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.

Iatrogenic radiation exposure to patients with early onset spine and chest wall deformities.

PubMed

Khorsand, Derek; Song, Kit M; Swanson, Jonathan; Alessio, Adam; Redding, Gregory; Waldhausen, John

2013-08-01

Retrospective cohort series. Characterize average iatrogenic radiation dose to a cohort of children with thoracic insufficiency syndrome (TIS) during assessment and treatment at a single center with vertically expandable prosthetic titanium rib. Children with TIS undergo extensive evaluations to characterize their deformity. No standardized radiographical evaluation exists, but all reports use extensive imaging. The source and level of radiation these patients receive is not currently known. We evaluated a retrospective consecutive cohort of 62 children who had surgical treatment of TIS at our center from 2001-2011. Typical care included obtaining serial radiographs, spine and chest computed tomographic (CT) scans, ventilation/perfusion scans, and magnetic resonance images. Epochs of treatment were divided into time of initial evaluation to the end of initial vertically expandable prosthetic titanium rib implantation with each subsequent epoch delineated by the next surgical intervention. The effective dose for each examination was estimated within millisieverts (mSv). Plain radiographs were calculated from references. Effective dose was directly estimated for CT scans since 2007 and an average of effective dose from 2007-2011 was used for scans before 2007. Effective dose from fluoroscopy was directly estimated. All doses were reported in mSv. A cohort of 62 children had a total of 447 procedures. There were a total of 290 CT scans, 4293 radiographs, 147 magnetic resonance images, and 134 ventilation/perfusion scans. The average accumulated effective dose was 59.6 mSv for children who had completed all treatment, 13.0 mSv up to initial surgery, and 3.2 mSv for each subsequent epoch of treatment. CT scans accounted for 74% of total radiation dose. Children managed for TIS using a consistent protocol received iatrogenic radiation doses that were on average 4 times the estimated average US background radiation exposure of 3 mSv/yr. CT scans comprised 74% of the total dose. 3.

Routine repeat head CT may not be necessary for patients with mild TBI

PubMed Central

Rosen, Claire B; Luy, Diego D; Deane, Molly R; Scalea, Thomas M; Stein, Deborah M

2018-01-01

Background Routine repeat cranial CT (RHCT) is standard of care for CT-verified traumatic brain injury (TBI). Despite mixed evidence, those with mild TBI are subject to radiation and expense from serial CT scans. Thus, we investigated the necessity and utility of RHCT for patients with mild TBI. We hypothesized that repeat head CT in these patients would not alter patient care or outcomes. Methods We retrospectively studied patients suffering from mild TBI (Glasgow Coma Scale (GCS) score 13–15) and treated at the R Adams Cowley Shock Trauma Center from November 2014 through January 2015. The primary outcome was the need for surgical intervention. Outcomes were compared using paired Student’s t-test, and stratified by injury on initial CT, GCS change, demographics, and presenting vital signs (mean ± SD). Results Eighty-five patients met inclusion criteria with an average initial GCS score=14.6±0.57. Our center sees about 2800 patients with TBI per year, or about 230 per month. This includes patients with concussions. This sample represents about 30% of patients with TBI seen during the study period. Ten patients required operation (four based on initial CT and others for worsening GCS, headaches, large unresolving injury). There was progression of injury on repeat CT scan in only two patients that required operation, and this accompanied clinical deterioration. The mean brain Abbreviated Injury Scale (AIS) score was 4.8±0.3 for surgical patients on initial CT scan compared with 3.4±0.6 (P<0.001) for non-surgical patients. Initial CT subdural hematoma size was 1.1±0.6 cm for surgical patients compared with 0.49±0.3 cm (P=0.05) for non-surgical patients. There was no significant difference between intervention groups in terms of other intracranial injuries, demographics, vital signs, or change in GCS. Overall, 75 patients that did not require surgical intervention received RHCT. At $340 per CT, $51 000 was spent on unnecessary imaging ($367 000/year, extrapolated). Discussion In an environment of increased scrutiny on healthcare expenditures, it is necessary to question dogma and eliminate unnecessary cost. Our data questions the use of routine repeat head CT scans in every patient with anatomic TBI and suggests that clinically stable patients with small injury can simply be followed clinically. Level of evidence Level III. PMID:29766124

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

Management of paediatric periorbital cellulitis: Our experience of 243 children managed according to a standardised protocol 2012-2015.

PubMed

Crosbie, Robin A; Nairn, Jonathan; Kubba, Haytham

2016-08-01

Paediatric periorbital cellulitis is a common condition. Accurate assessment can be challenging and appropriate use of CT imaging is essential. We audited admissions to our unit over a four year period, with reference to CT scanning and adherence to our protocol. Retrospective audit of paediatric patients admitted with periorbital cellulitis, 2012-2015. Total of 243 patients included, mean age 4.7 years with slight male predominance, the median length of admission was 2 days. 48/243 (20%) underwent CT during admission, 25 (52%) of these underwent surgical drainage. As per protocol, CT brain performed with all orbital scans; no positive intracranial findings on any initial scan. Three children developed intracranial complications subsequently; all treated with antibiotics. Our re-admission rate within 30 days was 2.5%. Our audit demonstrates benefit of standardising practice and the low CT rate, with high percentage taken to theatre and no missed abscesses, supports the protocol. There may be an argument to avoid CT brain routinely in all initial imaging sequences in those children without neurological signs or symptoms. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

[Renal angiomyolipomas without fat component: tomodensitometric and histologic characteristics, clinical course].

PubMed

Negre, T; Faure, A; Andre, M; Daniel, L; Coulange, C; Lechevallier, E

2011-11-01

Angiomyolipoma is the most frequent benign renal solid tumor. Because of the lack of fat component on the CT scan, diagnosis of this tumor is hard and can require percutaneous biopsy of unknown renal tumor. The follow-up of the poor fat CT scan component AML (PFCT AML) is uncertain. Five hundred percutaneous renal biopsy under tomodenstitometry have been realised between 1998 and 2008. There was 41 PFCT AML on the 500 biopsy. By definition, a PFCT AML is an AML where the diagnosis is done on a percutaneous biopsy but where there was no fat component on the first CT scan. We studied and compared clinical, tomodensitometric and histologic parameters of these 41 patients (mean age: 56, 9±11.04; sexe rate M/F: 6/35) where renal AML was diagnosed on percutaneous renal biopsy but without fat component on CT scan. Average size was 26.44±14.68mm. We phone-called 16 patients for the long-term follow-up. Average follow-up was 41±28.3 months. For four patients on 16, initial diagnosis was done in front of local symptoms, for one of the 16 diagnosis was done in front of general symptoms, for one of the diagnosis was done during Bourneville tuberous sclerosis evolution and 10 of the 16 was done fortuitously. After review of the initial CT scan, fat density was found on 24% of them. Ten percent was epithelioid angiomyolipoma. Four renal biopsy on 41 (10%) was epithelioid AML. No epithelioid AML had fat component after the second look of the CT scan. Among the 16 patients who were phone-called, three (19%) underwent a complication. Two had abdominal pain and was treated medically. Initial sizes were 26 and 30mm. Only one patient must be operated by radical nephrectomy for acute hemorrhage. Initial size was 45mm. No neoplasic degeneration was identified for those 16 patients. In our study, the PFCT AML rate was 8.2%. In 25% cases, CT scan read-through shown a fat component and could help for the diagnosis. PFCT AML evolution seems to be the same as a classic AML. Conservative treatment had a good covering because there was no death and no malignant evolution. However, we found 10% of epithelioid angiomyolipoma in which malignant risk is high. PFCT AML diagnosed on renal percutaneous biopsy of unknown renal tumor requires the same management than the classic AML. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Diagnosis of unsuspected facial fractures on routine head computerized tomographic scans in the unconscious multiply injured patient.

PubMed

Rehm, C G; Ross, S E

1995-05-01

This article assessed the value of routine head computerized axial tomographic (CT) scans for diagnosis of unsuspected facial fractures and its clinical implications in the multiply injured patient who is intubated, unconscious, or sedated at the time of initial assessment and requires a head CT scan to assess for brain injury. At a level I trauma center from June 1, 1992 to June 1, 1993 all intubated blunt trauma patients who required routine CT scan evaluation at initial assessment were studied prospectively. Routine scanning started at the foramen magnum and included the maxilla. Patients who died within the first 24 hours were excluded. The study population included 116 patients (85 male, 21 female) aged 12 to 85 years (mean, 28 years) with injury severity scores ranging from 1 to 50 (mean, 23). The mechanism of injury was: motor vehicle accidents (n = 74), motorcycling (n = 5), pedestrians accidents (n = 13), falls (n = 10), bicycling (n = 5), assaults (n = 8), and boating accident (n = 1). There were 19 suspected facial fractures; 18 required surgical repair. There were 27 unsuspected facial fractures; 13 required surgical care. Three suspected fractures were ruled out. Routine head CT scans to assess for brain injury in the multiply injured patient are also very useful in the diagnosis of unsuspected facial fractures, almost half of which will require surgical intervention.

Preablation 131-I scans with SPECT/CT in postoperative thyroid cancer patients: what is the impact on staging?

PubMed

Avram, Anca M; Fig, Lorraine M; Frey, Kirk A; Gross, Milton D; Wong, Ka Kit

2013-03-01

The utility of preablation radioiodine scans for the management of differentiated thyroid cancer remains controversial. To determine the contribution of preablation Iodine 131 (131-I) planar with single-photon emission computed tomography/computed tomography (SPECT/CT; diagnostic [Dx] scans) to differentiated thyroid cancer staging. Prospective sequential series at university clinic. Using American Joint Committee on Cancer (AJCC) tumor, node, metastasis (TNM) staging, seventh edition 320 patients post-total thyroidectomy were initially staged based on clinical and pathology data (pTN) and then restaged after imaging (TNM). The impact of Dx scans with SPECT/CT on N and M scores, and TNM stage, was assessed in younger, age <45 years, n = 138 (43%), and older, age ≥ 45 years, n = 182 (57%) patients, with subgroup analysis for T1a and T1b tumors. In younger patients Dx scans detected distant metastases in 5 of 138 patients (4%), and nodal metastases in 61 of 138 patients (44%), including unsuspected nodal metastases in 24 of 63 (38%) patients initially assigned pathologic (p) N0 or pNx. In older patients distant metastases were detected in 18 of 182 patients (10%), and nodal metastases in 51 of 182 patients (28%), including unsuspected nodal metastases in 26 of 108 (24%) patients initially assigned pN0 or pNx. Dx scans detected distant metastases in 2 of 49 (4%) T1a, and 3 of 67 (4.5%) T1b patients. Dx scans detected regional metastases in 35% of patients, and distant metastases in 8% of patients. Information acquired with Dx scans changed staging in 4% of younger, and 25% of older patients. Preablation scans with SPECT/CT contribute to staging of thyroid cancer. Identification of regional and distant metastases prior to radioiodine therapy has significant potential to alter patient management.

Gray Matter-White Matter De-Differentiation on Brain Computed Tomography Predicts Brain Death Occurrence.

PubMed

Vigneron, C; Labeye, V; Cour, M; Hannoun, S; Grember, A; Rampon, F; Cotton, F

2016-01-01

Previous studies have shown that a loss of distinction between gray matter (GM) and white matter (WM) on unenhanced CT scans was predictive of poor outcome after cardiac arrest. The aim of this study was to identify a marker/predictor of imminent brain death. In this retrospective study, 15 brain-dead patients after anoxia and cardiac arrest were included. Patients were paired (1:1) with normal control subjects. Only patients' unenhanced CT scans performed before brain death and during the 24 hours after initial signs were analyzed. WM and GM densities were measured in predefined regions of interest (basal ganglia level, centrum semi-ovale level, high convexity level, brainstem level). At each level, GM and WM density and GM/WM ratio for brain-dead patients and normal control subjects were compared using the Wilcoxon signed-rank test. At each level, a lower GM/WM ratio and decreased GM and WM densities were observed in brain-dead patients' CT scans when compared with normal control subject CT scans. A cut-off value of 1.21 at the basal ganglia level was identified, below which brain death systematically occurred. GM/WM dedifferentiation on unenhanced CT scan is measurable before the occurrence of brain death, highlighting its importance in brain death prediction. The mechanism of GM/WM differentiation loss could be explained by the lack of oxygen caused by ischemia initially affecting the mitochondrial system. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

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.

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.

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

MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems.

PubMed

Avanesov, Maxim; Weinrich, Julius M; Kraus, Thomas; Derlin, Thorsten; Adam, Gerhard; Yamamura, Jin; Karul, Murat

2016-11-01

The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose. In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48-64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p=0.25; mCTSI: 4.0 vs. 4.0, p=0.10; EPIC: 2.0 vs. 2.0, p=0.41; NP: CTSI: 8.0 vs. 7.0, p=0.64; mCTSI: 8.0 vs. 8.0, p=0.10; EPIC: 3.0 vs. 3.0, p=0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan. An initial dual-phase abdominal CT after ≥72h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a single-phase protocol. Copyright © 2016. Published by Elsevier Ireland Ltd.

Investigating the necessity of computed tomographic scans in children with headaches: a retrospective review.

PubMed

Gandhi, Rohit; Lewis, Evan Cole; Evans, Jeanette W; Sell, Erick

2015-03-01

Headaches are a common problem in the pediatric population. In 2002, the American Academy of Neurology (AAN) developed guidelines on neuroimaging for patients presenting with headache. Our objective was to determine the frequency of computed tomographic (CT) scanning ordered by a range of medical practitioners for pediatric patients presenting with primary headache. A retrospective chart review was conducted at the Children's Hospital of Eastern Ontario (CHEO), a tertiary care centre in Ontario. One hundred fifty-one records of patients referred to the outpatient neurology clinic at CHEO with ''headache'' or ''migraine'' as the primary complaint from 2004 to 2009 were randomly selected. Ninety-nine patients with normal neurologic examinations were ultimately included. Thirty-four patients (34%; 95% CI 25-45) had undergone CT scanning. None of the 34 CT scans (0%; 95% CI 0-10) showed significant findings, and none changed the headache diagnosis or management. Eleven (32%) of the CT scans were ordered by CHEO neurologists, 15 (44%) by community physicians, and 8 (24%) by CHEO emergency physicians. A high proportion of children presenting with primary headaches and a normal neurologic examination undergo CT scanning, despite well-established AAN guidelines regarding neuroimaging. Most of these CT scans do not appear to alter diagnosis and management. A variety of non-evidencebased factors may be encouraging physicians to overinvestigate this population and, as a result, increasing the risk of adverse events due to radiation exposure. Implementing initiatives at a site-based level that promote the use of established guidelines before performing CT scanning in this population may be beneficial.

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.

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.

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.

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.

18F-FDG uptake and its clinical relevance in primary gastric lymphoma.

PubMed

Yi, Jun Ho; Kim, Seok Jin; Choi, Joon Young; Ko, Young Hyeh; Kim, Byung-Tae; Kim, Won Seog

2010-06-01

We studied the clinical relevance of (18)F-fluorodeoxyglucose ((18)F-FDG) uptake in patients with primary gastric lymphoma underwent positron emission tomography (PET)/ computed tomography (CT) scan. Forty-two patients with primary gastric lymphoma were analysed: 32 diffuse large B-cell lymphomas (DLBCL) and 10 extranodal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT lymphomas). The PET/CT scans were compared with clinical and pathologic features, and the results of CT and endoscopy. Nine patients were up-staged based on the results of their PET/CT scan compared to CT (seven DLBCLs, two MALT lymphomas) while six patients were down-staged by the PET/CT scan. The standard uptake value (SUV) was used as an indicator of a lesion with a high metabolic rate. The high SUVmax group, defined as an SUVmax >or= median value, was significantly associated with an advanced Lugano stage (p < 0.001). Three patients with DLBCL, who showed an initially high SUVmax, died of disease progression. Among 24 patients for whom follow-up PET/CT scan with endoscopy was performed, 11 patients with ulcerative or mucosal lesions showed residual (18)F-FDG uptake. All of these gastric lesions were grossly and pathologically benign lesions without evidence of lymphoma cells. In conclusion, PET/CT scan can be used in staging patients with primary gastric lymphoma; however, the residual (18)F-FDG uptake observed during follow-up should be interpreted cautiously and should be combined with endoscopy and multiple biopsies of the stomach. (c) 2009 John Wiley & Sons, Ltd.

[Traumatic intracerebral pneumocephalus communicating with two different paranasal sinuses: a case report].

PubMed

Wakamoto, H; Miyazaki, H; Hayashi, T; Shimamoto, Y; Ishiyama, N

1998-02-01

We report a case of a 17-year-old male who had hit the front of his head in a traffic accident. CT scan revealed contusional hemorrhage and pneumocephalus of the left frontal lobe 10 hours after the accident. A month later he complained of rhinorrhea and CT scan revealed intracerebral pneumocephalus. One day he complained of headache and began to vomit after he sneezed. CT scan revealed that the pneumocephalus had become worse and air had spread throughout the subarachnoid space. Bone CT scan revealed the air communicated from the frontal sinus to the intracerebral air cavity. 3D-CT scan revealed bone defect in the roof of the ethmoid sinus. The intraoperative findings revealed that the intracerebral air cavity communicated with the frontal sinus and ethmoid sinus. Though the brain which dropped into the paranasal sinus, adhered to the dura mater around the bone defect, a part of the brain had come off from the dura mater around the frontal sinus. We suspected that the intracerebral air cavity communicated with the frontal sinus initially. When the air cavity communicated with the ethmoid sinus secondarily, intracranial pressure abated and air came into the subarachnoid space from the frontal sinus.

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.

The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI): A Completed Reference Database of Lung Nodules on CT Scans

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

NONE

2011-02-15

Purpose: The development of computer-aided diagnostic (CAD) methods for lung nodule detection, classification, and quantitative assessment can be facilitated through a well-characterized repository of computed tomography (CT) scans. The Lung Image Database Consortium (LIDC) and Image Database Resource Initiative (IDRI) completed such a database, establishing a publicly available reference for the medical imaging research community. Initiated by the National Cancer Institute (NCI), further advanced by the Foundation for the National Institutes of Health (FNIH), and accompanied by the Food and Drug Administration (FDA) through active participation, this public-private partnership demonstrates the success of a consortium founded on a consensus-based process.more » Methods: Seven academic centers and eight medical imaging companies collaborated to identify, address, and resolve challenging organizational, technical, and clinical issues to provide a solid foundation for a robust database. The LIDC/IDRI Database contains 1018 cases, each of which includes images from a clinical thoracic CT scan and an associated XML file that records the results of a two-phase image annotation process performed by four experienced thoracic radiologists. In the initial blinded-read phase, each radiologist independently reviewed each CT scan and marked lesions belonging to one of three categories (''nodule{>=}3 mm,''''nodule<3 mm,'' and ''non-nodule{>=}3 mm''). In the subsequent unblinded-read phase, each radiologist independently reviewed their own marks along with the anonymized marks of the three other radiologists to render a final opinion. The goal of this process was to identify as completely as possible all lung nodules in each CT scan without requiring forced consensus. Results: The Database contains 7371 lesions marked ''nodule'' by at least one radiologist. 2669 of these lesions were marked ''nodule{>=}3 mm'' by at least one radiologist, of which 928 (34.7%) received such marks from all four radiologists. These 2669 lesions include nodule outlines and subjective nodule characteristic ratings. Conclusions: The LIDC/IDRI Database is expected to provide an essential medical imaging research resource to spur CAD development, validation, and dissemination in clinical practice.« less

The value of FDG PET/CT for follow-up of patients with melanoma: a retrospective analysis

PubMed Central

Vensby, Philip H; Schmidt, Grethe; Kjær, Andreas; Fischer, Barbara M

2017-01-01

The incidence of melanoma (MM) is among the fastest rising cancers in the western countries. Positron Emission Tomography with Computed Tomography (PET/CT) is a valuable non-invasive tool for the diagnosis and staging of patients with MM. However, research on the value of PET/CT in follow-up of melanoma patients is limited. This study assesses the diagnostic value of PET/CT for follow-up after melanoma surgery. This retrospective study includes patients with MM who performed at least one PET/CT scan after initial surgery and staging. PET/CT findings were compared to histology, MRI or fine needle aspiration (FNA) to estimate the diagnostic accuracy. The diagnostic performance of PET/CT performed in patients with and without a clinical suspicion of relapse was compared. 238 patients (526 scans) were included. Of the 526 scans 130 (25%) scans were PET-positive, 365 (69%) PET-negative, and 28 (5%) had equivocal findings. Sensitivity was 89% [0.82-0.94], specificity 92% [0.89-0.95], positive and negative predictive values of 78% [0.70-0.84] and 97% [0.94-0.98] respectively. When stratified for reason of referral there was no statistical significant difference in the diagnostic accuracy of PET/CT between patients referred with or without a clinical suspicion of relapse. This study demonstrates that PET/CT despite a moderate sensitivity has a high negative predictive value in the follow-up of melanoma patients. Thus, a negative PET/CT-scan essentially rules out relapse. However, the frequency of false positive findings is relatively high, especially among patients undergoing a “routine” PET/CT with no clinical suspicion of relapse, potentially causing anxiety and leading to further diagnostic procedures. PMID:29348980

The value of FDG PET/CT for follow-up of patients with melanoma: a retrospective analysis.

PubMed

Vensby, Philip H; Schmidt, Grethe; Kjær, Andreas; Fischer, Barbara M

2017-01-01

The incidence of melanoma (MM) is among the fastest rising cancers in the western countries. Positron Emission Tomography with Computed Tomography (PET/CT) is a valuable non-invasive tool for the diagnosis and staging of patients with MM. However, research on the value of PET/CT in follow-up of melanoma patients is limited. This study assesses the diagnostic value of PET/CT for follow-up after melanoma surgery. This retrospective study includes patients with MM who performed at least one PET/CT scan after initial surgery and staging. PET/CT findings were compared to histology, MRI or fine needle aspiration (FNA) to estimate the diagnostic accuracy. The diagnostic performance of PET/CT performed in patients with and without a clinical suspicion of relapse was compared. 238 patients (526 scans) were included. Of the 526 scans 130 (25%) scans were PET-positive, 365 (69%) PET-negative, and 28 (5%) had equivocal findings. Sensitivity was 89% [0.82-0.94], specificity 92% [0.89-0.95], positive and negative predictive values of 78% [0.70-0.84] and 97% [0.94-0.98] respectively. When stratified for reason of referral there was no statistical significant difference in the diagnostic accuracy of PET/CT between patients referred with or without a clinical suspicion of relapse. This study demonstrates that PET/CT despite a moderate sensitivity has a high negative predictive value in the follow-up of melanoma patients. Thus, a negative PET/CT-scan essentially rules out relapse. However, the frequency of false positive findings is relatively high, especially among patients undergoing a "routine" PET/CT with no clinical suspicion of relapse, potentially causing anxiety and leading to further diagnostic procedures.

Use of Intraoperative Computed Tomography for Revisional Procedures in Patients with Complex Maxillofacial Trauma

PubMed Central

Singh, Mansher; Ricci, Joseph A.

2015-01-01

Background: In patients with panfacial fractures and distorted anatomic landmarks of zygomatic and orbital complex, there is a risk of zygomaticomaxillary complex (ZMC) malpositioning even with the best efforts for surgical repair. This results in increased number of additional procedures to achieve accurate positioning. Methods: We describe the usage of intraoperative C-arm cone-beam computed tomographic (CT) scan for ZMC malpositioning in a representative patient with panfacial fractures. Results: We have successfully used intraoperative CT scan for ZMC malpositioning in 3 patients. The representative patient had ZMC malposition after the initial attempt of surgical repair without any intraoperative imaging. On using intraoperative CT scan during the next attempt, we were able to reposition the ZMC accurately. Conclusions: Intraoperative CT scan might improve the accuracy of ZMC positioning and decrease the chances of potential additional surgeries. In patients with distorted anatomical landmarks and panfacial fractures, it can be especially helpful toward correcting ZMC malposition. PMID:26301152

Hemispheric Chronic Subdural Hematoma Concealing Subdural Metastases: Terrible Surprise Behind Routine Emergency Department Consultation.

PubMed

Caruso, Riccardo; Pesce, Alessandro; Martines, Valentina

2017-10-01

The patient is a 79-year-old male, suffering from advanced metastatic prostate cancer, who developed a progressively worsening ideomotor slowing and was therefore referred to the emergency department of our institution. A plain axial computed tomography (CT) scan revealed a vast hemispheric subdural fluid collection, apparently a subdural hematoma. On closer inspection, and most of all, in hindsight, a tenuously isohyperdense signal irregularity at the frontal aspect of the fluid collection appears. Because of the declined general medical conditions and the paucity of the neurologic impairment, a high-dose, corticosteroid-based conservative strategy was performed. The total body CT scan for the routine oncologic follow-up of the prostate cancer scan fell at 20 days from the first CT of the emergency department. A second contrast-enhanced axial CT scan demonstrated the presence of 2 subdural metastases, presumably the initial pathogenesis of the subdural fluid collection. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Anteroposterior chest radiograph vs. chest CT scan in early detection of pneumothorax in trauma patients.

PubMed

Omar, Hesham R; Mangar, Devanand; Khetarpal, Suneel; Shapiro, David H; Kolla, Jaya; Rashad, Rania; Helal, Engy; Camporesi, Enrico M

2011-09-27

Pneumothorax is a common complication following blunt chest wall trauma. In these patients, because of the restrictions regarding immobilization of the cervical spine, Anteroposterior (AP) chest radiograph is usually the most feasible initial study which is not as sensitive as the erect chest X-ray or CT chest for detection of a pneumothorax. We will present 3 case reports which serve for better understanding of the entity of occult pneumothorax. The first case is an example of a true occult pneumothorax where an initial AP chest X-ray revealed no evidence of pneumothorax and a CT chest immediately performed revealed evidence of pneumothorax. The second case represents an example of a missed rather than a truly occult pneumothorax where the initial chest radiograph revealed clues suggesting the presence of pneumothorax which were missed by the reading radiologist. The third case emphasizes the fact that "occult pneumothorax is predictable". The presence of subcutaneous emphesema and pulmonary contusion should call for further imaging with CT chest to rule out pneumothorax. Thoracic CT scan is therefore the "gold standard" for early detection of a pneumothorax in trauma patients. This report aims to sensitize readers to the entity of occult pneumothorax and create awareness among intensivists and ER physicians regarding the proper diagnosis and management.

Follow-up brain imaging of 37 children with congenital Zika syndrome: case series study

PubMed Central

Aragao, Maria de Fatima Vasco; van der Linden, Vanessa; Parizel, Paul; Jungmann, Patricia; Araújo, Luziany; Abath, Marília; Fernandes, Andrezza; Brainer-Lima, Alessandra; Holanda, Arthur; Mello, Roberto; Sarteschi, Camila; Duarte, Maria do Carmo Menezes Bezerra

2017-01-01

Objective To compare initial brain computed tomography (CT) scans with follow-up CT scans at one year in children with congenital Zika syndrome, focusing on cerebral calcifications. Design Case series study. Setting Barão de Lucena Hospital, Pernambuco state, Brazil. Participants 37 children with probable or confirmed congenital Zika syndrome during the microcephaly outbreak in 2015 who underwent brain CT shortly after birth and at one year follow-up. Main outcome measure Differences in cerebral calcification patterns between initial and follow-up scans. Results 37 children were evaluated. All presented cerebral calcifications on the initial scan, predominantly at cortical-white matter junction. At follow-up the calcifications had diminished in number, size, or density, or a combination in 34 of the children (92%, 95% confidence interval 79% to 97%), were no longer visible in one child, and remained unchanged in two children. No child showed an increase in calcifications. The calcifications at the cortical-white matter junction which were no longer visible at follow-up occurred predominately in the parietal and occipital lobes. These imaging changes were not associated with any clear clinical improvements. Conclusion The detection of cerebral calcifications should not be considered a major criterion for late diagnosis of congenital Zika syndrome, nor should the absence of calcifications be used to exclude the diagnosis. PMID:29030384

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.

Characteristics of Rib Fractures in Child Abuse-The Role of Low-Dose Chest Computed Tomography.

PubMed

Sanchez, Thomas R; Grasparil, Angelo D; Chaudhari, Ruchir; Coulter, Kevin P; Wootton-Gorges, Sandra L

2018-02-01

Our aim is to describe the radiologic characteristics of rib fractures in clinically diagnosed cases of child abuse and suggest a complementary imaging for radiographically occult injuries in highly suspicious cases of child abuse. Retrospective analysis of initial and follow-up skeletal surveys and computed tomography (CT) scans of 16 patients younger than 12 months were reviewed after obtaining approval from our institutional review board. The number, location, displacement, and age of the rib fractures were recorded. Out of a total 105 rib fractures, 84% (87/105) were detected on the initial skeletal survey. Seventeen percent (18/105) were seen only after follow-up imaging, more than half of which (11/18) were detected on a subsequent CT. Majority of the fractures were posterior (43%) and anterior (30%) in location. An overwhelming majority (96%) of the fractures are nondisplaced. Seventeen percent of rib fractures analyzed in the study were not documented on the initial skeletal survey. Majority of fractures are nondisplaced and located posteriorly or anteriorly, areas that are often difficult to assess especially in the acute stage. The CT scan is more sensitive in evaluating these types of fractures. Low-dose chest CT can be an important imaging modality for suspicious cases of child abuse when initial radiographic findings are inconclusive.

Second cancers discovered by (18)FDG PET/CT imaging for choroidal melanoma.

PubMed

Chin, Kimberly; Finger, Paul T; Kurli, Madhavi; Tena, Lawrence B; Reddy, Shantan

2007-08-01

Positron-emission tomography/computed tomography (PET/CT) is a unique imaging tool that aids in the detection of cancerous lesions. It is currently and widely used for cancer staging (both initial and follow-up). Here we report our findings of second primary cancers incidentally discovered during PET/CT staging of patients with choroidal melanomas. We performed a retrospective case review of 139 patients with uveal melanoma who were subsequently evaluated by whole-body [18-fluorine-labeled] 2-deoxy-2-fluoro-D-glucose ((18)FDG) PET/CT imaging. In this series, 93 were scanned before treatment and 46 during the course of their follow-up systemic examinations. Their mean follow-up was 50.9 months. Six patients (4.3%) had second primary cancers revealed by PET/CT imaging. Three patients (50%) were synchronous (found at initial staging), and the remaining 3 patients (50%) were metachronous (found at follow-up staging). Second primary cancers were found in the lung, breast, uterus, colon, and thyroid. Although whole-body PET/CT scans were ordered as part of the staging process of patients with diagnosed choroidal melanoma, both synchronous and metachronous second primary cancers were found. PET/CT has become an indispensable tool for staging, diagnosis, and treatment planning for choroidal melanoma. The possibility of detecting second primary cancers should also be considered valuable.

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.

A clip-based protocol for breast boost radiotherapy provides clear target visualisation and demonstrates significant volume reduction over time

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

Lewis, Lorraine; Cox, Jennifer; Faculty of Health Sciences, University of Sydney, Sydney, New South Wales

2015-09-15

The clinical target volume (CTV) for early stage breast cancer is difficult to clearly identify on planning computed tomography (CT) scans. Surgical clips inserted around the tumour bed should help to identify the CTV, particularly if the seroma has been reabsorbed, and enable tracking of CTV changes over time. A surgical clip-based CTV delineation protocol was introduced. CTV visibility and its post-operative shrinkage pattern were assessed. The subjects were 27 early stage breast cancer patients receiving post-operative radiotherapy alone and 15 receiving post-operative chemotherapy followed by radiotherapy. The radiotherapy alone (RT/alone) group received a CT scan at median 25 daysmore » post-operatively (CT1rt) and another at 40 Gy, median 68 days (CT2rt). The chemotherapy/RT group (chemo/RT) received a CT scan at median 18 days post-operatively (CT1ch), a planning CT scan at median 126 days (CT2ch), and another at 40 Gy (CT3ch). There was no significant difference (P = 0.08) between the initial mean CTV for each cohort. The RT/alone cohort showed significant CTV volume reduction of 38.4% (P = 0.01) at 40 Gy. The Chemo/RT cohort had significantly reduced volumes between CT1ch: median 54 cm{sup 3} (4–118) and CT2ch: median 16 cm{sup 3}, (2–99), (P = 0.01), but no significant volume reduction thereafter. Surgical clips enable localisation of the post-surgical seroma for radiotherapy targeting. Most seroma shrinkage occurs early, enabling CT treatment planning to take place at 7 weeks, which is within the 9 weeks recommended to limit disease recurrence.« 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 ...

Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

NASA Astrophysics Data System (ADS)

Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

2016-03-01

In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

Four-arm variable-resolution x-ray detector for CT target imaging

NASA Astrophysics Data System (ADS)

DiBianca, Frank A.; Gulabani, Daya; Jordan, Lawrence M.; Vangala, Sravanthi; Rendon, David; Laughter, Joseph S.; Melnyk, Roman; Gaber, M. W.; Keyes, Gary S.

2005-04-01

The basic VRX technique boosts spatial resolution of a CT scanner in the scan plane by two or more orders of magnitude by reducing the angle of incidence of the x-ray beam with respect to the detector surface. A four-arm Variable-Resolution X-ray (VRX) detector has been developed for CT scanning. The detector allows for "target imaging" in which an area of interest is scanned at higher resolution than the remainder of the subject, yielding even higher resolution for the focal area than that obtained from the basic VRX technique. The new VRX-CT detector comprises four quasi-identical arms each containing six 24-cell modules (576 cells total). The modules are made of individual custom CdWO4 scintillators optically-coupled to custom photodiode arrays. The maximum scan field is 40 cm for a magnification of 1.4. A significant advantage of the four-arm geometry is that it can transform quickly to the two-arm, or even the single-arm geometry, for comparison studies. These simpler geometries have already been shown experimentally to yield in-plane CT detector resolution exceeding 60 cy/mm (<8μ) for small fields of view. Geometrical size and resolution limits of the target VRX field are calculated. Two-arm VRX-CT data are used to simulate and establish the feasibility of VRX CT target imaging. A prototype target VRX-CT scanner has been built and is undergoing initial testing.

Using three-dimensional-computerized tomography as a diagnostic tool for temporo-mandibular joint ankylosis: a case report.

PubMed

Kao, S Y; Chou, J; Lo, J; Yang, J; Chou, A P; Joe, C J; Chang, R C

1999-04-01

Roentgenographic examination has long been a useful diagnostic tool for temporo-mandibular joint (TMJ) disease. The methods include TMJ tomography, panoramic radiography and computerized tomography (CT) scan with or without injection of contrast media. Recently, three-dimensional CT (3D-CT), reconstructed from the two-dimensional image of a CT scan to simulate the soft tissue or bony structure of the real target, was proposed. In this report, a case of TMJ ankylosis due to traumatic injury is presented. 3D-CT was employed as one of the presurgical roentgenographic diagnostic tools. The conventional radiographic examination including panoramic radiography and tomography showed lesions in both sides of the mandible. CT scanning further suggested that the right-sided lesion was more severe than that on the left. With 3D-CT image reconstruction the size and extent of the lesions were clearly observable. The decision was made to proceed with an initial surgical approach on the right side. With condylectomy and condylar replacement using an autogenous costochondral graft on the right side, the range of mouth opening improved significantly. In this case report, 3D-CT demonstrates its advantages as a tool for the correct and precise diagnosis of TMJ ankylosis.

Occult pneumomediastinum in blunt chest trauma: clinical significance.

PubMed

Rezende-Neto, J B; Hoffmann, J; Al Mahroos, M; Tien, H; Hsee, L C; Spencer Netto, F; Speers, V; Rizoli, S B

2010-01-01

Thoracic injuries are potentially responsible for 25% of all trauma deaths. Chest X-ray is commonly used to screen patients with chest injury. However, the use of computed tomography (CT) scan for primary screening is increasing, particularly for blunt trauma. CT scans are more sensitive than chest X-ray in detecting intra-thoracic abnormalities such as pneumothoraces and pneumomediastinums. Pneumomediastinum detected by chest X-ray or "overt pneumomediastinum", raises the concern of possible aerodigestive tract injuries. In contrast, there is scarce information on the clinical significance of pneumomediastinum diagnosed by CT scan only or "occult pneumomediastinum". Therefore we investigated the clinical consequences of occult pneumomediastinum in our blunt trauma population. A 2-year retrospective chart review of all blunt chest trauma patients with initial chest CT scan admitted to a level I trauma centre. Data extracted from the medical records include; demographics, occult, overt, or no pneumomediastinum, the presence of intra-thoracic aerodigestive tract injuries (trachea, bronchus, and/or esophagus), mechanism and severity of injury, endotracheal intubation, chest thoracostomy, operations and radiological reports by an attending radiologist. All patients with intra-thoracic aerodigestive tract injuries from 1994 to 2004 were also investigated. Of 897 patients who met the inclusion criteria 839 (93.5%) had no pneumomediastinum. Five patients (0.6%) had overt pneumomediastinum and 53 patients (5.9%) had occult pneumomediastinum. Patients with occult pneumomediastinum had significantly higher ISS and AIS chest (p<0.0001) than patients with no pneumomediastinum. A chest thoracostomy tube was more common (p<0.0001) in patients with occult pneumomediastinum (47.2%) than patients with no pneumomediastinum (10.4%), as well as occult pneumothorax. None of the patients with occult pneumomediastinum had aerodigestive tract injuries (95%CI 0-0.06). Follow up CT scan of patients with occult pneumomediastinum showed complete resolution in all cases, in average 3 h after the initial exam. Occult pneumomediastinum occurred in approximately 6% of all trauma patients with blunt chest injuries in our institution. Patients who had occult pneumomediastinum were more severely injured than those who without. However, none of the patients with occult pneumomediastinum had aerodigestive tract injuries and follow up chest CT scans demonstrated their complete and spontaneous resolution.

Combined endeavor of Neutrosophic Set and Chan-Vese model to extract accurate liver image from CT scan.

PubMed

Siri, Sangeeta K; Latte, Mrityunjaya V

2017-11-01

Many different diseases can occur in the liver, including infections such as hepatitis, cirrhosis, cancer and over effect of medication or toxins. The foremost stage for computer-aided diagnosis of liver is the identification of liver region. Liver segmentation algorithms extract liver image from scan images which helps in virtual surgery simulation, speedup the diagnosis, accurate investigation and surgery planning. The existing liver segmentation algorithms try to extort exact liver image from abdominal Computed Tomography (CT) scan images. It is an open problem because of ambiguous boundaries, large variation in intensity distribution, variability of liver geometry from patient to patient and presence of noise. A novel approach is proposed to meet challenges in extracting the exact liver image from abdominal CT scan images. The proposed approach consists of three phases: (1) Pre-processing (2) CT scan image transformation to Neutrosophic Set (NS) and (3) Post-processing. In pre-processing, the noise is removed by median filter. The "new structure" is designed to transform a CT scan image into neutrosophic domain which is expressed using three membership subset: True subset (T), False subset (F) and Indeterminacy subset (I). This transform approximately extracts the liver image structure. In post processing phase, morphological operation is performed on indeterminacy subset (I) and apply Chan-Vese (C-V) model with detection of initial contour within liver without user intervention. This resulted in liver boundary identification with high accuracy. Experiments show that, the proposed method is effective, robust and comparable with existing algorithm for liver segmentation of CT scan images. Copyright © 2017 Elsevier B.V. All rights reserved.

Inter-observer variability in diagnosing radiological features of aneurysmal subarachnoid hemorrhage; a preliminary single centre study comparing observers from different specialties and levels of training.

PubMed

Siddiqui, Usman T; Khan, Anjum F; Shamim, Muhammad Shahzad; Hamid, Rana Shoaib; Alam, Muhammad Mehboob; Emaduddin, Muhammad

2014-01-01

A noncontrast computed tomography (CT) scan remains the initial radiological investigation of choice for a patient with suspected aneurysmal subarachnoid hemorrhage (aSAH). This initial scan may be used to derive key information about the underlying aneurysm which may aid in further management. The interpretation, however, is subject to the skill and experience of the interpreting individual. The authors here evaluate the interpretation of such CT scans by different individuals at different levels of training, and in two different specialties (Radiology and Neurosurgery). Initial nonontrast CT scan of 35 patients with aSAH was evaluated independently by four different observers. The observers selected for the study included two from Radiology and two from Neurosurgery at different levels of training; a resident currently in mid training and a resident who had recently graduated from training of each specialty. Measured variables included interpreter's suspicion of presence of subarachnoid blood, side of the subarachnoid hemorrhage, location of the aneurysm, the aneurysm's proximity to vessel bifurcation, number of aneurysm(s), contour of aneurysm(s), presence of intraventricular hemorrhage (IVH), intracerebral hemorrhage (ICH), infarction, hydrocephalus and midline shift. To determine the inter-observer variability (IOV), weighted kappa values were calculated. There was moderate agreement on most of the CT scan findings among all observers. Substantial agreement was found amongst all observers for hydrocephalus, IVH, and ICH. Lowest agreement rates were seen in the location of aneurysm being supra or infra tentorial. There were, however, some noteworthy exceptions. There was substantial to almost perfect agreement between the radiology graduate and radiology resident on most CT findings. The lowest agreement was found between the neurosurgery graduate and the radiology graduate. Our study suggests that although agreements were seen in the interpretation of some of the radiological features of aSAH, there is still considerable IOV in the interpretation of most features among physicians belonging to different levels of training and different specialties. Whether these might affect management or outcome is unclear.

Improved surgical procedure using intraoperative navigation for the implantation of the SPG microstimulator in patients with chronic cluster headache.

PubMed

Kohlmeier, Carsten; Behrens, Peter; Böger, Andreas; Ramachandran, Brinda; Caparso, Anthony; Schulze, Dirk; Stude, Philipp; Heiland, Max; Assaf, Alexandre T

2017-12-01

The ATI SPG microstimulator is designed to be fixed on the posterior maxilla, with the integrated lead extending into the pterygopalatine fossa to electrically stimulate the sphenopalatine ganglion (SPG) as a treatment for cluster headache. Preoperative surgical planning to ensure the placement of the microstimulator in close proximity (within 5 mm) to the SPG is critical for treatment efficacy. The aim of this study was to improve the surgical procedure by navigating the initial dissection prior to implantation using a passive optical navigation system and to match the post-operative CBCT images with the preoperative treatment plan to verify the accuracy of the intraoperative placement of the microstimulator. Custom methods and software were used that result in a 3D rotatable digitally reconstructed fluoroscopic image illustrating the patient-specific placement with the ATI SPG microstimulator. Those software tools were preoperatively integrated with the planning software of the navigation system to be used intraoperatively for navigated placement. Intraoperatively, the SPG microstimulator was implanted by completing the initial dissection with CT navigation, while the final position of the stimulator was verified by 3D CBCT. Those reconstructed images were then immediately matched with the preoperative CT scans with the digitally inserted SPG microstimulator. This method allowed for visual comparison of both CT scans and verified correct positioning of the SPG microstimulator. Twenty-four surgeries were performed using this new method of CT navigated assistance during SPG microstimulator implantation. Those results were compared to results of 21 patients previously implanted without the assistance of CT navigation. Using CT navigation during the initial dissection, an average distance reduction of 1.2 mm between the target point and electrode tip of the SPG microstimulator was achieved. Using the navigation software for navigated implantation and matching the preoperative planned scans with those performed post-operatively, the average distance was 2.17 mm with navigation, compared to 3.37 mm in the 28 surgeries without navigation. Results from this new procedure showed a significant reduction (p = 0.009) in the average distance from the SPG microstimulator to the desired target point. Therefore, a distinct improvement could be achieved in positioning of the SPG microstimulator through the use of intraoperative navigation during the initial dissection and by post-operative matching of pre- and post-operatively performed CBCT scans.

TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors

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

La Fontaine, M; Bradshaw, T; Kubicek, L

2014-06-15

Purpose: Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis. Methods: Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (r{sub spatial})more » on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t{sub 1}), blood flow (F), vasculature fraction (v{sub 1}), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (r{sub ROI}) the mean Cu-ATSM SUV (SUV{sub mean}) with median kinetic parameter values. Results: The spatial correlations (r{sub spatial}) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t{sub 1} was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t{sub 1} (r{sub ROI} = -0.25) and F (r{sub ROI} = 0.56). PS and v{sub 1} may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (r{sub ROI} = 0.41), and v{sub 1} (r{sub ROI} = 0.57). Conclusion: Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis. Funding: R01 CA136927.« less

CT Evolution of Hematoma and Surrounding Hypodensity in a Cadaveric Model of Intracerebral Hemorrhage.

PubMed

Majidi, Shahram; Rahim, Basit; Gilani, Sarwat I; Gilani, Waqas I; Adil, Malik M; Qureshi, Adnan I

2016-05-01

The evolution of intracerebral hematoma and perihematoma edema in the ultra-early period on computed tomographic (CT) scans in patients with intracerebral hemorrhage (ICH) is not well understood. We aimed to investigate hematoma and perihematoma changes in "neutral brain" models of ICH. One human and five goat cadaveric heads were used as "neutral brains" to provide physical properties of brain without any biological activity or new bleeding. ICH was induced by slow injection of 4 ml of fresh human blood into the right basal ganglia of the goat brains. Similarly, 20 ml of fresh blood was injected deep into the white matter of the human cadaver head in each hemisphere. Serial CT scans of the heads were obtained immediately after hematoma induction and then 1, 3, and 5 hours afterward. Analyze software (AnalyzeDirect, Overland Park, KS, USA) was used to measure hematoma and perihematoma hypodensity volumes in the baseline and follow-up CT scans. The initial hematoma volumes of 11.6 ml and 10.5 ml in the right and left hemispheres of the cadaver brains gradually decreased to 6.6 ml and 5.4 ml at 5 hours, showing 43% and 48% retraction of hematoma, respectively. The volume of the perihematoma hypodensity in the right and left hemisphere increased from 2.6 ml and 2.2 ml in the 1-hour follow-up CT scans to 4.9 ml and 4.4 ml in the 5-hour CT scan, respectively. Hematoma retraction was also observed in all five goat brains ICH models with the mean ICH volume decreasing from 1.49 ml at baseline scan to 1.01 ml at the 5-hour follow-up CT scan (29.6% hematoma retraction). Perihematoma hypodensity was visualized in 70% of ICH in goat brains, with an increasing mean hypodensity volume of 0.4 ml in the baseline CT scan to 0.8 ml in the 5-hour follow-up CT scan. Our study demonstrated that substantial hematoma retraction and perihematoma hypodensity occurs in ICH in the absence of any new bleeding or biological activity of surrounding brain. Such observations suggest that active bleeding is underestimated in patients with no or small hematoma expansion and our understanding of perihematoma hypodensity needs to be reconsidered. Copyright © 2015 by the American Society of Neuroimaging.

Radiation dose exposure in patients affected by lymphoma undergoing repeat CT examinations: how to manage the radiation dose variability.

PubMed

Paolicchi, Fabio; Bastiani, Luca; Guido, Davide; Dore, Antonio; Aringhieri, Giacomo; Caramella, Davide

2018-03-01

To assess the variability of radiation dose exposure in patients affected by lymphoma undergoing repeat CT (computed tomography) examinations and to evaluate the influence of different scan parameters on the overall radiation dose. A series of 34 patients (12 men and 22 women with a median age of 34.4 years) with lymphoma, after the initial staging CT underwent repeat follow-up CT examinations. For each patient and each repeat examination, age, sex, use of AEC system (Automated Exposure Control, i.e. current modulation), scan length, kV value, number of acquired scans (i.e. number of phases), abdominal size diameter and dose length product (DLP) were recorded. The radiation dose of just one venous phase was singled out from the DLP of the entire examination. All scan data were retrieved by our PACS (Picture Archiving and Communication System) by means of a dose monitoring software. Among the variables we considered, no significant difference of radiation dose was observed among patients of different ages nor concerning tube voltage. On the contrary the dose delivered to the patients varied depending on sex, scan length and usage of AEC. No significant difference was observed depending on the behaviour of technologists, while radiologists' choices had indirectly an impact on the radiation dose due to the different number of scans requested by each of them. Our results demonstrate that patients affected by lymphoma who undergo repeat whole body CT scanning may receive unnecessary overexposure. We quantified and analyzed the most relevant variables in order to provide a useful tool to manage properly CT dose variability, estimating the amount of additional radiation dose for every single significant variable. Additional scans, incorrect scan length and incorrect usage of AEC system are the most relevant cause of patient radiation exposure.

False Positive Positron Emission Tomography / Computed Tomography Scans in Treated Head and Neck Cancers

PubMed Central

Cheung, Michael K; Ong, Shawn Y; Goyal, Uma; Wertheim, Betsy C; Hsu, Charles C

2017-01-01

Objective Positron emission tomography/computed tomography (PET/CT) imaging for head and neck cancers (HNC) is commonly utilized for post-treatment assessment. Though PET/CT in this setting has been reported to have high negative predictive values (> 90%), positive predictive values have been reported at approximately 50%, leading to high rates of false positivity (FP) and troubling management decisions for both patient and practitioner. The objective of this study was to identify patient, disease, treatment and imaging factors that might be associated with a higher likelihood of FP on initial post-treatment PET/CT imaging for patients treated for HNC.  Materials and methods A retrospective chart review was performed on 84 patients treated for HNC who received radiation therapy (RT) as part of their overall management from October 2005 to August 2013. Of the patients screened, 19 were found to have mucosally based squamous cell carcinoma (SCC) with positive initial post-treatment PET/CT studies (23%). Fisher’s exact test was used to analyze the association between categorical variables and FP, including patient's gender, disease laterality, primary tumor site and stage, nodal and overall stage, high dose RT fraction size, number of RT fractions completed, total RT dose, biologically effective dose and timing of PET/CT acquisition. Wilcoxon rank-sum test was used to analyze the association between continuous variables and FP, including patient age, total elapsed days of RT, an amount of infused fluorodeoxyglucose 18F-FDG, pre-PET/CT serum glucose levels, and maximum standardized uptake value SUVmax. Statistically significant findings were those that were deemed p <0.05. Results Among patients with positive initial post-treatment PET/CT scans for treated HNC, there was a lower proportion of higher primary disease stage associated with FP versus true positivity (T-stage 3-4: 20 vs 78%, respectively, p=0.023). We also discovered that 50% of patients that underwent confirmation for FP findings suffered serious complications as a direct consequence of invasive exploratory procedures. Conclusions Although PET/CT is known for its exceptional negative predictive value (> 90%) in the post-treatment setting for HNC, high rates of FP remains a clinical challenge. Our study suggests that tumor stage (T-stage) may impact FP rates in positive initial post-treatment PET/CT scans. We recommend careful multidisciplinary discussion regarding positive PET/CT studies in the post-treatment setting for HNC, particularly if invasive intervention is considered. PMID:28497009

Integration of prior CT into CBCT reconstruction for improved image quality via reconstruction of difference: first patient studies

NASA Astrophysics Data System (ADS)

Zhang, Hao; Gang, Grace J.; Lee, Junghoon; Wong, John; Stayman, J. Webster

2017-03-01

Purpose: There are many clinical situations where diagnostic CT is used for an initial diagnosis or treatment planning, followed by one or more CBCT scans that are part of an image-guided intervention. Because the high-quality diagnostic CT scan is a rich source of patient-specific anatomical knowledge, this provides an opportunity to incorporate the prior CT image into subsequent CBCT reconstruction for improved image quality. We propose a penalized-likelihood method called reconstruction of difference (RoD), to directly reconstruct differences between the CBCT scan and the CT prior. In this work, we demonstrate the efficacy of RoD with clinical patient datasets. Methods: We introduce a data processing workflow using the RoD framework to reconstruct anatomical changes between the prior CT and current CBCT. This workflow includes processing steps to account for non-anatomical differences between the two scans including 1) scatter correction for CBCT datasets due to increased scatter fractions in CBCT data; 2) histogram matching for attenuation variations between CT and CBCT; and 3) registration for different patient positioning. CBCT projection data and CT planning volumes for two radiotherapy patients - one abdominal study and one head-and-neck study - were investigated. Results: In comparisons between the proposed RoD framework and more traditional FDK and penalized-likelihood reconstructions, we find a significant improvement in image quality when prior CT information is incorporated into the reconstruction. RoD is able to provide additional low-contrast details while correctly incorporating actual physical changes in patient anatomy. Conclusions: The proposed framework provides an opportunity to either improve image quality or relax data fidelity constraints for CBCT imaging when prior CT studies of the same patient are available. Possible clinical targets include CBCT image-guided radiotherapy and CBCT image-guided surgeries.

Evaluation of Cervical Spine Clearance by Computed Tomographic Scan Alone in Intoxicated Patients With Blunt Trauma.

PubMed

Bush, Lisa; Brookshire, Robert; Roche, Breanna; Johnson, Amelia; Cole, Frederic; Karmy-Jones, Riyad; Long, William; Martin, Matthew J

2016-09-01

Current trauma guidelines dictate that the cervical spine should not be cleared in intoxicated patients, resulting in prolonged immobilization or additional imaging. Modern computed tomography (CT) technology may obviate this and allow for immediate clearance. To analyze cervical spine clearance practices and the utility of CT scans of the cervical spine in intoxicated patients with blunt trauma. We performed a prospective observational study of 1668 patients with blunt trauma aged 18 years and older who underwent cervical spine CT scans from March 2014 to March 2015 at an American College of Surgeons-verified Level I trauma center. Intoxication was determined by serum alcohol levels and urine drug screens. Physical examination and CT scan findings were evaluated for cervical spine injuries (CSI) and the incidence of missed injuries. Clinically relevant CSIs requiring cervical stabilization. The hypotheses formed prior to data collection were that cervical CT scans are sensitive and specific enough to diagnose CSIs that require stabilization and that normal CT scans are sufficient to clear CSIs in intoxicated patients. Of 1668 patients, 1103 (66.1%) were male, with a mean (SD) age of 49 (20) years and a mean (SD) Injury Severity Score of 10 (9). Vehicular (734 [44.0%]) and falls (579 [34.7%]) were the most common mechanisms for hospitalization. Intoxication was identified in 632 of 1429 of patients tested (44.2%; 425 [29.7%] by serum alcohol levels and 350 [24.5%] by urine drug screens). Half (316 [50.0%]) were admitted with cervical spine immobilization, and 38 (12%) of these were solely owing to the presence of intoxication. There were 65 abnormal CT scans (10.3%) in the intoxicated group. Among 567 normal CT scans, 4 (0.7%) had central cord syndrome found on initial physical examination, and 1 (0.2%) had a symptomatic unstable ligament injury that was misread as normal on CT scan but was abnormal on magnetic resonance imaging. The 316 patients kept in a cervical collar for intoxication had no missed CSIs but were kept immobilized for a mean (SD) of 12 (19) hours. Computed tomographic scans had an overall negative predictive value of 99.2% for patients with CSIs and a negative predictive value of 99.8% for ruling out CSIs that required immobilization or stabilization. In this study, alcohol or drug intoxication was common and resulted in significant delays to cervical spine clearance. Computed tomographic scans were highly reliable for identifying all clinically significant CSIs. Spine clearance based on a normal CT scan among intoxicated patients with no gross motor deficits appears to be safe and avoids prolonged and unnecessary immobilization.

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.

Detecting active pelvic arterial haemorrhage on admission following serious pelvic fracture in multiple trauma patients.

PubMed

Brun, Julien; Guillot, Stéphanie; Bouzat, Pierre; Broux, Christophe; Thony, Frédéric; Genty, Céline; Heylbroeck, Christophe; Albaladejo, Pierre; Arvieux, Catherine; Tonetti, Jérôme; Payen, Jean-Francois

2014-01-01

The early diagnosis of pelvic arterial haemorrhage is challenging for initiating treatment by transcatheter arterial embolization (TAE) in multiple trauma patients. We use an institutional algorithm focusing on haemodynamic status on admission and on a whole-body CT scan in stabilized patients to screen patients requiring TAE. This study aimed to assess the effectiveness of this approach. This retrospective cohort study included 106 multiple trauma patients admitted to the emergency room with serious pelvic fracture [pelvic abbreviated injury scale (AIS) score of 3 or more]. Of the 106 patients, 27 (25%) underwent pelvic angiography leading to TAE for active arterial haemorrhage in 24. The TAE procedure was successful within 3h of arrival in 18 patients. In accordance with the algorithm, 10 patients were directly admitted to the angiography unit (n=8) and/or operating room (n=2) for uncontrolled haemorrhagic shock on admission. Of the remaining 96 stabilized patients, 20 had contrast media extravasation on pelvic CT scan that prompted pelvic angiography in 16 patients leading to TAE in 14. One patient underwent a pelvic angiography despite showing no contrast media extravasation on pelvic CT scan. All 17 stabilized patients who underwent pelvic angiography presented a more severely compromised haemodynamic status on admission, and they required more blood products during their initial management than the 79 patients who did not undergo pelvic angiography. The incidence of unstable pelvic fractures was however comparable between the two groups. Overall, haemodynamic instability and contrast media extravasation on the CT-scan identified 26 out of the 27 patients who required subsequent pelvic angiography leading to TAE in 24. An algorithm focusing on haemodynamic status on arrival and on the whole-body CT scan in stabilized patients may be effective at triaging multiple trauma patients with serious pelvic fractures. Copyright © 2013 Elsevier Ltd. All rights reserved.

The diagnostic challenge of the sequelae of acute pancreatitis on CT imaging: a pictorial essay.

PubMed

Hughey, Mark; Taffel, Myles; Zeman, Robert K; Patel, Smita; Hill, Michael C

2017-04-01

The purpose of the study was to present a pictorial review of the long-term sequelae of acute pancreatitis on CT imaging as these findings can cause diagnostic confusion in the absence of a proper clinical history and/or prior CT imaging. We retrospectively identified 81 patients who had an episode of acute pancreatitis with diagnostic findings on CT and also underwent one or more follow-up CT scans at least 1 month beyond the acute episode. The residual findings on all follow-up CT scans were tabulated, including the time interval since the initial bout of acute pancreatitis. Residual inflammatory changes were present in 19.8% of cases, with a median time period lasting 86 days since the initial episode of acute pancreatitis. Residual fluid collections were seen in 27.2% and persisted for a median of 132 days. Three patients had residual solid-appearing inflammatory masses, which could be mistaken for neoplasms. Other long-term sequelae were also tabulated, including pancreatic ductal dilatation, pancreatic atrophy, new or increased pancreatic calcifications, biliary tract dilatation, central portal venous occlusion, and pseudoaneurysm formation. These residual findings and long-term complications are presented as a pictorial essay. Recognizing the spectrum of residual findings of acute pancreatitis, some of which can be long term, is important in the correct interpretation of a pancreatic CT. These findings can mimic acute pancreatitis or a pancreatic/peripancreatic neoplasm and often cause diagnostic confusion, especially in the absence of prior CT imaging.

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.

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 ...

Evaluation and management of 2 ferocactus spines in the orbit.

PubMed

Russell, David J; Kim, Tim I; Kubis, Kenneth

2013-01-01

A 49-year-old woman, who had fallen face first in a cactus 1 week earlier, presented with a small, mobile, noninflamed subcutaneous nodule at the rim of her right lateral orbit with no other functional deficits. A CT scan was obtained, which revealed a 4-cm intraorbital tubular-shaped foreign body resembling a large cactus spine. A second preoperative CT scan, obtained for an intraoperative guidance system, demonstrated a second cactus spine, which was initially not seen on the first CT scan. Both spines were removed surgically without complication. The authors discuss factors that can cause diagnosis delay, review the radiographic features of cactus spines, and discuss the often times benign clinical course of retained cactus spine foreign bodies. To the authors' knowledge, this is the first case report of cactus spines in the orbit. Health-care professionals should have a low threshold for imaging in cases of traumatic injuries involving cactus spines.

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.

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 ...

CT Imaging, Data Reduction, and Visualization of Hardwood Logs

Treesearch

Daniel L. Schmoldt

1996-01-01

Computer tomography (CT) is a mathematical technique that, combined with noninvasive scanning such as x-ray imaging, has become a powerful tool to nondestructively test materials prior to use or to evaluate materials prior to processing. In the current context, hardwood lumber processing can benefit greatly by knowing what a log looks like prior to initial breakdown....

Delayed diagnosis of injuries in pediatric trauma: the role of radiographic ordering practices.

PubMed

Willner, Emily L; Jackson, Hollie A; Nager, Alan L

2012-01-01

We sought to describe the use of radiographic studies in pediatric major trauma patients and determine the extent to which a selective, clinically guided use of imaging contributes to delayed diagnosis of injury (DDI). We conducted a retrospective chart review of 324 consecutive pediatric major trauma patients at our level 1 trauma center. One radiologist reviewed all imaging. Delayed diagnosis of injury was defined as detection after more than 12 hours. Equivalency testing was performed to compare radiology use in patients with and without DDI. Twenty-six (8%) of 324 patients had 36 DDI; 27 (75%) of 36 were orthopedic injuries. Median time to DDI detection was 20.5 hours (interquartile range, 15-60.5). During initial evaluation, DDI patients had similar numbers of plain radiographs (3.5 vs 3, P = .54) but more computed tomographic (CT) scans (4 vs 3, P = .03) compared with patients without DDI. Sixteen percent of all patients received CT thorax; 55%, CT cervical spine; and 56%, CT abdomen. Only 1 clinically important DDI was detected solely on the basis of a later CT scan (0.3%; 95% confidence interval, 0-1.5). No cervical spine, intrathoracic, or intraabdominal DDI was attributable to failure to obtain a CT during initial evaluation. Patients with DDI had higher injury severity scores, intubation rates, and pediatric intensive care unit admission rates than those without DDI. Patients with DDI had similar initial plain x-ray evaluations to patients without DDI, despite DDI patients being more severely injured. Delayed diagnosis of injury was not attributable to inadequate CT use. Most DDIs were orthopedic, highlighting the importance of a tertiary survey and a low threshold for skeletal radiographs. Copyright © 2012 Elsevier Inc. All rights reserved.

Application of fluence field modulation to proton computed tomography for proton therapy imaging.

PubMed

Dedes, G; De Angelis, L; Rit, S; Hansen, D; Belka, C; Bashkirov, V; Johnson, R P; Coutrakon, G; Schubert, K E; Schulte, R W; Parodi, K; Landry, G

2017-07-12

This simulation study presents the application of fluence field modulated computed tomography, initially developed for x-ray CT, to proton computed tomography (pCT). By using pencil beam (PB) scanning, fluence modulated pCT (FMpCT) may achieve variable image quality in a pCT image and imaging dose reduction. Three virtual phantoms, a uniform cylinder and two patients, were studied using Monte Carlo simulations of an ideal list-mode pCT scanner. Regions of interest (ROI) were selected for high image quality and only PBs intercepting them preserved full fluence (FF). Image quality was investigated in terms of accuracy (mean) and noise (standard deviation) of the reconstructed proton relative stopping power compared to reference values. Dose calculation accuracy on FMpCT images was evaluated in terms of dose volume histograms (DVH), range difference (RD) for beam-eye-view (BEV) dose profiles and gamma evaluation. Pseudo FMpCT scans were created from broad beam experimental data acquired with a list-mode pCT prototype. FMpCT noise in ROIs was equivalent to FF images and accuracy better than  -1.3%(-0.7%) by using 1% of FF for the cylinder (patients). Integral imaging dose reduction of 37% and 56% was achieved for the two patients for that level of modulation. Corresponding DVHs from proton dose calculation on FMpCT images agreed to those from reference images and 96% of BEV profiles had RD below 2 mm, compared to only 1% for uniform 1% of FF. Gamma pass rates (2%, 2 mm) were 98% for FMpCT while for uniform 1% of FF they were as low as 59%. Applying FMpCT to preliminary experimental data showed that low noise levels and accuracy could be preserved in a ROI, down to 30% modulation. We have shown, using both virtual and experimental pCT scans, that FMpCT is potentially feasible and may allow a means of imaging dose reduction for a pCT scanner operating in PB scanning mode. This may be of particular importance to proton therapy given the low integral dose found outside the target.

Dedicated Cone-Beam CT System for Extremity Imaging

PubMed Central

Al Muhit, Abdullah; Zbijewski, Wojciech; Thawait, Gaurav K.; Stayman, J. Webster; Packard, Nathan; Senn, Robert; Yang, Dong; Foos, David H.; Yorkston, John; Siewerdsen, Jeffrey H.

2014-01-01

Purpose To provide initial assessment of image quality and dose for a cone-beam computed tomographic (CT) scanner dedicated to extremity imaging. Materials and Methods A prototype cone-beam CT scanner has been developed for imaging the extremities, including the weight-bearing lower extremities. Initial technical assessment included evaluation of radiation dose measured as a function of kilovolt peak and tube output (in milliampere seconds), contrast resolution assessed in terms of the signal difference–to-noise ratio (SDNR), spatial resolution semiquantitatively assessed by using a line-pair module from a phantom, and qualitative evaluation of cadaver images for potential diagnostic value and image artifacts by an expert CT observer (musculoskeletal radiologist). Results The dose for a nominal scan protocol (80 kVp, 108 mAs) was 9 mGy (absolute dose measured at the center of a CT dose index phantom). SDNR was maximized with the 80-kVp scan technique, and contrast resolution was sufficient for visualization of muscle, fat, ligaments and/or tendons, cartilage joint space, and bone. Spatial resolution in the axial plane exceeded 15 line pairs per centimeter. Streaks associated with x-ray scatter (in thicker regions of the patient—eg, the knee), beam hardening (about cortical bone—eg, the femoral shaft), and cone-beam artifacts (at joint space surfaces oriented along the scanning plane—eg, the interphalangeal joints) presented a slight impediment to visualization. Cadaver images (elbow, hand, knee, and foot) demonstrated excellent visibility of bone detail and good soft-tissue visibility suitable to a broad spectrum of musculoskeletal indications. Conclusion A dedicated extremity cone-beam CT scanner capable of imaging upper and lower extremities (including weight-bearing examinations) provides sufficient image quality and favorable dose characteristics to warrant further evaluation for clinical use. © RSNA, 2013 Online supplemental material is available for this article. PMID:24475803

Substantial observer variability in the differentiation between primary intracerebral hemorrhage and hemorrhagic transformation of infarction on CT brain imaging.

PubMed

Lovelock, Caroline E; Anslow, Philip; Molyneux, Andrew J; Byrne, James V; Kuker, Wilhelm; Pretorius, Pieter M; Coull, Andrew; Rothwell, Peter M

2009-12-01

CT remains the most commonly used imaging technique in acute stroke but is often delayed after minor stroke. Interobserver reliability in distinguishing hemorrhagic transformation of infarction from intracerebral hemorrhage may depend on delays to CT but has not been reported previously despite the clinical importance of this distinction. Initial CT scans with intraparenchymal hematoma from the first 1000 patients with stroke in the Oxford Vascular Study were independently categorized as intracerebral hemorrhage or hemorrhagic transformation of infarction by 5 neuroradiologists, both blinded and unblinded to clinical history. Thirty scans were reviewed twice. Agreement was quantified by the kappa statistic. Seventy-eight scans showed intraparenchymal hematoma. Blinded pairwise interrater agreements for a diagnosis of intracerebral hemorrhage ranged from kappa=0.15 to 0.48 with poor overall agreement (kappa=0.35; 95% CI, 0.15 to 0.54) even after unblinding (kappa=0.41; 0.21 to 0.60). Blinded intrarater agreements ranged from kappa=0.21 to 0.92. Lack of consensus after unblinding was greatest in patients scanned >or=24 hours after stroke onset (67% versus 25%, P=0.001) and in minor stroke (National Institutes of Health Stroke Scale or=24 hours after minor stroke and in 48% of all 30-day stroke survivors in whom reliable diagnosis would be expected to influence long-term management. Reliability of diagnosis of intraparenchymal hematoma on CT brain scan in minor stroke is poor, particularly if scanning is delayed. Immediate brain imaging is justified in patients with minor stroke.

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.

Follow-up brain imaging of 37 children with congenital Zika syndrome: case series study.

PubMed

Petribu, Natacha Calheiros de Lima; Aragao, Maria de Fatima Vasco; van der Linden, Vanessa; Parizel, Paul; Jungmann, Patricia; Araújo, Luziany; Abath, Marília; Fernandes, Andrezza; Brainer-Lima, Alessandra; Holanda, Arthur; Mello, Roberto; Sarteschi, Camila; Duarte, Maria do Carmo Menezes Bezerra

2017-10-13

Objective  To compare initial brain computed tomography (CT) scans with follow-up CT scans at one year in children with congenital Zika syndrome, focusing on cerebral calcifications. Design  Case series study. Setting  Barão de Lucena Hospital, Pernambuco state, Brazil. Participants  37 children with probable or confirmed congenital Zika syndrome during the microcephaly outbreak in 2015 who underwent brain CT shortly after birth and at one year follow-up. Main outcome measure  Differences in cerebral calcification patterns between initial and follow-up scans. Results  37 children were evaluated. All presented cerebral calcifications on the initial scan, predominantly at cortical-white matter junction. At follow-up the calcifications had diminished in number, size, or density, or a combination in 34 of the children (92%, 95% confidence interval 79% to 97%), were no longer visible in one child, and remained unchanged in two children. No child showed an increase in calcifications. The calcifications at the cortical-white matter junction which were no longer visible at follow-up occurred predominately in the parietal and occipital lobes. These imaging changes were not associated with any clear clinical improvements. Conclusion  The detection of cerebral calcifications should not be considered a major criterion for late diagnosis of congenital Zika syndrome, nor should the absence of calcifications be used to exclude the diagnosis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Impact of creatine kinase correction on the predictive value of S-100B after mild traumatic brain injury.

PubMed

Bazarian, Jeffrey J; Beck, Christopher; Blyth, Brian; von Ahsen, Nicolas; Hasselblatt, Martin

2006-01-01

To validate a correction factor for the extracranial release of the astroglial protein, S-100B, based on concomitant creatine kinase (CK) levels. The CK- S-100B relationship in non-head injured marathon runners was used to derive a correction factor for the extracranial release of S-100B. This factor was then applied to a separate cohort of 96 mild traumatic brain injury (TBI) patients in whom both CK and S-100B levels were measured. Corrected S-100B was compared to uncorrected S-100B for the prediction of initial head CT, three-month headache and three-month post concussive syndrome (PCS). Corrected S-100B resulted in a statistically significant improvement in the prediction of 3-month headache (area under curve [AUC] 0.46 vs 0.52, p=0.02), but not PCS or initial head CT. Using a cutoff that maximizes sensitivity (> or = 90%), corrected S-100B improved the prediction of initial head CT scan (negative predictive value from 75% [95% CI, 2.6%, 67.0%] to 96% [95% CI: 83.5%, 99.8%]). Although S-100B is overall poorly predictive of outcome, a correction factor using CK is a valid means of accounting for extracranial release. By increasing the proportion of mild TBI patients correctly categorized as low risk for abnormal head CT, CK-corrected S100-B can further reduce the number of unnecessary brain CT scans performed after this injury.

Is computed tomography a necessary part of a metastatic evaluation for castration-resistant prostate cancer? Results from the Shared Equal Access Regional Cancer Hospital Database.

PubMed

Hanyok, Brian T; Howard, Lauren E; Amling, Christopher L; Aronson, William J; Cooperberg, Matthew R; Kane, Christopher J; Terris, Martha K; Posadas, Edwin M; Freedland, Stephen J

2016-01-15

Metastatic lesions in prostate cancer beyond the bone have prognostic importance and affect clinical therapeutic decisions. Few data exist regarding the prevalence of soft-tissue metastases at the initial diagnosis of metastatic castration-resistant prostate cancer (mCRPC). This study analyzed 232 men with nonmetastatic (M0) castration-resistant prostate cancer (CRPC) who developed metastases detected by a bone scan or computed tomography (CT). All bone scans and CT scans within the 30 days before or after the mCRPC diagnosis were reviewed. The rate of soft-tissue metastases among those undergoing CT was determined. Then, predictors of soft-tissue metastases and visceral and lymph node metastases were identified. Compared with men undergoing CT (n = 118), men undergoing only bone scans (n = 114) were more likely to have received primary treatment (P = .048), were older (P = .013), and less recently developed metastases (P = .018). Among those undergoing CT, 52 (44%) had soft-tissue metastases, including 20 visceral metastases (17%) and 41 lymph node metastases (35%), whereas 30% had no bone involvement. In a univariable analysis, only prostate-specific antigen (PSA) predicted soft-tissue metastases (odds ratio [OR], 1.27; P = .047), and no statistically significant predictors of visceral metastases were found. A higher PSA level was associated with an increased risk of lymph node metastases (OR, 1.38; P = .014), whereas receiving primary treatment was associated with decreased risk (OR, 0.36; P = .015). The data suggest that there is a relatively high rate of soft-tissue metastasis (44%) among CRPC patients undergoing CT at the initial diagnosis of metastases, including some men with no bone involvement. Therefore, forgoing CT during a metastatic evaluation may lead to an underdiagnosis of soft-tissue metastases and an underdiagnosis of metastases in general. Cancer 2015. © 2015 American Cancer Society. Cancer 2016;122:222-229. © 2015 American Cancer Society. © 2015 American Cancer Society.

Anastomotic leaks: what is the best diagnostic imaging study?

PubMed

Nicksa, G A; Dring, R V; Johnson, K H; Sardella, W V; Vignati, P V; Cohen, J L

2007-02-01

Postoperative anastomotic leaks are one of the most devastating consequences of colorectal surgery. Diagnostic imaging for upper gastrointestinal anastomotic leaks has been evaluated and reported on extensively. No study has compared the utility and effectiveness of CT scans and water-soluble enemas for the identification of postoperative lower gastrointestinal anastomotic leaks. The present study was designed to evaluate and compare these two common radiographic imaging modalities in detecting lower gastrointestinal anastomotic leaks. A retrospective chart review was performed that identified 36 patients during a seven-year period who underwent reoperative surgery for a lower gastrointestinal anastomotic leak. Patient's imaging studies were classified as positive if extravasation of contrast material was demonstrated. When negative, a study was retrospectively reviewed in an attempt to identify findings suggestive of an anastomotic leak. There were 36 patients identified with a postoperative lower gastrointestinal leak requiring surgical intervention. There were 28 of 36 patients (78 percent) re-explored on the basis of a radiologic study demonstrating an anastomotic leak. A total of 27 CT scans were performed, of which 4 (14.8 percent) were considered positive for an anastomotic leak. On review of the remaining negative CT scans, nine (33.3 percent) were considered descriptive positive with a large amount of fluid or air in the peritoneal cavity but without obvious extravasation of contrast. Eighteen patients were evaluated with a water-soluble enema and 15 (83.3 percent) demonstrated extravasation of contrast material. In the 26 patients with a distal anastomotic leak, 17 water-soluble enemas were performed, with 15 (88 percent) demonstrating a leak. In contrast, only 2 of 17 (12 percent) CT scans were positive in this group of patients (P < 0.001). There were ten patients who initially had a CT scan followed by a water-soluble enema. Of these patients, eight of nine (88 percent) initially had a negative CT scan but were considered to be clinically suspicious of having an anastomotic leak and subsequently had a leak demonstrated on a water-soluble enema. Early intervention in patients who develop an anastomotic leak can be shown to improve the ultimate outcome, especially with respect to mortality. It is usually necessary to obtain objective tests of anastomotic integrity because of the nonspecificity of clinical signs. Our study supported the superiority of water-soluble enema to CT imaging in patients in whom both modalities were used. This difference was most pronounced for distal anastomotic leaks, whereas no radiologic imaging study proved effective in evaluating proximal anastomoses.

Spontaneous dissolution of a guaifenesin stone.

PubMed

Nguyen, Thai T; Fallon, Bernard; Winfield, Howard N

2005-08-01

Guaifenesin is a commonly used expectorant whose use may lead to the occasional formation of guaifenesin urinary stones. We herein describe a patient who was taking 2400 mg Guaifenesin per day as part of his treatment for asthma. He had a past history of a guaifenesin stone removed ureteroscopically. His current presentation was with a 9 mm by 6 mm stone in the upper left ureter, seen on CT scan, and treated initially with a ureteral stent and hydration. After 3 weeks, the stone had disappeared, as confirmed by repeat CT scan. The genesis and treatment of guaifenesin stones is discussed.

Contribution of postmortem multidetector CT scanning to identification of the deceased in a mass disaster: Experience gained from the 2009 Victorian bushfires.

PubMed

O'Donnell, C; Iino, M; Mansharan, K; Leditscke, J; Woodford, N

2011-02-25

CT scanning of the deceased is an established technique performed on all individuals admitted to VIFM over the last 5 years. It is used primarily to assist pathologists in determining cause and manner of death but is also invaluable for identification of unknown deceased individuals where traditional methods are not possible. Based on this experience, CT scanning was incorporated into phase 2 of the Institute's DVI process for the 2009 Victorian bushfires. All deceased individuals and fragmented remains admitted to the mortuary were CT scanned in their body bags using established protocols. Images were reviewed by 2 teams of 2 radiologists experienced in forensic imaging and the findings transcribed onto a data sheet constructed specifically for the DVI exercise. The contents of 255 body bags were examined in the 28 days following the fires. 164 missing persons were included in the DVI process with 163 deceased individuals eventually identified. CT contributed to this identification in 161 persons. In 2 cases, radiologists were unable to recognize commingled remains. CT was utilized in the initial triage of each bag's contents. If radiological evaluation determined that bodies were incomplete then this information was provided to search teams who revisited the scenes of death. CT was helpful in differentiation of human from non-human remains in 8 bags, recognition of human/animal commingling in 10 bags and human commingling in 6 bags. In 61% of cases gender was able to be determined on CT using a novel technique of genitalia detection and in all but 2 cases this was correct. Age range was able to be determined on CT in 94% with an accuracy of 76%. Specific identification features detected on CT included the presence of disease (14 disease entities in 13 cases), medical devices (26 devices in 19 cases) and 274 everyday metallic items associated with the remains of 135 individuals. CT scanning provided useful information prior to autopsy by flagging likely findings including the presence of non-human remains, at the time of autopsy by assisting in the localization of identifying features in heavily disfigured bodies, and after autopsy by retrospective review of images for clarification of issues that arose at the time of pathologist case review. In view of the success of CT scanning in this mass disaster, DVI administrators should explore the incorporation of CT services into their disaster plans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Early prosthetic aortic valve infection identified with the use of positron emission tomography in a patient with lead endocarditis.

PubMed

Amraoui, Sana; Tlili, Ghoufrane; Sohal, Manav; Bordenave, Laurence; Bordachar, Pierre

2016-12-01

18-Fluorodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) scanning has recently been proposed as a diagnostic tool for lead endocarditis (LE). FDG PET/CT might be also useful to localize associated septic emboli in patients with LE. We report an interesting case of a LE patient with a prosthetic aortic valve in whom a trans-esophageal echocardiogram did not show associated aortic endocarditis. FDG PET/CT revealed prosthetic aortic valve infection. A second TEE performed 2 weeks after identified aortic vegetation. A longer duration of antimicrobial therapy with serial follow-up echocardiography was initiated. There was also increased uptake in the sigmoid colon, corresponding to focal polyps resected during a colonoscopy. FDG PET/CT scanning seems to be highly sensitive for prosthetic aortic valve endocarditis diagnosis. This promising diagnostic tool may be beneficial in LE patients, by identifying septic emboli and potential sites of pathogen entry.

Comparison of Intralaminar and Interlaminar Mode-I Fracture Toughness of Unidirectional IM7/8552 Graphite/Epoxy Composite

NASA Technical Reports Server (NTRS)

Czabaj, Michael W.; Ratcliffe, James

2012-01-01

The intralaminar and interlaminar mode-I fracture-toughness of a unidirectional IM7/8552 graphite/epoxy composite were measured using compact tension (CT) and double cantilever beam (DCB) test specimens, respectively. Two starter crack geometries were considered for both the CT and DCB specimen configurations. In the first case, starter cracks were produced by 12.5 micron thick, Teflon film inserts. In the second case, considerably sharper starter cracks were produced by fatigue precracking. For each specimen configuration, use of the Teflon film starter cracks resulted in initially unstable crack growth and artificially high initiation fracture-toughness values. Conversely, specimens with fatigue precracks exhibited stable growth onset and lower initiation fracture toughness. For CT and DCB specimens with fatigue precracks, the intralaminar and interlaminar initiation fracture toughnesses were approximately equal. However, during propagation, the CT specimens exhibited more extensive fiber bridging, and rapidly increasing R-curve behavior as compared to the DCB specimens. Observations of initiation and propagation of intralaminar and interlaminar fracture, and the measurements of fracture toughness, were supported by fractographic analysis using scanning electron microscopy.

Importance of Second-look Endoscopy on an Empty Stomach for Finding Gastric Bezoars in Patients with Gastric Ulcers.

PubMed

Iwamuro, Masaya; Tanaka, Shouichi; Moritou, Yuki; Inaba, Tomoki; Higashi, Reiji; Kusumoto, Chiaki; Yunoki, Naoko; Ishikawa, Shin; Okamoto, Yuko; Kawai, Yoshinari; Kitada, Ken-Ichi; Takenaka, Ryuta; Toyokawa, Tatsuya; Okada, Hiroyuki

2017-06-01

　Most gastric bezoars can be treated with endoscopic fragmentation combined with or without cola dissolution, whereas laparotomy or laparoscopic surgery is generally inevitable for small intestinal bezoars because they cause small bowel obstruction. Therefore, early diagnosis and management of gastric bezoars are necessary to prevent bezoar-induced ileus. To investigate the incidence of overlooked gastric bezoars during the initial esophagogastroduodenoscopy, we retrospectively reviewed the cases of 27 patients diagnosed with gastrointestinal bezoars. The bezoars were diagnosed using esophagogastroduodenoscopy (n=25), abdominal ultrasonography (n=1), and barium follow-through examination (n=1). Bezoars were overlooked in 9/25 patients (36.0%) during the initial endoscopy examination because the bezoars were covered with debris in the stomach. Of the 9 patients, 8 had concomitant gastric ulcers, and the other patient had gastric lymphoma. Although a computed tomography (CT) scan was performed before the second-look endoscopy in 8 of the 9 patients, the bezoars were mistaken as food debris on CT findings and were overlooked in these patients. In conclusion, gastric bezoars may not be discovered during the initial esophagogastroduodenoscopy and CT scan. In cases with debris in the stomach, second-look endoscopy is essential to detect bezoars.

Clinical implications of immediate or later periportal edema in MS-CT trauma scans: surrogate parameter of intravenous fluid status and venous congestion.

PubMed

Kleber, C; Buschmann, C T

2013-06-01

Periportal edema (PPE) of the liver in multislice computed tomography (MS-CT) scans that develops immediately (primary PPE [pPPE]) or later (secondary PPE [sPPE]) is not uncommon in severe trauma patients. Although PPE may serve as a marker for blunt abdominal trauma (22-31 % of cases), distinct causes and clinical implications of PPE are unclear. We analyzed the incidence of pPPE and sPPE in 68 MS-CT scans in severe trauma patients (2007-2009). Exclusion criteria were severely burned patients and patients with preexistent liver diseases predisposing to PPE. We divided PPE+ patients into two subpopulations-either initial/primary PPE (pPPE+) or later/secondary PPE (sPPE+). Further patient data were collected and statistically analyzed. PPE+ was found in 27.9 % (n = 19). Females predominated (p = 0.01), and PPE+ patients presented with a significantly better pH at admission (p = 0.008). The total amount of volume resuscitation (1,983 ± 1,155 ml; p = 0.02) and crystalloids (1,117 ± 796 ml; p = 0.006) administered before MS-CT scans was significantly higher in PPE+, whereas the amount of administered colloids (797 ± 640 ml) showed no significant difference in both groups. PPE+ was not associated with further patient data, i.e., trauma mechanism, injury severity, prognosis-relevant factors, adverse clinical events, or mortality. pPPE+ in MS-CT may serve as a surrogate parameter for intravenous volume load and/or venous congestion, and sPPE+ may also indicate venous congestion and right heart failure after severe trauma. In severe trauma patients with pPPE+/sPPE+ in MS-CT scans, causes of PPE relating to intravenous fluid overload and/or venous congestion should be excluded or treated.

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

[Virtual otoscopy--technique, indications and initial experiences with multislice spiral CT].

PubMed

Klingebiel, R; Bauknecht, H C; Lehmann, R; Rogalla, P; Werbs, M; Behrbohm, H; Kaschke, O

2000-11-01

We report the standardized postprocessing of high-resolution CT data acquired by incremental CT and multi-slice CT in patients with suspected middle ear disorders to generate three-dimensional endoluminal views known as virtual otoscopy. Subsequent to the definition of a postprocessing protocol, standardized endoluminal views of the middle ear were generated according to their otological relevance. The HRCT data sets of 26 ENT patients were transferred to a workstation and postprocessed to 52 virtual otoscopies. Generation of predefined endoluminal views from the HRCT data sets was possible in all patients. Virtual endoscopic views added meaningful information to the primary cross-sectional data in patients suffering from ossicular pathology, having contraindications for invasive tympanic endoscopy or being assessed for surgery of the tympanic cavity. Multi slice CT improved the visualization of subtle anatomic details such as the stapes suprastructure and reduced the scanning time. Virtual endoscopy allows for the non invasive endoluminal visualization of various tympanic lesions. Use of the multi-slice CT technique reduces the scanning time and improves image quality in terms of detail resolution.

Ventricular Geometry From Non-contrast Non-ECG-gated CT Scans: An Imaging Marker of Cardiopulmonary Disease in Smokers.

PubMed

Rahaghi, Farbod N; Vegas-Sanchez-Ferrero, Gonzalo; Minhas, Jasleen K; Come, Carolyn E; De La Bruere, Isaac; Wells, James M; González, Germán; Bhatt, Surya P; Fenster, Brett E; Diaz, Alejandro A; Kohli, Puja; Ross, James C; Lynch, David A; Dransfield, Mark T; Bowler, Russel P; Ledesma-Carbayo, Maria J; San José Estépar, Raúl; Washko, George R

2017-05-01

Imaging-based assessment of cardiovascular structure and function provides clinically relevant information in smokers. Non-cardiac-gated thoracic computed tomographic (CT) scanning is increasingly leveraged for clinical care and lung cancer screening. We sought to determine if more comprehensive measures of ventricular geometry could be obtained from CT using an atlas-based surface model of the heart. Subcohorts of 24 subjects with cardiac magnetic resonance imaging (MRI) and 262 subjects with echocardiography were identified from COPDGene, a longitudinal observational study of smokers. A surface model of the heart was manually initialized, and then automatically optimized to fit the epicardium for each CT. Estimates of right and left ventricular (RV and LV) volume and free-wall curvature were then calculated and compared to structural and functional metrics obtained from MRI and echocardiograms. CT measures of RV dimension and curvature correlated with similar measures obtained using MRI. RV and LV volume obtained from CT inversely correlated with echocardiogram-based estimates of RV systolic pressure using tricuspid regurgitation jet velocity and LV ejection fraction respectively. Patients with evidence of RV or LV dysfunction on echocardiogram had larger RV and LV dimensions on CT. Logistic regression models based on demographics and ventricular measures from CT had an area under the curve of >0.7 for the prediction of elevated right ventricular systolic pressure and ventricular failure. These data suggest that non-cardiac-gated, non-contrast-enhanced thoracic CT scanning may provide insight into cardiac structure and function in smokers. Copyright © 2017. Published by Elsevier Inc.

Automatic initialization for 3D bone registration

NASA Astrophysics Data System (ADS)

Foroughi, Pezhman; Taylor, Russell H.; Fichtinger, Gabor

2008-03-01

In image-guided bone surgery, sample points collected from the surface of the bone are registered to the preoperative CT model using well-known registration methods such as Iterative Closest Point (ICP). These techniques are generally very sensitive to the initial alignment of the datasets. Poor initialization significantly increases the chances of getting trapped local minima. In order to reduce the risk of local minima, the registration is manually initialized by locating the sample points close to the corresponding points on the CT model. In this paper, we present an automatic initialization method that aligns the sample points collected from the surface of pelvis with CT model of the pelvis. The main idea is to exploit a mean shape of pelvis created from a large number of CT scans as the prior knowledge to guide the initial alignment. The mean shape is constant for all registrations and facilitates the inclusion of application-specific information into the registration process. The CT model is first aligned with the mean shape using the bilateral symmetry of the pelvis and the similarity of multiple projections. The surface points collected using ultrasound are then aligned with the pelvis mean shape. This will, in turn, lead to initial alignment of the sample points with the CT model. The experiments using a dry pelvis and two cadavers show that the method can align the randomly dislocated datasets close enough for successful registration. The standard ICP has been used for final registration of datasets.

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 ...

SU-G-TeP2-11: Initial Evaluation of a Novel Split-Filter Dual-Energy CT for Use in Radiation Oncology

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

Miller, J; Huang, J; Szczykutowicz, T

2016-06-15

Purpose: To perform an initial evaluation of a novel split-filter dual-energy CT (DECT) system with the goal of understanding the clinical utility and limitations of the system for radiation therapy. Methods: Several phantoms were imaged using the split-filter DECT technique on the Siemens Edge CT scanner using a range of clinically-relevant doses. The optimum-contrast reconstruction, the mixed reconstruction, and the monoenergetic reconstructions (ranging from 40 keV to 190 keV) were evaluated. Each image was analyzed for CT number accuracy, uniformity, noise, low-contrast visibility (LCV), spatial resolution and geometric distortion. For comparison purposes, all parameters were evaluated on 120 kVp single-energymore » CT (SECT) scans used for treatment planning, as well as, a sequential-scan DECT technique for corresponding doses. Results: For all DECT reconstructions no observable geometric distortion was found. Both the optimal-contrast and mixed images demonstrated slight improvements in LCV and noise when compared to the SECT, and slight reductions in CT number accuracy and spatial resolution. The CT numbers trended as expected for the monoenergetic reconstructions, with CT number accuracy within 50 HU for materials of density <2 g/cm3. Spatial resolution increased with energy, and for monoenergetic reconstructions >70 keV the spatial resolution exceeded that of the SECT. The noise in the monoenergetic reconstructions increased with decreasing energy. Thus, the image uniformity, signal-to-noise ratio and LCV were diminished at lower energies (70 keV). Applying iterative reconstruction techniques to the low-energy images reduced noise and improved LCV. The signal-to-noise ratio was stable for energies >100 keV. Conclusion: The initial commissioning of the novel split-filter DECT technology demonstrated favorable results for clinical implementation. The mixed reconstruction showed potential as a replacement for the treatment planning SECT. The image parameters for the monoenergetic reconstructions varied appropriately with energy. This work provides an initial understanding of the limitations and potential applications for monoenergetic imaging.« less

Radiation exposure in the young level 1 trauma patient: a retrospective review.

PubMed

Gottschalk, Michael B; Bellaire, Laura L; Moore, Thomas

2015-01-01

Computed tomography (CT) has become an increasingly popular and powerful tool for clinicians managing trauma patients with life-threatening injuries, but the ramifications of increasing radiation burden on individual patients are not insignificant. This study examines a continuous series of 337 patients less than 40 years old admitted to a level 1 trauma center during a 4-month period. Primary outcome measures included number of scans; effective dose of radiation from radiographs and CT scans, respectively; and total effective dose from both sources over patients' hospital stays. Several variables, including hospital length of stay, initial Glasgow Coma Scale score, and Injury Severity Score, correlated with greater radiation exposure. Blunt trauma victims were more prone to higher doses than those with penetrating or combined penetrating and blunt trauma. Location and mechanism of injury were also found to correlate with radiation exposure. Trauma patients as a group are exposed to high levels of radiation from X-rays and CT scans, and CT scans contribute a very high proportion (91.3% ± 11.7%) of that radiation. Certain subgroups of patients are at a particularly high risk of exposure, and greater attention to cumulative radiation dose should be paid to patients with the above mentioned risk factors.

The effects of misinterpretation of an artefact on multidetector row CT scans in children.

PubMed

du Plessis, Anne-Marie; Theron, Salomine; Andronikou, Savvas

2009-02-01

Artefacts reflect problems with radiographic technique rather than true pathology. These may be misinterpreted as pathology with serious consequences. An artefact caused such problems in one paediatric imaging department. To determine the incidence, and consequences of misinterpretation, of a CT artefact in a paediatric imaging department. A retrospective review of images and reports of paediatric CT scans over a set period with a known artefact was performed. Reports were correlated with reviewers' evaluation of the presence of artefact and reviewed for correct identification of artefact, misinterpretation as pathology, and action taken as a result. A total of 74 CT scans had been performed over the study period and an artefact detected by reviewers on 32 (43%). Six (18.75%) of these were misinterpreted as pathology, of which three (9.4%) were reported as tuberculous granulomas, two (6.2%) as haemorrhages and one (3.1%) as an unknown hyperdensity. Two patients (6.2%) had subsequent MRI studies performed, and treatment for tuberculosis was continued in one patient (3.1%). No initial report identified the artefact. One-fifth of the scans with the artefact were misinterpreted as pathology and half of these misinterpretations led to further action. Artefacts result in false diagnoses and unnecessary investigations; vigilance is needed.

Value of initial radiological investigations in patients admitted to hospital with appendicitis, acute gallbladder disease or acute pancreatitis.

PubMed

Bhangu, Aneel; Richardson, Charlotte; Winter, Hannah; Bleetman, Anthony

2010-10-01

To determine the value of abdominal radiography (AXR) for investigating patients attending hospital with a first episode of appendicitis (requiring appendicectomy), acute gallbladder disease or acute pancreatitis, and to identify if early (within 18 h) ultrasound or CT scanning reduces the use of AXR. Setting Two acute teaching hospitals during August-September 2008 and February-March 2009. Audit of 355 patients (179 patients (50%) who underwent appendicectomy, 128 (36%) admitted with acute gallbladder disease and 48 (14%) with acute pancreatitis). AXR was performed in 53 patients (30%) who underwent appendicectomy, 73 (57%) with acute gallstone disease and 38 (78%) with acute pancreatitis. The useful abnormality pick-up rate was low; 9% (n=5), 5% (n=4) and 0% (n=0), respectively. When used, ultrasound confirmed the diagnosis in 84% (140/166) and CT scanning (either after AXR or as first line) in 97% (34/35). 42 patients underwent early ultrasound (n=27) or CT scanning (n=15), which together reduced the rate of AXR usage by 34% (14/42 early vs 107/159 delayed, p<0.001). AXR does not aid diagnosis of these conditions but is still performed. Early ultrasound or CT scanning reduces the use of AXR and are more sensitive; methods of providing these should be explored.

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 ...

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 ...

SU-F-T-26: A Study of the Consistency of Brachytherapy Treatments for Vaginal Cuff

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

Shojaei, M; Pella, S; Dumitru, N

2016-06-15

Purpose: To evaluate to treatment consistency over the total number of fractions when treatment what HDR brachytherapy using the ML cylinders. At the same time the dosimetric impact on the critical organs is monitored over the total number of fractions. Methods: A retrospective analysis of 10 patients treated with Cylinder applicators, from 2015–2016 were considered for this study. The CT scans of these patients, taken before each treatment were separately imported in to the treatment planning system and paired with the initial CT scan after completing the contouring. Two sets of CT images were fused together with respective to themore » applicator, using landmark registration. The doses of each plan were imported as well and a cumulative dosimetric analysis was made for bladder, bowels, and rectum and PTV. Results: No contour of any of the OAR was exactly similar when CT images were fused on each other. The PTV volumes vary from fraction to fraction. There was always a difference between the doses received by the OARs between treatments. The maximum dose varied between 5% and 30% in rectum and bladder. The minimum dose varied between 5% and 8% in rectum and bladder. The average dose varied between 15% and 20% in rectum and bladder. Deviation in placement were noticed between fractions. Conclusion: The variation in volumes of OARs and isodoses near the OARs, indicate that the estimated doses to OARs on the planning system may not be the same dose delivered to the patient in all the fractions. There are no major differences between the prescribed dose and the delivered dose over the total number of fractions. In some cases the critical organs will benefit if the consecutive plans will made after the CT scans will be registered with the initial scan and then planned.« less

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.

An Indirect Method to Measure Abutment Screw Preload: A Pilot Study Based on Micro-CT Scanning.

PubMed

Rezende, Carlos Eduardo E; Griggs, Jason Alan; Duan, Yuanyuan; Mushashe, Amanda M; Nolasco, Gisele Maria Correr; Borges, Ana Flávia Sanches; Rubo, José Henrique

2015-01-01

This study aimed to measure the preload in different implant platform geometries based on micro-CT images. External hexagon (EH) implants and Morse Tapered (MT) implants (n=5) were used for the preload measurement. The abutment screws were scanned in micro-CT to obtain their virtual models, which were used to record their initial length. The abutments were screwed on the implant with a 20 Ncm torque and the set composed by implant, abutment screw and abutment were taken to the micro-CT scanner to obtain virtual slices of the specimens. These slices allowed the measurement of screw lengths after torque application and based on the screw elongation. Preload values were calculated using the Hooke's Law. The preloads of both groups were compared by independent t-test. Removal torque of each specimen was recorded. To evaluate the accuracy of the micro-CT technique, three rods with known lengths were scanned and the length of their virtual model was measured and compared with the original length. One rod was scanned four times to evaluate the measuring method variation. There was no difference between groups for preload (EH = 461.6 N and MT = 477.4 N), but the EH group showed higher removal torque values (13.8 ± 4.7 against 8.2 ± 3.6 N cm for MT group). The micro-CT technique showed a variability of 0.053% and repeatability showed an error of 0.23 to 0.28%. Within the limitations of this study, there was no difference between external hexagon and Morse taper for preload. The method using micro-CT may be considered for preload calculation.

Relative plan robustness of step-and-shoot vs rotational intensity–modulated radiotherapy on repeat computed tomographic simulation for weight loss in head and neck cancer

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

Thomson, David J.; The University of Manchester, Manchester Academic Health Science Centre, Institute of Cancer Sciences, Manchester; Beasley, William J.

Introduction: Interfractional anatomical alterations may have a differential effect on the dose delivered by step-and-shoot intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT). The increased degrees of freedom afforded by rotational delivery may increase plan robustness (measured by change in target volume coverage and doses to organs at risk [OARs]). However, this has not been evaluated for head and neck cancer. Materials and methods: A total of 10 patients who required repeat computed tomography (CT) simulation and replanning during head and neck IMRT were included. Step-and-shoot IMRT and VMAT plans were generated from the original planning scan. The initial andmore » second CT simulation scans were fused and targets/OAR contours transferred, reviewed, and modified. The plans were applied to the second CT scan and doses recalculated without repeat optimization. Differences between step-and-shoot IMRT and VMAT for change in target volume coverage and doses to OARs between first and second CT scans were compared by Wilcoxon signed rank test. Results: There were clinically relevant dosimetric changes between the first and the second CT scans for both the techniques (reduction in mean D{sub 95%} for PTV2 and PTV3, D{sub min} for CTV2 and CTV3, and increased mean doses to the parotid glands). However, there were no significant differences between step-and-shoot IMRT and VMAT for change in any target coverage parameter (including D{sub 95%} for PTV2 and PTV3 and D{sub min} for CTV2 and CTV3) or dose to any OARs (including parotid glands) between the first and the second CT scans. Conclusions: For patients with head and neck cancer who required replanning mainly due to weight loss, there were no significant differences in plan robustness between step-and-shoot IMRT and VMAT. This information is useful with increased clinical adoption of VMAT.« less

Malignant external otitis: early scintigraphic detection

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

Strashun, A.M.; Nejatheim, M.; Goldsmith, S.J.

1984-02-01

Pseudomonas otitis externa in elderly diabetics may extend aggressively to adjacent bone, cranial nerves, meninges, and vessels, leading to a clinical diagnosis of ''malignant'' external otitis. Early diagnosis is necessary for successful treatment. This study compares the findings of initial radiographs, thin-section tomography of temporal bone, CT scans of head and neck, technetium-99m methylene diphosphonate (MDP) and gallium-67 citrate scintigraphy, and single-photon emission computed tomography (SPECT) for detection of temporal bone osteomylitis in ten patients fulfilling the clinical diagnostic criteria of malignant external otitis. Skull radiographs were negative in all of the eight patients studied. Thin-section tomography was positive inmore » one of the seven patients studied using this modality. CT scanning suggested osteomyelitis in three of nine patients. Both Tc-99m and Ga-67 citrate scintigraphy were positive in 10 of 10 patients. These results suggest that technetium and gallium scintigraphy are more sensitive than radiographs and CT scans for early detection of malignant external otitis.« less

F-18 fluoride positron emission tomography/computed tomography in the diagnosis of avascular necrosis of the femoral head: Comparison with magnetic resonance imaging

PubMed Central

Gayana, Shankaramurthy; Bhattacharya, Anish; Sen, Ramesh Kumar; Singh, Paramjeet; Prakash, Mahesh; Mittal, Bhagwant Rai

2016-01-01

Objective: Femoral head avascular necrosis (FHAVN) is one of the increasingly common causes of musculoskeletal disability and poses a major diagnostic and therapeutic challenge. Although radiography, scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI) have been widely used in the diagnosis of FHAVN, positron emission tomography (PET) has recently been evaluated to assess vascularity of the femoral head. In this study, the authors compared F-18 fluoride PET/CT with MRI in the initial diagnosis of FHAVN. Patients and Methods: We prospectively studied 51 consecutive patients with a high clinical suspicion of FHAVN. All patients underwent MRI and F-18 fluoride PET/CT, the time interval between the two scans being 4–10 (mean 8) days. Two nuclear medicine physicians blinded to the MRI report read the PET/CT scans. Clinical assessment was also done. Final diagnoses were made by surgical pathology or clinical and radiologic follow-up. Results: A final diagnosis of avascular necrosis (AVN) was made in 40 patients. MRI was 96.5% sensitive, 100% specific, and 98.03% accurate while PET/CT was 100% sensitive, specific, and accurate in diagnosing FHAVN. The agreement between the two imaging modalities for the diagnosis of AVN was 96.07%. Conclusion: F-18 fluoride PET/CT showed good agreement with MRI in the initial diagnosis of FHAVN and can be better than MRI in detecting early disease. PMID:26917886

High energy x-ray phase contrast CT using glancing-angle grating interferometers

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

Sarapata, A., E-mail: adrian.sarapata@tum.de; Stayman, J. W.; Siewerdsen, J. H.

Purpose: The authors present initial progress toward a clinically compatible x-ray phase contrast CT system, using glancing-angle x-ray grating interferometry to provide high contrast soft tissue images at estimated by computer simulation dose levels comparable to conventional absorption based CT. Methods: DPC-CT scans of a joint phantom and of soft tissues were performed in order to answer several important questions from a clinical setup point of view. A comparison between high and low fringe visibility systems is presented. The standard phase stepping method was compared with sliding window interlaced scanning. Using estimated dose values obtained with a Monte-Carlo code themore » authors studied the dependence of the phase image contrast on exposure time and dose. Results: Using a glancing angle interferometer at high x-ray energy (∼45 keV mean value) in combination with a conventional x-ray tube the authors achieved fringe visibility values of nearly 50%, never reported before. High fringe visibility is shown to be an indispensable parameter for a potential clinical scanner. Sliding window interlaced scanning proved to have higher SNRs and CNRs in a region of interest and to also be a crucial part of a low dose CT system. DPC-CT images of a soft tissue phantom at exposures in the range typical for absorption based CT of musculoskeletal extremities were obtained. Assuming a human knee as the CT target, good soft tissue phase contrast could be obtained at an estimated absorbed dose level around 8 mGy, similar to conventional CT. Conclusions: DPC-CT with glancing-angle interferometers provides improved soft tissue contrast over absorption CT even at clinically compatible dose levels (estimated by a Monte-Carlo computer simulation). Further steps in image processing, data reconstruction, and spectral matching could make the technique fully clinically compatible. Nevertheless, due to its increased scan time and complexity the technique should be thought of not as replacing, but as complimentary to conventional CT, to be used in specific applications.« less

SU-F-I-47: Optimizing Protocols for Image Quality and Dose in Abdominal CT of Large Patients

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

Johnson, L; Yester, M

Purpose: Newer CT scanners are able to use scout views to adjust mA throughout the scan in order to achieve a given noise level. However, given constraints of radiologist preferences for kVp and rotation time, it may not be possible to achieve an acceptable noise level for large patients. A study was initiated to determine for which patients kVp and/or rotation time should be changed in order to achieve acceptable image quality. Methods: Patient scans were reviewed on two new Emergency Department scanners (Philips iCT) to identify patients over a large range of sizes. These iCTs were set with amore » limit of 500 mA to safeguard against a failure that might cause a CT scan to be (incorrectly) obtained at too-high mA. Scout views of these scans were assessed for both AP and LAT patient width and AP and LAT standard deviation in an ROI over the liver. Effective diameter and product of the scout standard deviations over the liver were both studied as possible metrics for identifying patients who would need kVp and/or rotation time changed. The mA used for the liver in the CT was compared to these metrics for those patients whose CT scans showed acceptable image quality. Results: Both effective diameter and product of the scout standard deviations over the liver result in similar predictions for which patients will require the kVp and/or rotation time to be changed to achieve an optimal combination of image quality and dose. Conclusion: Two mechanisms for CT technologists to determine based on scout characteristics what kVp, mA limit, and rotation time to use when DoseRight with our physicians’ preferred kVp and rotation time will not yield adequate image quality are described.« 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.

SU-F-R-39: Effects of Radiation Dose Reduction On Renal Cell Carcinoma Discrimination Using Multi-Phasic CT Imaging

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

Wahi-Anwar, M; Young, S; Lo, P

Purpose: A method to discriminate different types of renal cell carcinoma (RCC) was developed using attenuation values observed in multiphasic contrast-enhanced CT. This work evaluates the sensitivity of this RCC discrimination task at different CT radiation dose levels. Methods: We selected 5 cases of kidney lesion patients who had undergone four-phase CT scans covering the abdomen to the lilac crest. Through an IRB-approved study, the scans were conducted on 64-slice CT scanners (Definition AS/Definition Flash, Siemens Healthcare) using automatic tube-current modulation (TCM). The protocol included an initial baseline unenhanced scan, followed by three post-contrast injection phases. CTDIvol (32 cm phantom)more » measured between 9 to 35 mGy for any given phase. As a preliminary study, we limited the scope to the cortico-medullary phase—shown previously to be the most discriminative phase. A previously validated method was used to simulate a reduced dose acquisition via adding noise to raw CT sinogram data, emulating corresponding images at simulated doses of 50%, 25%, and 10%. To discriminate the lesion subtype, ROIs were placed in the most enhancing region of the lesion. The mean HU value of an ROI was extracted and used to discriminate to the worst-case RCC subtype, ranked in the order of clear cell, papillary, chromophobe and the benign oncocytoma. Results: Two patients exhibited a change of worst case RCC subtype between original and simulated scans, at 25% and 10% doses. In one case, the worst-case RCC subtype changed from oncocytoma to chromophobe at 10% and 25% doses, while the other case changed from oncocytoma to clear cell at 10% dose. Conclusion: Based on preliminary results from an initial cohort of 5 patients, worst-case RCC subtypes remained constant at all simulated dose levels except for 2 patients. Further study conducted on more patients will be needed to confirm our findings. Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical Systems; Consultant, Samsung Electronics; NIH Grant Support from: U01 CA181156.« less

Fully automatic segmentation of the femur from 3D-CT images using primitive shape recognition and statistical shape models.

PubMed

Ben Younes, Lassad; Nakajima, Yoshikazu; Saito, Toki

2014-03-01

Femur segmentation is well established and widely used in computer-assisted orthopedic surgery. However, most of the robust segmentation methods such as statistical shape models (SSM) require human intervention to provide an initial position for the SSM. In this paper, we propose to overcome this problem and provide a fully automatic femur segmentation method for CT images based on primitive shape recognition and SSM. Femur segmentation in CT scans was performed using primitive shape recognition based on a robust algorithm such as the Hough transform and RANdom SAmple Consensus. The proposed method is divided into 3 steps: (1) detection of the femoral head as sphere and the femoral shaft as cylinder in the SSM and the CT images, (2) rigid registration between primitives of SSM and CT image to initialize the SSM into the CT image, and (3) fitting of the SSM to the CT image edge using an affine transformation followed by a nonlinear fitting. The automated method provided good results even with a high number of outliers. The difference of segmentation error between the proposed automatic initialization method and a manual initialization method is less than 1 mm. The proposed method detects primitive shape position to initialize the SSM into the target image. Based on primitive shapes, this method overcomes the problem of inter-patient variability. Moreover, the results demonstrate that our method of primitive shape recognition can be used for 3D SSM initialization to achieve fully automatic segmentation of the femur.

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.

Mastoid bone fracture presenting as unusual delayed onset of facial nerve palsy.

PubMed

Hsu, Ko-Chiang; Wang, Ann-Ching; Chen, Shyi-Jou

2008-03-01

Delayed-onset facial nerve paralysis is a rather uncommon complication of a mastoid bone fracture for children younger than 10 years. We routinely arrange a cranial computed tomography (CT) for patients encountering initial loss of consciousness, severe headache, intractable vomiting, and/or any neurologic deficit arising from trauma to the head. However, minor symptomatic cranial nerve damage may be missed and the presenting symptom diagnosed as being a peripheral nerve problem. Herein, we report a case of a young boy who presented at our emergency department (ED) 3 days subsequent to his accident, complaining of hearing loss in the right ear and paralysis of the ipsilateral face. Unpredictably, we observed his cranial CT scan revealing a linear fracture of the skull over the right temporal bone involving the right mastoid air cells. The patient was treated conservatively and recovered well without any adverse neurologic consequences. We emphasize that ED physicians should arrange a cranial CT scan for a head-injured child with symptomatic facial nerve palsy, even if there are no symptoms such as severe headache, vomiting, Battle sign, and/or initial loss of consciousness.

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.

Post-infectious bronchiolitis obliterans in children: CT features that predict responsiveness to pulse methylprednisolone.

PubMed

Yoon, H M; Lee, J S; Hwang, J-Y; Cho, Y A; Yoon, H-K; Yu, J; Hong, S-J; Yoon, C H

2015-05-01

Intravenous pulse methylprednisolone therapy (IPMT) is an important treatment option for post-infectious obliterative bronchiolitis (OB), although it must be used carefully and only in selected patients because of its drawbacks. This study evaluated whether CT and clinical features of children with post-infectious OB can predict their responsiveness to IPMT. We searched the medical records for patients (less than 18 years of age) who were diagnosed with post-infectious OB between January 2000 and December 2011. 17 children who received IPMT were included in this study. All underwent chest CT before and after IPMT. The radiological features seen on pre-treatment CT were recorded. The air-trapping area percentages on pre- and post-treatment CT images were determined. The nine patients who exhibited decreased air trapping on post-treatment CT scans relative to pre-treatment scans were classed as responders. The patient ages and time from initial pneumonia to IPMT were recorded. All responders and only four non-responders had thickened bronchial walls before treatment (p = 0.029). The two groups did not differ significantly in terms of bronchiolitis, bronchiectasis or the extent of air trapping, although the responders had a significantly shorter median interval between initial pneumonia and IPMT (4 vs 50 months; p = 0.005) and were significantly younger (median, 2.0 vs 7.5 years; p = 0.048). Immediate IPMT may improve the degree of air trapping in children with post-infectious OB if they show a thickened bronchial wall on CT. Children with post-infectious OB may respond favourably to IPMT when pre-treatment CT indicates bronchial-wall thickening.

Serial changes and prognostic implications of CT findings in combined pulmonary fibrosis and emphysema: comparison with fibrotic idiopathic interstitial pneumonias alone.

PubMed

Lee, Geewon; Kim, Ki Uk; Lee, Ji Won; Suh, Young Ju; Jeong, Yeon Joo

2017-05-01

Background Although fibrotic idiopathic interstitial pneumonias (IIPs) alone and those combined with pulmonary emphysema are naturally progressive diseases, the process of deterioration and outcomes are variable. Purpose To evaluate and compare serial changes of computed tomography (CT) abnormalities and prognostic predictive factors in fibrotic IIPs alone and those combined with pulmonary emphysema. Material and Methods A total of 148 patients with fibrotic IIPs alone (82 patients) and those combined with pulmonary emphysema (66 patients) were enrolled. Semi-quantitative CT analysis was used to assess the extents of CT characteristics which were evaluated on initial and follow-up CT images. Univariate and multivariate analyses were performed to assess the effects of clinical and CT variables on survival. Results Significant differences were noted between fibrotic scores, as determined using initial CT scans, in the fibrotic IIPs alone (21.22 ± 9.83) and those combined with pulmonary emphysema groups (14.70 ± 7.28) ( P < 0.001). At follow-up CT scans, changes in the extent of ground glass opacities (GGO) were greater ( P = 0.031) and lung cancer was more prevalent ( P = 0.001) in the fibrotic IIPs combined with pulmonary emphysema group. Multivariate Cox proportional hazards analysis showed changes in the extent of GGO (hazard ratio, 1.056) and the presence of lung cancer (hazard ratio, 4.631) were predictive factors of poor survivals. Conclusion Although patients with fibrotic IIPs alone and those combined with pulmonary emphysema have similar mortalities, lung cancer was more prevalent in patients with fibrotic IIPs combined with pulmonary emphysema. Furthermore, changes in the extent of GGO and the presence of lung cancer were independent prognostic factors of poor survivals.

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.

SU-E-I-48: The Behavior of AEC in Scan Regions Outside the Localizer Radiograph FOV: An In Phantom Study of CT Systems From Four Vendors

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

Supanich, M; Bevins, N

Purpose: This review of scanners from 4 major manufacturers examines the clinical impact of performing CT scans that extend into areas of the body that were not acquired in the CT localizer radiograph. Methods: Anthropomorphic chest and abdomen phantoms were positioned together on the tables of CT scanners from 4 different vendors. All of the scanners offered an Automatic Exposure Control (AEC) option with both lateral and axial tube current modulation. A localizer radiograph was taken covering the entire extent of both phantoms and then the scanner's Chest-Abdomen-Pelvis (CAP) study was performed with the clinical AEC settings employed and themore » scan and reconstruction range extending from the superior portion of the chest phantom through the inferior portion of the abdomen phantom. A new study was then initiated with a localizer radiograph extending the length of the chest phantom (not covering the abdomen phantom). The same CAP protocol and AEC settings were then used to scan and reconstruct the entire length of both phantoms. Scan parameters at specific locations in the abdomen phantom from both studies were investigated using the information contained in the DICOM metadata of the reconstructed images. Results: The AEC systems on all scanners utilized different tube current settings in the abdomen phantom for the scan completed without the full localizer radiograph. The AEC system behavior was also scanner dependent with the default manual tube current, the maximum tube current and the tube current at the last known position observed as outcomes. Conclusion: The behavior of the AEC systems of CT scanners in regions not covered by the localizer radiograph is vendor dependent. To ensure optimal image quality and radiation exposure it is important to include the entire planned scan region in the localizer radiograph.« less

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.

Dissecting aneurysm of arch and descending thoracic aorta presenting as a left sided hemorrhagic pleural effusion

PubMed Central

Shamim, Shelley; Thakur, Sumitra Basu; Sengupta, Amitava; Bhattacharyya, Sujit Kumar; Sit, Niranjan

2010-01-01

The most common cause of massive hemorrhagic effusion is malignancy. Herein we present a case of dissecting aneurysm of descending thoracic aorta presenting initially with shortness of breath due to left sided massive pleural effusion. Effusion was hemorrhagic in nature with high hematocrit value. CT scan of thorax with CT angiogram was done and that revealed the diagnosis. PMID:21139725

Delayed hydronephrosis due to retroperitoneal hematoma after a seatbelt injury: A case report.

PubMed

Yumoto, Tetsuya; Kondo, Yoshitaka; Kumon, Kento; Masaoka, Yoshihisa; Hiraki, Takao; Yamada, Taihei; Naito, Hiromichi; Nakao, Atsunori

2018-06-01

Hydronephrosis caused by retroperitoneal hematoma after a seatbelt injury is a unique clinical entity. A 21-year-old man, who had been wearing a seatbelt, was brought to our hospital after a motor vehicle collision, complaining of abdominal pain. Computed tomography (CT) revealed retroperitoneal hematoma in the upper pelvic region. Since he was hemodynamically stable throughout admission, he was managed conservatively. Seventeen days after initial discharge, the patient revisited our emergency department due to right back pain. CT scans indicated retroperitoneal hematoma growth resulting in hydronephrosis of the right kidney. Laparoscopic drainage of the retroperitoneal hematoma was successfully performed. His symptoms resolved after the surgery. Follow-up CT scans three months later demonstrated complete resolution of the hydronephrosis and retroperitoneal hematoma. Our case highlights a patient with delayed hydronephrosis because of retroperitoneal hematoma expansion after a seatbelt injury.

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: ...

F-18 FDG PET/CT findings in a patient with bilateral orbital and gastric mucosa-associated lymphoid tissue lymphomas.

PubMed

Suga, Kazuyoshi; Yasuhiko, Kawakami; Hiyama, Atsuto; Takeda, Koumei; Matsunaga, Naofumi

2009-09-01

Orbital mucosa-associated lymphoid tissue (MALT) lymphoma is an uncommon disease, while the incidence is recently increasing. We describe the F-18 fluorodeoxyglucose positron emission tomography computerized tomography (FDG PET/CT) findings in a case of bilateral orbital MALT lymphomas with a coexisting gastric lesion. Although only the lesion in the left orbit was initially identified on MR imaging, FDG PET/CT scan unexpectedly and additionally could identify the tiny lesion of the contralateral orbit and the gastric lesion. This patient received radiotherapy to all these lesions, with a combination of rituximab monoclonal antibody therapy. The follow-up PET/CT studies at 3, 6, and 9 months and 1.5 years after treatment showed regression or disappearance of all these FDG-avid lesions. Accurate localization and staging are crucial to select an adequate treatment in MALT lymphoma at any location. This case indicates the feasibility of FDG PET/CT scan for accurate localization and staging and also for monitoring treatment in patients with orbital MALT lymphoma.

Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors

PubMed Central

Yu, Tong; Gao, Jun; Liu, Zhi-Min; Zhang, Qi-Feng; Liu, Yong; Jiang, Ling; Peng, Yun

2017-01-01

Background: Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors. Methods: Forty-five patients with solid tumors who had initial CT (Group B) and follow-up CT (Group A) after chemotherapy were enrolled. The initial diagnostic CT scan (Group B) was performed using the standard two-phase enhanced CT with 320 mgI/ml concentration contrast, and the follow-up scan (Group A) was performed using a single-phase enhanced CT at 45 s after the beginning of the 270 mgI/ml contrast injection using spectral mode. Forty percent ASiR was used for the images in Group B and monochromatic images with energy levels ≥60 keV in Group A. In addition, filtered back-projection (FBP) reconstruction was used for monochromatic images <60 keV in Group A. The total radiation dose, total iodine load, contrast injection speed, and maximum injection pressure were compared between the two groups. The 40 keV and 60 keV spectral CT images of Group A were compared with the images of Group B to evaluate overall image quality. Results: The total radiation dose, total iodine load, injection speed, and maximum injection pressure for Group A were decreased by 19%, 15%, 34.4%, and 18.3%, respectively. The optimal energy level in spectral CT for displaying the abdominal vessels was 40 keV. At this level, the CT values in the abdominal aorta and its three branches, the portal vein and its two branches, and the inferior vena cava were all greater than 340 hounsfield unit (HU). The abdominal organs of Groups A and B had similar degrees of absolute and relative enhancement (t = 0.36 and −1.716 for liver, −0.153 and −1.546 for pancreas, and 2.427 and 0.866 for renal cortex, all P > 0.05). Signal-to-noise ratio of the abdominal organs was significantly lower in Group A than in Group B (t = −8.11 for liver, −7.83 for pancreas, and −5.38 for renal cortex, all P < 0.05). However, the subjective scores for the 40 keV (FBP) and 60 keV (40% ASiR) spectral CT images determined by two radiologists were all >3, indicating clinically acceptable image quality. Conclusions: Single-phase, dual-energy spectral CT used for children with solid abdominal tumors can reduce contrast dose and radiation dose and can also maintain clinically acceptable image quality. PMID:28345547

Contrast Dose and Radiation Dose Reduction in Abdominal Enhanced Computerized Tomography Scans with Single-phase Dual-energy Spectral Computerized Tomography Mode for Children with Solid Tumors.

PubMed

Yu, Tong; Gao, Jun; Liu, Zhi-Min; Zhang, Qi-Feng; Liu, Yong; Jiang, Ling; Peng, Yun

2017-04-05

Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors. Forty-five patients with solid tumors who had initial CT (Group B) and follow-up CT (Group A) after chemotherapy were enrolled. The initial diagnostic CT scan (Group B) was performed using the standard two-phase enhanced CT with 320 mgI/ml concentration contrast, and the follow-up scan (Group A) was performed using a single-phase enhanced CT at 45 s after the beginning of the 270 mgI/ml contrast injection using spectral mode. Forty percent ASiR was used for the images in Group B and monochromatic images with energy levels ≥60 keV in Group A. In addition, filtered back-projection (FBP) reconstruction was used for monochromatic images <60 keV in Group A. The total radiation dose, total iodine load, contrast injection speed, and maximum injection pressure were compared between the two groups. The 40 keV and 60 keV spectral CT images of Group A were compared with the images of Group B to evaluate overall image quality. The total radiation dose, total iodine load, injection speed, and maximum injection pressure for Group A were decreased by 19%, 15%, 34.4%, and 18.3%, respectively. The optimal energy level in spectral CT for displaying the abdominal vessels was 40 keV. At this level, the CT values in the abdominal aorta and its three branches, the portal vein and its two branches, and the inferior vena cava were all greater than 340 hounsfield unit (HU). The abdominal organs of Groups A and B had similar degrees of absolute and relative enhancement (t = 0.36 and -1.716 for liver, -0.153 and -1.546 for pancreas, and 2.427 and 0.866 for renal cortex, all P> 0.05). Signal-to-noise ratio of the abdominal organs was significantly lower in Group A than in Group B (t = -8.11 for liver, -7.83 for pancreas, and -5.38 for renal cortex, all P< 0.05). However, the subjective scores for the 40 keV (FBP) and 60 keV (40% ASiR) spectral CT images determined by two radiologists were all> 3, indicating clinically acceptable image quality. Single-phase, dual-energy spectral CT used for children with solid abdominal tumors can reduce contrast dose and radiation dose and can also maintain clinically acceptable image quality.

18F-FDG PET/CT evaluation of children and young adults with suspected spinal fusion hardware infection.

PubMed

Bagrosky, Brian M; Hayes, Kari L; Koo, Phillip J; Fenton, Laura Z

2013-08-01

Evaluation of the child with spinal fusion hardware and concern for infection is challenging because of hardware artifact with standard imaging (CT and MRI) and difficult physical examination. Studies using (18)F-FDG PET/CT combine the benefit of functional imaging with anatomical localization. To discuss a case series of children and young adults with spinal fusion hardware and clinical concern for hardware infection. These people underwent FDG PET/CT imaging to determine the site of infection. We performed a retrospective review of whole-body FDG PET/CT scans at a tertiary children's hospital from December 2009 to January 2012 in children and young adults with spinal hardware and suspected hardware infection. The PET/CT scan findings were correlated with pertinent clinical information including laboratory values of inflammatory markers, postoperative notes and pathology results to evaluate the diagnostic accuracy of FDG PET/CT. An exempt status for this retrospective review was approved by the Institution Review Board. Twenty-five FDG PET/CT scans were performed in 20 patients. Spinal fusion hardware infection was confirmed surgically and pathologically in six patients. The most common FDG PET/CT finding in patients with hardware infection was increased FDG uptake in the soft tissue and bone immediately adjacent to the posterior spinal fusion rods at multiple contiguous vertebral levels. Noninfectious hardware complications were diagnosed in ten patients and proved surgically in four. Alternative sources of infection were diagnosed by FDG PET/CT in seven patients (five with pneumonia, one with pyonephrosis and one with superficial wound infections). FDG PET/CT is helpful in evaluation of children and young adults with concern for spinal hardware infection. Noninfectious hardware complications and alternative sources of infection, including pneumonia and pyonephrosis, can be diagnosed. FDG PET/CT should be the first-line cross-sectional imaging study in patients with suspected spinal hardware infection. Because pneumonia was diagnosed as often as spinal hardware infection, initial chest radiography should also be performed.

Clinical values of (18) F-FDG PET/CT in oral cavity cancer with dental artifacts on CT or MRI.

PubMed

Hong, Hye Ran; Jin, Soyoung; Koo, Hyun Jung; Roh, Jong-Lyel; Kim, Jae Seung; Cho, Kyung-Ja; Choi, Seung-Ho; Nam, Soon Yuhl; Kim, Sang Yoon

2014-11-01

2a To investigate the role of (18) F-FDG PET/CT in tumor staging, extent, and volume measurements in oral cavity squamous cell carcinoma (OSCC) patients with/without dental artifacts on CT or MRI. This study was conducted in 63 consecutive patients with OSCC who received initial workups including (18) F-FDG PET/CT and MRI. The results of the imaging modalities were compared to those of pathology, using McNemar's test and the paired t-test. Thirty-seven patients (59%) had dental or metallic artifacts obscuring primary tumors. (18) F-FDG PET/CT scanning was superior to MRI in tumor staging (weighted κ = 0.870 vs. 0.518, P = 0.004) in patients with dental artifacts. In addition, (18) F-FDG PET/CT scans were more specific than MRI in detecting sublingual gland (P = 0.014) and mouth floor (P = 0.011) involvement. In patients with dental artifacts, there was a significant discrepancy between primary tumor volume (PTV) measured by pathology and MRI (P = 0.018), but not between PTV measured from pathology and (18) F-FDG PET/CT at SUV2.5 (P = 0.245), which showed the highest intraclass correlation coefficient value (0.860). (18) F-FDG PET/CT scans provide accurate tumor staging and volume measurements in OSCC patients with CR/MRI dental artifacts, leading to improved preoperative planning. 2b CONDENSED ABSTRACT This study evaluated the clinical value of (18) F-FDG PET/CT in 63 patients with oral cavity cancers. In 37 (59%) patients with dental artifacts on CT/MRI, (18) F-FDG PET/CT showed superior results compared to MRI in tumor staging and represented the highest intraclass correlation coefficient value to tumor volume determined by pathology. © 2014 Wiley Periodicals, Inc.

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.

Value of Surveillance Studies for Patients With Stage I to II Diffuse Large B-Cell Lymphoma in the Rituximab Era

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

Hiniker, Susan M.; Pollom, Erqi L.; Khodadoust, Michael S.

2015-05-01

Background: The role of surveillance studies in limited-stage diffuse large B-cell lymphoma (DLBCL) in the rituximab era has not been well defined. We sought to evaluate the use of imaging (computed tomography [CT] and positron emission tomography [PET]-CT) scans and lactate dehydrogenase (LDH) in surveillance of patients with stage I to II DLBCL. Methods: A retrospective analysis was performed of patients who received definitive treatment between 2000 and 2013. Results: One hundred sixty-two consecutive patients with stage I to II DLBCL were treated with chemotherapy +/− rituximab, radiation, or combined modality therapy. The 5-year rates of overall survival (OS) and freedommore » from progression (FFP) were 81.2% and 80.8%, respectively. Of the 162 patients, 124 (77%) were followed up with at least 1 surveillance PET scan beyond end-of-treatment scans; of those, 94 of 124 (76%) achieved a complete metabolic response on PET scan after completion of chemotherapy, and this was associated with superior FFP (P=.01, HR=0.3) and OS (P=.01, HR 0.3). Eighteen patients experienced relapse after initial response to therapy. Nine relapses were initially suspected by surveillance imaging studies (8 PET, 1 CT), and 9 were suspected clinically (5 by patient-reported symptoms and 4 by symptoms and physical examination). No relapses were detected by surveillance LDH. The median duration from initiation of treatment to relapse was 14.3 months among patients with relapses suspected by imaging, and 59.8 months among patients with relapses suspected clinically (P=.077). There was no significant difference in OS from date of first therapy or OS after relapse between patients whose relapse was suspected by imaging versus clinically. Thirteen of 18 patients underwent successful salvage therapy after relapse. Conclusions: A complete response on PET scan immediately after initial chemotherapy is associated with superior FFP and OS in stage I to II DLBCL. The use of PET scans as posttreatment surveillance is not associated with a survival advantage. LDH is not a sensitive marker for relapse. Our results argue for limiting the use of posttreatment surveillance in patients with limited-stage DLBCL.« less

Trends in CT scan rates in children and pregnant women: teaching, private, public and nonprofit facilities.

PubMed

Hoshiko, Sumi; Smith, Daniel; Fan, Cathyn; Jones, Carrie R; McNeel, Sandra V; Cohen, Ronald A

2014-05-01

Radiation exposure from medical sources now equals or exceeds that from natural background sources, largely attributable to a 20-fold increase in CT use since 1980. Increasing exposure to children and fetuses is of most concern due to their heightened susceptibility. More recently, CT use may be leveling or decreasing, but it is unclear whether this change is widespread or varies by type of institution. We sought to characterize trends in CT utilization in California hospitals and emergency departments among children and pregnant women, looking at different types of facilities, such as teaching, private, public and nonprofit institutions. We examined frequency of CT examinations by year from 229 facilities reporting CT usage in routinely collected California statewide data for 2005-2012. We modeled trends overall and by facility type. CT scans for pediatric and pregnant patient visits in the emergency department increased initially, then started to decline after 2008. Among hospital admissions, rates declined or leveled after 2005. In the emergency department, CT rates varied between types of facilities, with teaching hospitals reducing use sooner and more sharply than other types of facilities. CT utilization in California among children and pregnant women has begun to level or decline. Still, population exposure remains at historically high levels, warranting consideration of potential public health implications. Further examination of reasons for trends among hospital types, particularly how teaching hospitals have reduced rates of CT utilization, may help identify strategies for CT reduction without compromising patient care.

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

Assessment of Osteoporosis in Injured Older Women Admitted to a Safety-Net Level One Trauma Center: A Unique Opportunity to Fulfill an Unmet Need

PubMed Central

Young, Elisabeth S.; Reed, May J.; Pham, Tam N.; Gross, Joel A.; Taitsman, Lisa A.

2017-01-01

Background Older trauma patients often undergo computed tomography (CT) as part of the initial work-up. CT imaging can also be used opportunistically to measure bone density and assess osteoporosis. Methods In this retrospective cohort study, osteoporosis was ascertained from admission CT scans in women aged ≥65 admitted to the ICU for traumatic injury during a 3-year period at a single, safety-net, level 1 trauma center. Osteoporosis was defined by established CT-based criteria of average L1 vertebral body Hounsfield units <110. Evidence of diagnosis and/or treatment of osteoporosis was the primary outcome. Results The study cohort consisted of 215 women over a 3-year study period, of which 101 (47%) had evidence of osteoporosis by CT scan criteria. There were no differences in injury severity score, hospital length of stay, cost, or discharge disposition between groups with and without evidence of osteoporosis. Only 55 (59%) of the 94 patients with osteoporosis who survived to discharge had a documented osteoporosis diagnosis and/or corresponding evaluation/treatment plan. Conclusion Nearly half of older women admitted with traumatic injuries had underlying osteoporosis, but 41% had neither clinical recognition of this finding nor a treatment plan for osteoporosis. Admission for traumatic injury is an opportunity to assess osteoporosis, initiate appropriate intervention, and coordinate follow-up care. Trauma and acute care teams should consider assessment of osteoporosis in women who undergo CT imaging and provide a bridge to outpatient services. PMID:29234352

Computed tomography in the evaluation of penetrating neck trauma: a preliminary study.

PubMed

Gracias, V H; Reilly, P M; Philpott, J; Klein, W P; Lee, S Y; Singer, M; Schwab, C W

2001-11-01

Penetrating neck trauma has traditionally been evaluated by surgical exploration and/or invasive diagnostic studies. We hypothesized that computed tomography (CT), used as an early diagnostic tool to accurately determine trajectory, would direct or eliminate further studies or procedures in stable patients with penetrating neck trauma. Retrospective case series. Academic, urban, level I trauma center. Hemodynamically stable patients without hard signs of vascular injury or aerodigestive violation who had sustained penetrating trauma to the neck. Patients underwent a spiral CT as an initial diagnostic study after initial evaluation in the trauma bay. Further invasive studies were directed by CT findings. Number of invasive studies performed. Twenty-three patients were identified during the 30-month period. Nineteen patients sustained gunshot wounds; 3, shotgun wounds; and 1, a stab wound. One patient died of a cranial gunshot wound. Three isolated zone I, 1 isolated zone II, 9 isolated zone III, and 10 multiple neck zone trajectories were evaluated. Thirteen patients were identified by CT to have trajectories remote from vital structures and required no further evaluation. Ten patients underwent angiography. Only 2 underwent bronchoscopy and esophagoscopy. Four patients were discharged from the emergency department; 7 other patients were discharged within 24 hours. No adverse patient events occurred before, during, or after CT scan. Computed tomography in stable selected patients with penetrating neck trauma appears safe. Invasive studies can often be eliminated from the diagnostic algorithm when CT demonstrates trajectories remote from vital structures. As a result, efficient evaluation and early discharge from the trauma bay or emergency department can be realized. Further prospective study of CT scan after penetrating neck trauma is needed.

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.

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.

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 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.

Characterization of a parallel beam CCD optical-CT apparatus for 3D radiation dosimetry

NASA Astrophysics Data System (ADS)

Krstajić, Nikola; Doran, Simon J.

2006-12-01

This paper describes the initial steps we have taken in establishing CCD based optical-CT as a viable alternative for 3-D radiation dosimetry. First, we compare the optical density (OD) measurements from a high quality test target and variable neutral density filter (VNDF). A modulation transfer function (MTF) of individual projections is derived for three positions of the sinusoidal test target within the scanning tank. Our CCD is then characterized in terms of its signal-to-noise ratio (SNR). Finally, a sample reconstruction of a scan of a PRESAGETM (registered trademark of Heuris Pharma, NJ, Skillman, USA.) dosimeter is given, demonstrating the capabilities of the apparatus.

A novel computer-aided detection system for pulmonary nodule identification in CT images

NASA Astrophysics Data System (ADS)

Han, Hao; Li, Lihong; Wang, Huafeng; Zhang, Hao; Moore, William; Liang, Zhengrong

2014-03-01

Computer-aided detection (CADe) of pulmonary nodules from computer tomography (CT) scans is critical for assisting radiologists to identify lung lesions at an early stage. In this paper, we propose a novel approach for CADe of lung nodules using a two-stage vector quantization (VQ) scheme. The first-stage VQ aims to extract lung from the chest volume, while the second-stage VQ is designed to extract initial nodule candidates (INCs) within the lung volume. Then rule-based expert filtering is employed to prune obvious FPs from INCs, and the commonly-used support vector machine (SVM) classifier is adopted to further reduce the FPs. The proposed system was validated on 100 CT scans randomly selected from the 262 scans that have at least one juxta-pleural nodule annotation in the publicly available database - Lung Image Database Consortium and Image Database Resource Initiative (LIDC-IDRI). The two-stage VQ only missed 2 out of the 207 nodules at agreement level 1, and the INCs detection for each scan took about 30 seconds in average. Expert filtering reduced FPs more than 18 times, while maintaining a sensitivity of 93.24%. As it is trivial to distinguish INCs attached to pleural wall versus not on wall, we investigated the feasibility of training different SVM classifiers to further reduce FPs from these two kinds of INCs. Experiment results indicated that SVM classification over the entire set of INCs was in favor of, where the optimal operating of our CADe system achieved a sensitivity of 89.4% at a specificity of 86.8%.

(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.

Is the routine CT head scan justified for psychiatric patients? A prospective study.

PubMed Central

Ananth, J; Gamal, R; Miller, M; Wohl, M; Vandewater, S

1993-01-01

Thirty-four psychiatric patients, assessed for a physical illness that was missed during diagnosis, underwent a CT scan. After investigation, the diagnosis of 14 patients changed from a functional to an organic illness. In nine patients, the CT scan was reported to be abnormal, and yet only two were diagnosed as having an organic syndrome. In seven patients, the CT scan was normal but the patients had an undisputed organic brain syndrome. These findings indicate that the use of CT scans should be restricted to cases in which the diagnosis is seriously in question. The clinical findings should dictate the use of CT scans either to clarify or to complement them. PMID:8461285

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, ...

Radiation dose in 320-slice multidetector cardiac CT: a single center experience of evolving dose minimization.

PubMed

Tung, Matthew K; Cameron, James D; Casan, Joshua M; Crossett, Marcus; Troupis, John M; Meredith, Ian T; Seneviratne, Sujith K

2013-01-01

Minimization of radiation exposure remains an important subject that occurs in parallel with advances in scanner technology. We report our experience of evolving radiation dose and its determinants after the introduction of 320-multidetector row cardiac CT within a single tertiary cardiology referral service. Four cohorts of consecutive patients (total 525 scans), who underwent cardiac CT at defined time points as early as 2008, are described. These include a cohort just after scanner installation, after 2 upgrades of the operating system, and after introduction of an adaptive iterative image reconstruction algorithm. The proportions of nondiagnostic coronary artery segments and studies with nondiagnostic segments were compared between cohorts. Significant reductions were observed in median radiation doses in all cohorts compared with the initial cohort (P < .001). Median dose-length product fell from 944 mGy · cm (interquartile range [IQR], 567.3-1426.5 mGy · cm) to 156 mGy · cm (IQR, 99.2-265.0 mGy · cm). Although the proportion of prospectively triggered scans has increased, reductions in radiation dose have occurred independently of distribution of scan formats. In multiple regression that combined all groups, determinants of dose-length product were tube output, the number of cardiac cycles scanned, tube voltage, scan length, scan format, body mass index, phase width, and heart rate (adjusted R(2) = 0.85, P < .001). The proportion of nondiagnostic coronary artery segments was slightly increased in group 4 (2.9%; P < .01). While maintaining diagnostic quality in 320-multidetector row cardiac CT, the radiation dose has decreased substantially because of a combination of dose-reduction protocols and technical improvements. Continued minimization of radiation dose will increase the potential for cardiac CT to expand as a cardiac imaging modality. Copyright © 2013 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

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.

Clostridium perfringens's necrotizing acute pancreatitis: a case of success

PubMed Central

Mendes, Joana; Amaral, Luís; Quintanilha, Rui; Rama, Tiago; Melo, António

2017-01-01

Abstract The authors report a case of a 62-year-old man with upper abdominal pain with few hours of onset and vomits. The initial serum amylase was 2306 U/L. The first CT showed signs of a non-complicated acute pancreatitis. He suffered clinical deterioration and for this reason he was admitted on the intensive care unit where he progressed to multiple organ failure in <24 h. A new CT scan was performed that showed pneumoperitoneum and pneumoretroperitoneum. He underwent an exploratory laparotomy and pancreatic necrosectomy and vacuum pack laparostomy were performed. Intraoperative peritoneal fluid culture was positive for Clostridium perfringens confirming the diagnosis. He was discharged from hospital after 61 days. According to our research this is the second case reported in literature of a spontaneous acute necrotizing pancreatitis caused by C. perfringens, with pneumoretroperitoneum and pneumoperitoneum on evaluation by CT scan, that survived after surgical treatment and vigorous resuscitation. PMID:28702167

Delayed hydronephrosis due to retroperitoneal hematoma after a seatbelt injury

PubMed Central

Yumoto, Tetsuya; Kondo, Yoshitaka; Kumon, Kento; Masaoka, Yoshihisa; Hiraki, Takao; Yamada, Taihei; Naito, Hiromichi; Nakao, Atsunori

2018-01-01

Abstract Rationale: Hydronephrosis caused by retroperitoneal hematoma after a seatbelt injury is a unique clinical entity. Patient concerns: A 21-year-old man, who had been wearing a seatbelt, was brought to our hospital after a motor vehicle collision, complaining of abdominal pain. Computed tomography (CT) revealed retroperitoneal hematoma in the upper pelvic region. Since he was hemodynamically stable throughout admission, he was managed conservatively. Seventeen days after initial discharge, the patient revisited our emergency department due to right back pain. Diagnoses: CT scans indicated retroperitoneal hematoma growth resulting in hydronephrosis of the right kidney. Interventions: Laparoscopic drainage of the retroperitoneal hematoma was successfully performed. Outcomes: His symptoms resolved after the surgery. Follow-up CT scans three months later demonstrated complete resolution of the hydronephrosis and retroperitoneal hematoma. Lessons: Our case highlights a patient with delayed hydronephrosis because of retroperitoneal hematoma expansion after a seatbelt injury. PMID:29879068

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.

SU-E-T-287: Robustness Study of Passive-Scattering Proton Therapy in Lung: Is Range and Setup Uncertainty Calculation On the Initial CT Enough to Predict the Plan Robustness?

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

Ding, X; Dormer, J; Kenton, O

Purpose: Plan robustness of the passive-scattering proton therapy treatment of lung tumors has been studied previously using combined uncertainties of 3.5% in CT number and 3 mm geometric shifts. In this study, we investigate whether this method is sufficient to predict proton plan robustness by comparing to plans performed on weekly verification CT scans. Methods: Ten lung cancer patients treated with passive-scattering proton therapy were randomly selected. All plans were prescribed 6660cGy in 37 fractions. Each initial plan was calculated using +/− 3.5% range and +/− 0.3cm setup uncertainty in x, y and z directions in Eclipse TPS(Method-A). Throughout themore » treatment course, patients received weekly verification CT scans to assess the daily treatment variation(Method-B). After contours and imaging registrations are verified by the physician, the initial plan with the same beamline and compensator was mapped into the verification CT. Dose volume histograms (DVH) were evaluated for robustness study. Results: Differences are observed between method A and B in terms of iCTV coverage and lung dose. Method-A shows all the iCTV D95 are within +/− 1% difference, while 20% of cases fall outside +/−1% range in Method-B. In the worst case scenario(WCS), the iCTV D95 is reduced by 2.5%. All lung V5 and V20 are within +/−5% in Method-A while 15% of V5 and 10% of V20 fall outside of +/−5% in Method-B. In the WCS, Lung V5 increased by 15% and V20 increased by 9%. Method A and B show good agreement with regard to cord maximum and Esophagus mean dose. Conclusion: This study suggests that using range and setup uncertainty calculation (+/−3.5% and +/−3mm) may not be sufficient to predict the WCS. In the absence of regular verification scans, expanding the conventional uncertainty parameters(e.g., to +/−3.5% and +/−4mm) may be needed to better reflect plan actual robustness.« less

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.

Six-Minute Walk Distance Predictors, Including CT Scan Measures, in the COPDGene Cohort

PubMed Central

Rambod, Mehdi; Porszasz, Janos; Make, Barry J.; Crapo, James D.

2012-01-01

Background: Exercise tolerance in COPD is only moderately well predicted by airflow obstruction assessed by FEV1. We determined whether other phenotypic characteristics, including CT scan measures, are independent predictors of 6-min walk distance (6MWD) in the COPDGene cohort. Methods: COPDGene recruits non-Hispanic Caucasian and African American current and ex-smokers. Phenotyping measures include postbronchodilator FEV1 % predicted and inspiratory and expiratory CT lung scans. We defined % emphysema as the percentage of lung voxels < −950 Hounsfield units on the inspiratory scan and % gas trapping as the percentage of lung voxels < −856 Hounsfield units on the expiratory scan. Results: Data of the first 2,500 participants of the COPDGene cohort were analyzed. Participant age was 61 ± 9 years; 51% were men; 76% were non-Hispanic Caucasians, and 24% were African Americans. Fifty-six percent had spirometrically defined COPD, with 9.3%, 23.4%, 15.0%, and 8.3% in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV, respectively. Higher % emphysema and % gas trapping predicted lower 6MWD (P < .001). However, in a given spirometric group, after adjustment for age, sex, race, and BMI, neither % emphysema nor % gas trapping, or their interactions with FEV1 % predicted, remained a significant 6MWD predictor. In a given spirometric group, only 16% to 27% of the variance in 6MWD could be explained by age, male sex, Caucasian race, and lower BMI as significant predictors of higher 6MWD. Conclusions: In this large cohort of smokers in a given spirometric stage, phenotypic characteristics were only modestly predictive of 6MWD. CT scan measures of emphysema and gas trapping were not predictive of 6MWD after adjustment for other phenotypic characteristics. PMID:21960696

Six-minute walk distance predictors, including CT scan measures, in the COPDGene cohort.

PubMed

Rambod, Mehdi; Porszasz, Janos; Make, Barry J; Crapo, James D; Casaburi, Richard

2012-04-01

Exercise tolerance in COPD is only moderately well predicted by airflow obstruction assessed by FEV(1). We determined whether other phenotypic characteristics, including CT scan measures, are independent predictors of 6-min walk distance (6MWD) in the COPDGene cohort. COPDGene recruits non-Hispanic Caucasian and African American current and ex-smokers. Phenotyping measures include postbronchodilator FEV(1) % predicted and inspiratory and expiratory CT lung scans. We defined % emphysema as the percentage of lung voxels < -950 Hounsfield units on the inspiratory scan and % gas trapping as the percentage of lung voxels < -856 Hounsfield units on the expiratory scan. Data of the first 2,500 participants of the COPDGene cohort were analyzed. Participant age was 61 ± 9 years; 51% were men; 76% were non-Hispanic Caucasians, and 24% were African Americans. Fifty-six percent had spirometrically defined COPD, with 9.3%, 23.4%, 15.0%, and 8.3% in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stages I to IV, respectively. Higher % emphysema and % gas trapping predicted lower 6MWD (P < .001). However, in a given spirometric group, after adjustment for age, sex, race, and BMI, neither % emphysema nor % gas trapping, or their interactions with FEV(1) % predicted, remained a significant 6MWD predictor. In a given spirometric group, only 16% to 27% of the variance in 6MWD could be explained by age, male sex, Caucasian race, and lower BMI as significant predictors of higher 6MWD. In this large cohort of smokers in a given spirometric stage, phenotypic characteristics were only modestly predictive of 6MWD. CT scan measures of emphysema and gas trapping were not predictive of 6MWD after adjustment for other phenotypic characteristics.

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.

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

Delayed Enhancement of Ascites After IV Contrast Material Administration at CT: Time Course and Clinical Correlation

PubMed Central

Benedetti, Nancy; Aslam, Rizwan; Wang, Zhen J.; Joe, Bonnie N.; Fu, Yanjun; Yee, Judy; Yeh, Benjamin M.

2010-01-01

OBJECTIVE The objective of our study was to determine the prevalence and clinical predictors of delayed contrast enhancement of ascites. MATERIALS AND METHODS In this retrospective study, 132 consecutive patients with ascites who underwent repeated abdominopelvic CT examinations performed within 7 days of each other were identified. These patients included 112 patients who received and 20 who did not receive IV contrast material at the initial CT examination. For each examination, we recorded the CT attenuation of the ascites. For the follow-up scan, the presence of delayed enhancement of ascites was defined as an increase in CT attenuation > 10 HU over baseline. The Fisher’s exact test, unpaired Student’s t test, and logistic regression were used to determine predictors of delayed enhancement of ascites. RESULTS A threshold increase in the attenuation of ascites by > 10 HU or more between the initial and follow-up CT examinations occurred only when IV contrast material was given with the initial examination. The increased attenuation was due to delayed contrast enhancement of ascites and occurred in 15 of the 112 patients (13%). Of the 16 patients scanned less than 1 day apart, 10 (63%) showed delayed enhancement of ascites. Delayed enhancement was not observed 3 or more days after IV contrast material administration. For each 1 mg/dL increase in serum creatinine level, the likelihood of delayed enhancement of ascites increased (odds ratio, 2.02; 95% CI, 1.11–3.69). Multivariate logistic regression showed that a short time interval between examinations (p < 0.001), increased serum creatinine level (p < 0.001), and presence of loculated ascites (p = < 0.01) were independent predictors of the magnitude of delayed enhancement of ascites. CONCLUSION Delayed contrast enhancement of ascites occurs commonly after recent prior IV contrast material administration and should not be mistaken for hemoperitoneum or proteinaceous fluid such as pus. PMID:19696286

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.

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.

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

Bacterial sinusitis and its frightening complications: subdural empyema and Lemierre syndrome.

PubMed

Benevides, Gabriel Núncio; Salgado, German Alcoba; Ferreira, Cristiane Rúbia; Felipe-Silva, Aloísio; Gilio, Alfredo Elias

2015-01-01

The symptoms of a previously healthy 14-year-old female with an initial history of tooth pain and swelling of the left maxillary evolved to a progressive headache and altered neurological findings characterized by auditory hallucinations, sleep disturbances, and aggressiveness. She was brought to the emergency department after 21 days of the initial symptoms. An initial computed tomography (CT) scan showed frontal subdural empyema with bone erosion. The symptoms continued to evolve to brain herniation 24 hours after admission. A second CT scan showed a left internal jugular vein thrombosis. The outcome was unfavorable and the patient died on the second day after admission. The autopsy findings depicted rarefaction of the cranial bone at the left side of the frontal sinus, and overt meningitis. The severe infection was further complicated by thrombophlebitis of the left internal jugular vein up to the superior vena cava with septic embolization to the lungs, pneumonia, and sepsis. This case report highlights the degree of severity that a trivial infection can reach. The unusual presentation of the sinusitis may have wrongly guided the approach of this unfortunate case.

Assessing Tumor Response to Treatment in Patients with Lung Cancer Using Dynamic Contrast-Enhanced CT.

PubMed

Strauch, Louise S; Eriksen, Rie Ø; Sandgaard, Michael; Kristensen, Thomas S; Nielsen, Michael B; Lauridsen, Carsten A

2016-07-21

The aim of this study was to provide an overview of the literature available on dynamic contrast-enhanced computed tomography (DCE-CT) as a tool to evaluate treatment response in patients with lung cancer. This systematic review was compiled according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only original research articles concerning treatment response in patients with lung cancer assessed with DCE-CT were included. To assess the validity of each study we implemented Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). The initial search yielded 651 publications, and 16 articles were included in this study. The articles were divided into groups of treatment. In studies where patients were treated with systemic chemotherapy with or without anti-angiogenic drugs, four out of the seven studies found a significant decrease in permeability after treatment. Four out of five studies that measured blood flow post anti-angiogenic treatments found that blood flow was significantly decreased. DCE-CT may be a useful tool in assessing treatment response in patients with lung cancer. It seems that particularly permeability and blood flow are important perfusion values for predicting treatment outcome. However, the heterogeneity in scan protocols, scan parameters, and time between scans makes it difficult to compare the included studies.

Recurrent Bleeding After Perimesencephalic Hemorrhage.

PubMed

Kauw, Frans; Velthuis, Birgitta K; Kizilates, Ufuk; van der Schaaf, Irene C; Rinkel, Gabriel J E; Vergouwen, Mervyn D I

2017-12-01

Perimesencephalic hemorrhage (PMH) is a type of subarachnoid hemorrhage with excellent long-term outcomes. Only 1 well-documented case of in-hospital rebleeding after PMH is described in the literature, which occurred after initiating antithrombotic treatment because of myocardial ischemia. We describe a patient with PMH without antithrombotic treatment who had 2 episodes of recurrent bleeding on the day of ictus. To validate the radiologic findings, we conducted a case-control study. Six neuroradiologists and 2 neuroradiology fellows performed a blinded assessment of serial unenhanced head computed tomography (CT) scans of 8 patients with a perimesencephalic bleeding pattern (1 index patient, 6 patients with PMH, 1 patient with perimesencephalic bleeding pattern and basilar artery aneurysm) to investigate a potential increase in amount of subarachnoid blood. A 56-year-old woman with a perimesencephalic bleeding pattern and negative CT angiography had 2 episodes after the onset headache with a sudden increase of the headache. Blinded assessment of serial head CT scans of 8 patients with a perimesencephalic bleeding pattern identified the patient who was clinically suspected to have 2 episodes of recurrent bleeding to have an increased amount of subarachnoid blood on 2 subsequent CT scans. Recurrent bleeding after PMH may also occur in patients not treated with antithrombotics. Even after early rebleeding, the prognosis of PMH is excellent. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Absent Inferior Vena Cava Leading to Recurrent Lower Extremity Deep Vein Thrombosis in a United States Marine.

PubMed

Kim, Sang; Kunkel, Scott; Browske, Kristin

2018-01-01

Anomalies of the inferior vena cava (AIVC) are rare but well-recognized anatomic abnormalities that can lead to clinically significant deep vein thrombosis (DVT) in a subset of otherwise healthy patients. This report illustrates an uncommon congenital anomaly that military clinicians should consider when evaluating unprovoked DVT in young patients. Single case report and literature review. We describe a case of a 24-yr-old United States Marine who presented with abdominal pain for 2 wk. After conservative therapy failed, a contrast-enhanced abdominal computed tomography (CT) scan was performed. The CT scan revealed an absent inferior vena cava with evidence of right venous thrombophlebitis. We include four contrast-enhanced helical CT scans that illustrate this phenomenon. Due to the lack of available studies and data, we do not know the relative risk of DVT in patients with AIVC. However, the literature review suggests that there is a pro-thrombogenic effect of this congenital anomaly. Clinicians should include AIVC in their differential when treating young, otherwise healthy patients with unprovoked DVT. This population is much more likely to have an AIVC than the general population. In addition to thrombophilia markers, a contrast-enhanced CT scan should be considered as part of the initial workup. Published by Oxford University Press on behalf of the Association of Military Surgeons of the United States 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

3D intrathoracic region definition and its application to PET-CT analysis

NASA Astrophysics Data System (ADS)

Cheirsilp, Ronnarit; Bascom, Rebecca; Allen, Thomas W.; Higgins, William E.

2014-03-01

Recently developed integrated PET-CT scanners give co-registered multimodal data sets that offer complementary three-dimensional (3D) digital images of the chest. PET (positron emission tomography) imaging gives highly specific functional information of suspect cancer sites, while CT (X-ray computed tomography) gives associated anatomical detail. Because the 3D CT and PET scans generally span the body from the eyes to the knees, accurate definition of the intrathoracic region is vital for focusing attention to the central-chest region. In this way, diagnostically important regions of interest (ROIs), such as central-chest lymph nodes and cancer nodules, can be more efficiently isolated. We propose a method for automatic segmentation of the intrathoracic region from a given co-registered 3D PET-CT study. Using the 3D CT scan as input, the method begins by finding an initial intrathoracic region boundary for a given 2D CT section. Next, active contour analysis, driven by a cost function depending on local image gradient, gradient-direction, and contour shape features, iteratively estimates the contours spanning the intrathoracic region on neighboring 2D CT sections. This process continues until the complete region is defined. We next present an interactive system that employs the segmentation method for focused 3D PET-CT chest image analysis. A validation study over a series of PET-CT studies reveals that the segmentation method gives a Dice index accuracy of less than 98%. In addition, further results demonstrate the utility of the method for focused 3D PET-CT chest image analysis, ROI definition, and visualization.

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.

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.

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.

Noninvasive CT to Iso-C3D registration for improved intraoperative visualization in computer assisted orthopedic surgery

NASA Astrophysics Data System (ADS)

Rudolph, Tobias; Ebert, Lars; Kowal, Jens

2006-03-01

Supporting surgeons in performing minimally invasive surgeries can be considered as one of the major goals of computer assisted surgery. Excellent intraoperative visualization is a prerequisite to achieve this aim. The Siremobil Iso-C 3D has become a widely used imaging device, which, in combination with a navigation system, enables the surgeon to directly navigate within the acquired 3D image volume without any extra registration steps. However, the image quality is rather low compared to a CT scan and the volume size (approx. 12 cm 3) limits its application. A regularly used alternative in computer assisted orthopedic surgery is to use of a preoperatively acquired CT scan to visualize the operating field. But, the additional registration step, necessary in order to use CT stacks for navigation is quite invasive. Therefore the objective of this work is to develop a noninvasive registration technique. In this article a solution is being proposed that registers a preoperatively acquired CT scan to the intraoperatively acquired Iso-C 3D image volume, thereby registering the CT to the tracked anatomy. The procedure aligns both image volumes by maximizing the mutual information, an algorithm that has already been applied to similar registration problems and demonstrated good results. Furthermore the accuracy of such a registration method was investigated in a clinical setup, integrating a navigated Iso-C 3D in combination with an tracking system. Initial tests based on cadaveric animal bone resulted in an accuracy ranging from 0.63mm to 1.55mm mean error.

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 ...

[Etiology and diagnostic methods in vocal cord paralysis].

PubMed

Jørgensen, Gita; Clausen, Eva Wiinstedt; Mantoni, Margit Y; Misciattelli, Lorenzo; Balle, Viggo

2003-02-10

The etiology of vocal cord paralysis (VCP) is varied. There is lack of consensus regarding the choice of investigations to be used in the evaluation of VCP. The aim of this study was to establish the etiology, assess the diagnostic methods used in the evaluation, and outline an algorithm for future evaluation of unilateral vocal cord paralysis (UVCP). Charts of all patients (n = 94) with the diagnostic code of VCP were reviewed, and reexaminations were performed of patients in whom no etiology was found after the initial symptoms. The etiology of UVCP was neoplasm in 34%, surgical trauma in 12%, and miscellaneous causes in 54%. The etiology of bilateral vocal cord paralysis (BVCP) was neoplasm in 24%, surgical trauma in 24%, and miscellaneous causes in 52%. The reexaminations did not reveal any cancer diseases in the patients concerned. The most effective diagnostic method was CT-scanning while the least effective was thyroid scanning. Because cancer is a common cause of VCP a thorough evaluation is necessary. For UVCP we recommend history and physical examination, X-ray of the chest, ultrasonography of the neck, and CT-scanning of the superior mediastinum. If these prove negative, panendoscopy should be performed. Workup of patients with idiopathic VCP should include examination, X-ray of the chest at 6-month intervals, and annual CT-scanning for two years.

Community-Based Multidisciplinary Computed Tomography Screening Program Improves Lung Cancer Survival.

PubMed

Miller, Daniel L; Mayfield, William R; Luu, Theresa D; Helms, Gerald A; Muster, Alan R; Beckler, Vickie J; Cann, Aaron

2016-05-01

Lung cancer is the most common cause of cancer deaths in the United States. Overall survival is less than 20%, with the majority of patients presenting with advanced disease. The National Lung Screening Trial, performed mainly in academic medical centers, showed that cancer mortality can be reduced with computed tomography (CT) screening compared with chest radiography in high-risk patients. To determine whether this survival advantage can be duplicated in a community-based multidisciplinary thoracic oncology program, we initiated a CT scan screening program for lung cancer within an established health care system. In 2008, we launched a lung cancer CT screening program within the WellStar Health System (WHS) consisting of five hospitals, three health parks, 140 outpatient medical offices, and 12 imaging centers that provide care in a five-county area of approximately 1.4 million people in Metro-Atlanta. Screening criteria incorporated were the International Early Lung Cancer Action Program (2008 to 2010) and National Comprehensive Cancer Network guidelines (2011 to 2013) for moderate- and high-risk patients. A total of 1,267 persons underwent CT lung cancer screening in WHS from 2008 through 2013; 53% were men, 87% were 50 years of age or older, and 83% were current or former smokers. Noncalcified indeterminate pulmonary nodules were found in 518 patients (41%). Thirty-six patients (2.8%) underwent a diagnostic procedure for positive findings on their CT scan; 30 proved to have cancer, 28 (2.2%) primary lung cancer and 2 metastatic cancer, and 6 had benign disease. Fourteen patients (50%) had their lung cancer discovered on their initial CT scan, 11 on subsequent scans associated with indeterminate pulmonary nodules growth and 3 patients who had a new indeterminate pulmonary nodules. Only 15 (54%) of these 28 patients would have qualified as a National Lung Screening Trial high-risk patient; 75% had stage I or II disease. Overall 5-year survival was 64% and 5-year cancer specific survival was 71% in the screened patients, whereas nonscreened lung cancer patients during that time in WHS had an overall survival of only 19% (p < 0.001). A community-based multidisciplinary lung cancer screening program can improve survival of patients with lung cancer outside of a large multicenter study. This survival advantage was caused by a significant stage shift to earlier disease. Lung cancer CT screening may also benefit patients not meeting the National Lung Screening Trial criteria who are at moderate or high risk for lung cancer. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

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.

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 ...

Eccentric apical hypertrophic cardiomyopathy unmasked by multimodality imaging: an uncommon but missed cause of out of hospital cardiac arrest

PubMed Central

Towe, Eric; Sharma, Saurabh; Geske, Jeffrey; Ackerman, Michael J

2015-01-01

A woman in her late 50s experienced a witnessed, sudden out of hospital cardiac arrest. Initial workup included coronary angiography, transthoracic echocardiogram and a CT scan of the chest to rule out pulmonary embolus. She was subsequently discharged home without an implantable cardioverter defibrillator (ICD) or a life vest. On follow-up at another facility, an ICD was placed and a Holter monitor showed no ventricular ectopy. Further transthoracic echocardiographic images were obtained, which were suggestive of apical hypertrophic cardiomyopathy. A limited transthoracic echocardiogram with contrast was performed, which did not elucidate the hypertrophy. However, eccentric left ventricular apical wall hypertrophy was visualised by a coronary CT scan. PMID:26153133

Characteristics and outcomes of secondary nodules identified on initial computed tomography scan for patients undergoing resection for primary non-small cell lung cancer.

PubMed

Stiles, Brendon M; Schulster, Michael; Nasar, Abu; Paul, Subroto; Lee, Paul C; Port, Jeffrey L; Altorki, Nasser K

2015-01-01

We sought to define the prevalence, malignancy rate, and outcome of secondary nodules (SNs) detected on computed tomography (CT) scan for patients undergoing resection for primary non-small cell lung cancer (NSCLC). In consecutive patients with NSCLC, we reviewed all CT scan reports obtained at diagnosis of the dominant tumor for description of SNs. When resected, pathology was reviewed. Serial CT reports for 2 years postoperatively were evaluated to follow SNs not resected. Among 155 patients, 88 (57%) were found to have SNs. A total of 137 SNs were evaluated (median size, 0.5 cm). Thirty-two nodules were resected at primary resection. Nineteen (61%) resected nodules were benign, whereas 13 (39%) were malignant (8 synchronous primary tumors and 5 lobar metastases). A total of 105 unresected nodules were followed by CT. Of these, 32 (30%) resolved completely, 20 (19%) shrunk, and 28 (27%) were stable, whereas 11 (11%) were lost to follow-up. Fourteen SNs (13%) grew, of which 5 were found to be malignant, each a new primary. Overall 5-year survival was not different between patients with or without SNs (67% vs 64%; P = .88). The prevalence of SNs on CT scan in patients undergoing resection for primary NSCLC is high. Only a low proportion of SNs are ever found to be malignant, predominantly those on the ipsilateral side as the dominant tumor. The presence of SNs has no effect on survival. Patients with SNs, if otherwise appropriately staged, should not be denied surgical therapy. Copyright © 2015. Published by Elsevier Inc.

Anthropometry of Arabian nose using computed tomography scanning.

PubMed

Alharethy, Sami; Al-Quniabut, Ibrahim; Jang, Yong Ju

2017-01-01

The nose plays a critical role in determining the external appearance of an individual. We studied the craniofacial anthropometrics by CT scanning since previous studies in the field were conducted in Saudi populations using photometric analysis. Obtain objective and quantitative data that can help surgeons plan cosmetic procedures for the nose. A cross-sectional analytical study. Department of Otorhinolaryngology, Head and Neck Surgery, King Abdulaziz University Hospital, King Saud University, Riyadh, Saudi Arabia from February 2015 to December 2015. Facial CT scans were performed on native Saudis who underwent CT of the paranasal sinuses. Three anthropometric parameters: the nasofrontal angle, the pyramidal angle, and the linear distance between the nasion and the tip of the nasal bone. In 160 native Saudis (86 males and 74 females) who underwent CT, the mean nasofrontal angle was 125.3° in males and 135.6° in females. The mean linear distance between the nasion and the tip of the nasal bone was 23.0 mm for males and 20.9 mm for females. The mean nasal pyramidal angle was 110.8° in males and 111.9° for females at the level of the nasal root, 105.6° in males and 104.8° in females at the mid-level of the nasal bone, and 116.8° males and 107.9° in females at the level of the tip of the nasal bone. Nasal bone lengths and angles can be obtained accurately from CT scans. These angles differ in different ethnic groups. The sample represents native Saudis but not a cross section of the Saudi population. The relatively small sample size is a limitation of the study, but we consider these to be initial findings.

SU-F-207-06: CT-Based Assessment of Tumor Volume in Malignant Pleural Mesothelioma

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

Qayyum, F; Armato, S; Straus, C

Purpose: To determine the potential utility of computed tomography (CT) scans in the assessment of physical tumor bulk in malignant pleural mesothelioma patients. Methods: Twenty-eight patients with malignant pleural mesothelioma were used for this study. A CT scan was acquired for each patient prior to surgical resection of the tumor (median time between scan and surgery: 27 days). After surgery, the ex-vivo tumor volume was measured by a pathologist using a water displacement method. Separately, a radiologist identified and outlined the tumor boundary on each CT section that demonstrated tumor. These outlines then were analyzed to determine the total volumemore » of disease present, the number of sections with outlines, and the mean volume of disease per outlined section. Subsets of the initial patient cohort were defined based on these parameters, i.e. cases with at least 30 sections of disease with a mean disease volume of at least 3mL per section. For each subset, the R- squared correlation between CT-based tumor volume and physical ex-vivo tumor volume was calculated. Results: The full cohort of 28 patients yielded a modest correlation between CT-based tumor volume and the ex-vivo tumor volume with an R-squared value of 0.66. In general, as the mean tumor volume per section increased, the correlation of CT-based volume with the physical tumor volume improved substantially. For example, when cases with at least 40 CT sections presenting a mean of at least 2mL of disease per section were evaluated (n=20) the R-squared correlation increased to 0.79. Conclusion: While image-based volumetry for mesothelioma may not generally capture physical tumor volume as accurately as one might expect, there exists a set of conditions in which CT-based volume is highly correlated with the physical tumor volume. SGA receives royalties and licensing fees through the University of Chicago for computer-aided diagnosis technology.« less

[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.

Validating automatic semantic annotation of anatomy in DICOM CT images

NASA Astrophysics Data System (ADS)

Pathak, Sayan D.; Criminisi, Antonio; Shotton, Jamie; White, Steve; Robertson, Duncan; Sparks, Bobbi; Munasinghe, Indeera; Siddiqui, Khan

2011-03-01

In the current health-care environment, the time available for physicians to browse patients' scans is shrinking due to the rapid increase in the sheer number of images. This is further aggravated by mounting pressure to become more productive in the face of decreasing reimbursement. Hence, there is an urgent need to deliver technology which enables faster and effortless navigation through sub-volume image visualizations. Annotating image regions with semantic labels such as those derived from the RADLEX ontology can vastly enhance image navigation and sub-volume visualization. This paper uses random regression forests for efficient, automatic detection and localization of anatomical structures within DICOM 3D CT scans. A regression forest is a collection of decision trees which are trained to achieve direct mapping from voxels to organ location and size in a single pass. This paper focuses on comparing automated labeling with expert-annotated ground-truth results on a database of 50 highly variable CT scans. Initial investigations show that regression forest derived localization errors are smaller and more robust than those achieved by state-of-the-art global registration approaches. The simplicity of the algorithm's context-rich visual features yield typical runtimes of less than 10 seconds for a 5123 voxel DICOM CT series on a single-threaded, single-core machine running multiple trees; each tree taking less than a second. Furthermore, qualitative evaluation demonstrates that using the detected organs' locations as index into the image volume improves the efficiency of the navigational workflow in all the CT studies.

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.

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.

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

Interfractional Dose Variations in Intensity-Modulated Radiotherapy With Breath-Hold for Pancreatic Cancer

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

Nakamura, Mitsuhiro; Shibuya, Keiko, E-mail: kei@kuhp.kyoto-u.ac.jp; Nakamura, Akira

2012-04-01

Purpose: To investigate the interfractional dose variations for intensity-modulated radiotherapy (RT) combined with breath-hold (BH) at end-exhalation (EE) for pancreatic cancer. Methods and Materials: A total of 10 consecutive patients with pancreatic cancer were enrolled. Each patient was fixed in the supine position on an individualized vacuum pillow with both arms raised. Computed tomography (CT) scans were performed before RT, and three additional scans were performed during the course of chemoradiotherapy using a conventional RT technique. The CT data were acquired under EE-BH conditions (BH-CT) using a visual feedback technique. The intensity-modulated RT plan, which used five 15-MV coplanar ports,more » was designed on the initial BH-CT set with a prescription dose of 39 Gy at 2.6 Gy/fraction. After rigid image registration between the initial and subsequent BH-CT scans, the dose distributions were recalculated on the subsequent BH-CT images under the same conditions as in planning. Changes in the dose-volume metrics of the gross tumor volume (GTV), clinical target volume (CTV = GTV + 5 mm), stomach, and duodenum were evaluated. Results: For the GTV and clinical target volume (CTV), the 95th percentile of the interfractional variations in the maximal dose, mean dose, dose covering 95% volume of the region of structure, and percentage of the volume covered by the 90% isodose line were within {+-}3%. Although the volume covered by the 39 Gy isodose line for the stomach and duodenum did not exceed 0.1 mL at planning, the volume covered by the 39 Gy isodose line for these structures was up to 11.4 cm{sup 3} and 1.8 cm{sup 3}, respectively. Conclusions: Despite variations in the gastrointestinal state and abdominal wall position at EE, the GTV and CTV were mostly ensured at the planned dose, with the exception of 1 patient. Compared with the duodenum, large variations in the stomach volume receiving high-dose radiation were observed, which might be beyond the negligible range in achieving dose escalation with intensity-modulated RT combined with BH at EE.« less

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 ...

Abdomen/pelvis computed tomography in staging of pediatric Hodgkin Lymphoma: is it always necessary?

PubMed

Farruggia, Piero; Puccio, Giuseppe; Sala, Alessandra; Todesco, Alessandra; Terenziani, Monica; Mura, Rosamaria; D'Amico, Salvatore; Casini, Tommaso; Mosa, Clara; Pillon, Marta; Boaro, Maria Paola; Bottigliero, Gaetano; Burnelli, Roberta; Consarino, Caterina; Fedeli, Fausto; Mascarin, Maurizio; Perruccio, Katia; Schiavello, Elisabetta; Trizzino, Angela; Ficola, Umberto; Garaventa, Alberto; Rossello, Mario

2016-09-01

The purpose of the study was to determine if abdomen/pelvis computed tomography (CT) can be safety omitted in the initial staging of a subgroup of children affected by Hodgkin Lymphoma (HL). Every participating center of A.I.E.O.P (Associazione Italiana di Ematologia ed Oncologia Pediatrica) sent local staging reports of 18F-fluorodeoxyglucose positron emission tomography (PET) and abdominal ultrasound (US) along with digital images of staging abdomen/pelvis CT to the investigation center where the CT scans were evaluated by an experienced pediatric radiologist. The local radiologist who performed the US was unaware of local CT and PET reports (both carried out after US), and the reviewer radiologist examining the CT images was unaware of local US, PET and CT reports. A new abdominal staging of 123 patients performed on the basis of local US report, local PET report, and centralized CT report was then compared to a simpler staging based on local US and PET. No additional lesion was discovered by CT in patients with abdomen/pelvis negativity in both US and PET or isolated spleen positivity in US (or US and PET), and so it seems that in the initial staging, abdomen/pelvis CT can be safety omitted in about 1/2 to 2/3 of children diagnosed with HL. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

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

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

[A case of intragastric wall abscess formation during bevacizumab combined chemotherapy].

PubMed

Mori, Ayano; Kogawa, Takahiro; Arihara, Youhei; Abe, Masakazu; Tamura, Fumito; Abe, Seiichirou; Kukitsu, Takehiro; Ihara, Hideyuki; Sumiyoshi, Tetsuya; Yoshizaki, Naoto; Kondou, Hitoshi; Tsuji, Yasushi

2013-05-01

A 38-year-old man was given a diagnosis of as sigmoid colon cancer and underwent sigmoid colectomy. Post-operative pathological staging was stage IIIb. He then underwent adjuvant chemotherapy. One year and 4 months after the surgery, CT scans revealed multiple liver and lung metastases. He was given mFOLFOX6+bevacizumab, which was changed later to FOLFIRI+bevacizumab. After these chemotherapies, he was admitted to the hospital due to sudden abdominal pain and high grade fever. Obstructive jaundice was initially diagnosed, but detailed study of initial CT revealed intragastric wall abscess. After the drainage of the abscess, his conditions improved. We speculated that the abscess formation was caused by mucosal damage due to bevacizumab.

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.

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, ...

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

Ehrlichia Meningitis Mimicking Aneurysmal Subarachnoid Hemorrhage: A Case Study for Medical Decision-Making Heuristics.

PubMed

Dredla, Brynn; Freeman, William D

2016-04-01

Thunderclap headache is a sudden and severe headache that can occur after an aneurysmal subarachnoid hemorrhage (SAH). Subarachnoid hemorrhage is a medical emergency that requires prompt attention and hospitalization. Patients with thunderclap headache often undergo a noncontrast head computed tomography (CT) scan to ascertain SAH bleeding and, if the scan is negative, then undergo a lumbar puncture to look for cerebrospinal fluid (CSF) red blood cells (RBCs), which would be consistent with an aneurysmal leak. If the initial CT is negative and CSF is positive for RBCs, patients are usually admitted to the hospital for evaluation of intracranial aneurysm. We encountered a patient with thunderclap headache whose initial head CT was negative for SAH and whose CSF tested positive for RBCs. The patient was referred to our center for evaluation and management of aneurysmal SAH. However, on careful review of the patient's medical history, serum laboratory values, and spinal fluid values, the patient was diagnosed with Ehrlichia chaffeensis meningitis. While Ehrlichia meningitis is rare, it is important to recognize the clinical clues that could help avoid formal cerebral angiography, a costly and potentially unnecessary procedure. We present how this case represented a cognitive framing bias and anchoring heuristic as well as steps that medical providers can use to prevent such cognitive errors in diagnosis.

Peripheral Quantitative CT (pQCT) Using a Dedicated Extremity Cone-Beam CT Scanner

PubMed Central

Muhit, A. A.; Arora, S.; Ogawa, M.; Ding, Y.; Zbijewski, W.; Stayman, J. W.; Thawait, G.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Bingham, C.O.; Means, K.; Carrino, J. A.; Siewerdsen, J. H.

2014-01-01

Purpose We describe the initial assessment of the peripheral quantitative CT (pQCT) imaging capabilities of a cone-beam CT (CBCT) scanner dedicated to musculoskeletal extremity imaging. The aim is to accurately measure and quantify bone and joint morphology using information automatically acquired with each CBCT scan, thereby reducing the need for a separate pQCT exam. Methods A prototype CBCT scanner providing isotropic, sub-millimeter spatial resolution and soft-tissue contrast resolution comparable or superior to standard multi-detector CT (MDCT) has been developed for extremity imaging, including the capability for weight-bearing exams and multi-mode (radiography, fluoroscopy, and volumetric) imaging. Assessment of pQCT performance included measurement of bone mineral density (BMD), morphometric parameters of subchondral bone architecture, and joint space analysis. Measurements employed phantoms, cadavers, and patients from an ongoing pilot study imaged with the CBCT prototype (at various acquisition, calibration, and reconstruction techniques) in comparison to MDCT (using pQCT protocols for analysis of BMD) and micro-CT (for analysis of subchondral morphometry). Results The CBCT extremity scanner yielded BMD measurement within ±2–3% error in both phantom studies and cadaver extremity specimens. Subchondral bone architecture (bone volume fraction, trabecular thickness, degree of anisotropy, and structure model index) exhibited good correlation with gold standard micro-CT (error ~5%), surpassing the conventional limitations of spatial resolution in clinical MDCT scanners. Joint space analysis demonstrated the potential for sensitive 3D joint space mapping beyond that of qualitative radiographic scores in application to non-weight-bearing versus weight-bearing lower extremities and assessment of phalangeal joint space integrity in the upper extremities. Conclusion The CBCT extremity scanner demonstrated promising initial results in accurate pQCT analysis from images acquired with each CBCT scan. Future studies will include improved x-ray scatter correction and image reconstruction techniques to further improve accuracy and to correlate pQCT metrics with known pathology. PMID:25076823

Fuzzy Clustering Applied to ROI Detection in Helical Thoracic CT Scans with a New Proposal and Variants

PubMed Central

Castro, Alfonso; Boveda, Carmen; Arcay, Bernardino; Sanjurjo, Pedro

2016-01-01

The detection of pulmonary nodules is one of the most studied problems in the field of medical image analysis due to the great difficulty in the early detection of such nodules and their social impact. The traditional approach involves the development of a multistage CAD system capable of informing the radiologist of the presence or absence of nodules. One stage in such systems is the detection of ROI (regions of interest) that may be nodules in order to reduce the space of the problem. This paper evaluates fuzzy clustering algorithms that employ different classification strategies to achieve this goal. After characterising these algorithms, the authors propose a new algorithm and different variations to improve the results obtained initially. Finally it is shown as the most recent developments in fuzzy clustering are able to detect regions that may be nodules in CT studies. The algorithms were evaluated using helical thoracic CT scans obtained from the database of the LIDC (Lung Image Database Consortium). PMID:27517049

[Performance evaluation of CT automatic exposure control on fast dual spiral scan].

PubMed

Niwa, Shinji; Hara, Takanori; Kato, Hideki; Wada, Yoichi

2014-11-01

The performance of individual computed tomography automatic exposure control (CT-AEC) is very important for radiation dose reduction and image quality equalization in CT examinations. The purpose of this study was to evaluate the performance of CT-AEC in conventional pitch mode (Normal spiral) and fast dual spiral scan (Flash spiral) in a 128-slice dual-source CT scanner. To evaluate the response properties of CT-AEC in the 128-slice DSCT scanner, a chest phantom was placed on the patient table and was fixed at the center of the field of view (FOV). The phantom scan was performed using Normal spiral and Flash spiral scanning. We measured the effective tube current time product (Eff. mAs) of simulated organs in the chest phantom along the longitudinal (z) direction, and the dose dependence (distribution) of in-plane locations for the respective scan modes was also evaluated by using a 100-mm-long pencil-type ionization chamber. The dose length product (DLP) was evaluated using the value displayed on the console after scanning. It was revealed that the response properties of CT-AEC in Normal spiral scanning depend on the respective pitches and Flash spiral scanning is independent of the respective pitches. In-plane radiation dose of Flash spiral was lower than that of Normal spiral. The DLP values showed a difference of approximately 1.7 times at the maximum. The results of our experiments provide information for adjustments for appropriate scanning parameters using CT-AEC in a 128-slice DSCT scanner.

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.

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

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.

Sarcoidosis: correlation of pulmonary parenchymal pattern at CT with results of pulmonary function tests

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

Bergin, C.J.; Bell, D.Y.; Coblentz, C.L.

1989-06-01

The appearances of the lungs on radiographs and computed tomographic (CT) scans were correlated with degree of uptake on gallium scans and results of pulmonary function tests (PFTs) in 27 patients with sarcoidosis. CT scans were evaluated both qualitatively and quantitatively. Patients were divided into five categories on the basis of the pattern of abnormality at CT: 1 = normal (n = 4); 2 = segmental air-space disease (n = 4); 3 = spherical (alveolar) masslike opacities (n = 4); 4 = multiple, discrete, small nodules (n = 6); and 5 = distortion of parenchymal structures (fibrotic end-stage sarcoidosis) (nmore » = 9). The percentage of the volume judged to be abnormal (CT grade) was correlated with PFT results for each CT and radiographic category. CT grades were also correlated with gallium scanning results and percentage of lymphocytes recovered from bronchoalveolar lavage (BAL). Patients in CT categories 1 and 2 had normal lung function, those in category 3 had mild functional impairment, and those in categories 4 and 5 showed moderate to severe dysfunction. The overall CT grade correlated well with PFT results expressed as a percentage of the predicted value. In five patients, CT scans showed extensive parenchymal disease not seen on radiographs. CT grades did not correlate with the results of gallium scanning or BAL lymphocytes. The authors conclude that patterns of parenchymal sarcoidosis seen at CT correlate with the PFT results and can be used to indicate respiratory impairment.« less

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.

Three-step sequential positioning algorithm during sonographic evaluation for appendicitis increases appendiceal visualization rate and reduces CT use.

PubMed

Chang, Stephanie T; Jeffrey, R Brooke; Olcott, Eric W

2014-11-01

The purpose of this article is to examine the rates of appendiceal visualization by sonography, imaging-based diagnoses of appendicitis, and CT use after appendiceal sonography, before and after the introduction of a sonographic algorithm involving sequential changes in patient positioning. We used a search engine to retrospectively identify patients who underwent graded-compression sonography for suspected appendicitis during 6-month periods before (period 1; 419 patients) and after (period 2; 486 patients) implementation of a new three-step positional sonographic algorithm. The new algorithm included initial conventional supine scanning and, as long as the appendix remained nonvisualized, left posterior oblique scanning and then "second-look" supine scanning. Abdominal CT within 7 days after sonography was recorded. Between periods 1 and 2, appendiceal visualization on sonography increased from 31.0% to 52.5% (p < 0.001), postsonography CT use decreased from 31.3% to 17.7% (p < 0.001), and the proportion of imaging-based diagnoses of appendicitis made by sonography increased from 63.8% to 85.7% (p = 0.002). The incidence of appendicitis diagnosed by imaging (either sonography or CT) remained similar at 16.5% and 17.3%, respectively (p = 0.790). Sensitivity and overall accuracy were 57.8% (95% CI, 44.8-70.1%) and 93.0% (95% CI, 90.1-95.3%), respectively, in period 1 and 76.5% (95% CI, 65.8-85.2%) and 95.4% (95% CI, 93.1-97.1%), respectively, in period 2. Similar findings were observed for adults and children. Implementation of an ultrasound algorithm with sequential positioning significantly improved the appendiceal visualization rate and the proportion of imaging-based diagnoses of appendicitis made by ultrasound, enabling a concomitant decrease in abdominal CT use in both children and adults.

[Secondary Splenic Rupture after Initially Inconspicuous CAT Scan].

PubMed

Prokop, A; Koll, S; Chmielnicki, M

2016-04-01

Splenic injuries occur in 1-5 % of blunt abdominal trauma cases. After initial haemorrhagic compression, secondary delayed spleen rupture can occur with a latency of one day to a month or longer. Mortality is then up to 15 %. The spleen injury is almost always recognisable on CT or ultrasound. In one case from our clinic, secondary splenic rupture occurred in a patient after discharge from hospitalisation, even though the initial CT and ultrasound were unremarkable. The patient survived, and underwent emergent splenectomy 8 days after the trauma. An expert review of the case identified no errors in treatment. No case of secondary splenic rupture after initially unremarkable diagnostic studies and clinical course has previously been published. Secondary splenic rupture has a high mortality rate. Patients should be advised of potential complications after hospital discharge, and should return to the hospital immediately in case of symptoms. Georg Thieme Verlag KG Stuttgart · New York.

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.

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.

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.

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

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.

Diagnostic Value of Software-Based Image Fusion of Computed Tomography and F18-FDG PET Scans in Patients with Malignant Lymphoma

PubMed Central

Henninger, B.; Putzer, D.; Kendler, D.; Uprimny, C.; Virgolini, I.; Gunsilius, E.; Bale, R.

2012-01-01

Aim. The purpose of this study was to evaluate the accuracy of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET), computed tomography (CT), and software-based image fusion of both modalities in the imaging of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). Methods. 77 patients with NHL (n = 58) or HD (n = 19) underwent a FDG PET scan, a contrast-enhanced CT, and a subsequent digital image fusion during initial staging or followup. 109 examinations of each modality were evaluated and compared to each other. Conventional staging procedures, other imaging techniques, laboratory screening, and follow-up data constituted the reference standard for comparison with image fusion. Sensitivity and specificity were calculated for CT and PET separately. Results. Sensitivity and specificity for detecting malignant lymphoma were 90% and 76% for CT and 94% and 91% for PET, respectively. A lymph node region-based analysis (comprising 14 defined anatomical regions) revealed a sensitivity of 81% and a specificity of 97% for CT and 96% and 99% for FDG PET, respectively. Only three of 109 image fusion findings needed further evaluation (false positive). Conclusion. Digital fusion of PET and CT improves the accuracy of staging, restaging, and therapy monitoring in patients with malignant lymphoma and may reduce the need for invasive diagnostic procedures. PMID:22654631

First CT findings and improvement in GOS and GOSE scores 6 and 12 months after severe traumatic brain injury.

PubMed

Corral, Luisa; Herrero, José Ignacio; Monfort, José Luis; Ventura, José Luis; Javierre, Casimiro F; Juncadella, Montserrat; García-Huete, Lucía; Bartolomé, Carlos; Gabarrós, Andreu

2009-05-01

To analyse the association between individual initial computerized tomography (CT) scan characteristics and Glasgow Outcome Scale (GOS) and Extended Glasgow Outcome Scale (GOSE) improvement between 6 months and 1 year. Two hundred and twenty-four adult patients with severe traumatic brain injury and Glasgow Coma Scale (GCS) score of 8 or less who were admitted to an intensive care unit were studied. GOS and GOSE scores were obtained 6 and 12 months after injury in 203 subjects. Patients were predominantly male (84%) and median age was 35 years. Traumatic Coma Data Bank (TCDB) CT classification was associated with GOS/GOSE improvement between 6 months and 1 year, with diffuse injury type I, type II and evacuated mass improving more than diffuse injury type III, type IV and non-evacuated mass; for GOS 43/155 (28%) vs 3/48 (6%) (chi(2) = 9.66, p < 0.01) and for GOSE 71/155 (46%) vs 7/48 (15%) (chi(2) = 15.1, p < 0.01). CT individual abnormalities were not associated with GOS/GOSE improvement, with the exception of subarachnoid haemorrhage, which showed a negative association with GOSE improvement (chi(2) = 4.08, p < 0.05). TCDB CT scan classification and subarachnoid haemorrhage were associated with GOS/GOSE improvement from 6-12 months, but individual CT abnormalities were not associated.

Heart position variability during voluntary moderate deep inspiration breath-hold radiotherapy for breast cancer determined by repeat CBCT scans.

PubMed

van Haaren, Paul; Claassen-Janssen, Fiere; van de Sande, Ingrid; Boersma, Liesbeth; van der Sangen, Maurice; Hurkmans, Coen

2017-08-01

Voluntary moderate deep inspiration breath hold (vmDIBH) in left-sided breast cancer radiotherapy reduces cardiac dose. The aim of this study was to investigate heart position variability in vmDIBH using CBCT and to compare this variability with differences in heart position between vmDIBH and free breathing (FB). For 50 patients initial heart position with respect to the field edge (HP-FE) was measured on a vmDIBH planning CT scan. Breath-hold was monitored using an in-house developed vertical plastic stick. On pre-treatment CBCT scans, heart position variability with respect to the field edge (Δ HP-FE ) was measured, reflecting heart position variability when using an offline correction protocol. After registering the CBCT scan to the planning CT, heart position variability with respect to the chest wall (Δ HP-CW ) was measured, reflecting heart position variability when using an online correction protocol. As a control group, vmDIBH and FB computed tomography (CT) scans were acquired for 30 patients and registering both scans on the chest wall. For 34 out of 50 patients, the average HP-FE and HP-CW increased over the treatment course in comparison to the planning CT. Averaged over all patients and all treatment fractions, the Δ HP-FE and the Δ HP-CW was 0.8±4.2mm (range -9.4-+10.6mm) and 1.0±4.4mm (range -8.3-+10.4mm) respectively. The average gain in heart to chest wall distance was 11.8±4.6mm when using vmDIBH instead of FB. In conclusion, substantial variability in heart position using vmDIBH was observed during the treatment course. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

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.

Aorta and pulmonary artery segmentation using optimal surface graph cuts in non-contrast CT

NASA Astrophysics Data System (ADS)

Sedghi Gamechi, Zahra; Arias-Lorza, Andres M.; Pedersen, Jesper Holst; de Bruijne, Marleen

2018-03-01

Accurate measurements of the size and shape of the aorta and pulmonary arteries are important as risk factors for cardiovascular diseases, and for Chronicle Obstacle Pulmonary Disease (COPD).1 The aim of this paper is to propose an automated method for segmenting the aorta and pulmonary arteries in low-dose non-ECGgated non-contrast CT scans. Low contrast and the high noise level make the automatic segmentation in such images a challenging task. In the proposed method, first, a minimum cost path tracking algorithm traces the centerline between user-defined seed points. The cost function is based on a multi-directional medialness filter and a lumen intensity similarity metric. The vessel radius is also estimated from the medialness filter. The extracted centerlines are then smoothed and dilated non-uniformly according to the extracted local vessel radius and subsequently used as initialization for a graph-cut segmentation. The algorithm is evaluated on 225 low-dose non-ECG-gated non-contrast CT scans from a lung cancer screening trial. Quantitatively analyzing 25 scans with full manual annotations, we obtain a dice overlap of 0.94+/-0.01 for the aorta and 0.92+/-0.01 for pulmonary arteries. Qualitative validation by visual inspection on 200 scans shows successful segmentation in 93% of all cases for the aorta and 94% for pulmonary arteries.

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.

Use of Computed X-ray Tomographic Data for Analyzing the Thermodynamics of a Dissociating Porous Sand/Hydrate Mixture

DOE R&D Accomplishments Database

Freifeld, Barry M.; Kneafsey, Timothy J.; Tomutsa, Liviu; Stern, Laura A.; Kirby, Stephen H.

2002-02-28

X-ray computed tomography (CT) is a method that has been used extensively in laboratory experiments for measuring rock properties and fluid transport behavior. More recently, CT scanning has been applied successfully to detect the presence and study the behavior of naturally occurring hydrates. In this study, we used a modified medical CT scanner to image and analyze the progression of a dissociation front in a synthetic methane hydrate/sand mixture. The sample was initially scanned under conditions at which the hydrate is stable (atmospheric pressure and liquid nitrogen temperature, 77 K). The end of the sample holder was then exposed to the ambient air, and the core was continuously scanned as dissociation occurred in response to the rising temperature. CT imaging captured the advancing dissociation front clearly and accurately. The evolved gas volume was monitored as a function of time. Measured by CT, the advancing hydrate dissociation front was modeled as a thermal conduction problem explicitly incorporating the enthalpy of dissociation, using the Stefan moving-boundary-value approach. The assumptions needed to perform the analysis consisted of temperatures at the model boundaries. The estimated value for thermal conductivity of 2.6 W/m K for the remaining water ice/sand mixture is higher than expected based on conduction alone; this high value may represent a lumped parameter that incorporates the processes of heat conduction, methane gas convection, and any kinetic effects that occur during dissociation. The technique presented here has broad implications for future laboratory and field testing that incorporates geophysical techniques to monitor gas hydrate dissociation.

Wooden Foreign Body in the Skull Base: How Did We Miss It?

PubMed

Jusué-Torres, Ignacio; Burks, S Shelby; Levine, Corinna G; Bhatia, Rita G; Casiano, Roy; Bullock, Ross

2016-08-01

Timely detection of intraorbital and skull base wooden foreign bodies is crucial. Wooden foreign bodies are difficult to detect on imaging. The radiologist may fail to identify wooden foreign bodies on two thirds of initial scans and can miss them in almost one third of total cases. A 66-year-old woman sustained a penetrating injury through the left upper eyelid with a small tree branch. The branch was immediately removed in the field, and she was provided with prompt medical care at a local hospital. Initial computed tomography (CT) scan diagnosis was "posttraumatic sinusitis," and this was treated empirically with vancomycin and piperacillin/tazobactam. On the eighth day after injury, she developed progressive swelling and pain of her eyelid with left trigeminal/supraorbital numbness and complete left ophthalmoplegia. A new CT scan showed an open "track" from the region of the left upper orbit/superior rectus to the contralateral sphenoid sinus, which raised suspicion for a retained foreign body. Further imaging confirmed the suspicion. Endoscopic sinus surgery was performed with extraction of the wooden object and evacuation of the left orbital infection. This case indicates that intraorbital and skull base wooden foreign bodies are elusive, demanding a high index of suspicion from both clinicians and radiologists to identify retained material in the setting of ocular or sinus trauma. For better identification of wooden foreign bodies, bone windows on CT should have a width of -1000 Hounsfield units with a soft tissue window level of -500 Hounsfield units. Published by Elsevier Inc.

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.

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.

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.

Quality control of CT systems by automated monitoring of key performance indicators: a two-year study.

PubMed

Nowik, Patrik; Bujila, Robert; Poludniowski, Gavin; Fransson, Annette

2015-07-08

The purpose of this study was to develop a method of performing routine periodical quality controls (QC) of CT systems by automatically analyzing key performance indicators (KPIs), obtainable from images of manufacturers' quality assurance (QA) phantoms. A KPI pertains to a measurable or determinable QC parameter that is influenced by other underlying fundamental QC parameters. The established KPIs are based on relationships between existing QC parameters used in the annual testing program of CT scanners at the Karolinska University Hospital in Stockholm, Sweden. The KPIs include positioning, image noise, uniformity, homogeneity, the CT number of water, and the CT number of air. An application (MonitorCT) was developed to automatically evaluate phantom images in terms of the established KPIs. The developed methodology has been used for two years in clinical routine, where CT technologists perform daily scans of the manufacturer's QA phantom and automatically send the images to MonitorCT for KPI evaluation. In the cases where results were out of tolerance, actions could be initiated in less than 10 min. 900 QC scans from two CT scanners have been collected and analyzed over the two-year period that MonitorCT has been active. Two types of errors have been registered in this period: a ring artifact was discovered with the image noise test, and a calibration error was detected multiple times with the CT number test. In both cases, results were outside the tolerances defined for MonitorCT, as well as by the vendor. Automated monitoring of KPIs is a powerful tool that can be used to supplement established QC methodologies. Medical physicists and other professionals concerned with the performance of a CT system will, using such methods, have access to comprehensive data on the current and historical (trend) status of the system such that swift actions can be taken in order to ensure the quality of the CT examinations, patient safety, and minimal disruption of service.

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.

Computed tomography-magnetic resonance image fusion: a clinical evaluation of an innovative approach for improved tumor localization in primary central nervous system lesions.

PubMed

Lattanzi, J P; Fein, D A; McNeeley, S W; Shaer, A H; Movsas, B; Hanks, G E

1997-01-01

We describe our initial experience with the AcQSim (Picker International, St. David, PA) computed tomography-magnetic resonance imaging (CT-MRI) fusion software in eight patients with intracranial lesions. MRI data are electronically integrated into the CT-based treatment planning system. Since MRI is superior to CT in identifying intracranial abnormalities, we evaluated the precision and feasibility of this new localization method. Patients initially underwent CT simulation from C2 to the most superior portion of the scalp. T2 and post-contrast T1-weighted MRI of this area was then performed. Patient positioning was duplicated utilizing a head cup and bridge of nose to forehead angle measurements. First, a gross tumor volume (GTV) was identified utilizing the CT (CT/GTV). The CT and MRI scans were subsequently fused utilizing a point pair matching method and a second GTV (CT-MRI/GTV) was contoured with the aid of both studies. The fusion process was uncomplicated and completed in a timely manner. Volumetric analysis revealed the CT-MRI/GTV to be larger than the CT/GTV in all eight cases. The mean CT-MRI/GTV was 28.7 cm3 compared to 16.7 cm3 by CT alone. This translated into a 72% increase in the radiographic tumor volume by CT-MRI. A simulated dose-volume histogram in two patients revealed that marginal portions of the lesion, as identified by CT and MRI, were not included in the high dose treatment volume as contoured with the use of CT alone. Our initial experience with the fusion software demonstrated an improvement in tumor localization with this technique. Based on these patients the use of CT alone for treatment planning purposes in central nervous system (CNS) lesions is inadequate and would result in an unacceptable rate of marginal misses. The importation of MRI data into three-dimensional treatment planning is therefore crucial to accurate tumor localization. The fusion process simplifies and improves precision of this task.

Performance of Glial Fibrillary Acidic Protein (GFAP) in Detecting Traumatic Intracranial Lesions on Computed Tomography in Children and Youth with Mild Head Trauma

PubMed Central

Papa, Linda; Zonfrillo, Mark; Ramirez, Jose; Silvestri, Salvatore; Giordano, Philip; Braga, Carolina F.; Tan, Ciara N.; Ameli, Neema J.; Lopez, Marco; Mittal, Manoj K.

2015-01-01

Objectives This study examined the performance of serum glial fibrillary acidic protein (GFAP) in detecting traumatic intracranial lesions on computed tomography (CT) scan in children and youth with mild and moderate traumatic brain injury (TBI), and assessed its performance in trauma control patients without head trauma. Methods This prospective cohort study enrolled children and youth presenting to three Level I trauma centers following blunt head trauma with Glasgow Coma Scale (GCS) scores of 9 to 15, as well as trauma control patients with GCS scores of 15 who did not have blunt head trauma. The primary outcome measure was the presence of intracranial lesions on initial CT scan. Blood samples were obtained in all patients within six hours of injury and measured by ELISA for GFAP (ng/ml). Results A total of 257 children and youth were enrolled in the study and had serum samples drawn within 6 hours of injury for analysis: 197 had blunt head trauma and 60 were trauma controls. CT scan of the head was performed in 152 patients and traumatic intracranial lesions on CT scan were evident in 18 (11%), all of whom had GCS scores of 13 to 15. When serum levels of GFAP were compared in children and youth with traumatic intracranial lesions on CT scan to those without CT lesions, median GFAP levels were significantly higher in those with intracranial lesions (1.01, IQR 0.59 to 1.48) than those without lesions (0.18, IQR 0.06 to 0.47). The area under the receiver operating characteristic (ROC) curve (AUC) for GFAP in detecting children and youth with traumatic intracranial lesions on CT was 0.82 (95% CI = 0.71 to 0.93). In those presenting with GCS scores of 15, the AUC for detecting lesions was 0.80 (95% CI = 0.68 to 0.92). Similarly, in children under five years old the AUC was 0.83 (95% CI = 0.56 to 1.00). Performance for detecting intracranial lesions at a GFAP cutoff level of 0.15 ng/ml yielded a sensitivity of 94%, a specificity of 47%, and a negative predictive value of 98%. Conclusions In children and youth of all ages, GFAP measured within 6 hours of injury was associated with traumatic intracranial lesions on CT and with severity of TBI. Further study is required to validate these findings before clinical application. PMID:26469937

Renal arteriovenous malformation: an unusual cause of recurrent haematuria

PubMed Central

Ali, Mazhar; Aziz, Wajahat; Abbas, Farhat

2013-01-01

A 54-year-old woman presented with gross painless haematuria. Initial workup showed no abnormality except mild hydronephrosis on CT scan. Cystoscopy and retrograde pyelography did not find any gross lesion and her urine cytology was also negative. She had recurrent haematuria so her CT was reviewed with the radiologist with clinical suspicion of arteriovenous malformation (AVM) which was suggested by relatively increased contrast density in the hemiazygous vein and renal vein in the arterial phase. She underwent angioembiolisation of left renal AVM after which her haematuria settled. PMID:23867881

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.

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.

"Unusual brain stone": heavily calcified primary neoplasm with some features suggestive of angiocentric glioma.

PubMed

Sajjad, Jahangir; Kaliaperumal, Chandrasekaran; Bermingham, Niamh; Marks, Charles; Keohane, Catherine

2015-11-01

This 40-year-old man presented with a 5-month history of progressive right-sided headache associated with visual blurring. He also had a history of epilepsy but had been seizure free with medication for the past 10 years. An initial CT scan of his brain performed 16 years previously had revealed a small area of calcification in the right parietal region. In the current presentation, he had a left-sided homonymous hemianopia but no other neurological deficits. A CT scan of his brain showed a much larger calcified, partly cystic lesion in the right parietal region. Because he was symptomatic, the lesion was excised and the cyst was drained. Histological examination of the excised tissue showed an unusual primary tumor that was difficult to classify but had some features of angiocentric glioma. The heavy calcification, mixed-density cell population, and regions with features of angiocentric glioma were most unusual. The patient remained asymptomatic 5 years after surgery, and follow-up scans did not show recurrence.

SU-F-T-626: Intracranial SRS Re-Treatment Without Acquisition of New CT Images

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

Wiant, D; Manning, M; Liu, H

Purpose: Linear accelerator based stereotactic radiosurgery (SRS) for multiple intracranial lesions with frequent surveillance is becoming a popular treatment option. This strategy leads to retreatment with SRS as new lesions arise. Currently, each course of treatment uses magnetic resonance (MR) and computed tomography (CT) images for treatment planning. We propose that new MR images, with course 1 CT images, may be used for future treatment plans with negligible loss of dosimetric accuracy. Methods: Ten patients that received multiple courses of SRS were retrospectively reviewed. The treatment plans and contours from non-initial courses were copied to the initial CTs and recalculated.more » Doses metrics for the plans calculated on the initial CTs and later CTs were compared. All CT scans were acquired on a Philips CT scanner with a 600 mm field of view and 1 mm slice thickness (Philips Healthcare, Andover, MA). All targets were planned to 20 Gy and calculated in Eclipse V. 13.6 (Varian, Palo Alto, CA) using analytic anisotropic algorithm with 1 mm calculation grid. Results: Sixteen lesions were evaluated. The mean time between courses was 250 +/− 215 days (range 103–979). The mean target volume was 2.0 +/− 2.9 cc (range 0.1–10.1). The average difference in mean target dose between the two calculations was 0.2 +/− 0.3 Gy (range 0.0 – 1.0). The mean conformity index (CI) was 1.28 +/− 0.14 (range 1.07 – 1.82). The average difference in CI was 0.03 +/− 0.16 (range 0.00 – 0.44). Targets volumes < 0.5 cc showed the largest changes in both metrics. Conclusion: Continued treatment based on initial CT images is feasible. Dose calculation on the initial CT for future treatments provides reasonable dosimetric accuracy. Changes in dose metrics are largest for small volumes, and are likely dominated by partial volume effects in target definition.« less

SU-E-J-267: Change in Mean CT Intensity of Lung Tumors During Radiation Treatment

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

Mahon, R; Tennyson, N; Weiss, E

2015-06-15

Purpose: To evaluate CT intensity change of lung tumors during radiation therapy. Methods: Repeated 4D CT images were acquired on a CT simulator during the course of therapy for 27 lung cancer patients on IRB approved protocols. All subjects received definitive radiation treatment ± chemotherapy. CT scans were completed prior to treatment, and 2–7 times during the treatment course. Primary tumor was delineated by an experienced Radiation Oncologist. Contours were thresholded between −100 HU and 200 HU to remove airways and bone. Correlations between the change in the mean tumor intensity and initial tumor intensity, SUVmax, and tumor volume changemore » rate were investigated. Reproducibility was assessed by evaluating the variation in mean intensity over all phases in 4DCT, for a subgroup of 19 subjects. Results: Reproducibility of tumor intensity between phases as characterized by the root mean square of standard deviation across 19 subjects was 1.8 HU. Subjects had a mean initial tumor intensity of 16.5 ± 11.6 HU and an overall reduction in HU by 10.3 ± 8.5 HU. Evaluation of the changes in tumor intensity during treatment showed a decrease of 0.3 ± 0.3 HU/day for all subjects, except three. No significant correlation was found between change in HU/day and initial HU intensity (p=0.53), initial PET SUVmax (p=0.69), or initial tumor volume (p=0.70). The rate of tumor volume change was weakly correlated (R{sup 2}=0.05) with HU change (p=0.01). Conclusion: Most lung cancer subjects showed a marked trend of decreasing mean tumor CT intensity throughout radiotherapy, including early in the treatment course. Change in HU/day is not correlated with other potential early predictors for response, such as SUV and tumor volume change. This Result supports future studies to evaluate change in tumor intensity on CT as an early predictor of response.« less

PET/MRI: Where Might It Replace PET/CT?

PubMed Central

Ehman, Eric C.; Johnson, Geoffrey B.; Villanueva-Meyer, Javier E.; Cha, Soonmee; Leynes, Andrew Palmera; Larson, Peder Eric Zufall; Hope, Thomas A.

2017-01-01

Simultaneous positron emission tomography and MRI (PET/MRI) is a technology that combines the anatomic and quantitative strengths of MR imaging with physiologic information obtained from PET. PET and computed tomography (PET/ CT) performed in a single scanning session is an established technology already in widespread and accepted use worldwide. Given the higher cost and complexity of operating and interpreting the studies obtained on a PET/MRI system, there has been question as to which patients would benefit most from imaging with PET/MRI versus PET/CT. In this article, we compare PET/MRI with PET/CT, detail the applications for which PET/MRI has shown promise and discuss impediments to future adoption. It is our hope that future work will prove the benefit of PET/MRI to specific groups of patients, initially those in which PET/CT and MRI are already performed, leveraging simultaneity and allowing for greater degrees of multiparametric evaluation. PMID:28370695

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

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

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.

A Cinematic Magnetic Resonance Imaging Study of Milk of Magnesia Laxative and an Antiflatulent Diet to Reduce Intrafraction Prostate Motion

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

Nichol, Alan M.; Warde, Padraig R.; Lockwood, Gina A.

Purpose: To determine the reduction of prostate motion during a typical radiotherapy (RT) fraction from a bowel regimen comprising an antiflatulent diet and daily milk of magnesia. Methods and Materials: Forty-two patients with T1c-T2c prostate cancer voided the bladder and rectum before three cinematic magnetic resonance imaging scans obtained every 9 s for 9 min in a vacuum immobilization device. The MRIs were at baseline without bowel regimen (MRI-BL), before CT planning with bowel regimen (MRI-CT), and before a randomly assigned RT fraction (1-42) with bowel regimen (MRI-RT). A single observer tracked displacement of the posterior midpoint (PM) of themore » prostate. The primary endpoints were comparisons of the proportion of time that the PM was displaced >3 mm (PTPM3) from its initial position, and the secondary endpoints were comparisons of the reduction of initial rectal area, with and without the bowel regimen. Results: The mean rectal area was: 13.5 cm{sup 2} at MRI-BL, 12.7 cm{sup 2} at MRI-CT, and 12.3 cm{sup 2} at MRI-RT (MRI-BL vs. MRI-CT, p = 0.11; MRI-BL vs. MRI-CT, p = 0.07). Moving rectal gas alone (56%) and moving gas and stool (18%) caused 74% of intrafraction prostate motion. The PTPM3 was 11.3% at MRI-BL, 4.8% at MRI-CT, and 12.0% at MRI-RT (MRI-BL vs. MRI-CT, p = 0.12; MRI-BL vs. MRI-RT, p = 0.89). Conclusion: For subjects voiding their rectum before imaging, an antiflatulent diet and milk of magnesia laxative did not significantly reduce initial rectal area or intrafraction prostate motion.« less

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.

Follow-up segmentation of lung tumors in PET and CT data

NASA Astrophysics Data System (ADS)

Opfer, Roland; Kabus, Sven; Schneider, Torben; Carlsen, Ingwer C.; Renisch, Steffen; Sabczynski, Jörg

2009-02-01

Early response assessment of cancer therapy is a crucial component towards a more effective and patient individualized cancer therapy. Integrated PET/CT systems provide the opportunity to combine morphologic with functional information. We have developed algorithms which allow the user to track both tumor volume and standardized uptake value (SUV) measurements during the therapy from series of CT and PET images, respectively. To prepare for tumor volume estimation we have developed a new technique for a fast, flexible, and intuitive 3D definition of meshes. This initial surface is then automatically adapted by means of a model-based segmentation algorithm and propagated to each follow-up scan. If necessary, manual corrections can be added by the user. To determine SUV measurements a prioritized region growing algorithm is employed. For an improved workflow all algorithms are embedded in a PET/CT therapy monitoring software suite giving the clinician a unified and immediate access to all data sets. Whenever the user clicks on a tumor in a base-line scan, the courses of segmented tumor volumes and SUV measurements are automatically identified and displayed to the user as a graph plot. According to each course, the therapy progress can be classified as complete or partial response or as progressive or stable disease. We have tested our methods with series of PET/CT data from 9 lung cancer patients acquired at Princess Margaret Hospital in Toronto. Each patient underwent three PET/CT scans during a radiation therapy. Our results indicate that a combination of mean metabolic activity in the tumor with the PET-based tumor volume can lead to an earlier response detection than a purely volume based (CT diameter) or purely functional based (e.g. SUV max or SUV mean) response measures. The new software seems applicable for easy, faster, and reproducible quantification to routinely monitor tumor therapy.

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.

Using injectable hydrogel markers to assess resimulation for boost target volume definition in a patient undergoing whole-breast radiotherapy

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

Patel, Henal; Goyal, Sharad; Kim, Leonard, E-mail: kimlh@rutgers.edu

Several publications have recommended that patients undergoing whole-breast radiotherapy be resimulated for boost planning. The rationale for this is that the seroma may be smaller when compared with the initial simulation. However, the decision remains whether to use the earlier or later images to define an appropriate boost target volume. A patient undergoing whole-breast radiotherapy had new, injectable, temporary hydrogel fiducial markers placed 1 to 3 cm from the seroma at the time of initial simulation. The patient was resimulated 4.5 weeks later for conformal photon boost planning. Computed tomography (CT) scans acquired at the beginning and the end ofmore » whole-breast radiotherapy showed that shrinkage of the lumpectomy cavity was not matched by a corresponding reduction in the surrounding tissue volume, as demarcated by hydrogel markers. This observation called into question the usual interpretation of cavity shrinkage for boost target definition. For this patient, it was decided to define the boost target volume on the initial planning CT instead of the new CT.« 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.

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

Quantification of gross tumour volume changes between simulation and first day of radiotherapy for patients with locally advanced malignancies of the lung and head/neck.

PubMed

Kishan, Amar U; Cui, Jing; Wang, Pin-Chieh; Daly, Megan E; Purdy, James A; Chen, Allen M

2014-10-01

To quantify changes in gross tumour volume (GTV) between simulation and initiation of radiotherapy in patients with locally advanced malignancies of the lung and head/neck. Initial cone beam computed tomography (CT) scans from 12 patients with lung cancer and 12 with head/neck cancer (head and neck squamous cell carcinoma (HNSCC)) treated with intensity-modulated radiotherapy with image guidance were rigidly registered to the simulation CT scans. The GTV was demarcated on both scans. The relationship between percent GTV change and variables including time interval between simulation and start, tumour (T) stage, and absolute weight change was assessed. For lung cancer patients, the GTV increased a median of 35.06% (range, -16.63% to 229.97%) over a median interval of 13 days (range, 7-43), while for HNSCC patients, the median GTV increase was 16.04% (range, -8.03% to 47.41%) over 13 days (range, 7-40). These observed changes are statistically significant. The magnitude of this change was inversely associated with the size of the tumour on the simulation scan for lung cancer patients (P < 0.05). However, the observed changes in GTV did not correlate with the duration of the interval for either disease site. Similarly, T stage, absolute weight change and histologic type (the latter for lung cancer cases) did not correlate with degree of GTV change (P > 0.1). While the observed changes in GTV were moderate from the time of simulation to start of radiotherapy, these findings underscore the importance of image guidance for target localisation and verification, particularly for smaller tumours. Minimising the delay between simulation and treatment initiation may also be beneficial. © 2014 The Royal Australian and New Zealand College of Radiologists.

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.

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 ...

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.

Barium appendicitis after upper gastrointestinal imaging.

PubMed

Novotny, Nathan M; Lillemoe, Keith D; Falimirski, Mark E

2010-02-01

Barium appendicitis (BA) is a rarely seen entity with fewer than 30 reports in the literature. However, it is a known complication of barium imaging. To report a case of BA in a patient whose computed tomography (CT) scan was initially read as foreign body ingestion. An 18-year-old man presented with right lower quadrant pain after upper gastrointestinal imaging 2 weeks prior. A CT scan was obtained of his abdomen and pelvis that revealed a finding that was interpreted as a foreign body at the area of the terminal ileum. A plain X-ray study of the abdomen revealed radiopaque appendicoliths. Pathology confirmed the diagnosis of barium appendicitis. BA is a rare entity and the pathogenesis is unclear. Shorter intervals between barium study and presentation with appendicitis usually correlate with fewer complications. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Weight bearing cone beam CT scan versus gravity stress radiography for analysis of supination external rotation injuries of the ankle.

PubMed

Marzo, John M; Kluczynski, Melissa A; Clyde, Corey; Anders, Mark J; Mutty, Christopher E; Ritter, Christopher A

2017-12-01

For AO 44-B2 ankle fractures of uncertain stability, the current diagnostic standard is to obtain a gravity stress radiograph, but some have advocated for the use of weight-bearing radiographs. The primary aim was to compare measures of medial clear space (MCS) on weight-bearing cone beam computed tomography (CBCT) scans versus gravity stress radiographs for determining the state of stability of ankle fractures classified as AO SER 44-B2 or Weber B. The secondary aim was to evaluate the details offered by CBCT scans with respect to other findings that may be relevant to patient care. Nine patients were enrolled in this cross-sectional study between April 2016 and February 2017 if they had an AO SER 44-B2 fracture of uncertain stability, had a gravity stress radiograph, and were able to undergo CT scan within seven days. The width of the MCS was measured at the level of the talar dome on all radiographs and at the mid coronal slice on CT. Wilcoxon signed-ranks tests were used to compare MCS between initial radiographs, gravity stress radiographs and weight-bearing CBCT scans. MCS on weight-bearing CBCT scan (1.41±0.41 mm) was significantly less than standard radiographs (3.28±1.63 mm, P=0.004) and gravity stress radiographs (5.82±1.93 mm, P=0.02). There was no statistically significant difference in MCS measured on standard radiographs versus gravity stress radiographs (P=0.11). Detailed review of the multiplanar CT images revealed less than perfect anatomical reduction of the fractures, with residual fibular shortening, posterior displacement, and fracture fragments in the incisura as typical findings. Similar to weight-bearing radiographs, weight-bearing CBCT scan can predict stability of AO 44-B2 ankle fractures by showing restoration of the MCS, and might be used to indicate patients for non-operative treatment. None of the fractures imaged in this study were perfectly reduced however, and further clinical research is necessary to determine if any of the detailed weight-bearing CBCT findings are related to patient outcomes.

Are flexion extension films necessary for cervical spine clearance in patients with neck pain after negative cervical CT scan?

PubMed

Tran, Baotram; Saxe, Jonathan M; Ekeh, Akpofure Peter

2013-09-01

There are variations in cervical spine (CS) clearance protocols in neurologically intact blunt trauma patients with negative radiological imaging but persistent neck pain. Current guidelines from the current Eastern Association for the Surgery of Trauma include options of maintaining the cervical collar or obtaining either magnetic resonance imaging (MRI) or flexion-extension films (FEF). We evaluated the utility of FEF in the current era of routine computerized tomography (CT) for imaging the CS in trauma. All neurologically intact, awake, nonintoxicated patients who underwent FEF for persistent neck pain after negative CT scan of the CS at our level I trauma center over a 13-mo period were identified. Their charts were reviewed and demographic data obtained. There were 354 patients (58.5% male) with negative cervical CS CT scans who had FEF for residual neck pain. Incidental degenerative changes were seen in 37%--which did not affect their acute management. FEF were positive for possible ligamentous injury in 5 patients (1.4%). Two of these patients had negative magnetic resonance images and the other three had collars removed within 3 wk as the findings were ultimately determined to be degenerative. In the current era, where cervical CT has universally supplanted initial plain films, FEF appear to be of little value in the evaluation of persistent neck pain. Their use should be excluded from cervical spine clearance protocols in neurologically intact, awake patients. Copyright © 2013 Elsevier Inc. All rights reserved.

Using Micro CT Scanning to Assess Pteropod Shells in the Modern Ocean

NASA Astrophysics Data System (ADS)

Oakes, R. L.; Urbanski, J. M.; Bralower, T. J.

2016-02-01

Anthropogenic activities are causing fundamental changes to ocean chemistry. Calcareous plankton and nekton are predicted to be affected by these chemical changes, especially by ocean acidification. These groups are at the base of the marine food chain and therefore their demise will have a strong effect on the marine ecosystem as a whole. One challenge moving forward is to find a method to assess how chemical changes manifest themselves in plankton and nekton shells. Recent advancements in computed tomographic (CT) scanning technology allows for organisms to be imaged in three dimensions at micrometer resolution. CT data enables quantitative measurements of properties such as shell thickness, volume, and morphology. We apply this method to look at pteropods, nektonic molluscs which make their shells from the more soluble form of calcium carbonate, aragonite. Their shell mineralogy, and the fact that some groups live in polar and upwelling waters, place them at high risk for ocean acidification. We have scanned over 70 pteropods from 5 different locations globally. Analysis shows that there is a significant difference in pteropod shell thickness in different ocean basins with the thinnest shells being found off the coast of Washington. Changes in shell thickness may affect pteropod swimming efficiency, predation, and rate of sinking. Shell volume does not seem to vary with shell thickness suggesting that changes will impact pteropods at all ontogenetic stages. We are working towards a geometric morphometric analysis of these shells to see if the shape differs in areas with different ocean conditions. This initial set of CT scans of pteropods can be used as a baseline to which future changes can be compared. Furthermore, this technique has the potential to be easily transferred to other organisms as a method of assessing shell change in response to ocean acidification and associated factors.

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.

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...

From mice and men to earth and space: joint NASA-NCI workshop on lung cancer risk resulting from space and terrestrial radiation.

PubMed

Shay, Jerry W; Cucinotta, Francis A; Sulzman, Frank M; Coleman, C Norman; Minna, John D

2011-11-15

On June 27-28, 2011, scientists from the National Cancer Institute (NCI), NASA, and academia met in Bethesda to discuss major lung cancer issues confronting each organization. For NASA, available data suggest that lung cancer is the largest potential cancer risk from space travel for both men and women and quantitative risk assessment information for mission planning is needed. In space, the radiation risk is from high energy and charge (HZE) nuclei (such as Fe) and high-energy protons from solar flares and not from gamma radiation. In contrast, the NCI is endeavoring to estimate the increased lung cancer risk from the potential widespread implementation of computed tomographic (CT) screening in individuals at high risk for developing lung cancer based on the National Lung Cancer Screening Trial (NLST). For the latter, exposure will be X-rays from CT scans from the screening (which uses "low-dose" CT scans) and also from follow-up scans used to evaluate abnormalities found during initial screening. Topics discussed included the risk of lung cancer arising after HZE particle, proton, and low-dose exposure to Earth's radiation. The workshop examined preclinical models, epidemiology, molecular markers, "omics" technology, radiobiology issues, and lung stem cells that relate to the development of lung cancer. ©2011 AACR

Rifaximin suppresses background intestinal 18F-FDG uptake on PET/CT scans.

PubMed

Franquet, Elisa; Palmer, Mathew R; Gifford, Anne E; Selen, Daryl J; Chen, Yih-Chieh S; Sedora-Roman, Neda; Joyce, Robin M; Kolodny, Gerald M; Moss, Alan C

2014-10-01

Identification of cancer or inflammatory bowel disease in the intestinal tract by PET/computed tomography (CT) imaging can be hampered by physiological uptake of F-fluorodeoxyglucose (F-FDG) in the normal colon. Previous work has localized this F-FDG uptake to the intestinal lumen, predominantly occupied by bacteria. We sought to determine whether pretreatment with an antibiotic could reduce F-FDG uptake in the healthy colon. Thirty patients undergoing restaging PET/CT for nongastrointestinal lymphoma were randomly selected to receive rifaximin 550 mg twice daily for 2 days before their scan (post-rifaximin). Their PET/CT images were compared with those from their prior study (pre-rifaximin). Cecal maximum standard uptake value (SUVmax) and overall colonic F-FDG uptake were compared between scans. All PET/CT images were blindly scored by a radiologist. The same comparison of sequential scans was also undertaken in 30 patients who did not receive antibiotics. Thirty post-rifaximin scans were compared with 30 pre-rifaximin scans in the same patients. SUVmax in the cecum was significantly lower in the patient's post-rifaximin scans than in their pre-rifaximin scans (P=0.002). The percentage of scans with greater than grade 1 colonic F-FDG uptake was significantly lower in the post-rifaximin scans than in the pre-rifaximin scans (P<0.05). In contrast, there was no significant difference in the paired sequential scans from control patients, nor a reduction in the percentage of scans with greater than grade 1 colonic F-FDG uptake. This pilot study shows that treatment with rifaximin for 2 days before PET/CT scanning can significantly reduce physiological F-FDG uptake in the normal colonic lumen.

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.

Effect of clinical decision rules, patient cost and malpractice information on clinician brain CT image ordering: a randomized controlled trial.

PubMed

Gimbel, Ronald W; Pirrallo, Ronald G; Lowe, Steven C; Wright, David W; Zhang, Lu; Woo, Min-Jae; Fontelo, Paul; Liu, Fang; Connor, Zachary

2018-03-12

The frequency of head computed tomography (CT) imaging for mild head trauma patients has raised safety and cost concerns. Validated clinical decision rules exist in the published literature and on-line sources to guide medical image ordering but are often not used by emergency department (ED) clinicians. Using simulation, we explored whether the presentation of a clinical decision rule (i.e. Canadian CT Head Rule - CCHR), findings from malpractice cases related to clinicians not ordering CT imaging in mild head trauma cases, and estimated patient out-of-pocket cost might influence clinician brain CT ordering. Understanding what type and how information may influence clinical decision making in the ordering advanced medical imaging is important in shaping the optimal design and implementation of related clinical decision support systems. Multi-center, double-blinded simulation-based randomized controlled trial. Following standardized clinical vignette presentation, clinicians made an initial imaging decision for the patient. This was followed by additional information on decision support rules, malpractice outcome review, and patient cost; each with opportunity to modify their initial order. The malpractice and cost information differed by assigned group to test the any temporal relationship. The simulation closed with a second vignette and an imaging decision. One hundred sixteen of the 167 participants (66.9%) initially ordered a brain CT scan. After CCHR presentation, the number of clinicians ordering a CT dropped to 76 (45.8%), representing a 21.1% reduction in CT ordering (P = 0.002). This reduction in CT ordering was maintained, in comparison to initial imaging orders, when presented with malpractice review information (p = 0.002) and patient cost information (p = 0.002). About 57% of clinicians changed their order during study, while 43% never modified their imaging order. This study suggests that ED clinician brain CT imaging decisions may be influenced by clinical decision support rules, patient out-of-pocket cost information and findings from malpractice case review. NCT03449862 , February 27, 2018, Retrospectively registered.

Scandinavian guidelines for initial management of minor and moderate head trauma in children.

PubMed

Astrand, Ramona; Rosenlund, Christina; Undén, Johan

2016-02-18

The management of minor and moderate head trauma in children differs widely between countries. Presently, there are no existing guidelines for management of these children in Scandinavia. The purpose of this study was to produce new evidence-based guidelines for the initial management of head trauma in the paediatric population in Scandinavia. The primary aim was to detect all children in need of neurosurgical intervention. Detection of any traumatic intracranial injury on CT scan was an important secondary aim. General methodology according to the Appraisal of Guidelines for Research and Evaluation (AGREE) II and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used. Systematic evidence-based review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and based upon relevant clinical questions with respect to patient-important outcomes. Quality ratings of the included studies were performed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 and Centre of Evidence Based Medicine (CEBM)-2 tools. Based upon the results, GRADE recommendations, a guideline, discharge instructions and in-hospital observation instructions were drafted. For elements with low evidence, a modified Delphi process was used for consensus, which included relevant clinical stakeholders. The guidelines include criteria for selecting children for CT scans, in-hospital observation or early discharge, and suggestions for monitoring routines and discharge advice for children and guardians. The guidelines separate mild head trauma patients into high-, medium- and low-risk categories, favouring observation for mild, low-risk patients as an attempt to reduce CT scans in children. We present new evidence and consensus based Scandinavian Neurotrauma Committee guidelines for initial management of minor and moderate head trauma in children. These guidelines should be validated before extensive clinical use and updated within four years due to rapid development of new diagnostic tools within paediatric neurotrauma.

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

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.

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.

Effect of emergency department CT on neuroimaging case volume and positive scan rates.

PubMed

Oguz, Kader Karli; Yousem, David M; Deluca, Tom; Herskovits, Edward H; Beauchamp, Norman J

2002-09-01

The authors performed this study to determine the effect a computed tomographic (CT) scanner in the emergency department (ED) has on neuroimaging case volume and positive scan rates. The total numbers of ED visits and neuroradiology CT scans requested from the ED were recorded for 1998 and 2000, the years before and after the installation of a CT unit in the ED. For each examination type (brain, face, cervical spine), studies were graded for major findings (those that affected patient care), minor findings, and normal findings. The CT utilization rates and positive study rates were compared for each type of study performed for both years. There was a statistically significant increase in the utilization rate after installation of the CT unit (P < .001). The fractions of studies with major findings, minor findings, and normal findings changed significantly after installation of the CT unit for facial examinations (P = .002) but not for brain (P = .12) or cervical spine (P = .24) examinations. In all types of studies, the percentage of normal examinations increased. In toto, there was a significant decrease in the positive scan rate after installation of the CT scanner (P = .004). After installation of a CT scanner in the ED, there was increased utilization and a decreased rate of positive neuroradiologic examinations, the latter primarily due to lower positive rates for facial CT scans.

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

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.

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.

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-E-I-33: Initial Evaluation of Model-Based Iterative CT Reconstruction Using Standard Image Quality Phantoms

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

Gingold, E; Dave, J

2014-06-01

Purpose: The purpose of this study was to compare a new model-based iterative reconstruction with existing reconstruction methods (filtered backprojection and basic iterative reconstruction) using quantitative analysis of standard image quality phantom images. Methods: An ACR accreditation phantom (Gammex 464) and a CATPHAN600 phantom were scanned using 3 routine clinical acquisition protocols (adult axial brain, adult abdomen, and pediatric abdomen) on a Philips iCT system. Each scan was acquired using default conditions and 75%, 50% and 25% dose levels. Images were reconstructed using standard filtered backprojection (FBP), conventional iterative reconstruction (iDose4) and a prototype model-based iterative reconstruction (IMR). Phantom measurementsmore » included CT number accuracy, contrast to noise ratio (CNR), modulation transfer function (MTF), low contrast detectability (LCD), and noise power spectrum (NPS). Results: The choice of reconstruction method had no effect on CT number accuracy, or MTF (p<0.01). The CNR of a 6 HU contrast target was improved by 1–67% with iDose4 relative to FBP, while IMR improved CNR by 145–367% across all protocols and dose levels. Within each scan protocol, the CNR improvement from IMR vs FBP showed a general trend of greater improvement at lower dose levels. NPS magnitude was greatest for FBP and lowest for IMR. The NPS of the IMR reconstruction showed a pronounced decrease with increasing spatial frequency, consistent with the unusual noise texture seen in IMR images. Conclusion: Iterative Model Reconstruction reduces noise and improves contrast-to-noise ratio without sacrificing spatial resolution in CT phantom images. This offers the possibility of radiation dose reduction and improved low contrast detectability compared with filtered backprojection or conventional iterative reconstruction.« less

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.

Classification of intertrochanteric fractures with computed tomography: a study of intraobserver and interobserver variability and prognostic value.

PubMed

Chapman, Cary B; Herrera, Mauricio F; Binenbaum, Gil; Schweppe, Michael; Staron, Ronald B; Feldman, Frieda; Rosenwasser, Melvin P

2003-09-01

The purpose of this prospective study was to determine the level of interobserver and intraobserver agreement among orthopedic surgeons and radiologists when computed tomography (CT) scans are used with plain radiographs to evaluate intertrochanteric fractures. In addition, the prognostic value of current classifications systems concerning quality of life was evaluated. Sixty-one patients who presented with intertrochanteric fractures received open reduction and internal fixation with compression hip screw. Three orthopedic surgeons and 2 radiologists independently classified the fractures according to 2 systems: Evans-Jensen and AO (Arbeitsgemeinschaft für Osteo-synthesefragen). Fractures were initially graded with plain radiographs and then again in conjunction with CT. Results were analyzed using the (kappa) kappa coefficient. The 36-item Short-Form Health Survey was administered at baseline, 3 months, and 1 year, and results were correlated with fracture grade. Mean kappa coefficients when comparing radiography alone with radiography and CT scan were 0.63 for the AO system and 0.59 for the Evans-Jensen system. Both represent "fair" agreements. Mean overall interobserver kappa coefficients were 0.67 for radiologists and 0.57 for orthopedic surgeons. Radiologists also had higher intraobserver kappa coefficients. No significant relationships were found between follow-up Short Form Health Survey results and intraoperative grading of fractures. When these classification schemes are compared, interobserver agreement does not appear to change dramatically when information from CT scans is added. This may suggest that (1) more data have been provided by CT with greater possibilities for misinterpretation and (2) these classification schemes may not be comprehensive in describing fracture pattern and displacement. Finally, both systems failed to provide any prognostic value.

SU-E-J-133: Evaluation of Inter- and Intra-Fractional Pancreas Tumor Residual Motions with Abdominal Compression

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

Li, Y; Shi, F; Tian, Z

2014-06-01

Purpose: Abdominal compression (AC) has been widely used to reduce pancreas motion due to respiration for pancreatic cancer patients undergoing stereotactic body radiotherapy (SBRT). However, the inter-fractional and intra-fractional patient motions may degrade the treatment. The purpose of this work is to study daily CBCT projections and 4DCT to evaluate the inter-fractional and intra-fractional pancreatic motions. Methods: As a standard of care at our institution, 4D CT scan was performed for treatment planning. At least two CBCT scans were performed for daily treatment. Retrospective studies were performed on patients with implanted internal fiducial markers or surgical clips. The initial motionmore » pattern was obtained by extracting marker positions on every phase of 4D CT images. Daily motions were presented by marker positions on CBCT scan projection images. An adaptive threshold segmentation algorithm was used to extract maker positions. Both marker average positions and motion ranges were compared among three sets of scans, 4D CT, positioning CBCT, and conformal CBCT, for inter-fractional and intra-fractional motion variations. Results: Data from four pancreatic cancer patients were analyzed. These patients had three fiducial markers implanted. All patients were treated by an Elekta Synergy with single fraction SBRT. CBCT projections were acquired by XVI. Markers were successfully detected on most of the projection images. The inter-fractional changes were determined by 4D CT and the first CBCT while the intra-fractional changes were determined by multiple CBCT scans. It is found that the average motion range variations are within 2 mm, however, the average marker positions may drift by 6.5 mm. Conclusion: The patients respiratory motion variation for pancreas SBRT with AC was evaluated by detecting markers from CBCT projections and 4DCT, both the inter-fraction and intra-fraction motion range change is small but the drift of marker positions may be comparable to motion ranges.« less

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.

Personalized Circulating Tumor DNA Biomarkers Dynamically Predict Treatment Response and Survival In Gynecologic Cancers.

PubMed

Pereira, Elena; Camacho-Vanegas, Olga; Anand, Sanya; Sebra, Robert; Catalina Camacho, Sandra; Garnar-Wortzel, Leopold; Nair, Navya; Moshier, Erin; Wooten, Melissa; Uzilov, Andrew; Chen, Rong; Prasad-Hayes, Monica; Zakashansky, Konstantin; Beddoe, Ann Marie; Schadt, Eric; Dottino, Peter; Martignetti, John A

2015-01-01

High-grade serous ovarian and endometrial cancers are the most lethal female reproductive tract malignancies worldwide. In part, failure to treat these two aggressive cancers successfully centers on the fact that while the majority of patients are diagnosed based on current surveillance strategies as having a complete clinical response to their primary therapy, nearly half will develop disease recurrence within 18 months and the majority will die from disease recurrence within 5 years. Moreover, no currently used biomarkers or imaging studies can predict outcome following initial treatment. Circulating tumor DNA (ctDNA) represents a theoretically powerful biomarker for detecting otherwise occult disease. We therefore explored the use of personalized ctDNA markers as both a surveillance and prognostic biomarker in gynecologic cancers and compared this to current FDA-approved surveillance tools. Tumor and serum samples were collected at time of surgery and then throughout treatment course for 44 patients with gynecologic cancers, representing 22 ovarian cancer cases, 17 uterine cancer cases, one peritoneal, three fallopian tube, and one patient with synchronous fallopian tube and uterine cancer. Patient/tumor-specific mutations were identified using whole-exome and targeted gene sequencing and ctDNA levels quantified using droplet digital PCR. CtDNA was detected in 93.8% of patients for whom probes were designed and levels were highly correlated with CA-125 serum and computed tomography (CT) scanning results. In six patients, ctDNA detected the presence of cancer even when CT scanning was negative and, on average, had a predictive lead time of seven months over CT imaging. Most notably, undetectable levels of ctDNA at six months following initial treatment was associated with markedly improved progression free and overall survival. Detection of residual disease in gynecologic, and indeed all cancers, represents a diagnostic dilemma and a potential critical inflection point in precision medicine. This study suggests that the use of personalized ctDNA biomarkers in gynecologic cancers can identify the presence of residual tumor while also more dynamically predicting response to treatment relative to currently used serum and imaging studies. Of particular interest, ctDNA was an independent predictor of survival in patients with ovarian and endometrial cancers. Earlier recognition of disease persistence and/or recurrence and the ability to stratify into better and worse outcome groups through ctDNA surveillance may open the window for improved survival and quality and life in these cancers.

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.

Pulmonary parenchyma segmentation in thin CT image sequences with spectral clustering and geodesic active contour model based on similarity

NASA Astrophysics Data System (ADS)

He, Nana; Zhang, Xiaolong; Zhao, Juanjuan; Zhao, Huilan; Qiang, Yan

2017-07-01

While the popular thin layer scanning technology of spiral CT has helped to improve diagnoses of lung diseases, the large volumes of scanning images produced by the technology also dramatically increase the load of physicians in lesion detection. Computer-aided diagnosis techniques like lesions segmentation in thin CT sequences have been developed to address this issue, but it remains a challenge to achieve high segmentation efficiency and accuracy without much involvement of human manual intervention. In this paper, we present our research on automated segmentation of lung parenchyma with an improved geodesic active contour model that is geodesic active contour model based on similarity (GACBS). Combining spectral clustering algorithm based on Nystrom (SCN) with GACBS, this algorithm first extracts key image slices, then uses these slices to generate an initial contour of pulmonary parenchyma of un-segmented slices with an interpolation algorithm, and finally segments lung parenchyma of un-segmented slices. Experimental results show that the segmentation results generated by our method are close to what manual segmentation can produce, with an average volume overlap ratio of 91.48%.

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.

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).

Assessment of Treatment Response by 99mTc-MIP-1404 SPECT/CT: A Pilot Study in Patients With Metastatic Prostate Cancer.

PubMed

Schmidkonz, Christian; Cordes, Michael; Beck, Michael; Goetz, Theresa Ida; Schmidt, Daniela; Prante, Olaf; Bäuerle, Tobias; Cavallaro, Alexander; Uder, Michael; Wullich, Bernd; Goebell, Peter; Kuwert, Torsten; Ritt, Philipp

2018-06-19

We investigated the role of Tc-MIP-1404 (Progenics Pharmaceuticals, Inc, New York, NY) SPECT/CT of PSMA expression in the assessment of treatment response in patients with metastatic prostate cancer. We retrospectively analyzed Tc-MIP-1404 SPECT/CT scans from 28 patients with metastatic prostate cancer examined before initiation and after completion of therapy. Eight of these patients had been treated with androgen deprivation therapy, 10 with docetaxel, and another 10 with external beam radiotherapy. On the CT images from SPECT/CT, treatment response was assessed according to RECIST 1.1 criteria; independently from that analysis, maximal standardized uptake values (SUVmax) were quantified in representative tumor lesions and treatment response assumed at differences in SUVmax greater than 30%. Radiographic response assessment was correlated to biochemical response (BR) based on prostate-specific antigen serum levels. The concordance rate between SPECT and BR was 75% (95% confidence interval [CI], 0.55-0.89) (Cohen κ = 0.57; 95% CI, 0.29-0.85; P ≤ 0.01), higher than for that between SPECT and CT with 57% (95% CI, 0.37-0.76) (κ = 0.40; 95% CI, 0.14-0.65; P ≤ 0.01), as well as that between CT and BR with 50% (95% CI, 0.31-0.69) (κ = 0.31; 95% CI, 0.06-0.57, P ≤ 0.05). Discordant findings between SPECT and CT were most likely due to limitations of CT in assessing metastases in lymph nodes, as well as bone involvement, which was sometimes not detectable on CT scans. The high agreement between treatment response, as assessed by Tc-MIP-1404 SPECT/CT and BR, suggests a possible role of that imaging tool for monitoring treatment in metastatic prostate cancer. Larger, ideally prospective trials are needed to help to reveal the full potential of SPECT imaging of PSMA expression in that regard.

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.

Chemotherapy Response Assessment by FDG-PET-CT in Early-stage Classical Hodgkin Lymphoma: Moving Beyond the Five-Point Deauville Score

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

Milgrom, Sarah A., E-mail: samilgrom@mdanderson.org; Dong, Wenli; Akhtari, Mani

Purpose: In early-stage classical Hodgkin lymphoma, fluorodeoxyglucose positron emission tomography (PET)-computed tomography (CT) scans are performed routinely after chemotherapy, and the 5-point Deauville score is used to report the disease response. We hypothesized that other PET-CT parameters, considered in combination with Deauville score, would improve risk stratification. Methods and Materials: Patients treated for stage I to II Hodgkin lymphoma from 2003 to 2013, who were aged ≥18 years and had analyzable PET-CT scans performed before and after chemotherapy, were eligible. The soft tissue volume (STV), maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis were recorded from the PET-CTmore » scans before and after chemotherapy. Reductions were defined as 1 − (final PET-CT value)/(corresponding initial PET-CT value). The primary endpoint was freedom from progression (FFP). Results: For 202 patients treated with chemotherapy with or without radiation therapy, the 5-year FFP was 89% (95% confidence interval 85%-93%). All PET-CT parameters were strongly associated with the Deauville score (P<.001) and FFP (P<.0001) on univariate analysis. The Deauville score was highly predictive of FFP (C-index 0.89) but was less discriminating in the Deauville 1 to 4 subset (C-index 0.67). Therefore, we aimed to identify PET-CT parameters that would improve risk stratification for this subgroup (n=187). STV reduction was predictive of outcome (C-index 0.71) and was dichotomized with an optimal cutoff of 0.65 (65% reduction in STV). A model incorporating the Deauville score and STV reduction predicted FFP more accurately than either measurement alone in the Deauville 1 to 4 subset (C-index 0.83). The improvement in predictive accuracy of this composite measure compared with the Deauville score alone met statistical significance (P=.045). Conclusions: The relative reduction in tumor size is an independent predictor of outcome. Combined with the Deauville score, it might improve risk stratification and contribute to response-adapted individualization of therapy.« less

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.

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.

Development of Prior Image-Based, High-Quality, Low-Dose Kilovoltage Cone Beam CT for Use in Adaptive Radiotherapy of Prostate Cancer

DTIC Science & Technology

2013-05-01

for initial test of object coverage for these scanning trajectories. I have also acquired real data of physical phantoms by using a clinical CBCT system...scan. To test the extension of axial coverage, I car- ried out a simulated data study using numerical disk and anthropomorphic XCAT phantoms [15]. As an...imaging model in Eq. (1), I investigated the choice of data divergence, such as the Euclidean distance or Kullback - Leibler (K-L) divergence, which are

Struma Ovarii With Hyperthyroidism.

PubMed

Ang, Lynn P; Avram, Anca M; Lieberman, Richard W; Esfandiari, Nazanene H

2017-06-01

We report the case of a 61-year-old woman with persistent thyrotoxicosis for 7 years despite low thyroidal radioiodine uptake and methimazole treatment. Her initial I whole-body scan (WBS) was read as negative. Upon evaluation in our institution, she remained hyperthyroid after discontinuation of methimazole. Repeat WBS with SPECT/CT revealed low 24-hour thyroidal uptake (RAIU = 2%) and intensely focal radioiodine uptake in a large heterogeneous left pelvic mass, consistent with left adnexal struma ovarii. Resection of this mass confirmed benign struma ovarii. This case illustrates the advantage of fusion SPECT/CT imaging with planar I-WBS for diagnosis of extrathyroidal thyrotoxicosis.

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.

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.

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.

Accurate Segmentation of CT Male Pelvic Organs via Regression-based Deformable Models and Multi-task Random Forests

PubMed Central

Gao, Yaozong; Shao, Yeqin; Lian, Jun; Wang, Andrew Z.; Chen, Ronald C.

2016-01-01

Segmenting male pelvic organs from CT images is a prerequisite for prostate cancer radiotherapy. The efficacy of radiation treatment highly depends on segmentation accuracy. However, accurate segmentation of male pelvic organs is challenging due to low tissue contrast of CT images, as well as large variations of shape and appearance of the pelvic organs. Among existing segmentation methods, deformable models are the most popular, as shape prior can be easily incorporated to regularize the segmentation. Nonetheless, the sensitivity to initialization often limits their performance, especially for segmenting organs with large shape variations. In this paper, we propose a novel approach to guide deformable models, thus making them robust against arbitrary initializations. Specifically, we learn a displacement regressor, which predicts 3D displacement from any image voxel to the target organ boundary based on the local patch appearance. This regressor provides a nonlocal external force for each vertex of deformable model, thus overcoming the initialization problem suffered by the traditional deformable models. To learn a reliable displacement regressor, two strategies are particularly proposed. 1) A multi-task random forest is proposed to learn the displacement regressor jointly with the organ classifier; 2) an auto-context model is used to iteratively enforce structural information during voxel-wise prediction. Extensive experiments on 313 planning CT scans of 313 patients show that our method achieves better results than alternative classification or regression based methods, and also several other existing methods in CT pelvic organ segmentation. PMID:26800531

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.

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.

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.

Downstaging chemotherapy and alteration in the classic computed tomography/magnetic resonance imaging signs of vascular involvement in patients with pancreaticobiliary malignant tumors: influence on patient selection for surgery.

PubMed

Donahue, Timothy R; Isacoff, William H; Hines, O Joe; Tomlinson, James S; Farrell, James J; Bhat, Yasser M; Garon, Edward; Clerkin, Barbara; Reber, Howard A

2011-07-01

To determine whether computed tomography (CT)/magnetic resonance imaging (MRI) signs of vascular involvement are accurate after downstaging chemotherapy (DCTx) and to highlight factors associated with survival in patients who have undergone resection. Retrospective cohort study; prospective database. University pancreatic disease center. Patients with unresectable pancreaticobiliary cancer who underwent curative intent surgery after completing DCTx. Use of CT/MRI scan, pancreatic resection, and palliative bypass. Resectability after DCTx and disease-specific survival. We operated on 41 patients (1992-2009) with locally advanced periampullary malignant tumors after a median of 8.5 months of DCTx. Before DCTx, most patients (38 [93%]) were unresectable because of evidence of vascular contact on CT/MRI scan or operative exploration. Criteria for exploration after DCTx were CT/MRI evidence of tumor shrinkage and/or change in signs of vascular involvement, cancer antigen 19-9 decrease, and good functional status. None had progressive disease. At operation, we resected tumors in 34 of 41 patients (83%), and 6 had persistent vascular involvement. Surprisingly, CT/MRI scan was only 71% sensitive and 58% specific to detect vascular involvement after DCTx. "Involvement" on imaging was often from tumor fibrosis rather than viable cancer. Radiographic decrease in tumor size also did not predict resectability (P = .10). Patients with tumors that were resected had a median 87% decrease in cancer antigen 19-9 (P = .04) during DCTx. The median follow-up (all survivors) was 31 months, and disease-specific survival was 52 months for patients with resected tumors. In patients with initially unresectable periampullary malignant tumors, original CT/MRI signs of vascular involvement may persist after successful DCTx. Patients should be chosen for surgery on the basis of lack of disease progression, good functional status, and decrease in cancer antigen 19-9.

[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.

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

Serious unexpected sinus infection discovered by CT scanning for presumed neurological disease.

PubMed

Swift, A C; Gill, G V

1994-03-01

Serious infection in the paranasal sinuses may present with symptoms suggestive of neurological disease and thus lead to delay in the diagnosis and subsequent treatment. We present three such cases in whom the initial diagnoses had been acute optic neuritis, a posterior communicating aneurysm and an intracranial space occupying lesion. The fourth patient had meningitis but the paranasal sinuses had not initially been considered as a possible source of infection. The current methods of diagnosing sinusitis are discussed.

Quality control of CT systems by automated monitoring of key performance indicators: a two‐year study

PubMed Central

Bujila, Robert; Poludniowski, Gavin; Fransson, Annette

2015-01-01

The purpose of this study was to develop a method of performing routine periodical quality controls (QC) of CT systems by automatically analyzing key performance indicators (KPIs), obtainable from images of manufacturers' quality assurance (QA) phantoms. A KPI pertains to a measurable or determinable QC parameter that is influenced by other underlying fundamental QC parameters. The established KPIs are based on relationships between existing QC parameters used in the annual testing program of CT scanners at the Karolinska University Hospital in Stockholm, Sweden. The KPIs include positioning, image noise, uniformity, homogeneity, the CT number of water, and the CT number of air. An application (MonitorCT) was developed to automatically evaluate phantom images in terms of the established KPIs. The developed methodology has been used for two years in clinical routine, where CT technologists perform daily scans of the manufacturer's QA phantom and automatically send the images to MonitorCT for KPI evaluation. In the cases where results were out of tolerance, actions could be initiated in less than 10 min. 900 QC scans from two CT scanners have been collected and analyzed over the two‐year period that MonitorCT has been active. Two types of errors have been registered in this period: a ring artifact was discovered with the image noise test, and a calibration error was detected multiple times with the CT number test. In both cases, results were outside the tolerances defined for MonitorCT, as well as by the vendor. Automated monitoring of KPIs is a powerful tool that can be used to supplement established QC methodologies. Medical physicists and other professionals concerned with the performance of a CT system will, using such methods, have access to comprehensive data on the current and historical (trend) status of the system such that swift actions can be taken in order to ensure the quality of the CT examinations, patient safety, and minimal disruption of service PACS numbers: 87.57.C‐, 87.57.N‐, 87.57.Q‐ PMID:26219012

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

Planning the Breast Boost: Comparison of Three Techniques and Evolution of Tumor Bed During Treatment

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

Hepel, Jaroslaw T.; Department of Radiation Oncology, Brown University, Rhode Island Hospital, Providence, RI; Evans, Suzanne B.

2009-06-01

Purpose: To evaluate the accuracy of two clinical techniques for electron boost planning compared with computed tomography (CT)-based planning. Additionally, we evaluated the tumor bed characteristics at whole breast planning and boost planning. Methods and Materials: A total of 30 women underwent tumor bed boost planning within 2 weeks of completing whole breast radiotherapy using three planning techniques: scar-based planning, palpation/clinical-based planning, and CT-based planning. The plans were analyzed for dosimetric coverage of the CT-delineated tumor bed. The cavity visualization score was used to define the CT-delineated tumor bed as well or poorly defined. Results: Scar-based planning resulted in inferiormore » tumor bed coverage compared with CT-based planning, with the minimal dose received by 90% of the target volume >90% in 53% and a geographic miss in 53%. The results of palpation/clinical-based planning were significantly better: 87% and 10% for the minimal dose received by 90% of the target volume >90% and geographic miss, respectively. Of the 30 tumor beds, 16 were poorly defined by the cavity visualization score. Of these 16, 8 were well demarcated by the surgical clips. The evaluation of the 22 well-defined tumor beds revealed similar results. A comparison of the tumor bed volume from the initial planning CT scan to the boost planning CT scan revealed a decrease in size in 77% of cases. The mean decrease in volume was 52%. Conclusion: The results of our study have shown that CT-based planning allows for optimal tumor bed coverage compared with clinical and scar-based approaches. However, in the setting of a poorly visualized cavity on CT without surgical clips, palpation/clinical-based planning can help delineate the appropriate target volumes and is superior to scar-based planning. CT simulation at boost planning could allow for a reduction in the boost volumes.« less

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

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.

Acute venous thrombosis as complication and clue to diagnose a SAPHO syndrome case. A case report.

PubMed

Rosero, A; Ruano, R; Martin, M; Hidalgo, C; Garcia-Talavera, J

2013-01-01

This report concerns a male adult admitted for sternal and left arm pain, who was diagnosed and treated for acute deep venous thrombosis in the left subclavian and axillary veins. X-ray and a hybrid single photon emission tomography and computed tomography (SPECT-CT) scintigraphy scan revealed high intensity uptake in both sternoclavicular joints, which corresponded to hyperostosis, thereby suggesting a SAPHO syndrome. Upon reviewing the patient's medical history, we found dermatological pustulosis disease and an intermittent sternal chest pain untreated since 10 years ago. In the biochemical study we found erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) elevation, hyperglobulinemia, and mild anaemia. Initial treatment included nonsteroidal anti-inflammatory drugs (NSAIDs) with low response, which then changed to methotrexate, sulfasalazine, and prednisone. The patient's pain was controlled almost completely in 10 months. A control bone scan revealed a marked decrease in intensity of bone deposits according to clinical response. To our knowledge, there are only a few cases of SAPHO and thrombosis and none are followed up with a bone SPECT-CT scan.

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.

Segmenting the thoracic, abdominal and pelvic musculature on CT scans combining atlas-based model and active contour model

NASA Astrophysics Data System (ADS)

Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Summers, Ronald M.

2013-03-01

Segmentation of the musculature is very important for accurate organ segmentation, analysis of body composition, and localization of tumors in the muscle. In research fields of computer assisted surgery and computer-aided diagnosis (CAD), muscle segmentation in CT images is a necessary pre-processing step. This task is particularly challenging due to the large variability in muscle structure and the overlap in intensity between muscle and internal organs. This problem has not been solved completely, especially for all of thoracic, abdominal and pelvic regions. We propose an automated system to segment the musculature on CT scans. The method combines an atlas-based model, an active contour model and prior segmentation of fat and bones. First, body contour, fat and bones are segmented using existing methods. Second, atlas-based models are pre-defined using anatomic knowledge at multiple key positions in the body to handle the large variability in muscle shape. Third, the atlas model is refined using active contour models (ACM) that are constrained using the pre-segmented bone and fat. Before refining using ACM, the initialized atlas model of next slice is updated using previous atlas. The muscle is segmented using threshold and smoothed in 3D volume space. Thoracic, abdominal and pelvic CT scans were used to evaluate our method, and five key position slices for each case were selected and manually labeled as the reference. Compared with the reference ground truth, the overlap ratio of true positives is 91.1%+/-3.5%, and that of false positives is 5.5%+/-4.2%.

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.

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.

Whole brain analysis of postmortem density changes of grey and white matter on computed tomography by statistical parametric mapping.

PubMed

Nishiyama, Yuichi; Kanayama, Hidekazu; Mori, Hiroshi; Tada, Keiji; Yamamoto, Yasushi; Katsube, Takashi; Takeshita, Haruo; Kawakami, Kazunori; Kitagaki, Hajime

2017-06-01

This study examined the usefulness of statistical parametric mapping (SPM) for investigating postmortem changes on brain computed tomography (CT). This retrospective study included 128 patients (23 - 100 years old) without cerebral abnormalities who underwent unenhanced brain CT before and after death. The antemortem CT (AMCT) scans and postmortem CT (PMCT) scans were spatially normalized using our original brain CT template, and postmortem changes of CT values (in Hounsfield units; HU) were analysed by the SPM technique. Compared with AMCT scans, 58.6 % and 98.4 % of PMCT scans showed loss of the cerebral sulci and an unclear grey matter (GM)-white matter (WM) interface, respectively. SPM analysis revealed a significant decrease in cortical GM density within 70 min after death on PMCT scans, suggesting cytotoxic brain oedema. Furthermore, there was a significant increase in the density of the WM, lenticular nucleus and thalamus more than 120 min after death. The SPM technique demonstrated typical postmortem changes on brain CT scans, and revealed that the unclear GM-WM interface on early PMCT scans is caused by a rapid decrease in cortical GM density combined with a delayed increase in WM density. SPM may be useful for assessment of whole brain postmortem changes. • The original brain CT template achieved successful normalization of brain morphology. • Postmortem changes in the brain were independent of sex. • Cortical GM density decreased rapidly after death. • WM and deep GM densities increased following cortical GM density change. • SPM could be useful for assessment of whole brain postmortem changes.

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.

Factors influencing residual pleural opacity in tuberculous pleural effusion.

PubMed

Kwon, Jee Sook; Cha, Seung-Ick; Jeon, Kyung-Nyeo; Kim, Young-Joo; Kim, Eun-Jin; Kim, Chang-Ho; Park, Jae-Yong; Jung, Tae-Hoon

2008-08-01

Tuberculous pleural effusion (TPE) leads to residual pleural opacity (RPO) in a significant proportion of cases. The aim of this study was to investigate which TPE patients would have RPO following the treatment. This study was performed prospectively for a total of 60 TPE patients, who underwent pleural fluid analysis on the initial visit and chest radiographs and computed tomography (CT) scans before and after the administration of antituberculous medication. At the end of antituberculous medication, the incidence of RPO was 68.3% (41/60) on CT with a range of 2-50 mm. Compared with the non-RPO group, the RPO group had a longer symptom duration and lower pleural fluid glucose level. On initial CT, loculation, extrapleural fat proliferation, increased attenuation of extrapleural fat, and pleura-adjacent atelectasis were more frequent, and parietal pleura was thicker in the RPO group compared with the non-RPO group. By multivariate analysis, extrapleural fat proliferation, loculated effusion, and symptom duration were found to be predictors of RPO in TPE. In conclusion, RPO in TPE may be predicted by the clinico-radiologic parameters related to the chronicity of the effusion, such as symptom duration and extrapleural fat proliferation and loculated effusion on CT.

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.

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.

Development of a database of organ doses for paediatric and young adult CT scans in the United Kingdom

PubMed Central

Kim, K. P.; Berrington de González, A.; Pearce, M. S.; Salotti, J. A.; Parker, L.; McHugh, K.; Craft, A. W.; Lee, C.

2012-01-01

Despite great potential benefits, there are concerns about the possible harm from medical imaging including the risk of radiation-related cancer. There are particular concerns about computed tomography (CT) scans in children because both radiation dose and sensitivity to radiation for children are typically higher than for adults undergoing equivalent procedures. As direct empirical data on the cancer risks from CT scans are lacking, the authors are conducting a retrospective cohort study of over 240 000 children in the UK who underwent CT scans. The main objective of the study is to quantify the magnitude of the cancer risk in relation to the radiation dose from CT scans. In this paper, the methods used to estimate typical organ-specific doses delivered by CT scans to children are described. An organ dose database from Monte Carlo radiation transport-based computer simulations using a series of computational human phantoms from newborn to adults for both male and female was established. Organ doses vary with patient size and sex, examination types and CT technical settings. Therefore, information on patient age, sex and examination type from electronic radiology information systems and technical settings obtained from two national surveys in the UK were used to estimate radiation dose. Absorbed doses to the brain, thyroid, breast and red bone marrow were calculated for reference male and female individuals with the ages of newborns, 1, 5, 10, 15 and 20 y for a total of 17 different scan types in the pre- and post-2001 time periods. In general, estimated organ doses were slightly higher for females than males which might be attributed to the smaller body size of the females. The younger children received higher doses in pre-2001 period when adult CT settings were typically used for children. Paediatric-specific adjustments were assumed to be used more frequently after 2001, since then radiation doses to children have often been smaller than those to adults. The database here is the first detailed organ-specific paediatric CT scan database for the UK. As well as forming the basis for the UK study, the results and description of the methods will also serve as a key resource for paediatric CT scan studies currently underway in other countries. PMID:22228685

Development of a database of organ doses for paediatric and young adult CT scans in the United Kingdom.

PubMed

Kim, K P; Berrington de González, A; Pearce, M S; Salotti, J A; Parker, L; McHugh, K; Craft, A W; Lee, C

2012-07-01

Despite great potential benefits, there are concerns about the possible harm from medical imaging including the risk of radiation-related cancer. There are particular concerns about computed tomography (CT) scans in children because both radiation dose and sensitivity to radiation for children are typically higher than for adults undergoing equivalent procedures. As direct empirical data on the cancer risks from CT scans are lacking, the authors are conducting a retrospective cohort study of over 240,000 children in the UK who underwent CT scans. The main objective of the study is to quantify the magnitude of the cancer risk in relation to the radiation dose from CT scans. In this paper, the methods used to estimate typical organ-specific doses delivered by CT scans to children are described. An organ dose database from Monte Carlo radiation transport-based computer simulations using a series of computational human phantoms from newborn to adults for both male and female was established. Organ doses vary with patient size and sex, examination types and CT technical settings. Therefore, information on patient age, sex and examination type from electronic radiology information systems and technical settings obtained from two national surveys in the UK were used to estimate radiation dose. Absorbed doses to the brain, thyroid, breast and red bone marrow were calculated for reference male and female individuals with the ages of newborns, 1, 5, 10, 15 and 20 y for a total of 17 different scan types in the pre- and post-2001 time periods. In general, estimated organ doses were slightly higher for females than males which might be attributed to the smaller body size of the females. The younger children received higher doses in pre-2001 period when adult CT settings were typically used for children. Paediatric-specific adjustments were assumed to be used more frequently after 2001, since then radiation doses to children have often been smaller than those to adults. The database here is the first detailed organ-specific paediatric CT scan database for the UK. As well as forming the basis for the UK study, the results and description of the methods will also serve as a key resource for paediatric CT scan studies currently underway in other countries.

CT Scans - Multiple Languages

MedlinePlus

... Tomography) Scan - العربية (Arabic) Bilingual PDF Health Information Translations Chinese, Simplified (Mandarin dialect) (简体中文) Expand Section CT ( ... Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations Chinese, Traditional (Cantonese dialect) (繁體中文) Expand Section CT ( ...

The effect of sagittal rotation of the glenoid on axial glenoid width and glenoid version in computed tomography scan imaging.

PubMed

Gross, Daniel J; Golijanin, Petar; Dumont, Guillaume D; Parada, Stephen A; Vopat, Bryan G; Reinert, Steven E; Romeo, Anthony A; Provencher, C D R Matthew T

2016-01-01

Computed tomography (CT) scans of the shoulder are often not well aligned to the axis of the scapula and glenoid. The purpose of this paper was to determine the effect of sagittal rotation of the glenoid on axial measurements of anterior-posterior (AP) glenoid width and glenoid version attained by standard CT scan. In addition, we sought to define the angle of rotation required to correct the CT scan to optimal positioning. A total of 30 CT scans of the shoulder were reformatted using OsiriX software multiplanar reconstruction. The uncorrected (UNCORR) and corrected (CORR) CT scans were compared for measurements of both (1) axial AP glenoid width and (2) glenoid version at 5 standardized axial cuts. The mean difference in glenoid version was 2.6% (2° ± 0.1°; P = .0222) and the mean difference in AP glenoid width was 5.2% (1.2 ± 0.42 mm; P = .0026) in comparing the CORR and UNCORR scans. The mean angle of correction required to align the sagittal plane was 20.1° of rotation (range, 9°-39°; standard error of mean, 1.2°). These findings demonstrate that UNCORR CT scans of the glenohumeral joint do not correct for the sagittal rotation of the glenoid, and this affects the characteristics of the axial images. Failure to align the sagittal image to the 12-o'clock to 6-o'clock axis results in measurement error in both glenoid version and AP glenoid width. Use of UNCORR CT images may have notable implications for decision-making and surgical treatment. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Volumetric gain of the human pancreas after left partial pancreatic resection: A CT-scan based retrospective study.

PubMed

Phillip, Veit; Zahel, Tina; Danninger, Assiye; Erkan, Mert; Dobritz, Martin; Steiner, Jörg M; Kleeff, Jörg; Schmid, Roland M; Algül, Hana

2015-01-01

Regeneration of the pancreas has been well characterized in animal models. However, there are conflicting data on the regenerative capacity of the human pancreas. The aim of the present study was to assess the regenerative capacity of the human pancreas. In a retrospective study, data from patients undergoing left partial pancreatic resection at a single center were eligible for inclusion (n = 185). Volumetry was performed based on 5 mm CT-scans acquired through a 256-slice CT-scanner using a semi-automated software. Data from 24 patients (15 males/9 females) were included. Mean ± SD age was 68 ± 11 years (range, 40-85 years). Median time between surgery and the 1st postoperative CT was 9 days (range, 0-27 days; IQR, 7-13), 55 days (range, 21-141 days; IQR, 34-105) until the 2nd CT, and 191 days (range, 62-1902; IQR, 156-347) until the 3rd CT. The pancreatic volumes differed significantly between the first and the second postoperative CT scans (median volume 25.6 mL and 30.6 mL, respectively; p = 0.008) and had significantly increased further by the 3rd CT scan (median volume 37.9 mL; p = 0.001 for comparison with 1st CT scan and p = 0.003 for comparison with 2nd CT scan). The human pancreas shows a measurable and considerable potential of volumetric gain after partial resection. Multidetector-CT based semi-automated volume analysis is a feasible method for follow-up of the volume of the remaining pancreatic parenchyma after partial pancreatectomy. Effects on exocrine and endocrine pancreatic function have to be evaluated in a prospective manner. Copyright © 2015 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Use of PET/CT instead of CT-only when planning for radiation therapy does not notably increase life years lost in children being treated for cancer.

PubMed

Kornerup, Josefine S; Brodin, Patrik; Birk Christensen, Charlotte; Björk-Eriksson, Thomas; Kiil-Berthelsen, Anne; Borgwardt, Lise; Munck Af Rosenschöld, Per

2015-04-01

PET/CT may be more helpful than CT alone for radiation therapy planning, but the added risk due to higher doses of ionizing radiation is unknown. To estimate the risk of cancer induction and mortality attributable to the [F-18]2-fluoro-2-deoxyglucose (FDG) PET and CT scans used for radiation therapy planning in children with cancer, and compare to the risks attributable to the cancer treatment. Organ doses and effective doses were estimated for 40 children (2-18 years old) who had been scanned using PET/CT as part of radiation therapy planning. The risk of inducing secondary cancer was estimated using the models in BEIR VII. The prognosis of an induced cancer was taken into account and the reduction in life expectancy, in terms of life years lost, was estimated for the diagnostics and compared to the life years lost attributable to the therapy. Multivariate linear regression was performed to find predictors for a high contribution to life years lost from the radiation therapy planning diagnostics. The mean contribution from PET to the effective dose from one PET/CT scan was 24% (range: 7-64%). The average proportion of life years lost attributable to the nuclear medicine dose component from one PET/CT scan was 15% (range: 3-41%). The ratio of life years lost from the radiation therapy planning PET/CT scans and that of the cancer treatment was on average 0.02 (range: 0.01-0.09). Female gender was associated with increased life years lost from the scans (P < 0.001). Using FDG-PET/CT instead of CT only when defining the target volumes for radiation therapy of children with cancer does not notably increase the number of life years lost attributable to diagnostic examinations.

Variations in the intensive use of head CT for elderly patients with hemorrhagic stroke.

PubMed

Bekelis, Kimon; Fisher, Elliott S; Labropoulos, Nicos; Zhou, Weiping; Skinner, Jonathan

2015-04-01

To investigate the variability in head computed tomographic (CT) scanning in patients with hemorrhagic stroke in U.S. hospitals, its association with mortality, and the number of different physicians consulted. The study was approved by the Committee for the Protection of Human Subjects at Dartmouth College. A retrospective analysis of the Medicare fee-for-service claims data was performed for elderly patients admitted for hemorrhagic stroke in 2008-2009, with 1-year follow-up through 2010. Risk-adjusted primary outcome measures were mean number of head CT scans performed and high-intensity use of head CT (six or more head CT scans performed in the year after admission). We examined the association of high-intensity use of head CT with the number of different physicians consulted and mortality. A total of 53 272 patients (mean age, 79.6 years; 31 377 women [58.9%]) with hemorrhagic stroke were identified in the study period. The mean number of head CT scans conducted in the year after admission for stroke was 3.4; 8737 patients (16.4%) underwent six or more scans. Among the hospitals with the highest case volume (more than 50 patients with hemorrhagic stroke), risk-adjusted rates ranged from 8.0% to 48.1%. The correlation coefficient between number of physicians consulted and rates of high-intensity use of head CT was 0.522 (P < .01) for all hospitals and 0.50 (P < .01) for the highest-volume hospitals. No improvement in 1-year mortality was found for patients undergoing six or more head CT scans (odds ratio, 0.84; 95% confidence interval: 0.69, 1.02). High rates of head CT use for patients with hemorrhagic stroke are frequently observed, without an association with decreased mortality. A higher number of physicians consulted was associated with high-intensity use of head CT. © RSNA, 2014 Online supplemental material is available for this article.

Radiotherapy treatment planning: benefits of CT-MR image registration and fusion in tumor volume delineation.

PubMed

Djan, Igor; Petrović, Borislava; Erak, Marko; Nikolić, Ivan; Lucić, Silvija

2013-08-01

Development of imaging techniques, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), made great impact on radiotherapy treatment planning by improving the localization of target volumes. Improved localization allows better local control of tumor volumes, but also minimizes geographical misses. Mutual information is obtained by registration and fusion of images achieved manually or automatically. The aim of this study was to validate the CT-MRI image fusion method and compare delineation obtained by CT versus CT-MRI image fusion. The image fusion software (XIO CMS 4.50.0) was applied to delineate 16 patients. The patients were scanned on CT and MRI in the treatment position within an immobilization device before the initial treatment. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated on CT alone and on CT+MRI images consecutively and image fusion was obtained. Image fusion showed that CTV delineated on a CT image study set is mainly inadequate for treatment planning, in comparison with CTV delineated on CT-MRI fused image study set. Fusion of different modalities enables the most accurate target volume delineation. This study shows that registration and image fusion allows precise target localization in terms of GTV and CTV and local disease control.

Computer tomographic imaging and anatomic correlation of the human brain: A comparative atlas of thin CT-scan sections and correlated neuro-anatomic preparations

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

Plets, C.; Baert, A.L.; Nijs, G.L.

1986-01-01

It is of the greatest importance to the radiologist, the neurologist and the neurosurgeon to be able to localize topographically a pathological brain process on the CT scan as precisely as possible. For that purpose, the identification of as many anatomical structures as possible on the CT scan image are necessary and indispensable. In this atlas a great number of detailed anatomical data on frontal horizontal CT scan sections, each being only 2 mm thick, are indicated, e.g. the cortical gyri, the basal ganglia, details of the white matter, extracranial muscles and blood vessels, parts of the base and themore » vault of the skull, etc. The very precise topographical description of the numerous CT scan images was realized by the author by confrontation of these images with the corresponding anatomical sections of the same brain specimen, performed by an original technique.« less

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.

From Mice and Men to Earth and Space: Joint NASA-NCI Workshop on Lung Cancer Risk Resulting from Space and Terrestrial Radiation

PubMed Central

Shay, Jerry W.; Cucinotta, Francis A.; Sulzman, Frank M.; Coleman, C. Norman; Minna, John D.

2011-01-01

On June 27–28, 2011 scientists from the National Cancer Institute (NCI), NASA, and academia met in Bethesda to discuss major lung cancer issues confronting each organization. For NASA – available data suggest lung cancer is the largest potential cancer risk from space travel for both men and women and quantitative risk assessment information for mission planning is needed. In space the radiation risk is from high energy and charge (HZE) nuclei (such as Fe) and high energy protons from solar flares and not from gamma radiation. By contrast the NCI is endeavoring to estimate the increased lung cancer risk from the potential wide-spread implementation of computed tomography (CT) screening in individuals at high risk for developing lung cancer based on the National Lung Cancer Screening Trial (NLST). For the latter, exposure will be x-rays from CT scans from the screening (which uses “low dose” CT scans) and also from follow-up scans used to evaluate abnormalities found during initial screening. Topics discussed included the risk of lung cancer arising after HZE particle, proton, and low dose Earth radiation exposure. The workshop examined preclinical models, epidemiology, molecular markers, “omics” technology, radiobiology issues, and lung stem cells (LSC) that relate to the development of lung cancer. PMID:21900398

A case report of rapid spontaneous redistribution of acute supratentorial subdural hematoma to the entire spinal subdural space presenting as a Pourfour du Petit syndrome and review of the literature.

PubMed

Balik, Vladimir; Kolembus, Petr; Svajdler, Marian; Sulla, Igor; Vaverka, Miroslav; Hrabalek, Lumir

2013-07-01

This report illustrates the rare rapid spontaneous redistribution of an acute intracranial supratentorial subdural hematoma (AISSDH) to the entire spinal subdural space (SSS). The study is also unique in that the spinal subdural hematoma (SSH) manifested by the extremely rare Pourfour du Petit Syndrome (PPS). A 66-year-old man sustained blunt head trauma. On admission to the regional hospital, he scored 6 on GCS and his pupils were of equal size reacting to light. Initial computed tomography (CT) scan showed a unilateral AISSDH. The patient was referred to our department and arrived 16 h following the accident, at which time a repeat CT scan revealed almost complete resolution of the AISSDH without clinical improvement. On the 9th postinjury day transient anisocoria and tachycardia without spinal symptomatology developed. Since neither neurological examination nor follow-up CT scans showed intracranial pathology explaining the anisocoria, the patient was treated further conservatively. During the next 3 days circulatory instability developed and the patient succumbed to primary traumatic injury. Autopsy revealed a SSH occupying the entire SSS. This case calls attention to the unique combination of the displacement of an AISSDH to the SSS and the presentation of this clinical entity by the PPS. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Evaluation of Oral Anticoagulant-Associated Intracranial Parenchymal Hematomas Using CT Findings.

PubMed

Gökçe, E; Beyhan, M; Acu, B

2015-06-01

Intracranial hemorrhage (ICH) is one of the most serious and lethal complications of anticoagulants with a reported incidence of 5-18.5 %. Computed tomographic (CT) findings, should be carefully studied because early diagnosis and treatment of oral anticoagulant use-associated hematomas are vitally important. In the present study, CT findings of intraparenchymal hematomas associated with anticoagulant and antihypertensive use are presented. This study included 45 patients (25 men, 20 women) under anticoagulant (21 patients) or antihypertensive (24 patients) treatment who had brain CT examinations due to complaints and findings suggesting cerebrovascular disease during July 2010-October 2013 period. CT examinations were performed to determine hematoma volumes and presence of swirl sign, hematocrit effect, mid-line shift effect, and intraventricular extension. The patients were 40-89 years of age. In four cases, a total of 51 intraparenchymal hematomas (42 cerebral, 7 cerebellar and 2 brain stem) were detected in multiple foci. Hematoma volumes varied from 0.09 to 284.00 ml. Swirl sign was observed in 87.5 and 63.0 % of OAC-associated ICHs and non-OAC-associated ICHs, respectively. In addition, hematocrit effect was observed in 41.6 % of OAC-associated and in 3.7 % of non-OAC-associated ICHs. Volume increases were observed in all 19 hematomas where swirl sign was detected, and follow-up CT scanning was conducted. Mortality of OAC-associated ICHs was correlated with initial volumes of hematoma, mid-line shift amount, and intraventricular extension. Detection of hematocrit effect by CT scanning of intracranial hematomas should be cautionary in oral anticoagulant use, while detection of swirl sign should be suggestive of active hemorrhage.

X-ray Computed Tomography Observation of Methane Hydrate Dissociation

USGS Publications Warehouse

Tomutsa, L.; Freifeld, B.; Kneafsey, T.J.; Stern, L.A.

2002-01-01

Deposits of naturally occurring methane hydrate have been identified in permafrost and deep oceanic environments with global reserves estimated to be twice the total amount of energy stored in fossil fuels. The fundamental behavior of methane hydrate in natural formations, while poorly understood, is of critical importance if the economic recovery of methane from hydrates is to be accomplished. In this study, computed X-ray tomography (CT) scanning is used to image an advancing dissociation front in a heterogeneous gas hydrate/sand sample at 0.1 MPa. The cylindrical methane hydrate and sand aggregate, 2.54 cm in diameter and 6.3 cm long, was contained in a PVC sample holder that was insulated on all but one end. At the uninsulated end, the dissociated gas was captured and the volume of gas monitored. The sample was initially imaged axially using X-ray CT scanning within the methane hydrate stability zone by keeping the sample temperature at 77??K. Subsequently, as the sample warmed through the methane hydrate dissociation point at 194??K and room pressure, gas was produced and the temperature at the bottom of the sample plug was monitored while CT images were acquired. The experiment showed that CT imaging can resolve the reduction in density (as seen by a reduction in beam attenuation) of the hydrate/sand aggregate due to the dissociation of methane hydrate. In addition, a comparison of CT images with gas flow and temperature measurements reveals that the CT scanner is able to resolve accurately and spatially the advancing dissociation front. Future experiments designed to better understand the thermodynamics of hydrate dissociation are planned to take advantage of the temporal and spatial resolution that the CT scanner provides.

Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians

PubMed Central

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

2013-01-01

Objective To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. Design 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. Main outcome 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. Results 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. Conclusions 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. PMID:23694687

Relationship between Hounsfield unit in CT scan and gray scale in CBCT

NASA Astrophysics Data System (ADS)

Kamaruddin, Noorshaida; Rajion, Zainul Ahmad; Yusof, Asilah; Aziz, Mohd Ezane

2016-12-01

Cone-beam computed tomography (CBCT) is an imaging system which has advantages over computed tomography (CT). Recently, CBCT has become widely used for oral and maxillofacial imaging. In CT scan, Hounsfield Unit (HU) is proportional to the degree of x-ray attenuation by the tissue. In CBCT, the degree of x-ray attenuation is shown by gray scale (voxel value). The aim of the present (in vitro) study was to investigate the relationship between gray scale in CBCT and HU in CT scan. In this descriptive study, the anthropomorphic head phantom was scanned with CBCT and CT scanner. Gray scales and HUs were detected on images at the crown of the teeth, trabecular and cortical bone of mandible. The images were analyzed to obtain the gray scale value and HU value. The obtained value then used to investigate the relationship between CBCT gray scales and HUs. For the statistical analysis, t-test, Pearson's correlation and regression analysis were used. The differences between the gray scale of CBCT and HU of CT were statistically not significant, whereas the Pearson's correlation coefficients demonstrated a statistically significant correlation between gray scale of CBCT and HU of CT values. Considering the fact that gray scale in CBCT is important in pre assessment evaluation of bone density before implant treatments, it is recommended because of the lower dose and cost compared to CT scan.

Usefulness of image morphing techniques in cancer treatment by conformal radiotherapy

NASA Astrophysics Data System (ADS)

Atoui, Hussein; Sarrut, David; Miguet, Serge

2004-05-01

Conformal radiotherapy is a cancer treatment technique, that targets high-energy X-rays to tumors with minimal exposure to surrounding healthy tissues. Irradiation ballistics is calculated based on an initial 3D Computerized Tomography (CT) scan. At every treatment session, the random positioning of the patient, compared to the reference position defined by the initial 3D CT scan, can generate treatment inaccuracies. Positioning errors potentially predispose to dangerous exposure to healthy tissues as well as insufficient irradiation to the tumor. A proposed solution would be the use of portal images generated by Electronic Portal Imaging Devices (EPID). Portal images (PI) allow a comparison with reference images retained by physicians, namely Digitally Reconstructed Radiographs (DRRs). At present, physicians must estimate patient positional errors by visual inspection. However, this may be inaccurate and consumes time. The automation of this task has been the subject of many researches. Unfortunately, the intensive use of DRRs and the high computing time required have prevented real time implementation. We are currently investigating a new method for DRR generation that calculates intermediate DRRs by 2D deformation of previously computed DRRs. We approach this investigation with the use of a morphing-based technique named mesh warping.

[Two cases of curative resection by laparoscopic surgery following preoperative chemotherapy with bevacizumab for locally advanced colon cancer].

PubMed

Sakaguchi, Masazumi; Kan, Takatsugu; Tsubono, Michihiko; Kii, Eiji

2014-04-01

Here we report 2 cases of curative resection following preoperative chemotherapy with bevacizumab for locally advanced colon cancer. Case 1 was a 62-year-old man admitted with constipation, abdominal distention, and abdominal pain. An abdominal computed tomography(CT)scan revealed an obstructive tumor of the sigmoid colon with invasion into the bladder. A diverting colostomy was performed, and chemotherapy with mFOLFOX6(infusional 5-fluorouracil/Leucovorin+ oxaliplatin) plus bevacizumab was initiated. The tumor shrunk markedly after 6 courses of this treatment. Thereafter, laparoscopy- assisted sigmoidectomy was successfully performed. Case 2 was a 61-year-old woman admitted with diarrhea, abdominal pain, and fever. An abdominal CT scan revealed an obstructive tumor of the sigmoid colon with invasion into the ileum, uterus and retroperitoneum. A diverting colostomy was performed, and chemotherapy with XELOX(capecitabine+ oxaliplatin)plus bevacizumab was initiated. The tumor shrunk markedly after 6 courses of this treatment. Thereafter, laparoscopy- assisted sigmoidectomy was successfully performed. Both cases demonstrated partial clinical responses to chemotherapy; thus, curative resection surgeries were performed. There were no perioperative complications. Therefore, we conclude that oxaliplatin-based chemotherapy plus bevacizumab and laparoscopic resection could be very effective for locally advanced colon cancer.

Dual scan CT image recovery from truncated projections

NASA Astrophysics Data System (ADS)

Sarkar, Shubhabrata; Wahi, Pankaj; Munshi, Prabhat

2017-12-01

There are computerized tomography (CT) scanners available commercially for imaging small objects and they are often categorized as mini-CT X-ray machines. One major limitation of these machines is their inability to scan large objects with good image quality because of the truncation of projection data. An algorithm is proposed in this work which enables such machines to scan large objects while maintaining the quality of the recovered image.

Quantification of pleural effusion on CT by simple measurement.

PubMed

Hazlinger, Martin; Ctvrtlik, Filip; Langova, Katerina; Herman, Miroslav

2014-01-01

To find the simplest method for quantifying pleural effusion volume from CT scans. Seventy pleural effusions found on chest CT examination in 50 consecutive adult patients with the presence of free pleural effusion were included. The volume of pleural effusion was calculated from a three-dimensional reconstruction of CT scans. Planar measurements were made on CT scans and their two-dimensional reconstructions in the sagittal plane and at three levels on transversal scans. Individual planar measurements were statistically compared with the detected volume of pleural effusion. Regression equations, averaged absolute difference between observed and predicted values and determination coefficients were found for all measurements and their combinations. A tabular expression of the best single planar measurement was created. The most accurate correlation between the volume and a single planar measurement was found in the dimension measured perpendicular to the parietal pleura on transversal scan with the greatest depth of effusion. Conversion of this measurement to the appropriate volume is possible by regression equation: Volume = 0.365 × b(3) - 4.529 × b(2) + 159.723 × b - 88.377. We devised a simple method of conversion of a single planar measurement on CT scan to the volume of pleural effusion. The tabular expression of our equation can be easily and effectively used in routine practice.

Pelvic artery calcification detection on CT scans using convolutional neural networks

NASA Astrophysics Data System (ADS)

Liu, Jiamin; Lu, Le; Yao, Jianhua; Bagheri, Mohammadhadi; Summers, Ronald M.

2017-03-01

Artery calcification is observed commonly in elderly patients, especially in patients with chronic kidney disease, and may affect coronary, carotid and peripheral arteries. Vascular calcification has been associated with many clinical outcomes. Manual identification of calcification in CT scans requires substantial expert interaction, which makes it time-consuming and infeasible for large-scale studies. Many works have been proposed for coronary artery calcification detection in cardiac CT scans. In these works, coronary artery extraction is commonly required for calcification detection. However, there are few works about abdominal or pelvic artery calcification detection. In this work, we present a method for automatic pelvic artery calcification detection on CT scan. This method uses the recent advanced faster region-based convolutional neural network (R-CNN) to directly identify artery calcification without a need for artery extraction since pelvic artery extraction itself is challenging. Our method first generates category-independent region proposals for each slice of the input CT scan using region proposal networks (RPN). Then, each region proposal is jointly classified and refined by softmax classifier and bounding box regressor. We applied the detection method to 500 images from 20 CT scans of patients for evaluation. The detection system achieved a 77.4% average precision and a 85% sensitivity at 1 false positive per image.

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.

Dosimetric consequences of the parotid glands using CT-to-CBCT deformable registration during IMRT for late stage head and neck cancers

NASA Astrophysics Data System (ADS)

Conill, Annette L.

Patients receiving Intensity Modulated Radiation Therapy (IMRT) for late stage head and neck (HN) cancer often experience anatomical changes due to weight loss, tumor regression, and positional changes of normal anatomy (1). As a result, the actual dose delivered may vary from the original treatment plan. The purpose of this study was (a) to evaluate the dosimetric consequences of the parotid glands during the course of treatment, and (b) to determine if there would be an optimal timeframe for replanning. Nineteen locally advanced HN cancer patients underwent definitive IMRT. Each patient received an initial computerized tomography simulation (CT-SIM) scan and weekly cone beam computerized tomography (CBCT) scans. A Deformable Image Registration (DIR) was performed between the CT-SIM and CBCT of the parotid glands and Planning Target Volumes (PTVs) using the Eclipse treatment planning system (TPS) and the Velocity deformation software. A recalculation of the dose was performed on the weekly CBCTs using the original monitor units. The parameters for evaluation of our method were: the changes in volume of the PTVs and parotid glands, the dose coverage of the PTVs, the lateral displacement in the Center of Mass (COM), the mean dose, and Normal Tissue Complication Probability (NTCP) of the parotid glands. The studies showed a reduction of the volume in the PTVs and parotids, a medial displacement in COM, and alterations of the mean dose to the parotid glands as compared to the initial plans. Differences were observed for the dose volume coverage of the PTVs and NTCP of the parotid gland values between the initial plan and our proposed method utilizing deformable registration-based dose calculations.

No Association between Radiation Dose from Pediatric CT Scans and Risk of Subsequent Hodgkin Lymphoma.

PubMed

Berrington de Gonzalez, Amy; Journy, Neige; Lee, Choonsik; Morton, Lindsay M; Harbron, Richard W; Stewart, Douglas R; Parker, Louise; Craft, Alan W; McHugh, Kieran; Little, Mark P; Pearce, Mark S

2017-05-01

Background: We examined the relationship between estimated radiation dose from CT scans and subsequent Hodgkin lymphoma in the UK pediatric CT scans cohort. Methods: A retrospective, record linkage cohort included patients ages 0 to 21 years who underwent CT scans between 1980 and 2002 and were followed up for cancer or death until 2008. Poisson regression analysis was used to evaluate the relationship between estimated radiation dose (lagged by 2 years) and incident Hodgkin lymphoma diagnosed at least 2 years after the first CT scan. Results: There were 65 incident cases of Hodgkin lymphoma in the cohort of 178,601 patients. Neither estimated red bone marrow dose nor mean lymphocyte dose from CT scans was clearly associated with an increased risk of Hodgkin lymphoma (RR for 20+ mGy vs. <5 mGy = 0.92 (0.38-2.22) P trend > 0.5 and 1.44 (0.60-3.48) P trend > 0.5), respectively. Conclusions: Radiation exposure from pediatric CT scans 2 or more years before diagnosis was not associated with Hodgkin lymphoma in this large UK cohort. Impact: These findings are consistent with the majority of previous studies, which do not support a link between ionizing radiation and Hodgkin lymphoma. The results contrast our previous positive findings in this cohort for brain tumors and leukemia, both of which are known to be strongly linked to radiation exposure during childhood. Cancer Epidemiol Biomarkers Prev; 26(5); 804-6. ©2017 AACR . ©2017 American Association for Cancer Research.

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.

Estimation of skull table thickness with clinical CT and validation with microCT.

PubMed

Lillie, Elizabeth M; Urban, Jillian E; Weaver, Ashley A; Powers, Alexander K; Stitzel, Joel D

2015-01-01

Brain injuries resulting from motor vehicle crashes (MVC) are extremely common yet the details of the mechanism of injury remain to be well characterized. Skull deformation is believed to be a contributing factor to some types of traumatic brain injury (TBI). Understanding biomechanical contributors to skull deformation would provide further insight into the mechanism of head injury resulting from blunt trauma. In particular, skull thickness is thought be a very important factor governing deformation of the skull and its propensity for fracture. Current computed tomography (CT) technology is limited in its ability to accurately measure cortical thickness using standard techniques. A method to evaluate cortical thickness using cortical density measured from CT data has been developed previously. This effort validates this technique for measurement of skull table thickness in clinical head CT scans using two postmortem human specimens. Bone samples were harvested from the skulls of two cadavers and scanned with microCT to evaluate the accuracy of the estimated cortical thickness measured from clinical CT. Clinical scans were collected at 0.488 and 0.625 mm in plane resolution with 0.625 mm thickness. The overall cortical thickness error was determined to be 0.078 ± 0.58 mm for cortical samples thinner than 4 mm. It was determined that 91.3% of these differences fell within the scanner resolution. Color maps of clinical CT thickness estimations are comparable to color maps of microCT thickness measurements, indicating good quantitative agreement. These data confirm that the cortical density algorithm successfully estimates skull table thickness from clinical CT scans. The application of this technique to clinical CT scans enables evaluation of cortical thickness in population-based studies. © 2014 Anatomical Society.

Audit of radiation dose delivered in time-resolved four-dimensional computed tomography in a radiotherapy department.

PubMed

Hubbard, Patricia; Callahan, Jason; Cramb, Jim; Budd, Ray; Kron, Tomas

2015-06-01

To review the dose delivered to patients in time-resolved computed tomography (4D CT) used for radiotherapy treatment planning. 4D CT is used at Peter MacCallum Cancer Centre since July 2007 for radiotherapy treatment planning using a Philips Brilliance Wide Bore CT scanner (16 slice, helical 4D CT acquisition). All scans are performed at 140 kVp and reconstructed in 10 datasets for different phases of the breathing cycle. Dose records were analysed retrospectively for 387 patients who underwent 4D CT procedures between 2007 and 2013. A total of 444 4D CT scans were acquired with the majority of them (342) being for lung cancer radiotherapy. Volume CT dose index (CTDIvol) as recorded over this period was fairly constant at approximately 20 mGy for adults. The CTDI for 4D CT for lung cancers of 19.6 ± 9.3 mGy (n = 168, mean ± 1SD) was found to be 63% higher than CTDIs for conventional CT scans for lung patients that were acquired in the same period (CTDIvol 12 ± 4 mGy, sample of n = 25). CTDI and dose length product (DLP) increased with increasing field of view; however, no significant difference between DLPs for different indications (breast, kidney, liver and lung) could be found. Breathing parameters such as breathing rate or pattern did not affect dose. 4D CT scans can be acquired for radiotherapy treatment planning with a dose less than twice the one required for conventional CT scanning. © 2015 The Royal Australian and New Zealand College of Radiologists.

The Value of 18F-FDG PET/CT in Diagnosis and During Follow-up in 273 Patients with Chronic Q Fever.

PubMed

Kouijzer, Ilse J E; Kampschreur, Linda M; Wever, Peter C; Hoekstra, Corneline; van Kasteren, Marjo E E; de Jager-Leclercq, Monique G L; Nabuurs-Franssen, Marrigje H; Wegdam-Blans, Marjolijn C A; Ammerlaan, Heidi S M; Buijs, Jacqueline; Geus-Oei, Lioe-Fee de; Oyen, Wim J G; Bleeker-Rovers, Chantal P

2018-01-01

In 1%-5% of all acute Q fever infections, chronic Q fever develops, mostly manifesting as endocarditis, infected aneurysms, or infected vascular prostheses. In this study, we investigated the diagnostic value of 18 F-FDG PET/CT in chronic Q fever at diagnosis and during follow-up. Methods: All adult Dutch patients suspected of chronic Q fever who were diagnosed since 2007 were retrospectively included until March 2015, when at least one 18 F-FDG PET/CT scan was obtained. Clinical data and results from 18 F-FDG PET/CT at diagnosis and during follow-up were collected. 18 F-FDG PET/CT scans were prospectively reevaluated by 3 nuclear medicine physicians using a structured scoring system. Results: In total, 273 patients with possible, probable, or proven chronic Q fever were included. Of all 18 F-FDG PET/CT scans performed at diagnosis, 13.5% led to a change in diagnosis. Q fever-related mortality rate in patients with and without vascular infection based on 18 F-FDG PET/CT was 23.8% and 2.1%, respectively ( P = 0.001). When 18 F-FDG PET/CT was added as a major criterion to the modified Duke criteria, 17 patients (1.9-fold increase) had definite endocarditis. At diagnosis, 19.6% of 18 F-FDG PET/CT scans led to treatment modification. During follow-up, 57.3% of 18 F-FDG PET/CT scans resulted in treatment modification. Conclusion: 18 F-FDG PET/CT is a valuable technique in diagnosis of chronic Q fever and during follow-up, often leading to a change in diagnosis or treatment modification and providing important prognostic information on patient survival. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

(68)Ga-PSMA-11 PET/CT: a new technique with high potential for the radiotherapeutic management of prostate cancer patients.

PubMed

Sterzing, Florian; Kratochwil, Clemens; Fiedler, Hannah; Katayama, Sonja; Habl, Gregor; Kopka, Klaus; Afshar-Oromieh, Ali; Debus, Jürgen; Haberkorn, Uwe; Giesel, Frederik L

2016-01-01

Radiotherapy is the main therapeutic approach besides surgery of localized prostate cancer. It relies on risk stratification and exact staging. This report analyses the potential of [(68)Ga]Glu-urea-Lys(Ahx)-HBED-CC ((68)Ga-PSMA-11), a new positron emission tomography (PET) tracer targeting prostate-specific membrane antigen (PSMA) for prostate cancer staging and individualized radiotherapy planning. A cohort of 57 patients with prostate cancer scanned with (68)Ga-PSMA-11 PET/CT for radiotherapy planning was retrospectively reviewed; 15 patients were at initial diagnosis and 42 patients at time of biochemical recurrence. Staging results of conventional imaging, including bone scintigraphy, CT or MRI, were compared with (68)Ga-PSMA ligand PET/CT results and the influence on radiotherapeutic management was quantified. (68)Ga-PSMA ligand PET/CT had a dramatic impact on radiotherapy application in the presented cohort. In 50.8 % of the cases therapy was changed. The presented imaging technique of (68)Ga-PSMA PET/CT could be a key technology for individualized radiotherapy management in prostate cancer.

New scoring system for intra-abdominal injury diagnosis after blunt trauma.

PubMed

Shojaee, Majid; Faridaalaee, Gholamreza; Yousefifard, Mahmoud; Yaseri, Mehdi; Arhami Dolatabadi, Ali; Sabzghabaei, Anita; Malekirastekenari, Ali

2014-01-01

An accurate scoring system for intra-abdominal injury (IAI) based on clinical manifestation and examination may decrease unnecessary CT scans, save time, and reduce healthcare cost. This study is designed to provide a new scoring system for a better diagnosis of IAI after blunt trauma. This prospective observational study was performed from April 2011 to October 2012 on patients aged above 18 years and suspected with blunt abdominal trauma (BAT) admitted to the emergency department (ED) of Imam Hussein Hospital and Shohadaye Hafte Tir Hospital. All patients were assessed and treated based on Advanced Trauma Life Support and ED protocol. Diagnosis was done according to CT scan findings, which was considered as the gold standard. Data were gathered based on patient's history, physical exam, ultrasound and CT scan findings by a general practitioner who was not blind to this study. Chi-square test and logistic regression were done. Factors with significant relationship with CT scan were imported in multivariate regression models, where a coefficient (β) was given based on the contribution of each of them. Scoring system was developed based on the obtained total β of each factor. Altogether 261 patients (80.1% male) were enrolled (48 cases of IAI). A 24-point blunt abdominal trauma scoring system (BATSS) was developed. Patients were divided into three groups including low (score<8), moderate (8≤score<12) and high risk (score≥12). In high risk group immediate laparotomy should be done, moderate group needs further assessments, and low risk group should be kept under observation. Low risk patients did not show positive CT-scans (specificity 100%). Conversely, all high risk patients had positive CT-scan findings (sensitivity 100%). The receiver operating characteristic curve indicated a close relationship between the results of CT scan and BATSS (sensitivity=99.3%). The present scoring system furnishes a high precision and reproducible diagnostic tool for BAT detection and has the potential to reduce unnecessary CT scan and cut unnecessary costs.

An assessment of the intra- and inter-reliability of the lumbar paraspinal muscle parameters using CT scan and magnetic resonance imaging.

PubMed

Hu, Zhi-Jun; He, Jian; Zhao, Feng-Dong; Fang, Xiang-Qian; Zhou, Li-Na; Fan, Shun-Wu

2011-06-01

A reliability study was conducted. To estimate the intra- and intermeasurement errors in the measurements of functional cross-sectional area (FCSA), density, and T2 signal intensity of paraspinal muscles using computed tomography (CT) scan and magnetic resonance imaging (MRI). CT scan and MRI had been used widely to measure the cross-sectional area and degeneration of the back muscles in spine and muscle research. But there is still no systemic study to analyze the reliability of these measurements. This study measured the FCSA and fatty infiltration (density on CT scan and T2 signal intensity on MRI) of the paraspinal muscles at L3-L4, L4-L5, and L5-S1 in 29 patients with chronic low back pain. Two experienced musculoskeletal radiologists and one superior spine surgeon traced the region of interest twice within 3 weeks for measurement of the intra- and interobserver reliability. The intraclass correlation coefficients (ICCs) of the intra-reliability ranged from fair to excellent for FCSA, and good to excellent for fatty infiltration. The ICCs of the inter-reliability ranged from fair to excellent for FCSA, and good to excellent for fatty infiltration. There were no significant differences between CT scan and MRI in reliability results, except in the relative standard error of fatty infiltration measurement. The ICCs of the FCSA measurement between CT scan and MRI ranged from poor to good. The reliabilities of the CT scan and MRI for measuring the FCSA and fatty infiltration of the atrophied lumbar paraspinal muscles were acceptable. It was reliable for using uniform one image method for a single paraspinal muscle evaluation study. And the authors preferred to advise the MRI other than CT scan for paraspinal muscles measurements of FCSA and fatty infiltration.

Eye lens radiation exposure and repeated head CT scans: A problem to keep in mind.

PubMed

Michel, Morgane; Jacob, Sophie; Roger, Gilles; Pelosse, Béatrice; Laurier, Dominique; Le Pointe, Hubert Ducou; Bernier, Marie-Odile

2012-08-01

The deterministic character of radiation-induced cataract is being called into question, raising the possibility of a risk in patients, especially children, exposed to ionizing radiation in case of repeated head CT-scans. This study aims to estimate the eye lens doses of a pediatric population exposed to repeated head CTs and to assess the feasibility of an epidemiological study. Children treated for a cholesteatoma, who had had at least one CT-scan of the middle ear before their tenth birthday, were included. Radiation exposure has been assessed from medical records and telephone interviews. Out of the 39 subjects contacted, 32 accepted to participate. A total of 76 CT-scans were retrieved from medical records. At the time of the interview (mean age: 16 years), the mean number of CT per child was 3. Cumulative mean effective and eye lens doses were 1.7mSv and 168mGy, respectively. A relatively high lens radiation dose was observed in children exposed to repeated CT-scans. Due to that exposure and despite the difficulties met when trying to reach patients' families, a large scale epidemiological study should be performed in order to assess the risk of radiation-induced cataracts associated with repeated head CT. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Confounding of the association between radiation exposure from CT scans and risk of leukemia and brain tumors by cancer susceptibility syndromes.

PubMed

Meulepas, Johanna M; Ronckers, Cécile M; Merks, Johannes; Weijerman, Michel E; Lubin, Jay H; Hauptmann, Michael

2016-12-01

Recent studies linking radiation exposure from pediatric computed tomography (CT) to increased risks of leukemia and brain tumors lacked data to control for cancer susceptibility syndromes (CSS). These syndromes might be confounders because they are associated with an increased cancer risk and may increase the likelihood of pediatric CT scans. We identify CSS predisposing to leukemia and brain tumors through a systematic literature search and summarize prevalence and risk. Since empirical evidence is lacking in published literature on patterns of CT use for most types of CSS, we estimate confounding bias of relative risks (RR) for categories of radiation exposure based on expert opinion about patterns of CT scans among CSS patients. We estimate that radiation-related RRs for leukemia are not meaningfully confounded by Down syndrome, Noonan syndrome and other CSS. Moreover, tuberous sclerosis complex, von Hippel-Lindau disease, neurofibromatosis type 1 and other CSS do not meaningfully confound RRs for brain tumors. Empirical data on the use of CT scans among CSS patients is urgently needed. Our assessment indicates that associations with radiation exposure from pediatric CT scans and leukemia or brain tumors reported in previous studies are unlikely to be substantially confounded by unmeasured CSS.

The use of a fully integrated electronic medical record to minimize cumulative lifetime radiation exposure from CT scanning to detect urinary tract calculi.

PubMed

Kohler, Steven W; Chen, Richard; Kagan, Alex; Helvey, Dustin W; Buccigrossi, David

2013-06-01

In order to determine the effects of implementation of an electronic medical record on rates of repeat computed tomography (CT) scanning in the emergency department (ED) setting, we analyzed the utilization of CT of the kidneys, ureters, and bladder (CT KUB) for the detection of urinary tract calculi for periods before and after the implementation of a hospital-wide electronic medical record system. Rates of repeat CT scanning within a 6-month period of previous scan were determined pre- and post-implementation and compared. Prior to implementation, there was a 6-month repeat rate of 6.2 % compared with the post-implementation period, which was associated with a 6-month repeat rate of 4.1 %. Statistical analysis using a two-sample, one-tailed t test for difference of means was associated with a p value of 0.00007. This indicates that the implementation of the electronic medical record system was associated with a 34 % decrease in 6-month repeat CT KUB scans. We conclude that the use of an electronic medical record can be associated with a decrease in utilization of unnecessary repeat CT imaging, leading to decreased cumulative lifetime risk for cancer in these patients and more efficient utilization of ED and radiologic resources.

SU-F-I-31: Reproducibility of An Automatic Exposure Control Technique in the Low-Dose CT Scan of Cardiac PET/CT Exams

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

Park, M; Rosica, D; Agarwal, V

Purpose: Two separate low-dose CT scans are usually performed for attenuation correction of rest and stress N-13 ammonia PET/CT myocardial perfusion imaging (PET/CT). We utilize an automatic exposure control (AEC) technique to reduce CT radiation dose while maintaining perfusion image quality. Our goal is to assess the reproducibility of displayed CT dose index (CTDI) on same-day repeat CT scans (CT1 and CT2). Methods: Retrospectively, we reviewed CT images of PET/CT studies performed on the same day. Low-dose CT utilized AEC technique based on tube current modulation called Smart-mA. The scan parameters were 64 × 0.625mm collimation, 5mm slice thickness, 0.984more » pitch, 1-sec rotation time, 120 kVp, and noise index 50 with a range of 10–200 mA. The scan length matched with PET field of view (FOV) with the heart near the middle of axial FOV. We identified the reference slice number (RS) for an anatomical landmark (carina) and used it to estimate axial shift between two CTs. For patient size, we measured an effective diameter on the reference slice. The effect of patient positioning to CTDI was evaluated using the table height. We calculated the absolute percent difference of the CTDI (%diff) for estimation of the reproducibility. Results: The study included 168 adults with an average body-mass index of 31.72 ± 9.10 (kg/m{sup 2}) and effective diameter was 32.72 ± 4.60 cm. The average CTDI was 1.95 ± 1.40 mGy for CT1 and 1.97 ± 1.42mGy for CT2. The mean %diff was 7.8 ± 6.8%. Linear regression analysis showed a significant correlation between the table height and %diff CTDI. (r=0.82, p<0.001) Conclusion: We have shown for the first time in human subjects, using two same-day CT images, that the AEC technique in low-dose CT is reproducible within 10% and significantly depends on the patient centering.« less

Clinical Utility of Preoperative Computed Tomography in Patients With Endometrial Cancer.

PubMed

Bogani, Giorgio; Gostout, Bobbie S; Dowdy, Sean C; Multinu, Francesco; Casarin, Jvan; Cliby, William A; Frigerio, Luigi; Kim, Bohyun; Weaver, Amy L; Glaser, Gretchen E; Mariani, Andrea

2017-10-01

The aim of this study was to determine the clinical utility of routine preoperative pelvic and abdominal computed tomography (CT) examinations in patients with endometrial cancer (EC). We retrospectively reviewed records from patients with EC who underwent a preoperative endometrial biopsy and had surgery at our institution from January 1999 through December 2008. In the subset with an abdominal CT scan obtained within 3 months before surgery, we evaluated the clinical utility of the CT scan. Overall, 224 patients (18%) had a preoperative endometrial biopsy and an available CT scan. Gross intra-abdominal disease was observed in 10% and 20% of patients with preoperative diagnosis of endometrioid G3 and type II EC, respectively, whereas less than 5% of patients had a preoperative diagnosis of hyperplasia or low-grade EC. When examining retroperitoneal findings, we observed that a negative CT scan of the pelvis did not exclude the presence of pelvic node metastasis. Alternately, a negative CT scan in the para-aortic area generally reduced the probability of finding para-aortic dissemination but with an overall low sensitivity (42%). However, the sensitivity for para-aortic dissemination was as high as 67% in patients with G3 endometrioid cancer. In the case of negative para-aortic nodes in the CT scan, the risk of para-aortic node metastases decreased from 18.8% to 7.5% in patients with endometrioid G3 EC. Up to 15% of patients with endometrioid G3 cancer had clinically relevant incidental findings that necessitated medical or surgical intervention. In patients with endometrioid G3 and type II EC diagnosed by the preoperative biopsy, CT scans may help guide the operative plan by facilitating preoperative identification of gross intra-abdominal disease and enlarged positive para-aortic nodes that are not detectable during physical examinations. In addition, CT may reveal other clinically relevant incidental findings.

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

Contrast-Enhanced Computed Tomography Evaluation of Hepatic Metastases in Breast Cancer Patients Before and After Cytotoxic Chemotherapy or Targeted Therapy.

PubMed

He, Hongying; Cai, Chunyan; Charnsangavej, Chusilp; Theriault, Richard L; Green, Marjorie; Quraishi, Mohammad A; Yang, Wei T

2015-11-01

To evaluate change in size vs computed tomography (CT) density of hepatic metastases in breast cancer patients before and after cytotoxic chemotherapy or targeted therapy. A database search in a single institution identified 48 breast cancer patients who had hepatic metastases treated with either cytotoxic chemotherapy alone or targeted therapy alone, and who had contrast-enhanced CT (CECT) scans of the abdomen at baseline and within 4 months of initiation of therapy in the past 10 years. Two radiologists retrospectively evaluated CT scans and identified up to 2 index lesions in each patient. The size (centimeters) of each lesion was measured according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and CT density (Hounsfield units) was measured by drawing a region of interest around the margin of the entire lesion. The percent change in sum of lesion size and mean CT density on pre- and post-treatment scans was computed for each patient; results were compared within each treatment group. Thirty-nine patients with 68 lesions received cytotoxic chemotherapy only; 9 patients with 15 lesions received targeted therapy only. The mean percent changes in sum of lesion size and mean CT density were statistically significant within the cytotoxic chemotherapy group before and after treatment, but not significant in the targeted therapy group. The patients in the targeted therapy group tend to have better 2-year survival. The patients who survived at 2 years tend to have more decrease in tumour size in the cytotoxic chemotherapy group. Cytotoxic chemotherapy produced significant mean percent decrease in tumour size and mean CT density of hepatic metastases from breast cancer before and after treatment, whereas targeted therapy did not. Nonetheless, there is a trend that the patients in the targeted therapy group had better 2-year survival rate. This suggests that RECIST is potentially inadequate in evaluating tumour response in breast cancer liver metastases treated with targeted therapy alone, calling for an alternative marker for response evaluation in this subset of patients. Copyright © 2015 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

Clinical spectrum of patients with erosion of the inner ear by jugular bulb abnormalities.

PubMed

Friedmann, David R; Le, B Thuy; Pramanik, Bidyut K; Lalwani, Anil K

2010-02-01

Anatomic variants of the jugular bulb (JB) are common; however, abnormalities such as large high riding JB and JB diverticulum (JBD) are uncommon. Rarely, the abnormal JB may erode into the inner ear. The goal of our study is to report a large series of patients with symptomatic JB erosion into the inner ear. Retrospective review in an academic medical center. Eleven patients with JB abnormality eroding into the inner ear were identified on computed tomography (CT) scan of the temporal bone. Age at presentation was from 5 years to 82 years with six males and five females. The large JB or JBD eroded into the vestibular aqueduct (n = 9) or the posterior semicircular canal (n = 4). The official radiology report usually identified the JB abnormality; however, erosion into these structures by the JB was not mentioned in all but one case. All patients were symptomatic with five having conductive hearing loss (CHL) and three complaining of pulsatile tinnitus. Those with pulsatile tinnitus and four of five with CHL had erosion into the vestibular aqueduct. Vestibular evoked myogenic potential (VEMP) findings in three of six patients were consistent with dehiscence of the inner ear. High riding large JB or JBD can erode into the inner ear and may be associated with CHL and/or pulsatile tinnitus. CT scan is diagnostic and should be examined specifically for these lesions. As patients with pulsatile tinnitus may initially undergo a magnetic resonance imaging scan, identification of JB abnormality should prompt CT scan or VEMP testing to evaluate for inner ear erosion.

Utility of the PET-CT in the evaluation of early response to treatment in the diffuse large B-cell lymphoma. Preliminary results.

PubMed

Cortés Romera, M; Gámez Cenzano, C; Caresia Aróztegui, A P; Martín-Comín, J; González-Barca, E; Ricart Brulles, Y; Palacios Abufón, A; Robles Barba, J; Rodríguez-Bel, L; Rossi Seoane, S; Fernández de Sevilla, A

2012-01-01

To assess the role of FDG-PET/CT performed after the first cycles of chemotherapy in the prediction of response to treatment in patients with diffuse large B-cell lymphoma. Twenty patients (mean age: 48 years) were included, 16 initial staging and 4 relapse. All patients underwent PET/CT at 3 times: 1) Baseline, 2) After 1-3 cycles of chemotherapy (early response assessment), and 3) End of treatment (evaluation of final response). Early PET/CT findings were correlated to the end-treatment PET/CT and follow-up. The evaluation of the response was established according to the decrease in uptake of the lesions (SUVmax). In the early assessment, a good response indicator (GRI) was obtained when the lesion disappeared or had more than 50% reduction in SUVmax. At the end of the treatment, a complete metabolic response (CMR) was determined in negative PET scans. Follow-up was superior to 19 months and final outcome was established as progression/relapse or no evidence of disease (NED). At the early treatment evaluation, 16/16 patients of initial staging (100%) and 2/4 of relapse (50%) achieved GRI. At the end of treatment evaluation, 14/16 patients of initial staging with GRI achieved CMR and 1/16 PMR: 14 were alive with NED in the follow-up while 1 relapsed. In the second group, 2/2 patients with GRI achieved CMR (100%): 1 continued with NED in the follow-up and another relapsed. FDG-PET/CT after the first cycles of chemotherapy is useful to monitor treatment due to its high negative predictive value (87.5%), using it to modify treatment early in the non-responders. Copyright © 2011 Elsevier España, S.L. y SEMNIM. All rights reserved.

SU-F-T-92: Clinical Benefit for Breast and Chest Wall Setup in Using a Breast Board

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

Li, S; Miyamoto, C; Serratore, D

Purpose: To validate benefit of using a breast board (BB) by analyzing the geometry and dosimetry changes of the regions of interest (ROIs) between CT scans with and without BB. Methods: Seven patients, two chest walls (CW) and five breasts, use BB at CT simulation and no BB at diagnostic CT were included. By using deformable image registration software (Velocity AI), diagnostic CT and planning CT were rigidly co-registered according to the thoracic cage at the target. The heart and the target were then deformedly matched and the contours of the planned ROIs were transferred to the diagnostic CT. Whichmore » were brought back to the planning CT data set though the initial rigid co-registration in order to keep the deformed ROIs redefined in the diagnostic CT. Anatomic shifts and volume changes of a ROI beyond the rigid translation were recorded and dosimetry changes to ROIs were compared with recalculated DVHs. Results: Patient setup without the BB had small but systematic heart shifts superiorly by ∼5 mm. Torso rotations in two cases moved the heart in opposite directions by ∼10 mm. The breast target volume, shape, and locations were significantly changed with arm extension over the head but not in cases with the arm extended laterally. Breast setup without BB could increase the mean dose to the heart and the maximal dose to the anterior ventricle wall by 1.1 and 6.7 Gy, respectively. Conclusion: A method for evaluation of breast setup technique is introduced and applied for patients. Results of systematic heart displacement without using the BB and the potential increase of heart doses encourage us to further investigate the current trend of not using a BB for easy setup and CT scans. Using a BB would likely increase patient sag during prolonged IMRT and real-time patient position monitoring is clinically desired.« less

Micro computed tomography (CT) scanned anatomical gateway to insect pest bioinformatics

USDA-ARS?s Scientific Manuscript database

An international collaboration to establish an interactive Digital Video Library for a Systems Biology Approach to study the Asian citrus Psyllid and psyllid genomics/proteomics interactions is demonstrated. Advances in micro-CT, digital computed tomography (CT) scan uses X-rays to make detailed pic...

Different methods for anatomical targeting.

PubMed

Iacopino, D G; Conti, A; Angileri, F F; Tomasello, F

2003-03-01

Several procedures are used in the different neurosurgical centers in order to perform stereotactic surgery for movement disorders. At the moment no procedure can really be considered superior to the other. We contribute with our experience of targeting method. Ten patients were selected, in accordance to the guidelines for the treatment of Parkinson disease, and operated by several methods including pallidotomy, bilateral insertion of chronic deep brain electrodes within the internal pallidum and in the subthalamic nucleus (18 procedures). in each patient an MR scan was performed the day before surgery. Scans were performed axially parallel to the intercommissural line. The operating day a contrast CT scan was performed under stereotactic conditions. after digitalization of the MRI images, it was possible to visualize the surgical target and to relate it to parenchimal and vascular anatomic structures readable at the CT examination. The CT scan obtained was confronted with the MR previously performed, the geometrical relation between the different parenchimal and vascular structures and the selected targets were obtained. Stereotactic coordinates were obtained on the CT examination. It was possible to calculate the position of the subthalamic nucleus and of the internal pallidum on the CT scan, not only relating to the intercommissural line, but considering also the neurovascular structures displayed both on the MRI and the CT scans. The technique that our group presents consist in an integration between information derived from the CT and the MR techniques, so that we can benefit from the advantages of both methods and overcome the disadvantages.

Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences

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

Dowling, Jason A., E-mail: jason.dowling@csiro.au; University of Newcastle, Callaghan, New South Wales; Sun, Jidi

Purpose: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. Patients and Methods: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1wmore » flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. Results: The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). Conclusions: The MR-Sim setup and automatic sCT generation methods using standard MR sequences generates realistic contours and electron densities for prostate cancer radiation therapy dose planning and digitally reconstructed radiograph generation.« less

Ultrafast CT scanning of an oak log for internal defects

Treesearch

Francis G. Wagner; Fred W. Taylor; Douglas S. Ladd; Charles W. McMillin; Fredrick L. Roder

1989-01-01

Detecting internal defects in sawlogs and veneer logs with computerized tomographic (CT) scanning is possible, but has been impractical due to the long scanning time required. This research investigated a new scanner able to acquire 34 cross-sectional log scans per second. This scanning rate translates to a linear log feed rate of 85 feet (25.91 m) per minute at one...

Exploitation of diagnostic computed tomography scans to assess the impact of nutrition support on body composition changes in respiratory failure patients.

PubMed

Braunschweig, Carol A; Sheean, Patricia M; Peterson, Sarah J; Gomez Perez, Sandra; Freels, Sally; Troy, Karen L; Ajanaku, Folabomi C; Patel, Ankur; Sclamberg, Joy S; Wang, Zebin

2014-09-01

Assessment of nutritional status in intensive care unit (ICU) patients is limited. Computed tomography (CT) scans that include the first to fifth lumbar region completed for diagnostic purposes measures fat and lean body mass (LBM) depots and are frequently done in ICU populations and can be used to quantify fat and LBM depots. The purpose of this study was to assess if these scans could measure change in skeletal muscle (SKT), visceral adipose (VAT), and intermuscular adipose (IMAT) tissue and to examine the association between the amount of energy and protein received and changes in these depots. Cross-sectional area of SKT, VAT, and IMAT from CT scans at the third lumbar region was quantified at 2 time points (CT1 and CT2). Change scores between CT1 and CT2 for each of these depots and the percentage of estimated energy/protein needs received were determined in 33 adults that with acute respiratory failure. Descriptive statistics and multiple regression was used to evaluate the influence of baseline characteristics and the percentage energy/protein needs received between CT1 and CT2 on percentage change/day between CT1 and CT2 on SKM, IMAT, and VAT. Participants were on average (SD) 59.7 (16) years old, received 41% of energy and 57% of protein needs. The average time between CT1 and CT2 was 10 (5) days. SKM declined 0.49%/day (men P = .07, women P = .09) and percentage of energy needs received reduced loss (β = 0.024, P = .03). No change in VAT or IMAT occurred. CT scans can be exploited to assess change in body composition in ICU patients and may assist in detecting the causal link between nutritional support and outcomes in future clinical trials. © 2013 American Society for Parenteral and Enteral Nutrition.

CT dose reduction in children.

PubMed

Vock, Peter

2005-11-01

World wide, the number of CT studies in children and the radiation exposure by CT increases. The same energy dose has a greater biological impact in children than in adults, and scan parameters have to be adapted to the smaller diameter of the juvenile body. Based on seven rules, a practical approach to paediatric CT is shown: Justification and patient preparation are important steps before scanning, and they differ from the preparation of adult patients. The subsequent choice of scan parameters aims at obtaining the minimal signal-to-noise ratio and volume coverage needed in a specific medical situation; exposure can be divided in two aspects: the CT dose index determining energy deposition per rotation and the dose-length product (DLP) determining the volume dose. DLP closely parallels the effective dose, the best parameter of the biological impact. Modern scanners offer dose modulation to locally minimise exposure while maintaining image quality. Beyond the selection of the physical parameters, the dose can be kept low by scanning the minimal length of the body and by avoiding any non-qualified repeated scanning of parts of the body. Following these rules, paediatric CT examinations of good quality can be obtained at a reasonable cost of radiation exposure.

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.

Dosimetry in MARS spectral CT: TOPAS Monte Carlo simulations and ion chamber measurements.

PubMed

Lu, Gray; Marsh, Steven; Damet, Jerome; Carbonez, Pierre; Laban, John; Bateman, Christopher; Butler, Anthony; Butler, Phil

2017-06-01

Spectral computed tomography (CT) is an up and coming imaging modality which shows great promise in revealing unique diagnostic information. Because this imaging modality is based on X-ray CT, it is of utmost importance to study the radiation dose aspects of its use. This study reports on the implementation and evaluation of a Monte Carlo simulation tool using TOPAS for estimating dose in a pre-clinical spectral CT scanner known as the MARS scanner. Simulated estimates were compared with measurements from an ionization chamber. For a typical MARS scan, TOPAS estimated for a 30 mm diameter cylindrical phantom a CT dose index (CTDI) of 29.7 mGy; CTDI was measured by ion chamber to within 3% of TOPAS estimates. Although further development is required, our investigation of TOPAS for estimating MARS scan dosimetry has shown its potential for further study of spectral scanning protocols and dose to scanned objects.

A rare adult renal neuroblastoma better imaged by 18F-FDG than by 68Ga-dotanoc in the PET/CT scan.

PubMed

Jain, Tarun Kumar; Singh, Sharwan Kumar; Sood, Ashwani; Ashwathanarayama, Abhiram Gj; Basher, Rajender Kumar; Shukla, Jaya; Mittal, Bhagwant Rai

2017-01-01

Primary renal neuroblastoma is an uncommon tumor in children and extremely rare in adults. We present a case of a middle aged female having a large retroperitoneal mass involving the right kidney with features of neuroblastoma on pre-operative histopathology. Whole-body fluorine-18-fluoro-deoxyglucose positron emission tomography ( 18 F-FDG PET/CT) and 68 Ga-dotanoc PET/CT scans performed for staging and therapeutic potential revealed a tracer avid mass replacing the right kidney and also pelvic lymph nodes. The 18 F-FDG PET/CT scan showed better both the primary lesion and the metastases in the pelvic lymph nodes than the 68 Ga-dotanoc scan supporting diagnosis and treatment planning.

Dual energy CT with one full scan and a second sparse-view scan using structure preserving iterative reconstruction (SPIR)

NASA Astrophysics Data System (ADS)

Wang, Tonghe; Zhu, Lei

2016-09-01

Conventional dual-energy CT (DECT) reconstruction requires two full-size projection datasets with two different energy spectra. In this study, we propose an iterative algorithm to enable a new data acquisition scheme which requires one full scan and a second sparse-view scan for potential reduction in imaging dose and engineering cost of DECT. A bilateral filter is calculated as a similarity matrix from the first full-scan CT image to quantify the similarity between any two pixels, which is assumed unchanged on a second CT image since DECT scans are performed on the same object. The second CT image from reduced projections is reconstructed by an iterative algorithm which updates the image by minimizing the total variation of the difference between the image and its filtered image by the similarity matrix under data fidelity constraint. As the redundant structural information of the two CT images is contained in the similarity matrix for CT reconstruction, we refer to the algorithm as structure preserving iterative reconstruction (SPIR). The proposed method is evaluated on both digital and physical phantoms, and is compared with the filtered-backprojection (FBP) method, the conventional total-variation-regularization-based algorithm (TVR) and prior-image-constrained-compressed-sensing (PICCS). SPIR with a second 10-view scan reduces the image noise STD by a factor of one order of magnitude with same spatial resolution as full-view FBP image. SPIR substantially improves over TVR on the reconstruction accuracy of a 10-view scan by decreasing the reconstruction error from 6.18% to 1.33%, and outperforms TVR at 50 and 20-view scans on spatial resolution with a higher frequency at the modulation transfer function value of 10% by an average factor of 4. Compared with the 20-view scan PICCS result, the SPIR image has 7 times lower noise STD with similar spatial resolution. The electron density map obtained from the SPIR-based DECT images with a second 10-view scan has an average error of less than 1%.

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.

Combination of CT scanning and fluoroscopy imaging on a flat-panel CT scanner

NASA Astrophysics Data System (ADS)

Grasruck, M.; Gupta, R.; Reichardt, B.; Suess, Ch.; Schmidt, B.; Stierstorfer, K.; Popescu, S.; Brady, T.; Flohr, T.

2006-03-01

We developed and evaluated a prototype flat-panel detector based Volume CT (fpVCT) scanner. The fpVCT scanner consists of a Varian 4030CB a-Si flat-panel detector mounted in a multi slice CT-gantry (Siemens Medical Solutions). It provides a 25 cm field of view with 18 cm z-coverage at the isocenter. In addition to the standard tomographic scanning, fpVCT allows two new scan modes: (1) fluoroscopic imaging from any arbitrary rotation angle, and (2) continuous, time-resolved tomographic scanning of a dynamically changing viewing volume. Fluoroscopic imaging is feasible by modifying the standard CT gantry so that the imaging chain can be oriented along any user-selected rotation angle. Scanning with a stationary gantry, after it has been oriented, is equivalent to a conventional fluoroscopic examination. This scan mode enables combined use of high-resolution tomography and real-time fluoroscopy with a clinically usable field of view in the z direction. The second scan mode allows continuous observation of a timeevolving process such as perfusion. The gantry can be continuously rotated for up to 80 sec, with the rotation time ranging from 3 to 20 sec, to gather projection images of a dynamic process. The projection data, that provides a temporal log of the viewing volume, is then converted into multiple image stacks that capture the temporal evolution of a dynamic process. Studies using phantoms, ex vivo specimens, and live animals have confirmed that these new scanning modes are clinically usable and offer a unique view of the anatomy and physiology that heretofore has not been feasible using static CT scanning. At the current level of image quality and temporal resolution, several clinical applications such a dynamic angiography, tumor enhancement pattern and vascularity studies, organ perfusion, and interventional applications are in reach.

Selected PET radiomic features remain the same.

PubMed

Tsujikawa, Tetsuya; Tsuyoshi, Hideaki; Kanno, Masafumi; Yamada, Shizuka; Kobayashi, Masato; Narita, Norihiko; Kimura, Hirohiko; Fujieda, Shigeharu; Yoshida, Yoshio; Okazawa, Hidehiko

2018-04-17

We investigated whether PET radiomic features are affected by differences in the scanner, scan protocol, and lesion location using 18 F-FDG PET/CT and PET/MR scans. SUV, TMR, skewness, kurtosis, entropy, and homogeneity strongly correlated between PET/CT and PET/MR images. SUVs were significantly higher on PET/MR 0-2 min and PET/MR 0-10 min than on PET/CT in gynecological cancer ( p = 0.008 and 0.008, respectively), whereas no significant difference was observed between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images in oral cavity/oropharyngeal cancer. TMRs on PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min increased in this order in gynecological cancer and oral cavity/oropharyngeal cancer. In contrast to conventional and histogram indices, 4 textural features (entropy, homogeneity, SRE, and LRE) were not significantly different between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images. 18 F-FDG PET radiomic features strongly correlated between PET/CT and PET/MR images. Dixon-based attenuation correction on PET/MR images underestimated tumor tracer uptake more significantly in oral cavity/oropharyngeal cancer than in gynecological cancer. 18 F-FDG PET textural features were affected less by differences in the scanner and scan protocol than conventional and histogram features, possibly due to the resampling process using a medium bin width. Eight patients with gynecological cancer and 7 with oral cavity/oropharyngeal cancer underwent a whole-body 18 F-FDG PET/CT scan and regional PET/MR scan in one day. PET/MR scans were performed for 10 minutes in the list mode, and PET/CT and 0-2 min and 0-10 min PET/MR images were reconstructed. The standardized uptake value (SUV), tumor-to-muscle SUV ratio (TMR), skewness, kurtosis, entropy, homogeneity, short-run emphasis (SRE), and long-run emphasis (LRE) were compared between PET/CT, PET/MR 0-2 min , and PET/MR 0-10 min images.

Small bowel entrapment and ureteropelvic junction disruption associated with L3 Chance fracture-dislocation.

PubMed

Pesenti, Sebastien; Blondel, Benjamin; Faure, Alice; Peltier, Emilie; Launay, Franck; Jouve, Jean-Luc

2016-09-16

Paediatric Chance fracture are rare lesions but often associated with abdominal injuries. We herein present the case of a seven years old patient who sustained an entrapment of small bowel and an ureteropelvic disruption associated with a Chance fracture and spine dislocation following a traffic accident. Initial X-rays and computed tomographic (CT) scan showed a Chance fracture with dislocation of L3 vertebra, with an incarceration of a small bowel loop in the spinal canal and a complete section of the left lumbar ureter. Paraplegia was noticed on the initial neurological examination. A posterior L2-L4 osteosynthesis was performed firstly. In a second time she underwent a sus umbilical laparotomy to release the incarcerated jejunum loop in the spinal canal. An end-to-end anastomosis was performed on a JJ probe to suture the left injured ureter. One month after the traumatism, she started to complain of severe headaches related to a leakage of cerebrospinalis fluid. Three months after the traumatism there was a clear regression of the leakage. One year after the trauma, an anterior intervertebral fusion was done. At final follow-up, no neurologic recovery was noticed. In case of Chance fracture, all physicians should think about abdominal injuries even if the patient is asymptomatic. Initial abdominal CT scan and magnetic resonance imaging provide in such case crucial info for management of the spine and the associated lesions.

Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation.

PubMed

Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

2014-09-21

With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

Development of 1-year-old computational phantom and calculation of organ doses during CT scans using Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Pan, Yuxi; Qiu, Rui; Gao, Linfeng; Ge, Chaoyong; Zheng, Junzheng; Xie, Wenzhang; Li, Junli

2014-09-01

With the rapidly growing number of CT examinations, the consequential radiation risk has aroused more and more attention. The average dose in each organ during CT scans can only be obtained by using Monte Carlo simulation with computational phantoms. Since children tend to have higher radiation sensitivity than adults, the radiation dose of pediatric CT examinations requires special attention and needs to be assessed accurately. So far, studies on organ doses from CT exposures for pediatric patients are still limited. In this work, a 1-year-old computational phantom was constructed. The body contour was obtained from the CT images of a 1-year-old physical phantom and the internal organs were deformed from an existing Chinese reference adult phantom. To ensure the organ locations in the 1-year-old computational phantom were consistent with those of the physical phantom, the organ locations in 1-year-old computational phantom were manually adjusted one by one, and the organ masses were adjusted to the corresponding Chinese reference values. Moreover, a CT scanner model was developed using the Monte Carlo technique and the 1-year-old computational phantom was applied to estimate organ doses derived from simulated CT exposures. As a result, a database including doses to 36 organs and tissues from 47 single axial scans was built. It has been verified by calculation that doses of axial scans are close to those of helical scans; therefore, this database could be applied to helical scans as well. Organ doses were calculated using the database and compared with those obtained from the measurements made in the physical phantom for helical scans. The differences between simulation and measurement were less than 25% for all organs. The result shows that the 1-year-old phantom developed in this work can be used to calculate organ doses in CT exposures, and the dose database provides a method for the estimation of 1-year-old patient doses in a variety of CT examinations.

Prevalence of Extracochlear Electrodes: Computerized Tomography Scans, Cochlear Implant Maps, and Operative Reports.

PubMed

Holder, Jourdan T; Kessler, David M; Noble, Jack H; Gifford, René H; Labadie, Robert F

2018-06-01

To quantify and compare the number of cochlear implant (CI) electrodes found to be extracochlear on postoperative computerized tomography (CT) scans, the number of basal electrodes deactivated during standard CI mapping (without knowledge of the postoperative CT scan), and the extent of electrode insertion noted by the surgeon. Retrospective. Academic Medical Center. Two hundred sixty-two patients underwent standard cochlear implantation and postoperative temporal bone CT scanning. Scans were analyzed to determine the number of extracochlear electrodes. Standard CI programming had been completed without knowledge of the extracochlear electrodes identified on the CT. These standard CI maps were reviewed to record the number of deactivated basal electrodes. Lastly, each operative report was reviewed to record the extent of reported electrode insertion. 13.4% (n = 35) of CIs were found to have at least one electrode outside of the cochlea on the CT scan. Review of CI mapping indicated that audiologists had deactivated extracochlear electrodes in 60% (21) of these cases. Review of operative reports revealed that surgeons correctly indicated the number of extracochlear electrodes in 6% (2) of these cases. Extracochlear electrodes were correctly identified audiologically in 60% of cases and in surgical reports in 6% of cases; however, it is possible that at least a portion of these cases involved postoperative electrode migration. Given these findings, postoperative CT scans can provide information regarding basal electrode location, which could help improve programming accuracy, associated frequency allocation, and audibility with appropriate deactivation of extracochlear electrodes.

Spotting L3 slice in CT scans using deep convolutional network and transfer learning.

PubMed

Belharbi, Soufiane; Chatelain, Clément; Hérault, Romain; Adam, Sébastien; Thureau, Sébastien; Chastan, Mathieu; Modzelewski, Romain

2017-08-01

In this article, we present a complete automated system for spotting a particular slice in a complete 3D Computed Tomography exam (CT scan). Our approach does not require any assumptions on which part of the patient's body is covered by the scan. It relies on an original machine learning regression approach. Our models are learned using the transfer learning trick by exploiting deep architectures that have been pre-trained on imageNet database, and therefore it requires very little annotation for its training. The whole pipeline consists of three steps: i) conversion of the CT scans into Maximum Intensity Projection (MIP) images, ii) prediction from a Convolutional Neural Network (CNN) applied in a sliding window fashion over the MIP image, and iii) robust analysis of the prediction sequence to predict the height of the desired slice within the whole CT scan. Our approach is applied to the detection of the third lumbar vertebra (L3) slice that has been found to be representative to the whole body composition. Our system is evaluated on a database collected in our clinical center, containing 642 CT scans from different patients. We obtained an average localization error of 1.91±2.69 slices (less than 5 mm) in an average time of less than 2.5 s/CT scan, allowing integration of the proposed system into daily clinical routines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study

PubMed Central

Pearce, Mark S; Salotti, Jane A; Little, Mark P; McHugh, Kieran; Lee, Choonsik; Kim, Kwang Pyo; Howe, Nicola L; Ronckers, Cecile M; Rajaraman, Preetha; Craft, Alan W; Parker, Louise; de González, Amy Berrington

2012-01-01

Summary Background Although CT scans are very useful clinically, potential cancer risks exist from associated ionising radiation, in particular for children who are more radiosensitive than adults. We aimed to assess the excess risk of leukaemia and brain tumours after CT scans in a cohort of children and young adults. Methods In our retrospective cohort study, we included patients without previous cancer diagnoses who were first examined with CT in National Health Service (NHS) centres in England, Wales, or Scotland (Great Britain) between 1985 and 2002, when they were younger than 22 years of age. We obtained data for cancer incidence, mortality, and loss to follow-up from the NHS Central Registry from Jan 1, 1985, to Dec 31, 2008. We estimated absorbed brain and red bone marrow doses per CT scan in mGy and assessed excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. To avoid inclusion of CT scans related to cancer diagnosis, follow-up for leukaemia began 2 years after the first CT and for brain tumours 5 years after the first CT. Findings During follow-up, 74 of 178 604 patients were diagnosed with leukaemia and 135 of 176 587 patients were diagnosed with brain tumours. We noted a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy 0·036, 95% CI 0·005–0·120; p=0·0097) and brain tumours (0·023, 0·010–0·049; p<0·0001). Compared with patients who received a dose of less than 5 mGy, the relative risk of leukaemia for patients who received a cumulative dose of at least 30 mGy (mean dose 51·13 mGy) was 3·18 (95% CI 1·46–6·94) and the relative risk of brain cancer for patients who received a cumulative dose of 50–74 mGy (mean dose 60·42 mGy) was 2·82 (1·33–6·03). Interpretation Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain cancer. Because these cancers are relatively rare, the cumulative absolute risks are small: in the 10 years after the first scan for patients younger than 10 years, one excess case of leukaemia and one excess case of brain tumour per 10 000 head CT scans is estimated to occur. Nevertheless, although clinical benefits should outweigh the small absolute risks, radiation doses from CT scans ought to be kept as low as possible and alternative procedures, which do not involve ionising radiation, should be considered if appropriate. Funding US National Cancer Institute and UK Department of Health. PMID:22681860

Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study.

PubMed

Pearce, Mark S; Salotti, Jane A; Little, Mark P; McHugh, Kieran; Lee, Choonsik; Kim, Kwang Pyo; Howe, Nicola L; Ronckers, Cecile M; Rajaraman, Preetha; Sir Craft, Alan W; Parker, Louise; Berrington de González, Amy

2012-08-04

Although CT scans are very useful clinically, potential cancer risks exist from associated ionising radiation, in particular for children who are more radiosensitive than adults. We aimed to assess the excess risk of leukaemia and brain tumours after CT scans in a cohort of children and young adults. In our retrospective cohort study, we included patients without previous cancer diagnoses who were first examined with CT in National Health Service (NHS) centres in England, Wales, or Scotland (Great Britain) between 1985 and 2002, when they were younger than 22 years of age. We obtained data for cancer incidence, mortality, and loss to follow-up from the NHS Central Registry from Jan 1, 1985, to Dec 31, 2008. We estimated absorbed brain and red bone marrow doses per CT scan in mGy and assessed excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. To avoid inclusion of CT scans related to cancer diagnosis, follow-up for leukaemia began 2 years after the first CT and for brain tumours 5 years after the first CT. During follow-up, 74 of 178,604 patients were diagnosed with leukaemia and 135 of 176,587 patients were diagnosed with brain tumours. We noted a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy 0·036, 95% CI 0·005-0·120; p=0·0097) and brain tumours (0·023, 0·010-0·049; p<0·0001). Compared with patients who received a dose of less than 5 mGy, the relative risk of leukaemia for patients who received a cumulative dose of at least 30 mGy (mean dose 51·13 mGy) was 3·18 (95% CI 1·46-6·94) and the relative risk of brain cancer for patients who received a cumulative dose of 50-74 mGy (mean dose 60·42 mGy) was 2·82 (1·33-6·03). Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain cancer. Because these cancers are relatively rare, the cumulative absolute risks are small: in the 10 years after the first scan for patients younger than 10 years, one excess case of leukaemia and one excess case of brain tumour per 10,000 head CT scans is estimated to occur. Nevertheless, although clinical benefits should outweigh the small absolute risks, radiation doses from CT scans ought to be kept as low as possible and alternative procedures, which do not involve ionising radiation, should be considered if appropriate. US National Cancer Institute and UK Department of Health. Copyright © 2012 Elsevier Ltd. All rights reserved.

Are CT Scans Safe? Is It True That CT Scans May Increase My Risk of Cancer?

MedlinePlus

... products: Computed tomography (CT). U.S. Food and Drug Administration. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115317.htm. Accessed Jan. 19, 2018. Lee C, et al. Radiation-related risks of ...

Scout-view Assisted Interior Micro-CT

PubMed Central

Sen Sharma, Kriti; Holzner, Christian; Vasilescu, Dragoş M.; Jin, Xin; Narayanan, Shree; Agah, Masoud; Hoffman, Eric A.; Yu, Hengyong; Wang, Ge

2013-01-01

Micro computed tomography (micro-CT) is a widely-used imaging technique. A challenge of micro-CT is to quantitatively reconstruct a sample larger than the field-of-view (FOV) of the detector. This scenario is characterized by truncated projections and associated image artifacts. However, for such truncated scans, a low resolution scout scan with an increased FOV is frequently acquired so as to position the sample properly. This study shows that the otherwise discarded scout scans can provide sufficient additional information to uniquely and stably reconstruct the interior region of interest. Two interior reconstruction methods are designed to utilize the multi-resolution data without a significant computational overhead. While most previous studies used numerically truncated global projections as interior data, this study uses truly hybrid scans where global and interior scans were carried out at different resolutions. Additionally, owing to the lack of standard interior micro-CT phantoms, we designed and fabricated novel interior micro-CT phantoms for this study to provide means of validation for our algorithms. Finally, two characteristic samples from separate studies were scanned to show the effect of our reconstructions. The presented methods show significant improvements over existing reconstruction algorithms. PMID:23732478

Influence of anatomical location on CT numbers in cone beam computed tomography.

PubMed

Oliveira, Matheus L; Tosoni, Guilherme M; Lindsey, David H; Mendoza, Kristopher; Tetradis, Sotirios; Mallya, Sanjay M

2013-04-01

To assess the influence of anatomical location on computed tomography (CT) numbers in mid- and full field of view (FOV) cone beam computed tomography (CBCT) scans. Polypropylene tubes with varying concentrations of dipotassium hydrogen phosphate (K₂HPO₄) solutions (50-1200 mg/mL) were imaged within the incisor, premolar, and molar dental sockets of a human skull phantom. CBCT scans were acquired using the NewTom 3G and NewTom 5G units. The CT numbers of the K₂HPO₄ phantoms were measured, and the relationship between CT numbers and K₂HPO₄ concentration was examined. The measured CT numbers of the K₂HPO₄ phantoms were compared between anatomical sites. At all six anatomical locations, there was a strong linear relationship between CT numbers and K₂HPO₄ concentration (R(2)>0.93). However, the absolute CT numbers varied considerably with the anatomical location. The relationship between CT numbers and object density is not uniform through the dental arch on CBCT scans. Copyright © 2013 Elsevier Inc. All rights reserved.

Unenhanced Computed Tomography to Visualize Hollow Viscera and/or Mesenteric Injury After Blunt Abdominal Trauma: A Single-Institution Experience.

PubMed

Yang, Xu-Yang; Wei, Ming-Tian; Jin, Cheng-Wu; Wang, Meng; Wang, Zi-Qiang

2016-03-01

To identify and describe the major features of unenhanced computed tomography (CT) images of blunt hollow viscera and/or mesenteric injury (BHVI/MI) and to determine the value of unenhanced CT in the diagnosis of BHVI/MI. This retrospective study included 151 patients who underwent unenhanced CT before laparotomy for blunt abdominal trauma between January 2011 and December 2013. According to surgical observations, patients were classified as having BHVI/MI (n = 73) or not (n = 78). Sensitivity, specificity, P values, and likelihood ratios were calculated by comparing CT findings between the 2 groups. Six significant CT findings (P < 0.05) for BHVI/MI were identified and their sensitivity and specificity values determined, as follows: bowel wall thickening (39.7%, 96.2%), mesentery thickening (46.6%, 88.5%), mesenteric fat infiltration (12.3%, 98.7%), peritoneal fat infiltration (31.5%, 87.1%), parietal peritoneum thickening (30.1%, 85.9%), and intra- or retro-peritoneal air (34.2%, 96.2%). Unenhanced CT scan was useful as an initial assessment tool for BHVI/MI after blunt abdominal trauma. Six key features on CT were correlated with BHVI/MI.

Hollow organ perforation in blunt abdominal trauma: the role of diagnostic peritoneal lavage.

PubMed

Wang, Yu-Chun; Hsieh, Chi-Hsun; Fu, Chih-Yuan; Yeh, Chun-Chieh; Wu, Shih-Chi; Chen, Ray-Jade

2012-05-01

With recent advances in radiologic diagnostic procedures, the use of diagnostic peritoneal lavage (DPL) has markedly declined. In this study, we reviewed data to reevaluate the role of DPL in the diagnosis of hollow organ perforation in patients with blunt abdominal trauma. Adult patients who had sustained blunt abdominal trauma and who were hemodynamically stable after initial resuscitation underwent an abdominal computed tomographic (CT) scan. Diagnostic peritoneal lavage was performed for patients who were indicated to receive nonoperative management and where hollow organ perforation could not be ruled out. During a 60-month period, 64 patients who had received abdominal CT scanning underwent DPL. Nineteen patients were diagnosed as having a positive DPL based on cell count ratio of 1 or higher. There were 4 patients who sustained small bowel perforation. The sensitivity and specificity of the cell count ratio for a hollow organ perforation in this study were 100% and 75%, respectively. No missed hollow organ perforations were detected. For patients with blunt abdominal trauma and hemoperitoneum who plan to receive nonoperative management, DPL is still a useful tool to exclude hollow organ perforation that is undetected by CT. Copyright © 2012 Elsevier Inc. All rights reserved.

Diagnostic imaging for acute appendicitis: interfacility differences in practice patterns.

PubMed

Michailidou, Maria; Sacco Casamassima, Maria G; Karim, Omar; Gause, Colin; Salazar, Jose H; Goldstein, Seth D; Abdullah, Fizan

2015-04-01

To evaluate trends and factors associated with interfacility differences in imaging modality selection in the diagnosis and management of children with suspected acute appendicitis. We conducted a retrospective review of diagnostic imaging selection and outcomes in patients <20 years of age who underwent appendectomy at a single Children's Hospital from June 2008 to June 2013. These results were then compared with those of referring hospitals. A total of 232 children underwent appendectomy during the study period. Imaging results contributed to diagnostic and management decisions in 95.3 % of cases. CT scan was utilized as first-line imaging in 50 % of cases. CTs were preferentially performed at referring institutions (78 vs. 46 %, p < 0.001). Children were five times more likely to undergo CT at referring institutions (OR = 5.5, CI 3.0-10.2). Adjusting for demographics and Alvarado score, diagnostic imaging choice was independent of patient's clinical status. This study demonstrates that initial presentation to a referring hospital independently predicts the use of CT scan for suspected acute appendicitis. Further efforts should be undertaken to develop a clinical pathway that minimizes radiation exposure in the diagnosis of acute appendicitis, with focus on access to pediatric abdominal ultrasound.

Choroidal metastasis from carcinoma of breast detected on F18-FDG PET CT scan: A case report and review of literature.

PubMed

Solav, Shrikant; Bhandari, Ritu; Sowani, Anuradha; Saxena, Sameer

2010-10-01

Intraocular choroidal metastasis is a very rare cause of blindness. Choroidal hemangioma and melanoma are other causes that may mimic the condition. Carcinoma of breast is the most common primary malignancy that accounts for choroidal metastasis in females and carcinoma of lung is the most common cause in males. Other primary neoplasms which can uncommonly metastasize to the choroid are testis, gastrointestinal tract, kidney, thyroid, pancreas, and prostate. Metastatic neoplasm to the eye outnumbers the primary tumors such as retinoblastomas and malignant melanoma. Sonography is usually the initial investigation after fundus examination to look for the architecture of the lesion. However, it lacks in specificity. We present a case of carcinoma of breast that had visual disturbances and wholebody F18-fluorodeoxyglucose, positron emission tomography-computerized tomography (FDG PET CT) revealed a choroidal lesion in addition to cerebral, pulmonary, and skeletal metastases. Choroidal metastasis from carcinoma of lung has been reported previously on FDG PET. To the best of our knowledge, this is the first case report of carcinoma of breast demonstrating choroid metastasis on F18-FDG PET CT scan.

Abdomen and spinal cord segmentation with augmented active shape models.

PubMed

Xu, Zhoubing; Conrad, Benjamin N; Baucom, Rebeccah B; Smith, Seth A; Poulose, Benjamin K; Landman, Bennett A

2016-07-01

Active shape models (ASMs) have been widely used for extracting human anatomies in medical images given their capability for shape regularization of topology preservation. However, sensitivity to model initialization and local correspondence search often undermines their performances, especially around highly variable contexts in computed-tomography (CT) and magnetic resonance (MR) images. In this study, we propose an augmented ASM (AASM) by integrating the multiatlas label fusion (MALF) and level set (LS) techniques into the traditional ASM framework. Using AASM, landmark updates are optimized globally via a region-based LS evolution applied on the probability map generated from MALF. This augmentation effectively extends the searching range of correspondent landmarks while reducing sensitivity to the image contexts and improves the segmentation robustness. We propose the AASM framework as a two-dimensional segmentation technique targeting structures with one axis of regularity. We apply AASM approach to abdomen CT and spinal cord (SC) MR segmentation challenges. On 20 CT scans, the AASM segmentation of the whole abdominal wall enables the subcutaneous/visceral fat measurement, with high correlation to the measurement derived from manual segmentation. On 28 3T MR scans, AASM yields better performances than other state-of-the-art approaches in segmenting white/gray matter in SC.

Diagnostic value of FDG-PET/(CT) in children with fever of unknown origin and unexplained fever during immune suppression.

PubMed

Blokhuis, Gijsbert J; Bleeker-Rovers, Chantal P; Diender, Marije G; Oyen, Wim J G; Draaisma, Jos M Th; de Geus-Oei, Lioe-Fee

2014-10-01

Fever of unknown origin (FUO) and unexplained fever during immune suppression in children are challenging medical problems. The aim of this study is to investigate the diagnostic value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and FDG-PET combined with computed tomography (FDG-PET/CT) in children with FUO and in children with unexplained fever during immune suppression. All FDG-PET/(CT) scans performed in the Radboud university medical center for the evaluation of FUO or unexplained fever during immune suppression in the last 10 years were reviewed. Results were compared with the final clinical diagnosis. FDG-PET/(CT) scans were performed in 31 children with FUO. A final diagnosis was established in 16 cases (52 %). Of the total number of scans, 32 % were clinically helpful. The sensitivity and specificity of FDG-PET/CT in these patients was 80 % and 78 %, respectively. FDG-PET/(CT) scans were performed in 12 children with unexplained fever during immune suppression. A final diagnosis was established in nine patients (75 %). Of the total number of these scans, 58 % were clinically helpful. The sensitivity and specificity of FDG-PET/CT in children with unexplained fever during immune suppression was 78 % and 67 %, respectively. FDG-PET/CT appears a valuable imaging technique in the evaluation of children with FUO and in the diagnostic process of children with unexplained fever during immune suppression. Prospective studies of FDG-PET/CT as part of a structured diagnostic protocol are warranted to assess the additional diagnostic value.

Interobserver reliability of the young-burgess and tile classification systems for fractures of the pelvic ring.

PubMed

Koo, Henry; Leveridge, Mike; Thompson, Charles; Zdero, Rad; Bhandari, Mohit; Kreder, Hans J; Stephen, David; McKee, Michael D; Schemitsch, Emil H

2008-07-01

The purpose of this study was to measure interobserver reliability of 2 classification systems of pelvic ring fractures and to determine whether computed tomography (CT) improves reliability. The reliability of several radiographic findings was also tested. Thirty patients taken from a database at a Level I trauma facility were reviewed. For each patient, 3 radiographs (AP pelvis, inlet, and outlet) and CT scans were available. Six different reviewers (pelvic and acetabular specialist, orthopaedic traumatologist, or orthopaedic trainee) classified the injury according to Young-Burgess and Tile classification systems after reviewing plain radiographs and then after CT scans. The Kappa coefficient was used to determine interobserver reliability of these classification systems before and after CT scan. For plain radiographs, overall Kappa values for the Young-Burgess and Tile classification systems were 0.72 and 0.30, respectively. For CT scan and plain radiographs, the overall Kappa values for the Young-Burgess and Tile classification systems were 0.63 and 0.33, respectively. The pelvis/acetabular surgeons demonstrated the highest level of agreement using both classification systems. For individual questions, the addition of CT did significantly improve reviewer interpretation of fracture stability. The pre-CT and post-CT Kappa values for fracture stability were 0.59 and 0.93, respectively. The CT scan can improve the reliability of assessment of pelvic stability because of its ability to identify anatomical features of injury. The Young-Burgess system may be optimal for the learning surgeon. The Tile classification system is more beneficial for specialists in pelvic and acetabular surgery.

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.

Validation of calculation algorithms for organ doses in CT by measurements on a 5 year old paediatric phantom

NASA Astrophysics Data System (ADS)

Dabin, Jérémie; Mencarelli, Alessandra; McMillan, Dayton; Romanyukha, Anna; Struelens, Lara; Lee, Choonsik

2016-06-01

Many organ dose calculation tools for computed tomography (CT) scans rely on the assumptions: (1) organ doses estimated for one CT scanner can be converted into organ doses for another CT scanner using the ratio of the Computed Tomography Dose Index (CTDI) between two CT scanners; and (2) helical scans can be approximated as the summation of axial slices covering the same scan range. The current study aims to validate experimentally these two assumptions. We performed organ dose measurements in a 5 year-old physical anthropomorphic phantom for five different CT scanners from four manufacturers. Absorbed doses to 22 organs were measured using thermoluminescent dosimeters for head-to-torso scans. We then compared the measured organ doses with the values calculated from the National Cancer Institute dosimetry system for CT (NCICT) computer program, developed at the National Cancer Institute. Whereas the measured organ doses showed significant variability (coefficient of variation (CoV) up to 53% at 80 kV) across different scanner models, the CoV of organ doses normalised to CTDIvol substantially decreased (12% CoV on average at 80 kV). For most organs, the difference between measured and simulated organ doses was within  ±20% except for the bone marrow, breasts and ovaries. The discrepancies were further explained by additional Monte Carlo calculations of organ doses using a voxel phantom developed from CT images of the physical phantom. The results demonstrate that organ doses calculated for one CT scanner can be used to assess organ doses from other CT scanners with 20% uncertainty (k  =  1), for the scan settings considered in the study.

Socio-economic variation in CT scanning in Northern England, 1990-2002

PubMed Central

2012-01-01

Background Socio-economic status is known to influence health throughout life. In childhood, studies have shown increased injury rates in more deprived settings. Socio-economic status may therefore be related to rates of certain medical procedures, such as computed tomography (CT) scans. This study aimed to assess socio-economic variation among young people having CT scans in Northern England between 1990 and 2002 inclusive. Methods Electronic data were obtained from Radiology Information Systems of all nine National Health Service hospital Trusts in the region. CT scan data, including sex, date of scan, age at scan, number and type of scans were assessed in relation to quintiles of Townsend deprivation scores, obtained from linkage of postcodes with census data, using χ2 tests and Spearman rank correlations. Results During the study period, 39,676 scans were recorded on 21,089 patients, with 38,007 scans and 19,485 patients (11344 male and 8132 female) linkable to Townsend scores. The overall distributions of both scans and patients by quintile of Townsend deprivation scores were significantly different to the distributions of Townsend scores from the census wards included in the study (p < 0.0001). There was a significant association between type of scan and deprivation quintile (p < 0.0001), primarily due to the higher proportions of head scans in the three most deprived quintiles, and slightly higher proportions of chest scans and abdomen and pelvis scans in the least deprived groups. There was also a significant association (p < 0.0001) between the patient's age at the time of the CT scan and Townsend deprivation quintiles, with slightly increasing proportions of younger children with increasing deprivation. A similar association with age (p < 0.0001) was seen when restricting the data to include only the first scan of each patient. The number of scans per patient was also associated with Townsend deprivation quintiles (p = 0.014). Conclusions Social inequalities exist in the numbers of young people undergoing CT scans with those from deprived areas more likely to do so. This may reflect the rates of injuries in these individuals and implies that certain groups within the population may receive higher radiation doses than others due to medical procedures. PMID:22283843

Dynamic CT for Parathyroid Adenoma Detection: How Does Radiation Dose Compare With Nuclear Medicine?

PubMed

Czarnecki, Caroline A; Einsiedel, Paul F; Phal, Pramit M; Miller, Julie A; Lichtenstein, Meir; Stella, Damien L

2018-05-01

Dynamic CT is increasingly used for preoperative localization of parathyroid adenomas, but concerns remain about the radiation effective dose of CT compared with that of 99m Tc-sestamibi scintigraphy. The purpose of this study was to compare the radiation dose delivered by three-phase dynamic CT with that delivered by 99m Tc-sestamibi SPECT/CT performed in accordance with our current protocols and to assess the possible reduction in effective dose achieved by decreasing the scan length (i.e., z-axis) of two phases of the dynamic CT protocol. The effective dose of a 99m Tc-sestamibi nuclear medicine parathyroid study performed with and without coregistration CT was calculated and compared with the effective dose of our current three-phase dynamic CT protocol as well as a proposed protocol involving CT with reduced scan length. The median effective dose for a 99m Tc-sestamibi nuclear medicine study was 5.6 mSv. This increased to 12.4 mSv with the addition of coregistration CT, which is higher than the median effective dose of 9.3 mSv associated with the dynamic CT protocol. Reducing the scan length of two phases in the dynamic CT protocol could reduce the median effective dose to 6.1 mSv, which would be similar to that of the dose from the 99m Tc-sestamibi study alone. Dynamic CT used for the detection of parathyroid adenoma can deliver a lower radiation dose than 99m Tc-sestamibi SPECT/CT. It may be possible to reduce the dose further by decreasing the scan length of two of the phases, although whether this has an impact on accuracy of the localization needs further investigation.

Three-Dimensions Segmentation of Pulmonary Vascular Trees for Low Dose CT Scans

NASA Astrophysics Data System (ADS)

Lai, Jun; Huang, Ying; Wang, Ying; Wang, Jun

2016-12-01

Due to the low contrast and the partial volume effects, providing an accurate and in vivo analysis for pulmonary vascular trees from low dose CT scans is a challenging task. This paper proposes an automatic integration segmentation approach for the vascular trees in low dose CT scans. It consists of the following steps: firstly, lung volumes are acquired by the knowledge based method from the CT scans, and then the data are smoothed by the 3D Gaussian filter; secondly, two or three seeds are gotten by the adaptive 2D segmentation and the maximum area selecting from different position scans; thirdly, each seed as the start voxel is inputted for a quick multi-seeds 3D region growing to get vascular trees; finally, the trees are refined by the smooth filter. Through skeleton analyzing for the vascular trees, the results show that the proposed method can provide much better and lower level vascular branches.

Automated volumetry of temporal horn of lateral ventricle for detection of Alzheimer's disease in CT scan

NASA Astrophysics Data System (ADS)

Takahashi, Noriyuki; Kinoshita, Toshibumi; Ohmura, Tomomi; Matsuyama, Eri; Toyoshima, Hideto

2018-02-01

The rapid increase in the incidence of Alzheimer's disease (AD) has become a critical issue in low and middle income countries. In general, MR imaging has become sufficiently suitable in clinical situations, while CT scan might be uncommonly used in the diagnosis of AD due to its low contrast between brain tissues. However, in those countries, CT scan, which is less costly and readily available, will be desired to become useful for the diagnosis of AD. For CT scan, the enlargement of the temporal horn of the lateral ventricle (THLV) is one of few findings for the diagnosis of AD. In this paper, we present an automated volumetry of THLV with segmentation based on Bayes' rule on CT images. In our method, first, all CT data sets are normalized into an atlas by using linear affine transformation and non-linear wrapping techniques. Next, a probability map of THLV is constructed in the normalized data. Then, THLV regions are extracted based on Bayes' rule. Finally, the volume of the THLV is evaluated. This scheme was applied to CT scans from 20 AD patients and 20 controls to evaluate the performance of the method for detecting AD. The estimated THLV volume was markedly increased in the AD group compared with the controls (P < .0001), and the area under the receiver operating characteristic curve (AUC) was 0.921. Therefore, this computerized method may have the potential to accurately detect AD on CT images.

CT radiation profile width measurement using CR imaging plate raw data

PubMed Central

Yang, Chang‐Ying Joseph

2015-01-01

This technical note demonstrates computed tomography (CT) radiation profile measurement using computed radiography (CR) imaging plate raw data showing it is possible to perform the CT collimation width measurement using a single scan without saturating the imaging plate. Previously described methods require careful adjustments to the CR reader settings in order to avoid signal clipping in the CR processed image. CT radiation profile measurements were taken as part of routine quality control on 14 CT scanners from four vendors. CR cassettes were placed on the CT scanner bed, raised to isocenter, and leveled. Axial scans were taken at all available collimations, advancing the cassette for each scan. The CR plates were processed and raw CR data were analyzed using MATLAB scripts to measure collimation widths. The raw data approach was compared with previously established methodology. The quality control analysis scripts are released as open source using creative commons licensing. A log‐linear relationship was found between raw pixel value and air kerma, and raw data collimation width measurements were in agreement with CR‐processed, bit‐reduced data, using previously described methodology. The raw data approach, with intrinsically wider dynamic range, allows improved measurement flexibility and precision. As a result, we demonstrate a methodology for CT collimation width measurements using a single CT scan and without the need for CR scanning parameter adjustments which is more convenient for routine quality control work. PACS numbers: 87.57.Q‐, 87.59.bd, 87.57.uq PMID:26699559

SU-F-I-33: Estimating Radiation Dose in Abdominal Fat Quantitative CT

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

Li, X; Yang, K; Liu, B

Purpose: To compare size-specific dose estimate (SSDE) in abdominal fat quantitative CT with another dose estimate D{sub size,L} that also takes into account scan length. Methods: This study complied with the requirements of the Health Insurance Portability and Accountability Act. At our institution, abdominal fat CT is performed with scan length = 1 cm and CTDI{sub vol} = 4.66 mGy (referenced to body CTDI phantom). A previously developed CT simulation program was used to simulate single rotation axial scans of 6–55 cm diameter water cylinders, and dose integral of the longitudinal dose profile over the central 1 cm length wasmore » used to predict the dose at the center of one-cm scan range. SSDE and D{sub size,L} were assessed for 182 consecutive abdominal fat CT examinations with mean water-equivalent diameter (WED) of 27.8 cm ± 6.0 (range, 17.9 - 42.2 cm). Patient age ranged from 18 to 75 years, and weight ranged from 39 to 163 kg. Results: Mean SSDE was 6.37 mGy ± 1.33 (range, 3.67–8.95 mGy); mean D{sub size,L} was 2.99 mGy ± 0.85 (range, 1.48 - 4.88 mGy); and mean D{sub size,L}/SSDE ratio was 0.46 ± 0.04 (range, 0.40 - 0.55). Conclusion: The conversion factors for size-specific dose estimate in AAPM Report No. 204 were generated using 15 - 30 cm scan lengths. One needs to be cautious in applying SSDE to small length CT scans. For abdominal fat CT, SSDE was 80–150% higher than the dose of 1 cm scan length.« less

CT liver volumetry using geodesic active contour segmentation with a level-set algorithm

NASA Astrophysics Data System (ADS)

Suzuki, Kenji; Epstein, Mark L.; Kohlbrenner, Ryan; Obajuluwa, Ademola; Xu, Jianwu; Hori, Masatoshi; Baron, Richard

2010-03-01

Automatic liver segmentation on CT images is challenging because the liver often abuts other organs of a similar density. Our purpose was to develop an accurate automated liver segmentation scheme for measuring liver volumes. We developed an automated volumetry scheme for the liver in CT based on a 5 step schema. First, an anisotropic smoothing filter was applied to portal-venous phase CT images to remove noise while preserving the liver structure, followed by an edge enhancer to enhance the liver boundary. By using the boundary-enhanced image as a speed function, a fastmarching algorithm generated an initial surface that roughly estimated the liver shape. A geodesic-active-contour segmentation algorithm coupled with level-set contour-evolution refined the initial surface so as to more precisely fit the liver boundary. The liver volume was calculated based on the refined liver surface. Hepatic CT scans of eighteen prospective liver donors were obtained under a liver transplant protocol with a multi-detector CT system. Automated liver volumes obtained were compared with those manually traced by a radiologist, used as "gold standard." The mean liver volume obtained with our scheme was 1,520 cc, whereas the mean manual volume was 1,486 cc, with the mean absolute difference of 104 cc (7.0%). CT liver volumetrics based on an automated scheme agreed excellently with "goldstandard" manual volumetrics (intra-class correlation coefficient was 0.95) with no statistically significant difference (p(F<=f)=0.32), and required substantially less completion time. Our automated scheme provides an efficient and accurate way of measuring liver volumes.

TH-C-18A-08: A Management Tool for CT Dose Monitoring, Analysis, and Protocol Review

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

Wang, J; Chan, F; Newman, B

2014-06-15

Purpose: To develop a customizable tool for enterprise-wide managing of CT protocols and analyzing radiation dose information of CT exams for a variety of quality control applications Methods: All clinical CT protocols implemented on the 11 CT scanners at our institution were extracted in digital format. The original protocols had been preset by our CT management team. A commercial CT dose tracking software (DoseWatch,GE healthcare,WI) was used to collect exam information (exam date, patient age etc.), scanning parameters, and radiation doses for all CT exams. We developed a Matlab-based program (MathWorks,MA) with graphic user interface which allows to analyze themore » scanning protocols with the actual dose estimates, and compare the data to national (ACR,AAPM) and internal reference values for CT quality control. Results: The CT protocol review portion of our tool allows the user to look up the scanning and image reconstruction parameters of any protocol on any of the installed CT systems among about 120 protocols per scanner. In the dose analysis tool, dose information of all CT exams (from 05/2013 to 02/2014) was stratified on a protocol level, and within a protocol down to series level, i.e. each individual exposure event. This allows numerical and graphical review of dose information of any combination of scanner models, protocols and series. The key functions of the tool include: statistics of CTDI, DLP and SSDE, dose monitoring using user-set CTDI/DLP/SSDE thresholds, look-up of any CT exam dose data, and CT protocol review. Conclusion: our inhouse CT management tool provides radiologists, technologists and administration a first-hand near real-time enterprise-wide knowledge on CT dose levels of different exam types. Medical physicists use this tool to manage CT protocols, compare and optimize dose levels across different scanner models. It provides technologists feedback on CT scanning operation, and knowledge on important dose baselines and thresholds.« less

Delayed Traumatic Intracranial Haemorrhage and Progressive Traumatic Brain Injury in a Major Referral Centre Based in a Developing Country

PubMed Central

Jeng, Toh Charng; Haspani, Mohd Saffari Mohd; Adnan, Johari Siregar; Naing, Nyi Nyi

2008-01-01

A repeat Computer Tomographic (CT) brain after 24–48 hours from the 1st scanning is usually practiced in most hospitals in South East Asia where intracranial pressure monitoring (ICP) is routinely not done. This interval for repeat CT would be shortened if there was a deterioration in Glasgow Coma Scale (GCS). Most of the time the prognosis of any intervention may be too late especially in hospitals with high patient-to-doctor ratio causing high mortality and morbidity. The purpose of this study was to determine the important predictors for early detection of Delayed Traumatic Intracranial Haemorrhage (DTICH) and Progressive Traumatic Brain Injury (PTBI) before deterioration of GCS occurred, as well as the most ideal timing of repeated CT brain for patients admitted in Malaysian hospitals. A total of 81 patients were included in this study over a period of six months. The CT scan brain was studied by comparing the first and second CT brain to diagnose the presence of DTICH/PTBI. The predictors tested were categorised into patient factors, CT brain findings and laboratory investigations. The mean age was 33.1 ± 15.7 years with a male preponderance of 6.36:1. Among them, 81.5% were patients from road traffic accidents with Glasgow Coma Scale ranging from 4 – 15 (median of 12) upon admission. The mean time interval delay between trauma and first CT brain was 179.8 ± 121.3 minutes for the PTBI group. The DTICH group, 9.9% of the patients were found to have new intracranial clots. Significant predictors detected were different referral hospitals (p=0.02), total GCS status (p=0.026), motor component of GCS (p=0.043), haemoglobin level (p<0.001), platelet count (p=0.011) and time interval between trauma and first CT brain (p=0.022). In the PTBI group, 42.0% of the patients were found to have new changes (new clot occurrence, old clot expansion and oedema) in the repeat CT brain. Univariate statistical analysis revealed that age (p=0.03), race (p=0.035), types of admission (p=0.024), GCS status (p=0.02), pupillary changes (p=0.014), number of intracranial lesion (p=0.004), haemoglobin level (p=0.038), prothrombin time (p=0.016) as the best predictors of early detection of changes. Multiple logistics regression analysis indicated that age, severity, GCS status (motor component) and GCS during admission were significantly associated with second CT scan with changes. This study showed that 9.9% of the total patients seen in the period of study had DTICH and 42% had PTBI. In the early period after traumatic head injury, the initial CT brain did not reveal the full extent of haemorrhagic injury and associated cerebral oedema. Different referral hospitals of different trauma level, GCS status, motor component of the GCS, haemoglobin level, platelet count and time interval between trauma and the first CT brain were the significant predictors for DTICH. Whereas the key determinants of PTBI were age, race, types of admission, GCS status, pupillary changes, number of intracranial bleed, haemoglobin level, prothrombin time and of course time interval between trauma and first CT brain. Any patients who had traumatic head injury in hospitals with no protocol of repeat CT scan or intracranial pressure monitoring especially in developing countries are advised to have to repeat CT brain at the appropriate quickest time . PMID:22589639

Reducing Unnecessary Portable Pelvic Radiographs in Trauma Patients: A Resident-Driven Quality Improvement Initiative.

PubMed

Langer, Jessica M; Tsai, Emily B; Luhar, Aarti; McWilliams, Justin; Motamedi, Kambiz

2015-09-01

Quality improvement is increasingly important in the changing health care climate. We aim to establish a methodology and identify critical factors leading to successful implementation of a resident-led radiology quality improvement intervention at the institutional level. Under guidance of faculty mentors, the first-year radiology residents developed a quality improvement initiative to decrease unnecessary STAT pelvic radiographs (PXRs) in hemodynamically stable trauma patients who would additionally receive STAT pelvic CT scans. Development and implementation of this initiative required multiple steps, including: establishing resident and faculty leadership, gathering evidence from published literature, cultivating multidisciplinary support, and developing and implementing an institution-wide ordering algorithm. A visual aid and brief questionnaire were distributed to clinicians for use during treatment of trauma cases to ensure sustainability of the initiative. At multiple time points, pre- and post-intervention, residents performed a retrospective chart review to evaluate changes in imaging-ordering trends for trauma patients. Chart review showed a decline in the number of PXRs for hemodynamically stable trauma patients, as recommended in the ordering algorithm: 78% of trauma patients received both a PXR and a pelvic CT scan in the first 24 hours of the initiative, compared with 26% at 1 month; 24% at 6 months; and 18% at 10 to 12 months postintervention. The resident-led radiology quality improvement initiative created a shift in ordering culture at an institutional level. Development and implementation of this algorithm exemplified the impact of a multidisciplinary collaborative effort involving multiple departments and multiple levels of the medical hierarchy. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Utility of multiple rule out CT screening of high-risk atraumatic patients in an emergency department-a feasibility study.

PubMed

Pries-Heje, Mia M; Hasselbalch, Rasmus B; Raaschou, Henriette; Rezanavaz-Gheshlagh, Bijan; Heebøll, Hanne; Rehman, Shazia; Kristensen, Mariana; Andersen, Erik Henning; Ravn, Lisbet; Nèmery, Michel C; Lind, Morten N; Boel, Thomas; Ulriksen, Peter Sommer; Iversen, Kasper K

2018-02-17

Several large trials have evaluated the effect of CT screening based on specific symptoms, with varying outcomes. Screening of patients with CT based on their prognosis alone has not been examined before. For moderate-to-high risk patients presenting in the emergency department (ED), the potential gain from a CT scan might outweigh the risk of radiation exposure. We hypothesized that an accelerated "multiple rule out" CT screening of moderate-to-high risk patients will detect many clinically unrecognized diagnoses that affect change in treatment. Patients ≥ 40 years, triaged as high-risk or moderate-to-high risk according to vital signs, were eligible for inclusion. Patients were scanned with a combined ECG-gated and dual energy CT scan of cerebrum, thorax, and abdomen. The impact of the CT scan on patient diagnosis and treatment was examined prospectively by an expert panel. A total of 100 patients were included in the study, (53% female, mean age 73 years [age range, 43-93]). The scan lead to change in treatment or additional examinations in 37 (37%) patients, of which 24 (24%) were diagnostically significant, change in acute treatment in 11 (11%) cases and previously unrecognized malignant tumors in 10 (10%) cases. The mean size specific radiation dose was 15.9 mSv (± 3.1 mSv). Screening with a multi-rule out CT scan of high-risk patients in an ED is feasible and result in discovery of clinically unrecognized diagnoses and malignant tumors, but at the cost of radiation exposure and downstream examinations. The clinical impact of these findings should be evaluated in a larger randomized cohort.

Staging and follow-up of lacrimal gland carcinomas by 18F-FDG PET/CT imaging.

PubMed

Tafti, Bashir Akhavan; Shaba, Wisam; Li, Yuxin; Yevdayev, Ella; Berenji, Gholam Reza

2012-10-01

A 74-year-old man with right eye proptosis, diplopia, and orbital discomfort for 3 to 4 months underwent biopsy, the specimen of which showed transitional cell carcinoma of the lacrimal gland. 18F-FDG PET/CT was also performed for staging purposes. Six months after orbital exenteration, a follow-up CT scan demonstrated soft tissue thickening along the nasal bridge but could not differentiate between postsurgical changes and cancer recurrence. A concurrent PET/CT scan did not show any evidence of abnormal metabolic activity, further emphasizing the higher accuracy of PET/CT in staging and restaging of head and neck cancers. An annual follow-up scan was still negative for active disease.

[The application of multi-slice CT dynamic enhancement scan in the diagnosis and treatment of colonic lymphomas].

PubMed

Wang, Xi-ming; Wu, Le-bin; Zhang, Yun-ting; Li, Zhen-jia; Liu, Chen

2006-11-01

To discuss the value of multi-slice CT dynamic enhancement scan in the diagnosis and treatment of colonic lymphomas. 16 patients with colonic lymphomas underwent multi-slice CT dynamic enhancement scans, images of axial and reconstructive images of VR, MPR and CTVE were analyzed, patients were respectively diagnosed. Appearances of primary colorectal lymphomas were categorized into focal and diffuse lesions. Focal and diffuse lesions were 6 and 10 patients, respectively. The accuracy rate of diagnosis was 87.5%. MSCT dynamic scan has distinctive superiority in diagnosis and treatment of colonic lymphomas.

Fan-beam scanning laser optical computed tomography for large volume dosimetry

NASA Astrophysics Data System (ADS)

Dekker, K. H.; Battista, J. J.; Jordan, K. J.

2017-05-01

A prototype scanning-laser fan beam optical CT scanner is reported which is capable of high resolution, large volume dosimetry with reasonable scan time. An acylindrical, asymmetric aquarium design is presented which serves to 1) generate parallel-beam scan geometry, 2) focus light towards a small acceptance angle detector, and 3) avoid interference fringe-related artifacts. Preliminary experiments with uniform solution phantoms (11 and 15 cm diameter) and finger phantoms (13.5 mm diameter FEP tubing) demonstrate that the design allows accurate optical CT imaging, with optical CT measurements agreeing within 3% of independent Beer-Lambert law calculations.

Quantifying Three-Dimensional Morphology and RNA from Individual Embryos

PubMed Central

Green, Rebecca M.; Leach, Courtney L.; Hoehn, Natasha; Marcucio, Ralph S.; Hallgrímsson, Benedikt

2017-01-01

Quantitative analysis of morphogenesis aids our understanding of developmental processes by providing a method to link changes in shape with cellular and molecular processes. Over the last decade many methods have been developed for 3D imaging of embryos using microCT scanning to quantify the shape of embryos during development. These methods generally involve a powerful, cross-linking fixative such as paraformaldehyde to limit shrinkage during the CT scan. However, the extended time frames that these embryos are incubated in such fixatives prevent use of the tissues for molecular analysis after microCT scanning. This is a significant problem because it limits the ability to correlate variation in molecular data with morphology at the level of individual embryos. Here, we outline a novel method that allows RNA, DNA or protein isolation following CT scan while also allowing imaging of different tissue layers within the developing embryo. We show shape differences early in craniofacial development (E11.5) between common mouse genetic backgrounds, and demonstrate that we are able to generate RNA from these embryos after CT scanning that is suitable for downstream RT-PCR and RNAseq analyses. PMID:28152580

A Multi-Source Inverse-Geometry CT system: Initial results with an 8 spot x-ray source array

PubMed Central

Baek, Jongduk; De Man, Bruno; Uribe, Jorge; Longtin, Randy; Harrison, Daniel; Reynolds, Joseph; Neculaes, Bogdan; Frutschy, Kristopher; Inzinna, Louis; Caiafa, Antonio; Senzig, Robert; Pelc, Norbert J.

2014-01-01

We present initial experimental results of a rotating-gantry multi-source inverse-geometry CT (MS-IGCT) system. The MS-IGCT system was built with a single module of 2×4 x-ray sources and a 2D detector array. It produced a 75 mm in-plane field-of-view (FOV) with 160 mm axial coverage in a single gantry rotation. To evaluate system performance, a 2.5 inch diameter uniform PMMA cylinder phantom, a 200 μm diameter tungsten wire, and a euthanized rat were scanned. Each scan acquired 125 views per source and the gantry rotation time was 1 second per revolution. Geometric calibration was performed using a bead phantom. The scanning parameters were 80 kVp, 125 mA, and 5.4 us pulse per source location per view. A data normalization technique was applied to the acquired projection data, and beam hardening and spectral nonlinearities of each detector channel were corrected. For image reconstruction, the projection data of each source row were rebinned into a full cone beam data set, and the FDK algorithm was used. The reconstructed volumes from upper and lower source rows shared an overlap volume which was combined in image space. The images of the uniform PMMA cylinder phantom showed good uniformity and no apparent artefacts. The measured in-plane MTF showed 13 lp/cm at 10% cutoff, in good agreement with expectations. The rat data were also reconstructed reliably. The initial experimental results from this rotating-gantry MS-IGCT system demonstrated its ability to image a complex anatomical object without any significant image artefacts and to achieve high image resolution and large axial coverage in a single gantry rotation. PMID:24556567

Multi-energy spectral CT: adding value in emergency body imaging.

PubMed

Punjabi, Gopal V

2018-04-01

Most vendors offer scanners capable of dual- or multi-energy computed tomography (CT) imaging. Advantages of multi-energy CT scanning include superior tissue characterization, detection of subtle iodine uptake differences, and opportunities to reduce contrast dose. However, utilization of this technology in the emergency department (ED) remains low. The purpose of this pictorial essay is to illustrate the value of multi-energy CT scanning in emergency body imaging.

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.

Effect of androgen deprivation therapy on intraprostatic tumour volume identified on 18F choline PET/CT for prostate dose painting radiotherapy.

PubMed

Chan, Joachim; Carver, Antony; Brunt, John N H; Vinjamuri, Sobhan; Syndikus, Isabel

2017-03-01

Prostate dose painting radiotherapy requires the accurate identification of dominant intraprostatic lesions (DILs) to be used as boost volumes; these can be identified on multiparametric MRI (mpMRI) or choline positron emission tomography (PET)/CT. Planning scans are usually performed after 2-3 months of androgen deprivation therapy (ADT). We examine the effect of ADT on choline tracer uptake and boost volumes identified on choline PET/CT. Fluoroethylcholine ( 18 F choline) PET/CT was performed for dose painting radiotherapy planning in patients with intermediate- to high-risk prostate cancer. Initially, they were performed at planning. Owing to low visual tracer uptake, PET/CT for subsequent patients was performed at staging. We compared these two approaches on intraprostatic lesions obtained on PET using both visual and automatic threshold methods [prostate maximum standardized uptake value (SUV max ) 60%] when compared with mpMRI. PET/CT was performed during ADT in 11 patients (median duration of 85 days) and before ADT in 29 patients. ADT significantly reduced overall prostate volume by 17%. During ADT, prostate SUV max was lower although it did not reach statistical significance (4.2 vs 6.6, p = 0.06); three patients had no visually identifiable PET DIL; and visually defined PET DILs were significantly smaller than corresponding mpMRI DILs (p = 0.03). However, all patients scanned before ADT had at least one visually identifiable PET DIL, with no significant size difference between MRI and visually defined PET DILs. In both groups, threshold PET produced larger DILs than visual PET. Both PET methods have moderate sensitivity (0.50-0.68) and high specificity (0.85-0.98) for identifying MRI-defined disease. For visual contouring of boost volumes in prostate dose painting radiotherapy, 18 F choline PET/CT should be performed before ADT. For threshold contouring of boost volumes using our PET/CT scanning protocol, threshold levels of above 60% prostate SUV max may be more suitable. Additional use of PET with MRI for radiotherapy planning can significantly change the overall boost volumes compared with using MRI alone. Advances in knowledge: For prostate dose painting radiotherapy, the additional use of 18 F choline PET with MRI can significantly change the overall boost volumes, and PET should be performed before hormone therapy, especially if boost volumes are visually identified.

Technique: imaging earliest tooth development in 3D using a silver-based tissue contrast agent.

PubMed

Raj, Muhammad T; Prusinkiewicz, Martin; Cooper, David M L; George, Belev; Webb, M Adam; Boughner, Julia C

2014-02-01

Looking in microscopic detail at the 3D organization of initiating teeth within the embryonic jaw has long-proved technologically challenging because of the radio-translucency of these tiny un-mineralized oral tissues. Yet 3D image data showing changes in the physical relationships among developing tooth and jaw tissues are vital to understand the coordinated morphogenesis of vertebrate teeth and jaws as an animal grows and as species evolve. Here, we present a new synchrotron-based scanning solution to image odontogenesis in 3D and in histological detail using a silver-based contrast agent. We stained fixed, intact wild-type mice aged embryonic (E) day 10 to birth with 1% Protargol-S at 37°C for 12-32 hr. Specimens were scanned at 4-10 µm pixel size at 28 keV, just above the silver K-edge, using micro-computed tomography (µCT) at the Canadian Light Source synchrotron. Synchrotron µCT scans of silver-stained embryos showed even the earliest visible stages of tooth initiation, as well as many other tissue types and structures, in histological detail. Silver stain penetration was optimal for imaging structures in intact embryos E15 and younger. This silver stain method offers a powerful yet straightforward approach to visualize at high-resolution and in 3D the earliest stages of odontogenesis in situ, and demonstrates the important of studying the tooth organ in all three planes of view. Copyright © 2013 Wiley Periodicals, Inc.

Monte Carlo simulations of adult and pediatric computed tomography exams: Validation studies of organ doses with physical phantoms

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

Long, Daniel J.; Lee, Choonsik; Tien, Christopher

2013-01-15

Purpose: To validate the accuracy of a Monte Carlo source model of the Siemens SOMATOM Sensation 16 CT scanner using organ doses measured in physical anthropomorphic phantoms. Methods: The x-ray output of the Siemens SOMATOM Sensation 16 multidetector CT scanner was simulated within the Monte Carlo radiation transport code, MCNPX version 2.6. The resulting source model was able to perform various simulated axial and helical computed tomographic (CT) scans of varying scan parameters, including beam energy, filtration, pitch, and beam collimation. Two custom-built anthropomorphic phantoms were used to take dose measurements on the CT scanner: an adult male and amore » 9-month-old. The adult male is a physical replica of University of Florida reference adult male hybrid computational phantom, while the 9-month-old is a replica of University of Florida Series B 9-month-old voxel computational phantom. Each phantom underwent a series of axial and helical CT scans, during which organ doses were measured using fiber-optic coupled plastic scintillator dosimeters developed at University of Florida. The physical setup was reproduced and simulated in MCNPX using the CT source model and the computational phantoms upon which the anthropomorphic phantoms were constructed. Average organ doses were then calculated based upon these MCNPX results. Results: For all CT scans, good agreement was seen between measured and simulated organ doses. For the adult male, the percent differences were within 16% for axial scans, and within 18% for helical scans. For the 9-month-old, the percent differences were all within 15% for both the axial and helical scans. These results are comparable to previously published validation studies using GE scanners and commercially available anthropomorphic phantoms. Conclusions: Overall results of this study show that the Monte Carlo source model can be used to accurately and reliably calculate organ doses for patients undergoing a variety of axial or helical CT examinations on the Siemens SOMATOM Sensation 16 scanner.« less

Clinical importance of re-interpretation of PET/CT scanning in patients referred to a tertiary care medical centre.

PubMed

Löfgren, Johan; Loft, Annika; Barbosa de Lima, Vinicius Araújo; Østerlind, Kell; von Benzon, Eric; Højgaard, Liselotte

2017-03-01

To evaluate, in a controlled prospective manner with double-blind read, whether there are differences in interpretations of PET/CT scans at our tertiary medical centre, Rigshospitalet, compared to the external hospitals. Ninety consecutive patients referred to our department who had an external F-18-FDG PET/CT scan were included. Only information that had been available at the time of the initial reading at the external hospital was available at re-interpretation. Teams with one radiologist and one nuclear medicine physician working side by side performed the re-interpretation in consensus. Two oncologists subsequently and independently compared the original reports with the re-interpretation reports. In case of 'major discordance', the oncologists assessed the respective reports validities. The interpretations were graded as 'accordant' in 43 patients (48%), 'minor discordance' in 30 patients (33%) and 'major discordance' in 17 patients (19%). In 11 (65%) of the 17 cases graded as 'major discordance', it was possible to determine which report that was most correct. In 9 of these 11 cases (82%), the re-interpretation was most correct; in one case, the original report and in another case, both interpretations were incorrect. Major discordant interpretations were frequent [19% (17 of 90 cases)]. In those cases where follow-up could assess the validity, the re-interpretation at Rigshospitalet was most correct in 9 of 11 cases (82%), indicating that there is a difference in expertise in interpreting PET/CT at a tertiary referral hospital compared to primary local hospitals. © 2015 The Authors. Clinical Physiology and Functional Imaging published by John Wiley & Sons Ltd on behalf of Scandinavian Society of Clinical Physiology and Nuclear Medicine.

(11)C-Choline PET/CT for restaging prostate cancer. Results from 4,426 scans in a single-centre patient series.

PubMed

Graziani, Tiziano; Ceci, Francesco; Castellucci, Paolo; Polverari, Giulia; Lima, Giacomo Maria; Lodi, Filippo; Morganti, Alessio Giuseppe; Ardizzoni, Andrea; Schiavina, Riccardo; Fanti, Stefano

2016-10-01

To evaluate (11)C-choline PET/CT as a diagnostic tool for restaging prostate cancer (PCa), in a large, homogeneous and clinically relevant population of patients with biochemical recurrence (BCR) of PCa after primary therapy. The secondary aim was to assess the best timing for performing (11)C-choline PET/CT during BCR. We retrospectively analysed 9,632 (11)C-choline PET/CT scans performed in our institution for restaging PCa from January 2007 to June 2015. The inclusion criteria were: (1) proven PCa radically treated with radical prostatectomy (RP) or with primary external beam radiotherapy (EBRT); (2) PSA serum values available; (3) proven BCR (PSA >0.2 ng/mL after RP or PSA >2 ng/mL above the nadir after primary EBRT with rising PSA levels). Finally, 3,203 patients with recurrent PCa matching all the inclusion criteria were retrospectively enrolled and 4,426 scans were analysed. Overall, 52.8 % of the (11)C-choline PET/CT scans (2,337/4,426) and 54.8 % of the patients (1,755/3,203) were positive. In 29.4 % of the scans, at least one distant finding was observed. The mean and median PSA values were, respectively, 4.9 and 2.1 ng/mL at the time of the scan (range 0.2 - 50 ng/mL). In our series, 995 scans were performed in patients with PSA levels between 1 and 2 ng/mL. In this subpopulation the positivity rate in the 995 scans was 44.7 %, with an incidence of distant findings of 19.2 % and an incidence of oligometastatic disease (one to three lesions) of 37.7 %. The absolute PSA value at the time of the scan and ongoing androgen deprivation therapy were associated with an increased probability of a positive (11)C-choline PET/CT scan (p < 0.0001). In the ROC analysis, a PSA value of 1.16 ng/mL was the optimal cut-off value. In patients with a PSA value <1.16 ng/mL, 26.8 % of 1,426 (11)C-choline PET/CT scans were positive, with oligometastatic disease in 84.7 % of positive scans. In a large cohort of patients, the feasibility of (11)C-choline PET/CT for detecting the sites of metastatic disease in PCa patients with BCR was confirmed. The PSA level was the main predictor of a positive scan with 1.16 ng/mL as the optimal cut-off value. In the majority of positive scans oligometastatic disease, potentially treatable with salvage therapies, was observed.

SU-G-IeP4-11: Monitoring Tumor Growth in Subcutaneous Murine Tumor Model in Vivo: A Comparison Between MRI and Small Animal CT

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

Wang, B; He, W; Cvetkovic, D

Purpose: The purpose of the study is to compare the volume measurement of subcutaneous tumors in mice with different imaging platforms, namely a GE MRI and a Sofie-Biosciences small animal CT scanner. Methods: A549 human lung carcinoma cells and FaDu human head and neck squamous cell carcinoma cells were implanted subcutaneously into flanks of nude mice. Three FaDu tumors and three A549 tumors were included in this study. The MRI scans were done with a GE Signa 1.5 Tesla MR scanner using a fast T2-weighted sequence (70mm FOV and 1.2mm slice thickness), while the CT scans were done with themore » CT scanner on a Sofie-Biosciences G8 PET/CT platform dedicated for small animal studies (48mm FOV and 0.2mm slice thickness). Imaging contrast agent was not used in this study. Based on the DICOM images from MRI and CT scans, the tumors were contoured with Philips DICOM Viewer and the tumor volumes were obtained by summing up the contoured area and multiplied by the slice thickness. Results: The volume measurements based on the CT scans agree reasonably with that obtained with MR images for the subcutaneous tumors. The mean difference in the absolute tumor volumes between MRI- and CT-based measurements was found to be −6.2% ± 1.0%, with the difference defined as (VMR – VCT)*100%/VMR. Furthermore, we evaluated the normalized tumor volumes, which were defined for each tumor as V/V{sub 0} where V{sub 0} stands for the volume from the first MR or CT scan. The mean difference in the normalized tumor volumes was found to be 0.10% ± 0.96%. Conclusion: Despite the fact that the difference between normal and abnormal tissues is often less clear on small animal CT images than on MR images, one can still obtain reasonable tumor volume information with the small animal CT scans for subcutaneous murine xenograft models.« less

Pediatric Emergency CT Scans at a Children's Hospital and at Community Hospitals: Radiation Technical Factors Are an Important Source of Radiation Exposure.

PubMed

Agarwal, Saurabh; Jokerst, Clinton; Siegel, Marilyn J; Hildebolt, Charles

2015-08-01

This article compares the technical factors-in particular, tube current and voltage-and the resultant exposure to radiation associated with CT examinations performed at a children's hospital and at more general community hospital emergency departments (EDs). CT scans obtained at community hospital EDs were retrospectively reviewed and compared with CT scans obtained at a children's hospital, to assess differences in kilovoltage, tube current, and volume CT dose index (CTDIvol) used. The number of scans obtained during the contrast-enhanced phase was also assessed. Parametric and nonparametric statistical analyses were used to test differences. A total of 233 body CT examinations were performed at community hospitals, and 287 were performed at a children's hospital. At both types of hospital, the median patient age was 12 years (p = 0.66). Of the body CT scans obtained at community hospitals that focused on the care of adult patients, 194 of 233 (83%) used a tube voltage of 120 kVp, 29 of 233 (12%) used 100 kVp, and two of 233 (< 1%) used 80 kVp. Of the body CT scans obtained at the children's hospital, 121 of 287 (42%) used a tube voltage of 120 kVp, 129 of 287 (45%) used 100 kVp, and 36 of 287 (13%) used 80 kVp. The median tube current was also lower at the children's hospital (110 vs 125 mA) (p < 0.001). At the community hospitals, 11 of 233 studies were multiphasic, whereas at the children's hospital, there were no multiphasic studies. For all CT types, the median CTDIvol was 4.9 mGy (range, 2.5-8.2 mGy) at the children's hospital and 8.6 mGy (range, 6.0-14.4 mGy) at the community hospitals (p < 0.001). The results of this study suggest that a large proportion of children who undergo CT at community hospitals receive relatively higher radiation doses than children who undergo CT at children's hospitals. This finding is related to the higher tube settings (in particular, kilovoltage) used at community hospitals.

WE-AB-BRA-04: Evaluation of the Tumor Registration Error in Biopsy Procedures Performed Under Real Time PET/CT Guidance

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

Fanchon, L; INSERM U1101, Brest; Apte, A

2015-06-15

Purpose: PET/CT guidance is used for biopsies of metabolically active lesions, which are not well seen on CT alone or to target the metabolically active tissue in tumor ablations. It has also been shown that PET/CT guided biopsies provide an opportunity to verify the location of the lesion border at the place of needle insertion. However the error in needle placement with respect to the metabolically active region may be affected by motion between the PET/CT scan performed at the start of the procedure and the CT scan performed with the needle in place and this error has not beenmore » previously quantified. Methods: Specimens from 31 PET/CT guided biopsies were investigated and correlated to the intraoperative PET scan under an IRB approved HIPAA compliant protocol. For 4 of the cases in which larger motion was suspected a second PET scan was obtained with the needle in place. The CT and the PET images obtained before and after the needle insertion were used to calculate the displacement of the voxels along the needle path. CTpost was registered to CTpre using a free form deformable registration and then fused with PETpre. The shifts between the PET image contours (42% of SUVmax) for PETpre and PETpost were obtained at the needle position. Results: For these extreme cases the displacement of the CT voxels along the needle path ranged from 2.9 to 8 mm with a mean of 5 mm. The shift of the PET image segmentation contours (42% of SUVmax) at the needle position ranged from 2.3 to 7 mm between the two scans. Conclusion: Evaluation of the mis-registration between the CT with the needle in place and the pre-biopsy PET can be obtained using deformable registration of the respective CT scans and can be used to indicate the need of a second PET in real-time. This work is supported in part by a grant from Biospace Lab, S.A.« less

FDG-PET/CT in autosomal dominant polycystic kidney disease patients with suspected cyst infection.

PubMed

Pijl, Jordy Pieter; Glaudemans, Andor W J M; Slart, Riemer H J A; Kwee, Thomas Christian

2018-04-13

Purpose: To determine the value of 18 F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) for diagnosing renal or hepatic cyst infection in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods: This retrospective single-center study included all patients with ADPKD who underwent FDG-PET/CT because of suspected cyst infection between 2010 and 2017. Results: Thirty FDG-PET/CT scans of thirty individual patients were included, of which 19 were positive for cyst infection. According to a previously established clinical and biochemical reference standard, FDG-PET/CT achieved sensitivity of 88.9%, specificity of 75.0%, positive predictive value of 84.2%, and negative predictive value of 81.8% for the diagnosis of cyst infection. In 5 cases, FDG-PET/CT suggested a different pathologic process that explained the symptoms, including pneumonia ( n = 1), generalized peritonitis ( n = 1), pancreatitis ( n = 1), colitis ( n = 1), and cholangitis ( n = 1). Total duration of hospital stay and duration between FDG-PET/CT scan and hospital discharge of patients with an FDG-PET/CT scan positive for cyst infection were significantly longer than those with a negative scan ( P = 0.005 and P = 0.009, respectively). Creatinine levels were significantly higher in patients with an FDG-PET/CT scan positive for cyst infection than in patients with a negative scan ( P = 0.015). Other comparisons of clinical parameters (age, gender, presence of fever (>38.5°C) for more than 3 days, abdominal pain, history of solid organ transplantation and nephrectomy, immune status), laboratory values (C-reactive protein level (CRP), leukocyte count, estimated glomerular filtration rate), and microbiologic results (blood and urine cultures) were not significantly different ( P = 0.13-1.00) between FDG-PET/CT-positive and -negative patients. Conclusion: FDG-PET/CT is a useful and recommendable (upfront) imaging modality for the evaluation of patients with ADPKD and suspected cyst infection. Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Relevance of early head CT scans following neurosurgical procedures: an analysis of 892 intracranial procedures at Rush University Medical Center.

PubMed

Fontes, Ricardo B V; Smith, Adam P; Muñoz, Lorenzo F; Byrne, Richard W; Traynelis, Vincent C

2014-08-01

Early postoperative head CT scanning is routinely performed following intracranial procedures for detection of complications, but its real value remains uncertain: so-called abnormal results are frequently found, but active, emergency intervention based on these findings may be rare. The authors' objective was to analyze whether early postoperative CT scans led to emergency surgical interventions and if the results of neurological examination predicted this occurrence. The authors retrospectively analyzed 892 intracranial procedures followed by an early postoperative CT scan performed over a 1-year period at Rush University Medical Center and classified these cases according to postoperative neurological status: baseline, predicted neurological change, unexpected neurological change, and sedated or comatose. The interpretation of CT results was reviewed and unexpected CT findings were classified based on immediate action taken: Type I, additional observation and CT; Type II, active nonsurgical intervention; and Type III, surgical intervention. Results were compared between neurological examination groups with the Fisher exact test. Patients with unexpected neurological changes or in the sedated or comatose group had significantly more unexpected findings on the postoperative CT (p < 0.001; OR 19.2 and 2.3, respectively) and Type II/III interventions (p < 0.001) than patients at baseline. Patients at baseline or with expected neurological changes still had a rate of Type II/III changes in the 2.2%-2.4% range; however, no patient required an immediate return to the operating room. Over a 1-year period in an academic neurosurgery service, no patient who was neurologically intact or who had a predicted neurological change required an immediate return to the operating room based on early postoperative CT findings. Obtaining early CT scans should not be a priority in these patients and may even be cancelled in favor of MRI studies, if the latter have already been planned and can be performed safely and in a timely manner. Early postoperative CT scanning does not assure an uneventful course, nor should it replace accurate and frequent neurological checks, because operative interventions were always decided in conjunction with the neurological examination.

Geometry-constraint-scan imaging for in-line phase contrast micro-CT.

PubMed

Fu, Jian; Yu, Guangyuan; Fan, Dekai

2014-01-01

X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine.

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

A Comparison of Angular Values of the Pelvic Limb with Normal and Medial Patellar Luxation Stifles in Chihuahua Dogs Using Radiography and Computed Tomography.

PubMed

Phetkaew, Thitaporn; Kalpravidh, Marissak; Penchome, Rampaipat; Wangdee, Chalika

2018-02-01

 This article aimed to determine and compare the angular values of the pelvic limb in normal and medial patellar luxation (MPL) stifles in Chihuahuas using radiography and computed tomographic (CT) scan, to identify the relationship between pelvic limb angles and severity of MPL. In addition, radiographic and CT images were compared to determine the more suitable method of limb deformity assessment.  Sixty hindlimbs of Chihuahuas were divided into normal and grade 1, 2, 3 and 4 MPL groups. The pelvic limb angles in frontal and sagittal planes were evaluated on radiography and CT scan. Femoral and tibial torsion angles (FTA and TTA) were evaluated only by CT scan. All angles were compared among normal and MPL stifles and between radiography and CT scan.  Based on the CT scan, the mechanical lateral distal femoral angle (mLDFA), anatomical caudal proximal femoral angle (aCdPFA), and TTA were related to the severity of MPL. The mLDFA and TTA were significantly increased ( p  < 0.05) in grade 4 MPL, while the aCdPFA was significantly decreased in grade 2, 3 and 4 MPL groups. There were significant differences of many angles between radiography and CT scan.  The angles related to MPL in Chihuahuas are aLDFA, mLDFA, aCdPFA and TTA. Radiography had some limitations for evaluating pelvic limb angles. The caudocranial radiograph is recommended for the assessment of the distal femoral angles, while the craniocaudal radiograph is for the tibial angles. Schattauer GmbH Stuttgart.

Predicting hollow viscus injury in blunt abdominal trauma with computed tomography.

PubMed

Bhagvan, Savitha; Turai, Matthew; Holden, Andrew; Ng, Alexander; Civil, Ian

2013-01-01

Evaluation of blunt abdominal trauma is controversial. Computed tomography (CT) of the abdomen is commonly used but has limitations, especially in excluding hollow viscus injury in the presence of solid organ injury. To determine whether CT reports alone could be used to direct operative treatment in abdominal trauma, this study was undertaken. The trauma database at Auckland City Hospital was accessed for patients who had abdominal CT and subsequent laparotomy during a five-year period. The CT scans were reevaluated by a consultant radiologist who was blinded to operative findings. The CT findings were correlated with the operative findings. Between January 2002 and December 2007, 1,250 patients were evaluated for blunt abdominal injury with CT. A subset of 78 patients underwent laparotomy, and this formed the study group. The sensitivity and specificity of CT scan in predicting hollow viscus injury was 55.33 and 92.06 % respectively. The positive and negative predictive values were 61.53 and 89.23 % respectively. Presence of free fluid in CT scan was sensitive in diagnosing hollow viscus injury (90 %). Specific findings for hollow viscus injuries on CT scan were free intraperitoneal air (93 %), retroperitoneal air (100 %), oral contrast extravasation (100 %), bowel wall defect (98 %), patchy bowel enhancement (97 %), and mesenteric abnormality (94 %). CT alone cannot be used as a screening tool for hollow viscus injury. The decision to operate in hollow viscus injury has to be based on mechanism of injury and clinical findings together with radiological evidence.

Use of Bone Scan During Initial Prostate Cancer Workup, Downstream Procedures, and Associated Medicare Costs

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

Falchook, Aaron D.; Salloum, Ramzi G.; Hendrix, Laura H.

Purpose: For patients with a high likelihood of having metastatic disease (high-risk prostate cancer), bone scan is the standard, guideline-recommended test to look for bony metastasis. We quantified the use of bone scans and downstream procedures, along with associated costs, in patients with high-risk prostate cancer, and their use in low- and intermediate-risk patients for whom these tests are not recommended. Methods and Materials: Patients in the Surveillance, Epidemiology, and End Results (SEER)-Medicare database diagnosed with prostate cancer from 2004 to 2007 were included. Prostate specific antigen (PSA), Gleason score, and clinical T stage were used to define D'Amico riskmore » categories. We report use of bone scans from the date of diagnosis to the earlier of treatment or 6 months. In patients who underwent bone scans, we report use of bone-specific x-ray, computed tomography (CT), and magnetic resonance imaging (MRI) scans, and bone biopsy within 3 months after bone scan. Costs were estimated using 2012 Medicare reimbursement rates. Results: In all, 31% and 48% of patients with apparent low- and intermediate-risk prostate cancer underwent a bone scan; of these patients, 21% underwent subsequent x-rays, 7% CT, and 3% MRI scans. Bone biopsies were uncommon. Overall, <1% of low- and intermediate-risk patients were found to have metastatic disease. The annual estimated Medicare cost for bone scans and downstream procedures was $11,300,000 for low- and intermediate-risk patients. For patients with apparent high-risk disease, only 62% received a bone scan, of whom 14% were found to have metastasis. Conclusions: There is overuse of bone scans in patients with low- and intermediate-risk prostate cancers, which is unlikely to yield clinically actionable information and results in a potential Medicare waste. However, there is underuse of bone scans in high-risk patients for whom metastasis is likely.« less

SU-F-R-40: Robustness Test of Computed Tomography Textures of Lung Tissues to Varying Scanning Protocols Using a Realistic Phantom Environment

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

Lee, S; Markel, D; Hegyi, G

2016-06-15

Purpose: The reliability of computed tomography (CT) textures is an important element of radiomics analysis. This study investigates the dependency of lung CT textures on different breathing phases and changes in CT image acquisition protocols in a realistic phantom setting. Methods: We investigated 11 CT texture features for radiation-induced lung disease from 3 categories (first-order, grey level co-ocurrence matrix (GLCM), and Law’s filter). A biomechanical swine lung phantom was scanned at two breathing phases (inhale/exhale) and two scanning protocols set for PET/CT and diagnostic CT scanning. Lung volumes acquired from the CT images were divided into 2-dimensional sub-regions with amore » grid spacing of 31 mm. The distribution of the evaluated texture features from these sub-regions were compared between the two scanning protocols and two breathing phases. The significance of each factor on feature values were tested at 95% significance level using analysis of covariance (ANCOVA) model with interaction terms included. Robustness of a feature to a scanning factor was defined as non-significant dependence on the factor. Results: Three GLCM textures (variance, sum entropy, difference entropy) were robust to breathing changes. Two GLCM (variance, sum entropy) and 3 Law’s filter textures (S5L5, E5L5, W5L5) were robust to scanner changes. Moreover, the two GLCM textures (variance, sum entropy) were consistent across all 4 scanning conditions. First-order features, especially Hounsfield unit intensity features, presented the most drastic variation up to 39%. Conclusion: Amongst the studied features, GLCM and Law’s filter texture features were more robust than first-order features. However, the majority of the features were modified by either breathing phase or scanner changes, suggesting a need for calibration when retrospectively comparing scans obtained at different conditions. Further investigation is necessary to identify the sensitivity of individual image acquisition parameters.« less

Refixation of Osteochondral Fractures by an Ultrasound-Activated Pin System - An Ovine In Vivo Examination Using CT and Scanning Electron Microscope.

PubMed

H, Neumann; A P, Schulz; S, Breer; A, Unger; B, Kienast

2015-01-01

Osteochondral injuries, if not treated appropriately, often lead to severe osteoarthritis of the affected joint. Without refixation of the osteochondral fragment, human cartilage only repairs these defects imperfectly. All existing refixation systems for chondral defects have disadvantages, for instance bad MRI quality in the postoperative follow-up or low anchoring forces. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants a higher anchoring is assumed. Aim of the study was to investigate, if ultrasound-activated pins can provide a secure refixation of osteochondral fractures comparing to conventional screw and conventional, resorbable pin osteosynthesis. CT scans and scanning electron microscopy should proovegood refixation results with no further tissue damage by the melting of the ultrasound-activated pins in comparison to conventional osteosynthesis. Femoral osteochondral fragments in sheep were refixated with ultrasound-activated pins (SonicPin™), Ethipins(®) and screws (Asnis™). The quality of the refixated fragments was examined after three month of full weight bearing by CT scans and scanning electron microscopy of the cartilage surface. The CT examination found almost no statistically significant difference in the quality of refixation between the three different implants used. Concerning the CT morphology, ultrasound-activated pins demonstrated at least the same quality in refixation of osteochondral fragments as conventional resorbable pins or screws. The scanning electron microscopy showed no major surface damage by the three implants, especially any postulated cartilage damage induced by the heat of the ultrasound-activated pin. The screws protruded above the cartilage surface, which may affect the opposingtibial surface. Using CT scans and scanning electron microscopy, the SonicPin™, the Ethipin(®) and screws were at least equivalent in refixation quality of osteochondral fragments.

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.

Predictive validity of preoperative CT scans and the risk of pedicle screw loosening in spinal surgery.

PubMed

Bredow, Jan; Boese, C K; Werner, C M L; Siewe, J; Löhrer, L; Zarghooni, K; Eysel, P; Scheyerer, M J

2016-08-01

Pedicle screw fixation is the standard technique for the stabilization of the spine, a clinically relevant complication of which is screw loosening. This retrospective study investigates whether preoperative CT scanning can offer a predictor of screw loosening. CT-scan attenuation in 365 patients was evaluated to determine the mean bone density of each vertebral body. Screw loosening or dislocation was determined in CT scans postoperatively using the standard radiological criteria. Forty-five of 365 patients (12.3 %; 24 male, 21 female) suffered postoperative screw loosening (62 of 2038 screws) over a mean follow-up time of 50.8 months. Revision surgeries were necessary in 23 patients (6.3 %). The correlation between decreasing mean CT attenuation in Hounsfield Units (HU) and increasing patient age was significant (p < 0.001). Mean bone density was 116.3 (SD 53.5) HU in cases with screw loosening and 132.7 (SD 41.3) HU in cases in which screws remained fixed. The difference was statistically significant (p = 0.003). The determination of bone density with preoperative CT scanning can predict the risk of screw loosening and inform the decision to use cement augmentation to reduce the incidence of screw loosening.

Determination of the position of nucleus cochlear implant electrodes in the inner ear.

PubMed

Skinner, M W; Ketten, D R; Vannier, M W; Gates, G A; Yoffie, R L; Kalender, W A

1994-09-01

Accurate determination of intracochlear electrode position in patients with cochlear implants could provide a basis for detecting migration of the implant and could aid in the selection of stimulation parameters for sound processor programming. New computer algorithms for submillimeter resolution and 3-D reconstruction from spiral computed tomographic (CT) scans now make it possible to accurately determine the position of implanted electrodes within the cochlear canal. The accuracy of these algorithms was tested using an electrode array placed in a phantom model. Measurements of electrode length and interelectrode distance from spiral CT scan reconstructions were in close agreement with those from stereo microscopy. Although apparent electrode width was increased on CT scans due to partial volume averaging, a correction factor was developed for measurements from conventional radiographs and an expanded CT absorption value scale added to detect the presence of platinum electrodes and wires. The length of the cochlear canal was calculated from preoperative spiral CT scans for one patient, and the length of insertion of the electrode array was calculated from her postoperative spiral CT scans. The cross-sectional position of electrodes in relation to the outer bony wall and modiolus was measured and plotted as a function of distance with the electrode width correction applied.

Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography

PubMed Central

Periyasamy, M.; Dhanasekaran, R.

2014-01-01

The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning. PMID:24701187

Small-animal CT: Its difference from, and impact on, clinical CT

NASA Astrophysics Data System (ADS)

Ritman, Erik L.

2007-10-01

For whole-body computed tomography (CT) images of small rodents, a voxel resolution of at least 10 -3 mm 3 is needed for scale-equivalence to that currently achieved in clinical CT scanners (˜1 mm 3) in adult humans. These "mini-CT" images generally require minutes rather than seconds to complete a scan. The radiation exposure resulting from these mini-CT scans, while higher than clinical CT scans, is below the level resulting in acute tissue damage. Hence, these scans are useful for performing clinical-type diagnostic and monitoring scans for animal models of disease and their response to treatment. "Micro-CT", with voxel size <10 -5 mm 3, has been useful for imaging isolated, intact organs at an almost cellular level of resolution. Micro-CT has the great advantage over traditional microscopic methods in that it generates detailed three-dimensional images in relatively large, opaque volumes such as an intact rodent heart or kidney. The radiation exposure needed in these scans results in acute tissue damage if used in living animals. Experience with micro-CT is contributing to exploration of new applications for clinical CT imaging by providing insights into different modes of X-ray image formation as follows: Spatial resolution should be sufficient to detect an individual Basic Functional Unit (BFU, the smallest collection of diverse cells, such as hepatic lobule, that behaves like the organ), which requires voxels ˜10 -3 mm 3 in volume, so that the BFUs can be counted. Contrast resolution sufficient to allow quantitation of: New microvascular growth, which manifests as increased tissue contrast due to X-ray contrast agent in those vessels' lumens during passage of injected contrast agent in blood. Impaired endothelial integrity which manifests as increased opacification and delayed washout of contrast from tissues. Discrimination of pathological accumulations of metals such as Fe and Ca, which occur in the arterial wall following hemorrhage or tissue damage. Micro-CT can also be used as a test bed for exploring the utility of several modes of X-ray image formation, such as the use of dual-energy X-ray subtraction, X-ray scatter, phase delay and refraction-based imaging for increasing the contrast amongst soft tissue components. With the recent commercial availability of high speed, multi-slice CT scanners which can be operated in dual-energy mode, some of these micro-CT scanner capabilities and insights are becoming implementable in those CT scanners. As a result, the potential diagnostic spectrum that can be addressed with those scanners is broadened considerably.

A Method for the Automatic Exposure Control in Pediatric Abdominal CT: Application to the Standard Deviation Value and Tube Current Methods by Using Patient's Age and Body Size.

PubMed

Furuya, Ken; Akiyama, Shinji; Nambu, Atushi; Suzuki, Yutaka; Hasebe, Yuusuke

2017-01-01

We aimed to apply the pediatric abdominal CT protocol of Donnelly et al. in the United States to the pediatric abdominal CT-AEC. Examining CT images of 100 children, we found that the sectional area of the hepatic portal region (y) was strongly correlated with the body weight (x) as follows: y=7.14x + 84.39 (correlation coefficient=0.9574). We scanned an elliptical cone phantom that simulates the human body using a pediatric abdominal CT scanning method of Donnelly et al. in, and measured SD values. We further scanned the same phantom under the settings for adult CT-AEC scan and obtained the relationship between the sectional areas (y) and the SD values. Using these results, we obtained the following preset noise factors for CT-AEC at each body weight range: 6.90 at 4.5-8.9 kg, 8.40 at 9.0-17.9 kg, 8.68 at 18.0-26.9 kg, 9.89 at 27.0-35.9 kg, 12.22 at 36.0-45.0 kg, 13.52 at 45.1-70.0 kg, 15.29 at more than 70 kg. From the relation between age, weight and the distance of liver and tuber ischiadicum of 500 children, we obtained the CTDI vol values and DLP values under the scanning protocol of Donnelly et al. Almost all of DRL from these values turned out to be smaller than the DRL data of IAEA and various countries. Thus, by setting the maximum current values of CT-AEC to be the Donnelly et al.'s age-wise current values, and using our weight-wise noise factors, we think we can perform pediatric abdominal CT-AEC scans that are consistent with the same radiation safety and the image quality as those proposed by Donnelly et al.

Utility of cervical spinal and abdominal computed tomography in diagnosing occult pneumothorax in patients with blunt trauma: Computed tomographic imaging protocol matters.

PubMed

Akoglu, Haldun; Akoglu, Ebru Unal; Evman, Serdar; Akoglu, Tayfun; Denizbasi, Arzu; Guneysel, Ozlem; Onur, Ozge; Onur, Ender

2012-10-01

Small pneumothoraces (PXs), which are not initially recognized with a chest x-ray film and diagnosed by a thoracic computed tomography (CT), are described as occult PX (OCPX). The objective of this study was to evaluate cervival spine (C-spine) and abdominal CT (ACT) for diagnosing OCPX and overt PX (OVPX). All patients with blunt trauma who presented consecutively to the emergency department during a 26-months period were included. Among all the chest CTs (CCTs) (6,155 patients) conducted during that period, 254 scans were confirmed to have a true PX. The findings in their C-spine CT and ACT were compared with the findings in CCTs. Among these patients, 254 had a diagnosis of PX confirmed with CCT. OCPXs were identified on the chest computed tomographic scan of 128 patients (70.3%), whereas OVPXs were evident in 54 patients (29.7%). Computed tomographic imaging of the C-spine was performed in 74% of patients with OCPX and 66.7% of patients with OVPX trauma. Only 45 (35.2%) cases of OCPX and 42 (77.8%) cases of OVPX were detected by C-spine CT. ACT was performed in almost all patients, and 121 (95.3%) of 127 of these correctly identified an existing OCPX. Sensitivity of C-spine CT and ACT was 35.1% and 96.5%, respectively; specificity was 100% and 100%, respectively. Almost all OCPXs, regardless of intrathoracic location, could be detected by ACT or by combining C-spine and abdominal computed tomographic screening for patients. If the junction of the first and second vertebra is used as the caudad extent, C-spine CT does not have sufficient power to diagnose more than a third of the cases. Diagnostic study, level III.

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.

The evolution of computed tomography from organ-selective to whole-body scanning in managing unconscious patients with multiple trauma

PubMed Central

Hong, Zhi-Jie; Chen, Cheng-Jueng; Yu, Jyh-Cherng; Chan, De-Chuan; Chou, Yu-Ching; Liang, Chia-Ming; Hsu, Sheng-Der

2016-01-01

Abstract We aimed to evaluate the benefit of whole-body computed tomography (WBCT) scanning for unconscious adult patients suffering from high-energy multiple trauma compared with the conventional stepwise approach of organ-selective CT. Totally, 144 unconscious patients with high-energy multiple trauma from single level I trauma center in North Taiwan were enrolled from January 2009 to December 2013. All patients were managed by a well-trained trauma team and were suitable for CT examination. The enrolled patients are all transferred directly from the scene of an accident, not from other medical institutions with a definitive diagnosis. The scanning regions of WBCT include head, neck, chest, abdomen, and pelvis. We analyzed differences between non-WBCT and WBCT groups, including gender, age, hospital stay, Injury Severity Score, Glasgow Coma Scale, Revised Trauma Score, time in emergency department (ED), medical cost, and survival outcome. Fifty-five patients received the conventional approach for treating trauma, and 89 patients received immediate WBCT scanning after an initial examination. Patients’ time in ED was significantly shorter in the WBCT group in comparison with the non-WBCT group (158.62 ± 80.13 vs 216.56 ± 168.32 min, P = 0.02). After adjusting for all possible confounding factors, we also found that survival outcome of the WBCT group was better than that of the non-WBCT group (odds ratio: 0.21, 95% confidence interval: 0.06–0.75, P = 0.016). Early performing WBCT during initial trauma management is a better approach for treating unconscious patients with high-energy multiple trauma. PMID:27631215

The evolution of computed tomography from organ-selective to whole-body scanning in managing unconscious patients with multiple trauma: A retrospective cohort study.

PubMed

Hong, Zhi-Jie; Chen, Cheng-Jueng; Yu, Jyh-Cherng; Chan, De-Chuan; Chou, Yu-Ching; Liang, Chia-Ming; Hsu, Sheng-Der

2016-09-01

We aimed to evaluate the benefit of whole-body computed tomography (WBCT) scanning for unconscious adult patients suffering from high-energy multiple trauma compared with the conventional stepwise approach of organ-selective CT.Totally, 144 unconscious patients with high-energy multiple trauma from single level I trauma center in North Taiwan were enrolled from January 2009 to December 2013. All patients were managed by a well-trained trauma team and were suitable for CT examination. The enrolled patients are all transferred directly from the scene of an accident, not from other medical institutions with a definitive diagnosis. The scanning regions of WBCT include head, neck, chest, abdomen, and pelvis. We analyzed differences between non-WBCT and WBCT groups, including gender, age, hospital stay, Injury Severity Score, Glasgow Coma Scale, Revised Trauma Score, time in emergency department (ED), medical cost, and survival outcome.Fifty-five patients received the conventional approach for treating trauma, and 89 patients received immediate WBCT scanning after an initial examination. Patients' time in ED was significantly shorter in the WBCT group in comparison with the non-WBCT group (158.62 ± 80.13 vs 216.56 ± 168.32 min, P = 0.02). After adjusting for all possible confounding factors, we also found that survival outcome of the WBCT group was better than that of the non-WBCT group (odds ratio: 0.21, 95% confidence interval: 0.06-0.75, P = 0.016).Early performing WBCT during initial trauma management is a better approach for treating unconscious patients with high-energy multiple trauma.

The LISS--a public database of common imaging signs of lung diseases for computer-aided detection and diagnosis research and medical education.

PubMed

Han, Guanghui; Liu, Xiabi; Han, Feifei; Santika, I Nyoman Tenaya; Zhao, Yanfeng; Zhao, Xinming; Zhou, Chunwu

2015-02-01

Lung computed tomography (CT) imaging signs play important roles in the diagnosis of lung diseases. In this paper, we review the significance of CT imaging signs in disease diagnosis and determine the inclusion criterion of CT scans and CT imaging signs of our database. We develop the software of abnormal regions annotation and design the storage scheme of CT images and annotation data. Then, we present a publicly available database of lung CT imaging signs, called LISS for short, which contains 271 CT scans and 677 abnormal regions in them. The 677 abnormal regions are divided into nine categories of common CT imaging signs of lung disease (CISLs). The ground truth of these CISLs regions and the corresponding categories are provided. Furthermore, to make the database publicly available, all private data in CT scans are eliminated or replaced with provisioned values. The main characteristic of our LISS database is that it is developed from a new perspective of CT imaging signs of lung diseases instead of commonly considered lung nodules. Thus, it is promising to apply to computer-aided detection and diagnosis research and medical education.

Abdomen after a Puestow procedure: postoperative CT appearance, complications, and potential pitfalls.

PubMed

Freed, K S; Paulson, E K; Frederick, M G; Keogan, M T; Pappas, T N

1997-06-01

To evaluate the postoperative computed tomographic (CT) appearance, complications, and potential pitfalls after a Puestow procedure (lateral side-to-side pancreaticojejunostomy). Forty CT examinations were performed after the Puestow procedure in 20 patients. Images were retrospectively reviewed by three radiologists. The pancreaticojejunal anastomosis was identified at 30 examinations and was immediately anterior to the pancreatic body or tail. The anastomosis contained fluid or gas on 11 scans and oral contrast material on four scans. On 15 scans, the anastomosis appeared as collapsed bowel without gas, fluid, or oral contrast material. The Roux-en-Y loop was identified on 28 (70%) scans and contained fluid or gas on 16 scans and oral contrast material on six scans. The Roux-en-Y loop appeared as collapsed bowel on six scans. When the anastomosis or Roux-en-Y loop contained fluid and gas, the appearance mimicked that of a pancreatic or parapancreatic abscess. Peripancreatic stranding was present on 28 scans and was due to either ongoing pancreatitis or postoperative change. Complications included 15 transient fluid collections, three abscesses, four pseudocysts, one hematoma, and one small-bowel and Roux-en-Y obstruction. Knowledge of the anatomy after a Puestow procedure is essential for accurate interpretation of CT scans.

Liver disease

MedlinePlus

... Coccidioidomycosis Delta agent (hepatitis D) Drug-induced cholestasis Fatty liver disease Hemochromatosis Hepatitis A Hepatitis B Hepatitis C ... abscess Reye syndrome Sclerosing cholangitis Wilson disease Images Fatty liver, CT scan Liver with disproportional fattening, CT scan ...

Roles of posttherapy 18F-FDG PET/CT in patients with advanced squamous cell carcinoma of the uterine cervix receiving concurrent chemoradiotherapy.

PubMed

Liu, Feng-Yuan; Su, Tzu-Pei; Wang, Chun-Chieh; Chao, Angel; Chou, Hung-Hsueh; Chang, Yu-Chen; Yen, Tzu-Chen; Lai, Chyong-Huey

2018-07-01

To assess the clinical roles of [ 18 F]fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) performed 2-3 months after completion of concurrent chemoradiotherapy (CCRT), along with pretherapy characteristics, in patients with advanced squamous cell carcinoma of the uterine cervix enrolled in a prospective randomized clinical trial. Posttherapy PET/CT in patients with advanced FIGO stage or positive pelvic or para-aortic lymph node (PALN) defined on pretherapy PET/CT was classified as positive, equivocal, or negative. Overall survival (OS) rates between patients with different PET/CT results are compared. Pretherapy characteristics are examined for association with posttherapy PET/CT results and for prognostic significance in patients with equivocal or negative PET/CT. PET/CT scans (n = 55) were positive, equivocal and negative in 9, 13 and 33 patients, respectively. All patients with positive scans were confirmed to have residual or metastatic disease and died despite salvage therapies. There is a significant OS difference between patients with positive and equivocal scans (P < .001) but not between patients with equivocal and negative scans (P = .411). Positive pretherapy PALN is associated with positive posttherapy PET/CT (P = .033) and predicts a poorer survival in patients with equivocal or negative posttherapy PET/CT (P < .001). Positive PET/CT 2-3 months posttherapy implies treatment failure and novel therapy is necessary to improve outcomes for such patients. A more intense posttherapy surveillance may be warranted in patients with positive pretherapy PALN.

Diagnostic value of [(18)F]-FDG PET/CT in children with fever of unknown origin or unexplained signs of inflammation.

PubMed

Jasper, Niklas; Däbritz, Jan; Frosch, Michael; Loeffler, Markus; Weckesser, Matthias; Foell, Dirk

2010-01-01

Fever of unknown origin (FUO) and unexplained signs of inflammation are challenging medical problems especially in children and predominantly caused by infections, malignancies or noninfectious inflammatory diseases. The aim of this study was to assess the diagnostic value of (18)F-FDG PET and PET/CT in the diagnostic work-up in paediatric patients. In this retrospective study, 47 FDG PET and 30 PET/CT scans from 69 children (median age 8.1 years, range 0.2-18.1 years, 36 male, 33 female) were analysed. The diagnostic value of PET investigations in paediatric patients presenting with FUO (44 scans) or unexplained signs of inflammation without fever (33 scans) was analysed. A diagnosis in paediatric patients with FUO or unexplained signs of inflammation could be established in 32 patients (54%). Of all scans, 63 (82%) were abnormal, and of the total number of 77 PET and PET/CT scans 35 (45%) were clinically helpful. In patients with a final diagnosis, scans were found to have contributed to the diagnosis in 73%. Laboratory, demographic or clinical parameters of the children did not predict the usefulness of FDG PET scans. This is the first larger study demonstrating that FDG PET and PET/CT may be valuable diagnostic tools for the evaluation of children with FUO and unexplained signs of inflammation. Depicting inflammation in the whole body, while not being traumatic, it is attractive for use especially in children. The combination of PET with CT seems to be superior, since the site of inflammation can be localized more accurately.

1975 Memorial Award Paper. Image generation and display techniques for CT scan data. Thin transverse and reconstructed coronal and sagittal planes.

PubMed

Glenn, W V; Johnston, R J; Morton, P E; Dwyer, S J

1975-01-01

The various limitations to computerized axial tomographic (CT) interpretation are due in part to the 8-13 mm standard tissue plane thickness and in part to the absence of alternative planes of view, such as coronal or sagittal images. This paper describes a method for gathering multiple overlapped 8 mm transverse sections, subjecting these data to a deconvolution process, and then displaying thin (1 mm) transverse as well as reconstructed coronal and sagittal CT images. Verification of the deconvolution technique with phantom experiments is described. Application of the phantom results to human post mortem CT scan data illustrates this method's faithful reconstruction of coronal and sagittal tissue densities when correlated with actual specimen photographs of a sectioned brain. A special CT procedure, limited basal overlap scanning, is proposed for use on current first generation CT scanners without hardware modification.

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.

Automated assessment of breast tissue density in non-contrast 3D CT images without image segmentation based on a deep CNN

NASA Astrophysics Data System (ADS)

Zhou, Xiangrong; Kano, Takuya; Koyasu, Hiromi; Li, Shuo; Zhou, Xinxin; Hara, Takeshi; Matsuo, Masayuki; Fujita, Hiroshi

2017-03-01

This paper describes a novel approach for the automatic assessment of breast density in non-contrast three-dimensional computed tomography (3D CT) images. The proposed approach trains and uses a deep convolutional neural network (CNN) from scratch to classify breast tissue density directly from CT images without segmenting the anatomical structures, which creates a bottleneck in conventional approaches. Our scheme determines breast density in a 3D breast region by decomposing the 3D region into several radial 2D-sections from the nipple, and measuring the distribution of breast tissue densities on each 2D section from different orientations. The whole scheme is designed as a compact network without the need for post-processing and provides high robustness and computational efficiency in clinical settings. We applied this scheme to a dataset of 463 non-contrast CT scans obtained from 30- to 45-year-old-women in Japan. The density of breast tissue in each CT scan was assigned to one of four categories (glandular tissue within the breast <25%, 25%-50%, 50%-75%, and >75%) by a radiologist as ground truth. We used 405 CT scans for training a deep CNN and the remaining 58 CT scans for testing the performance. The experimental results demonstrated that the findings of the proposed approach and those of the radiologist were the same in 72% of the CT scans among the training samples and 76% among the testing samples. These results demonstrate the potential use of deep CNN for assessing breast tissue density in non-contrast 3D CT images.

Inter- and intra-observer reliability of measurement of pedicle screw breach assessed by postoperative CT scans.

PubMed

Lavelle, William F; Ranade, Ashish; Samdani, Amer F; Gaughan, John P; D'Andrea, Linda P; Betz, Randal R

2014-01-01

Pedicle screws are used increasingly in spine surgery. Concerns of complications associated with screw breach necessitates accurate pedicle screw placement. Postoperative CT imaging helps to detect screw malposition and assess its severity. However, accuracy is dependent on the reading of the CT scans. Inter- and intra-observer variability could affect the reliability of CT scans to assess multiple screw types and sites. The purpose of this study was to assess the reliability of multi-observer analysis of CT scans for determining pedicle screw breach for various screw types and sites in patients with spinal deformity or degenerative pathologies. Axial CT scan images of 23 patients (286 screws) were read by four experienced spine surgeons. Pedicle screw placement was considered 'In' when the screw was fully contained and/or the pedicle wall breach was ≤2 mm. 'Out' was defined as a breach in the medial or lateral pedicle wall >2 mm. Intra-class coefficients (ICC) were calculated to assess the inter- and intra-observer reliability. Marked inter- and intra-observer variability was noticed. The overall inter-observer ICC was 0.45 (95% confidence limits 0.25 to 0.65). The intra-observer ICC was 0.49 (95% confidence limits 0.29 to 0.69). Underlying spinal pathology, screw type, and patient age did not seem to impact the reliability of our CT assessments. Our results indicate the evaluation of pedicle screw breach on CT by a single surgeon is highly variable, and care should be taken when using individual CT evaluations of millimeters of breach as a basis for screw removal. This was a Level III study.

Just another abdominal pain? Psoas abscess-like metastasis in large cell lung cancer with adrenal insufficiency

PubMed Central

Bernardino, Vera; Val-Flores, Luis Silva; Lopes Dias, João; Bento, Luís

2015-01-01

The authors report the case of a 69-year-old man with chronic obstructive pulmonary disease and previous pulmonary tuberculosis, who presented to the emergency department with abdominal and low back pain, anorexia and weight loss, rapidly evolving into shock. An initial CT scan revealed pulmonary condensation with associated cavitation and an iliopsoas mass suggestive of a psoas abscess. He was admitted in an intensive care unit unit; after a careful examination and laboratory assessment, the aetiology was yet undisclosed. MRI showed multiple retroperitoneal lymphadenopathies, bulky nodular adrenal lesions and bilateral iliac lytic lesions. Hypocortisolism was detected and treated with steroids. A CT-guided biopsy to the psoas mass and lytic lesions identified infiltration of non-small lung carcinoma. The patient died within days. Psoas metastases and adrenal insufficiency as initial manifestations of malignancy are rare and can be misdiagnosed, particularly in the absence of a known primary tumour. PMID:26063108

Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

PubMed Central

Jornada, Tiago da Silva; da Silva, Teógenes Augusto

2014-01-01

Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

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

Laparoscopic microwave thermosphere ablation of malignant liver tumors: an initial clinical evaluation.

PubMed

Berber, Eren

2016-02-01

Microwave ablation (MWA) has been recently recognized as a technology to overcome the limitations of radiofrequency ablation. The aim of the current study was to evaluate the safety and efficacy of a new 2.45-GHz thermosphere MWA system in the treatment of malignant liver tumors. This was a prospective IRB-approved study of 18 patients with malignant liver tumors treated with MWA within a 3-month time period. Tumor sizes and response to MWA were obtained from triphasic liver CT scans done before and after MWA. The ablation zones were assessed for complete tumor response and spherical geometry. There were a total of 18 patients with an average of three tumors measuring 1.4 cm (range 0.2-4). Ablations were performed laparoscopically in all, but three patients who underwent combined liver resection. A single ablation was created in 72% and overlapping ablations in 28% of lesions. Total ablation time per patient was 15.6 ± 1.9 min. There was no morbidity or mortality. At 2-week CT scans, there was 100% tumor destruction, with no residual lesions. Roundness indices A, B and transverse were 1.1, 0.9 and 0.9, respectively, confirming the spherical nature of ablation zones. To the best of our knowledge, this is the first report of a new thermosphere MWA technology in the laparoscopic treatment of malignant liver tumors. The results demonstrate the safety of the technology, with satisfactory spherical ablation zones seen on post-procedural CT scans.