared with 6.2%; p<0.006). Despite a slightly higher prevalence of associated injuries in group 2, as well as a slightly longer length of hospital stay, there was a similar prevalence of intra-abdominal injuries detected in positive scans in the two groups. In addition, rates of small-bowel perforation in the two groups were similar. The rate of negative scans in group 3 was 46.2% (6/13), but all except one of these patients had a severe brain injury preventing adequate clinical evaluation of intra-abdominal injury. CT scanning for blunt abdominal trauma in children is essential in the presence of appropriate clinical indications. Ease of access probably increases availability, but the rate of negative scans may increase. Management guidelines should be in place to direct CT scanning to cases in which clinical examination and/or other modalities indicate a likelihood of intra-abdominal injury. The principle of 'as low (radiation) dose as reasonably achievable' (ALARA) should be adhered to because of the increased radiation exposure risks in children.

Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

PubMed

Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

2018-05-01

We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some differences in texture details. Moreover, quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation indicate that the short- and half-scan configurations yield results in close agreement with the ground-truth information and that of the full-scan configuration. The one-step method considered can compensate effectively for the nonlinear spectral response in full- and partial-angular-scan dual-energy CT. It can be exploited for enabling partial-angular-scan configurations on standard CT scanner without involving additional hardware. Visual inspection and quantitative studies reveal that, with the one-step method, partial-angular-scan configurations considered can perform at a level comparable to that of the full-scan configuration, thus suggesting the potential of the two partial-angular-scan configurations in reducing imaging dose and scan time in the standard single-kVp-switch full-scan CT in which two full rotations are performed. The work also yields insights into the investigation and design of other nonstandard scan configurations of potential practical significance in dual-energy CT. © 2018 American Association of Physicists in Medicine.

Incidental findings in children with blunt head trauma evaluated with cranial CT scans.

PubMed

Rogers, Alexander J; Maher, Cormac O; Schunk, Jeff E; Quayle, Kimberly; Jacobs, Elizabeth; Lichenstein, Richard; Powell, Elizabeth; Miskin, Michelle; Dayan, Peter; Holmes, James F; Kuppermann, Nathan

2013-08-01

Cranial computed tomography (CT) scans are frequently obtained in the evaluation of blunt head trauma in children. These scans may detect unexpected incidental findings. The objectives of this study were to determine the prevalence and significance of incidental findings on cranial CT scans in children evaluated for blunt head trauma. This was a secondary analysis of a multicenter study of pediatric blunt head trauma. Patients <18 years of age with blunt head trauma were eligible, with those undergoing cranial CT scan included in this substudy. Patients with coagulopathies, ventricular shunts, known previous brain surgery or abnormalities were excluded. We abstracted radiology reports for nontraumatic findings. We reviewed and categorized findings by their clinical urgency. Of the 43,904 head-injured children enrolled in the parent study, 15,831 underwent CT scans, and these latter patients serve as the study cohort. On 670 of these scans, nontraumatic findings were identified, with 16 excluded due to previously known abnormalities or surgeries. The remaining 654 represent a 4% prevalence of incidental findings. Of these, 195 (30%), representing 1% of the overall sample, warranted immediate intervention or outpatient follow-up. A small but important number of children evaluated with CT scans after blunt head trauma had incidental findings. Physicians who order cranial CTs must be prepared to interpret incidental findings, communicate with families, and ensure appropriate follow-up. There are ethical implications and potential health impacts of informing patients about incidental findings.

Unenhanced 320-row multidetector computed tomography of the brain in children: comparison of image quality and radiation dose among wide-volume, one-shot volume, and helical scan modes.

PubMed

Jeon, Sun Kyung; Choi, Young Hun; Cheon, Jung-Eun; Kim, Woo Sun; Cho, Yeon Jin; Ha, Ji Young; Lee, Seung Hyun; Hyun, Hyejin; Kim, In-One

2018-04-01

The 320-row multidetector computed tomography (CT) scanner has multiple scan modes, including volumetric modes. To compare the image quality and radiation dose of 320-row CT in three acquisition modes - helical, one-shot volume, and wide-volume scan - at pediatric brain imaging. Fifty-seven children underwent unenhanced brain CT using one of three scan modes (helical scan, n=21; one-shot volume scan, n=17; wide-volume scan, n=19). For qualitative analysis, two reviewers evaluated overall image quality and image noise using a 5-point grading system. For quantitative analysis, signal-to-noise ratio, image noise and posterior fossa artifact index were calculated. To measure the radiation dose, adjusted CT dose index per unit volume (CTDI adj ) and dose length product (DLP) were compared. Qualitatively, the wide-volume scan showed significantly less image noise than the helical scan (P=0.009), and less streak artifact than the one-shot volume scan (P=0.001). The helical mode showed significantly lower signal-to-noise ratio, with a higher image noise level compared with the one-shot volume and wide-volume modes (all P<0.05). The CTDI adj and DLP were significantly lower in the one-shot volume and wide-volume modes compared with those in the helical scan mode (all P<0.05). For pediatric unenhanced brain CT, both the wide-volume and one-shot volume scans reduced radiation dose compared to the helical scan mode, while the wide-volume scan mode showed fewer streak artifacts in the skull vertex and posterior fossa than the one-shot volume scan.

Symptomatic Cerebral Vasospasm and Delayed Cerebral Ischemia Following Transsphenoidal Resection of a Craniopharyngioma.

PubMed

Ricarte, Irapuá Ferreira; Funchal, Bruno F; Miranda Alves, Maramélia A; Gomes, Daniela L; Valiente, Raul A; Carvalho, Flávio A; Silva, Gisele S

2015-09-01

Vasospasm has been rarely described as a complication associated with craniopharyngioma surgery. Herein we describe a patient who developed symptomatic vasospasm and delayed cerebral ischemia after transsphenoidal surgery for a craniopharyngioma. A 67-year-old woman became drowsy 2 weeks after a transsphenoidal resection of a craniopharyngioma. A head computed tomography (CT) was unremarkable except for postoperative findings. Electroencephalogram and laboratory studies were within the normal limits. A repeated CT scan 48 hours after the initial symptoms showed bilateral infarcts in the territory of the anterior cerebral arteries (ACA). Transcranial Doppler (TCD) showed increased blood flow velocities in both anterior cerebral arteries (169 cm/second in the left ACA and 145 cm/second in the right ACA) and right middle cerebral artery (164 cm/second) compatible with vasospasm. A CT angiography confirmed the findings. She was treated with induced hypertension and her level of consciousness improved. TCD velocities normalized after 2 weeks. Cerebral vasospasm should be considered in the differential diagnosis of patients with altered neurologic status in the postoperative period following a craniopharyngioma resection. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Medical imaging by fluorescent x-ray CT: its preliminary clinical evaluation

NASA Astrophysics Data System (ADS)

Takeda, Tohoru; Zeniya, Tsutomu; Wu, Jin; Yu, Quanwen; Lwin, Thet T.; Tsuchiya, Yoshinori; Rao, Donepudi V.; Yuasa, Tetsuya; Yashiro, Toru; Dilmanian, F. Avraham; Itai, Yuji; Akatsuka, Takao

2002-01-01

Fluorescent x-ray CT (FXCT) with synchrotron radiation (SR) is being developed to detect the very low concentration of specific elements. The endogenous iodine of the human thyroid and the non-radioactive iodine labeled BMIPP in myocardium were imaged by FXCT. FXCT system consists of a silicon (111) double crystal monochromator, an x-ray slit, a scanning table for object positioning, a fluorescent x-ray detector, and a transmission x-ray detector. Monochromatic x-ray with 37 keV energy was collimated into a pencil beam (from 1 mm to 0.025 mm). FXCT clearly imaged endogenous iodine of thyroid and iodine labeled BMIPP in myocardium, whereas transmission x-ray CT could not demonstrate iodine. The distribution of iodine was heterogeneous within thyroid cancer, and its concentration was lower than that of normal thyroid. Distribution of BMIPP in normal rat myocardium was almost homogeneous; however, reduced uptake was slightly shown in ischemic region. FXCT is a highly sensitive imaging modality to detect very low concentration of specific element and will be applied to reveal endogenous iodine distribution in thyroid and to use tracer study with various kinds of labeled material.

Lung inhomogeneities, inflation and [18F]2-fluoro-2-deoxy-D-glucose uptake rate in acute respiratory distress syndrome.

PubMed

Cressoni, Massimo; Chiumello, Davide; Chiurazzi, Chiara; Brioni, Matteo; Algieri, Ilaria; Gotti, Miriam; Nikolla, Klodiana; Massari, Dario; Cammaroto, Antonio; Colombo, Andrea; Cadringher, Paolo; Carlesso, Eleonora; Benti, Riccardo; Casati, Rosangela; Zito, Felicia; Gattinoni, Luciano

2016-01-01

The aim of the study was to determine the size and location of homogeneous inflamed/noninflamed and inhomogeneous inflamed/noninflamed lung compartments and their association with acute respiratory distress syndrome (ARDS) severity.In total, 20 ARDS patients underwent 5 and 45 cmH2O computed tomography (CT) scans to measure lung recruitability. [(18)F]2-fluoro-2-deoxy-d-glucose ([(18)F]FDG) uptake and lung inhomogeneities were quantified with a positron emission tomography-CT scan at 10 cmH2O. We defined four compartments with normal/abnormal [(18)F]FDG uptake and lung homogeneity.The homogeneous compartment with normal [(18)F]FDG uptake was primarily composed of well-inflated tissue (80±16%), double-sized in nondependent lung (32±27% versus 16±17%, p<0.0001) and decreased in size from mild, moderate to severe ARDS (33±14%, 26±20% and 5±9% of the total lung volume, respectively, p=0.05). The homogeneous compartment with high [(18)F]FDG uptake was similarly distributed between the dependent and nondependent lung. The inhomogeneous compartment with normal [(18)F]FDG uptake represented 4% of the lung volume. The inhomogeneous compartment with high [(18)F]FDG uptake was preferentially located in the dependent lung (21±10% versus 12±10%, p<0.0001), mostly at the open/closed interfaces and related to recruitability (r(2)=0.53, p<0.001).The homogeneous lung compartment with normal inflation and [(18)F]FDG uptake decreases with ARDS severity, while the inhomogeneous poorly/not inflated compartment increases. Most of the lung inhomogeneities are inflamed. A minor fraction of healthy tissue remains in severe ARDS. Copyright ©ERS 2016.

Pretreatment with diphenoxylate hydrochloride/atropine sulfate (Lomotil) does not decrease physiologic bowel FDG activity on PET/CT scans of the abdomen and pelvis.

PubMed

Murphy, Robert; Doerger, Kirk M; Nathan, Mark A; Lowe, Val J

2009-01-01

Physiologic uptake of 2-[(18)F]-fluoro-2-deoxy-D: -glucose (FDG) by bowel can confound positron emission tomography/computed tomography (PET/CT) assessment for abdominal pathology, particularly within the bowel itself. We wished to determine if oral administration of the antimotility agent, Lomotil (5 mg diphenoxylate hydrochloride/0.05 mg atropine sulfate; G.D. Searle and Company, a division of Pfizer), prior to PET/CT scanning would reduce physiologic uptake of FDG by the small bowel and colon (lower gastrointestinal [GI] tract). Patients undergoing PET/CT scans for lymphoma were enrolled in a prospective, randomized, double-blinded study and received either 10 mL water (control group) or 10 mL Lomotil (experimental group) orally 30-60 min prior to scanning. Scans were reviewed independently by two blinded experienced readers and scored for the degree of FDG activity in the lower GI tract relative to liver activity. The administration of Lomotil prior to PET/CT scanning did not reduce physiologic FDG activity in the small bowel and colon. In contrast, increased radiotracer uptake by the lower GI tract was observed in the Lomotil group compared to the control group. Pretreatment with Lomotil prior to PET/CT scanning confers no benefit toward the reduction of physiologic FDG uptake by the small bowel and colon.

The role of laparoscopy in the diagnosis and treatment of peritoneal carcinomatosis: a case report.

PubMed Central

Takizawa, B. T.; Shin, E. K.; Masters, L.; Lancelle, F.; Anaf, V.; Shahabi, S.

2001-01-01

A patient presented with deep venous thrombosis and an elevated CA-125 level, but normal pelvic ultrasound and abdominal and pelvic CT scans. Laparoscopy revealed diffuse carcinomatosis and a diagnosis of stage IIIc, poorly differentiated epithelial ovarian carcinoma was made. Laparoscopy may provide an alternative means of diagnosis when conventional imaging fails, and may facilitate the placement of catheters for subsequent intraperitoneal therapy. PMID:11393262