Science.gov

Sample records for 64-slice multidetector ct

  1. A 64-slice multi-detector CT scan could evaluate the change of the left atrial appendage thrombi of the atrial fibrillation patient, which was reduced by warfarin therapy.

    PubMed

    Takeuchi, Hidekazu

    2011-08-19

    Curable cause of stroke is the left atrial appendage (LAA) thrombi of atrial fibrillation (AF) patients. Some AF patients have the LAA thrombi. It is very important to cure AF patients by warfarin. Transoesophageal echocardiography (TOE) is the usual clinical tool to detect the LAA thrombi. Recently, a 64-slice multi-detector CT (64-MDCT) scan enables us to display the LAA thrombi more easily than TOE. I reported a case that a 64-MDCT scan had been used successfully in displaying the change of the LAA thrombi reduced by warfarin therapy. The size of the LAA thrombi was reduced from 25.2 mm × 19.3 mm (figure 1) to 22.1 mm × 14.8 mm (figure 2) after the 3-month warfarin therapy. It was useful to estimate the LAA thrombi by a 64-MDCT scan to estimate LAA thrombi itself and the change of LAA thrombi to evaluate the effectiveness of warfarin therapy.

  2. Hemodialysis fistula occlusion: demonstration with 64-slice CT angiography.

    PubMed

    Neyman, Edward G; Johnson, Pamela T; Fishman, Elliot K

    2006-01-01

    The speed and resolution of 64-slice CT have resulted in new applications for CT angiography (CTA) owing to rapid data acquisition during the arterial phase, improved visualization of small vessels, and lengthened anatomic coverage. Extremity CT angiography is one such region. This case report shows the utility of multislice CTA for the evaluation of hemodialysis graft dysfunction.

  3. Integrated assessment of coronary anatomy and myocardial perfusion using a retractable SPECT camera combined with 64-slice CT: initial experience.

    PubMed

    Thilo, Christian; Schoepf, U Joseph; Gordon, Leonie; Chiaramida, Salvatore; Serguson, Jill; Costello, Philip

    2009-04-01

    We evaluated a prototype SPECT system integrated with multidetector row CT (MDCT) for obtaining complementary information on coronary anatomy and hemodynamic lesion significance. Twenty-five consecutive patients with known or suspected coronary artery disease (CAD) underwent routine SPECT myocardial perfusion imaging (MPI). All patients also underwent repeat MPI with a mobile SPECT unit which could be attached to a 64-slice MDCT system. Coronary CT angiography (cCTA) was performed without repositioning the patient. Investigational MPI was compared with routine MPI for detection of myocardial perfusion defects (PD). Two observers diagnosed presence or absence of CAD based on MPI alone, cCTA alone, and based on combined MPI and cCTA with fused image display. In 22/24 patients investigative MPI corresponded with routine MPI (r = 0.80). Stenosis >or= 50% at cCTA was detected in 6/24 patients. Six out of 24 patients had PD at regular MPI. Three of these six patients had no significant stenosis at cCTA. Three out of 19 patients with normal MPI studies had significant stenosis at cCTA. Our initial experience indicates that the integration of SPECT MPI with cCTA is technically feasible and enables the comprehensive evaluation of coronary artery anatomy and myocardial perfusion with a single instrumental setup.

  4. Dosimetric and image quality assessment of different acquisition protocols of a novel 64-slice CT scanner

    NASA Astrophysics Data System (ADS)

    Vite, Cristina; Mangini, Monica; Strocchi, Sabina; Novario, Raffaele; Tanzi, Fabio; Carrafiello, Gianpaolo; Conte, Leopoldo; Fugazzola, Carlo

    2006-03-01

    Dose and image quality assessment in computed tomography (CT) are almost affected by the vast variety of CT scanners (axial CT, spiral CT, low-multislice CT (2-16), high-multislice CT (32-64)) and imaging protocols in use. Very poor information is at the moment available on 64 slices CT scanners. Aim of this work is to assess image quality related to patient dose indexes and to investigate the achievable dose reduction for a commercially available 64 slices CT scanner. CT dose indexes (weighted computed tomography dose index, CTDI w and Dose Length Product, DLP) were measured with a standard CT phantom for the main protocols in use (head, chest, abdomen and pelvis) and compared with the values displayed by the scanner itself. The differences were always below 7%. All the indexes were below the Diagnostic Reference Levels defined by the European Council Directive 97/42. Effective doses were measured for each protocol with thermoluminescent dosimeters inserted in an anthropomorphic Alderson Rando phantom and compared with the same values computed by the ImPACT CT Patient Dosimetry Calculator software code and corrected by a factor taking in account the number of slices (from 16 to 64). The differences were always below 25%. The effective doses range from 1.5 mSv (head) to 21.8 mSv (abdomen). The dose reduction system of the scanner was assessed comparing the effective dose measured for a standard phantom-man (a cylinder phantom, 32 cm in diameter) to the mean dose evaluated on 46 patients. The standard phantom was considered as no dose reduction reference. The dose reduction factor range from 16% to 78% (mean of 46%) for all protocols, from 29% to 78% (mean of 55%) for chest protocol, from 16% to 76% (mean of 42%) for abdomen protocol. The possibility of a further dose reduction was investigated measuring image quality (spatial resolution, contrast and noise) as a function of CTDI w. This curve shows a quite flat trend decreasing the dose approximately to 90% and a

  5. Diagnostic Capabilities of 64 Slice CT Coronography Compared to Classic in Coronary Disease Detection

    PubMed Central

    Sehovic, Sanja

    2013-01-01

    Introduction: Cardiovascular disease, among which the most common is coronary disease of the hearth are the main cause of death at middle aged persons in the majority of European countries. Percent of cardiovascular disease in overall mortality among our population is even more than 50%. Up to 55 years of live myocardial infarction is by 5-6 times more common among men, and up to age of 75 years that difference decreases to 2.5 times. Goal: The goal of this study is to determine the diagnostic value of 64 slices computerized tomography in detection of coronary disease compared to classic, invasive coronography. Material and methods: Study included 50 patients, of both genders, at average age of 60 years. Patients underwent CT coronography as well as classic coronography. Results: Our research prove that the sensitivity of MSCT coronography 92% with positive predictive value of 86%. Mayor difference was in the analysis of CX artery in the evaluation of significant and non-significant stenosis in application of these two methods. During the analysis of LAD and RCA artery there was no statistically significant difference in findings of these two methods. Conclusion: CT coronography is non-invasive, comfortable and reliable method in coronary disease diagnostics. Thanks to its high sensitivity and PPV it enables reliable exclusion of coronary disease and takes significant place in a cardiovascular diseases diagnostic algorithm. PMID:24167394

  6. Evaluation of temporal windows for coronary artery bypass graft imaging with 64-slice CT.

    PubMed

    Desbiolles, Lotus; Leschka, Sebastian; Plass, André; Scheffel, Hans; Husmann, Lars; Gaemperli, Oliver; Garzoli, Elisabeth; Marincek, Borut; Kaufmann, Philipp A; Alkadhi, Hatem

    2007-11-01

    Temporal windows providing the best image quality of different segments and types of coronary artery bypass grafts (CABGs) with 64-slice computed tomography (CT) were evaluated in an experimental set-up. Sixty-four-slice CT with a rotation time of 330 ms was performed in 25 patients (four female; mean age 59.9 years). A total of 84 CABGs (62 individual and 22 sequential grafts) were evaluated, including 28 internal mammary artery (33.3%), one radial artery with sequential grafting (2.4%), and 54 saphenous vein grafts (64.3%). Ten data sets were reconstructed in 10% increments of the RR-interval. Each graft was separated into segments (proximal and distal anastomosis, and body), and CABG types were grouped according to target arteries. Two readers independently assessed image quality of each CABG segment in each temporal window. Diagnostic image quality was found with good inter-observer agreement (kappa=0.62) in 98.5% (202/205) of all graft segments. Image quality was significantly better for saphenous vein grafts versus arterial grafts (P<0.001) and for distal anastomosis to the right coronary compared with other target coronary arteries (P<0.05). Overall, best image quality was found at 60%. Image quality of proximal segments did not significantly vary with the temporal window, whereas for all other segments image quality was significantly better at 60% compared with other temporal windows (P<0.05). Sixty-four-slice CT provides best image quality of various segments and types of CABG at 60% of the RR-interval.

  7. The value of 64-slice spiral CT perfusion imaging in the treatment of liver cancer with argon-helium cryoablation

    PubMed Central

    Lv, Yinggang; Jin, Yurong; Yan, Qiaohuan; Yuan, Dingling; Wang, Yanling; Li, Xianping; Shen, Yanfeng

    2016-01-01

    We analyzed the effectiveness of using 64-slice spiral computed tomography (CT) and perfusion imaging to guide argon-helium cryoablation treatment of liver cancer. In total, 60 cases of advanced hepatocellular carcinoma before surgery treated with argon-helium cryoablation were inlcuded in the present study. Retrospective summary of the 60 cases of metaphase and advanced liver cancer were used as the control group. The control group were treated using cryoablation with argon-helium knife. We used enhanced scanning with 64-slice spiral CT to define the extent of their lesions and prepared a plan of percutaneous cryoablation for the treatment. Intraoperatively, we used the dynamics of CT perfusion imaging to observe the frozen ablation range and decreased the rate of complications. After surgery, the patients were followed-up regularly by 64-slice CT. We used conventional X-ray, CT and magnetic resonance imaging (MRI) for pre-operative lateralization. Intraoperative X-ray or ultrasound guidance and follow-up with CT or MTI were added to determine the clinical effectiveness and prognosis. The results showed that the total effective rate was improved significantly and incidence rate of overall complications decreased markedly in the observation group. Following treatment, AFP decreased significantly while the total freezing area and time were reduced significantly. The median survival time was increased significantly in the observation group. The numeric values of hepatic arterial perfusion, portal vein perfusion and hepatic arterial perfusion index were all markedly lowered after treatment. Differences were statistically significant (P<0.05). In conclusion, the use of 64-slice spiral CT perfusion imaging may considerably improve the effects of liver cancer treatment using the argon-helium cryoablation. It extended the survival time and reduced complications. PMID:28105165

  8. Assessments of Coronary Artery Visibility and Radiation Dose in Infants with Congenital Heart Disease on Cardiac 128-slice CT and on Cardiac 64-slice CT.

    PubMed

    Cui, Y; Huang, M; Zheng, J; Li, J; Liu, H; Liang, C

    2016-01-01

    The aim of this study was to compare the coronary artery visibility and radiation dose in infants with CHD on cardiac 128-slice CT and on cardiac 64-slice CT. The images of 200 patients were analyzed in this study, 100 patients were selected randomly from a group of 789 infants (<1 years old) with CHD undergoing 128-slice CT prospective ECG-triggered axial scan, and 100 were selected randomly from 911 infants with CHD undergoing 64-slice CT retrospective ECG-gated spiral scan. The visibility of coronary artery segments was graded on a four-point scale. The coronary arteries were considered to be detected or visible when grade was 2 or higher. The visibility of the coronary artery segments and the radiation dose was compared between the two groups. Except for the rate of LM (96 vs. 99%), the detection rates of the total, LAD, LCX, RCA, and the proximal segment of the RCA in the 256-slice CT group were significantly higher than those in the 64-slice CT group (51.7, 53.33, 33.67, 53.33, and 99 vs. 34.8, 34.33, 18, 30.67, and 75%, respectively). The counts of visibility score (4/3/2/1) for the LM and the proximal segment of the RCA were 62/22/12/4 and 56/20/17/7, respectively, in the 128-slice CT group and 17/42/30/1 and 9/30/38/25, respectively, in the 64-slice CT group. There were significant differences, especially for score 4 and 3, between the two groups. The radiation dose in the 128-slice CT group was significantly decreased than those in the 64-slice CT group (CTDIvol 1.88 ± 0.51 vs. 5.61 ± 0.63 mGy; SSDE 4.48 ± 1.15 vs. 13.97 ± 1.52 mGy; effective radiation dose 1.36 ± 0.44 vs. 4.06 ± 0.7 mSv). With reduced radiation dose, the visibility of the coronary artery in infants with CHD via prospective ECG-triggered mode on a 128-slice CT is superior to that of the 64-slice CT using retrospective ECG-gated spiral mode.

  9. Non-invasive Detection of Aortic and Coronary Atherosclerosis in Homozygous Familial Hypercholesterolemia by 64 Slice Multi-detector Row Computed Tomography Angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector-row ...

  10. Non-invasive detection of aortic and coronary atherosclerosis in homozygous familial hypercholesterolemia by 64 slice multi-detector row computed tomography angiography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row ...

  11. Image Quality and Radiation Dose for Prospectively Triggered Coronary CT Angiography: 128-Slice Single-Source CT versus First-Generation 64-Slice Dual-Source CT

    NASA Astrophysics Data System (ADS)

    Gu, Jin; Shi, He-Shui; Han, Ping; Yu, Jie; Ma, Gui-Na; Wu, Sheng

    2016-10-01

    This study sought to compare the image quality and radiation dose of coronary computed tomography angiography (CCTA) from prospectively triggered 128-slice CT (128-MSCT) versus dual-source 64-slice CT (DSCT). The study was approved by the Medical Ethics Committee at Tongji Medical College of Huazhong University of Science and Technology. Eighty consecutive patients with stable heart rates lower than 70 bpm were enrolled. Forty patients were scanned with 128-MSCT, and the other 40 patients were scanned with DSCT. Two radiologists independently assessed the image quality in segments (diameter >1 mm) according to a three-point scale (1: excellent; 2: moderate; 3: insufficient). The CCTA radiation dose was calculated. Eighty patients with 526 segments in the 128-MSCT group and 544 segments in the DSCT group were evaluated. The image quality 1, 2 and 3 scores were 91.6%, 6.9% and 1.5%, respectively, for the 128-MSCT group and 97.6%, 1.7% and 0.7%, respectively, for the DSCT group, and there was a statistically significant inter-group difference (P ≤ 0.001). The effective doses were 3.0 mSv in the 128-MSCT group and 4.5 mSv in the DSCT group (P ≤ 0.001). Compared with DSCT, CCTA with prospectively triggered 128-MSCT had adequate image quality and a 33.3% lower radiation dose.

  12. Acute chest pain in emergency room. Preliminary findings with 40-64-slice CT ECG-gated of the whole chest.

    PubMed

    Coche, E

    2007-01-01

    ECG-gated MDCT of the entire chest represents the latest technical advance in the diagnostic work-up of atypical chest pain. The authors report their preliminary experience with the use of 40 and 64-slice CT in the emergency room and recommend to study only patients with moderate likelihood of coronary artery disease. ECG-gated MDCT of the entire chest will be preferentially performed on 64-slice MDCT rather than 40-slice MDCT because it enable to reduce the scan time (18 seconds versus 28 seconds acquisition time), the volume of contrast medium (82 mL + 15 mL versus 97 mL + 15 mL of highly concentrated contrast agent for a patient of 70 kgs) and radiation exposure (17 mSv versus 19 mSv). Approximately 1500 to 2000 of images are produced and need to be analysed on a dedicated workstation by a radiologist expert in cardiac and thoracic disorders. At the present time, only a few studies exist in the literature showing some promising results but further large clinical studies are needed before to implement such sophisticated protocol in emergency room.

  13. Effect of Heart Rate and Body Mass Index on the Interscan and Interobserver Variability of Coronary Artery Calcium Scoring at Prospective ECG-Triggered 64-Slice CT

    PubMed Central

    Matsuura, Noriaki; Yamamoto, Hideya; Kiguchi, Masao; Fujioka, Chikako; Kitagawa, Toshiro; Ito, Katsuhide

    2009-01-01

    Objective To test the effects of heart rate, body mass index (BMI) and noise level on interscan and interobserver variability of coronary artery calcium (CAC) scoring on a prospective electrocardiogram (ECG)-triggered 64-slice CT. Materials and Methods One hundred and ten patients (76 patients with CAC) were scanned twice on prospective ECG-triggered scans. The scan parameters included 120 kV, 82 mAs, a 2.5 mm thickness, and an acquisition center at 45% of the RR interval. The interscan and interobserver variability on the CAC scores (Agatston, volume, and mass) was calculated. The factors affecting the variability were determined by plotting it against heart rate, BMI, and noise level (defined as the standard deviation: SD). Results The estimated effective dose was 1.5 ± 0.2 mSv. The mean heart rate was 63 ± 12 bpm (range, 44-101 bpm). The patient BMIs were 24.5 ± 4.5 kg/m2 (range, 15.5-42.3 kg/m2). The mean and median interscan variabilities were 11% and 6%, respectively by volume, and 11% and 6%, respectively, by mass. Moreover, the mean and median of the algorithms were lower than the Agatston algorithm (16% and 9%, respectively). The mean and median interobserver variability was 10% and 4%, respectively (average of algorithms). The mean noise levels were 15 ± 4 Hounsfield unit (HU) (range, 8-25 HU). The interscan and interobserver variability was not correlated with heart rate, BMI, or noise level. Conclusion The interscan and interobserver variability of CAC on a prospective ECG-triggered 64-slice CT with high image quality and 45% of RR acquisition is not significantly affected by heart rate, BMI, or noise level. The volume or mass algorithms show reduced interscan variability compared to the Agatston scoring (p < 0.05). PMID:19568461

  14. Evaluation of organ doses and specific k effective dose of 64-slice CT thorax examination using an adult anthropomorphic phantom

    NASA Astrophysics Data System (ADS)

    Hashim, S.; Karim, M. K. A.; Bakar, K. A.; Sabarudin, A.; Chin, A. W.; Saripan, M. I.; Bradley, D. A.

    2016-09-01

    The magnitude of radiation dose in computed tomography (CT) depends on the scan acquisition parameters, investigated herein using an anthropomorphic phantom (RANDO®) and thermoluminescence dosimeters (TLD). Specific interest was in the organ doses resulting from CT thorax examination, the specific k coefficient for effective dose estimation for particular protocols also being determined. For measurement of doses representing five main organs (thyroid, lung, liver, esophagus and skin), TLD-100 (LiF:Mg, Ti) were inserted into selected holes in a phantom slab. Five CT thorax protocols were investigated, one routine (R1) and four that were modified protocols (R2 to R5). Organ doses were ranked from greatest to least, found to lie in the order: thyroid>skin>lung>liver>breast. The greatest dose, for thyroid at 25 mGy, was that in use of R1 while the lowest, at 8.8 mGy, was in breast tissue using R3. Effective dose (E) was estimated using three standard methods: the International Commission on Radiological Protection (ICRP)-103 recommendation (E103), the computational phantom CT-EXPO (E(CTEXPO)) method, and the dose-length product (DLP) based approach. E103 k factors were constant for all protocols, ~8% less than that of the universal k factor. Due to inconsistency in tube potential and pitch factor the k factors from CTEXPO were found to vary between 0.015 and 0.010 for protocols R3 and R5. With considerable variation between scan acquisition parameters and organ doses, optimization of practice is necessary in order to reduce patient organ dose.

  15. Trapping volumetric measurement by multidetector CT in chronic obstructive pulmonary disease: Effect of CT threshold

    SciTech Connect

    Wang, Xiaohua; Yuan, Huishu; Duan, Jianghui; Du, Yipeng; Shen, Ning; He, Bei

    2013-08-15

    Purpose: The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD).Methods: Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and expiratory phase. CT thresholds of −950 Hu in inspiration and −950 to −890 Hu in expiration were used, after which trapping volumetric measurements were made using computer software. Trapping volume percentage (Vtrap%) under the different CT thresholds in the expiratory phase and below −950 Hu in the inspiratory phase was compared and correlated with lung function.Results: Mean Vtrap% was similar under −930 Hu in the expiratory phase and below −950 Hu in the inspiratory phase, being 13.18 ± 9.66 and 13.95 ± 6.72 (both lungs), respectively; this difference was not significant (P= 0.240). Vtrap% under −950 Hu in the inspiratory phase and below the −950 to −890 Hu threshold in the expiratory phase was moderately negatively correlated with the ratio of forced expiratory volume in one second to forced vital capacity and the measured value of forced expiratory volume in one second as a percentage of the predicted value.Conclusions: Trapping volumetric measurement with multidetector CT is a promising method for the quantification of COPD. It is important to know the effect of various CT thresholds on trapping volumetric measurements.

  16. Experimental assessment of the influence of beam hardening filters on image quality and patient dose in volumetric 64-slice X-ray CT scanners.

    PubMed

    Ay, Mohammad Reza; Mehranian, Abolfazl; Maleki, Asghar; Ghadiri, Hossien; Ghafarian, Pardis; Zaidi, Habib

    2013-05-01

    Beam hardening filters have long been employed in X-ray Computed Tomography (CT) to preferentially absorb soft and low-energy X-rays having no or little contribution to image formation, thus allowing the reduction of patient dose and beam hardening artefacts. In this work, we studied the influence of additional copper (Cu) and aluminium (Al) flat filters on patient dose and image quality and seek an optimum filter thickness for the GE LightSpeed VCT 64-slice CT scanner using experimental phantom measurements. Different thicknesses of Cu and Al filters (0.5-1.6mm Cu, 0.5-4mm Al) were installed on the scanner's collimator. A planar phantom consisting of 13 slabs of Cu having different thicknesses was designed and scanned to assess the impact of beam filtration on contrast in the intensity domain (CT detector's output). To assess image contrast and image noise, a cylindrical phantom consisting of a polyethylene cylinder having 16 holes filled with different concentrations of K2HPO4 solution mimicking different tissue types was used. The GE performance and the standard head CT dose index (CTDI) phantoms were also used to assess image resolution characterized by the modulation transfer function (MTF) and patient dose defined by the weighted CTDI. A 100mm pencil ionization chamber was used for CTDI measurement. Finally, an optimum filter thickness was determined from an objective figure of merit (FOM) metric. The results show that the contrast is somewhat compromised with filter thickness in both the planar and cylindrical phantoms. The contrast of the K2HPO4 solutions in the cylindrical phantom was degraded by up to 10% for a 0.68mm Cu filter and 6% for a 4.14mm Al filter. It was shown that additional filters increase image noise which impaired the detectability of low density K2HPO4 solutions. It was found that with a 0.48mm Cu filter the 50% MTF value is shifted by about 0.77lp/cm compared to the case where the filter is not used. An added Cu filter with approximately

  17. Body physique and heart rate variability determine the occurrence of stair-step artefacts in 64-slice CT coronary angiography with prospective ECG-triggering.

    PubMed

    Husmann, Lars; Herzog, Bernhard A; Burkhard, Nina; Tatsugami, Fuminari; Valenta, Ines; Gaemperli, Oliver; Wyss, Christophe A; Landmesser, Ulf; Kaufmann, Philipp A

    2009-07-01

    The purpose of this study was to describe and characterize the frequency and extent of stair-step artefacts in computed tomography coronary angiography (CTCA) with prospective electrocardiogram (ECG)-triggering and to identify their determinants. One hundred and forty three consecutive patients (55 women, mean age 57 +/- 13 years) underwent 64-slice CTCA using prospective ECG-triggering. Occurrence of stair-step artefacts in CTCA of the thoracic wall and the coronary arteries was determined and maximum offset was measured. If stair-step artefacts occurred in both cases, a difference between thoracic wall and coronary artery offset of 0.6 mm or greater was attributed to additional motion of the heart. Mean effective radiation dose was 2.1 +/- 0.7 mSv (range 1.0-3.5 mSv). Eighty-nine patients (62%) had stair-step artefacts in CTCA of the coronary arteries (mean offset of 1.7 +/- 1.1 mm), while only 77 patients had thoracic wall stair-step artefacts (mean offset of 1.0 +/- 0.3 mm; significantly different, P < 0.001). Stair-step artefacts in CTCA of the thoracic wall were determined by BMI and weight (P < 0.01), while artefacts in CTCA of the coronary arteries were associated with heart rate variability (P < 0.05). Stair-step artefacts in CTCA with prospective ECG-triggering are determined by (a) motion of the entire patient during table travel, particularly in large patients and (b) by motion of the heart, particularly when heart rates are variable.

  18. Lymphoepithelial cyst of the pancreas--evaluation with multidetector CT.

    PubMed

    Neyman, Edward G; Georgiades, Christos S; Horton, Karen H; Lillemoe, Keith D; Fishman, Elliot K

    2005-01-01

    Lymphoepithelial cyst of the pancreas is a rare cystic pancreatic tumor. In this case report we provide the imaging perspective of the lesion including the role of multidetector CT (MDCT) and CT angiography and 3D imaging.

  19. Multidetector CT of emergent biliary pathologic conditions.

    PubMed

    Patel, Neel B; Oto, Aytekin; Thomas, Stephen

    2013-01-01

    Various biliary pathologic conditions can lead to acute abdominal pain. Specific diagnosis is not always possible clinically because many biliary diseases have overlapping signs and symptoms. Imaging can help narrow the differential diagnosis and lead to a specific diagnosis. Although ultrasonography (US) is the most useful imaging modality for initial evaluation of the biliary system, multidetector computed tomography (CT) is helpful when US findings are equivocal or when biliary disease is suspected. Diagnostic accuracy can be increased by optimizing the CT protocol and using multiplanar reformations to localize biliary obstruction. CT can be used to diagnose and stage acute cholecystitis, including complications such as emphysematous, gangrenous, and hemorrhagic cholecystitis; gallbladder perforation; gallstone pancreatitis; gallstone ileus; and Mirizzi syndrome. CT also can be used to evaluate acute biliary diseases such as biliary stone disease, benign and malignant biliary obstruction, acute cholangitis, pyogenic hepatic abscess, hemobilia, and biliary necrosis and iatrogenic complications such as biliary leaks and malfunctioning biliary drains and stents. Treatment includes radiologic, endoscopic, or surgical intervention. Familiarity with CT imaging appearances of emergent biliary pathologic conditions is important for prompt diagnosis and appropriate clinical referral and treatment.

  20. Multi-detector row CT as a "one-stop" examination in the preoperative evaluation of the morphology and function of living renal donors: preliminary study.

    PubMed

    Su, Chen; Yan, Chaogui; Guo, Yan; Zhou, Xuhui; Chen, Yaqing; Liu, Mingjuan; Wang, Wenjuan; Zhang, Xiaoling

    2011-02-01

    We designed to investigate the feasibility of multi-detector row computerized tomography (CT) as a "one-stop" examination for the simultaneous preoperative evaluation of the morphology and function of living renal donors. 21 living renal donors were examined by 64-slice spiral CT with a three-phase enhancement CT scan and two inserted dynamic scans. The maximum intensity projection (MIP), multi-planar reformation (MPR), and volume reconstruction (VR) procedures were performed to compare the renal parenchyma, renal vessels, and collecting system with operational findings. The known Patlak equation was used to calculate the glomerular filtration rate (GFR); exact GFR information was acquired by single photon emission computed tomography (SPECT). Our results as following, there were 3 cases of artery variation and 3 cases of vein variation. CT findings all corresponded with the operation, and the sensitivity, positive predictive value, specialty, and negative predictive value of CT were all 100%. The r of the GFR values estimated from CT is 0.894 (left) (P < 0.001) and 0.881 (right) (P < 0.001). In conclusions, our findings demonstrate that 64-slice spiral CT may offer a "one-stop" examination to replace SPECT in the preoperative evaluation of living renal donors to simultaneously provide information regarding both anatomy and the GFR of living renal donors.

  1. Intraindividual comparison of gadolinium- and iodine-enhanced 64-slice multidetector CT pulmonary angiography for the detection of pulmonary embolism in a porcine model.

    PubMed

    Henes, Frank Oliver Gerhard; Groth, Michael; Begemann, Philipp G C; Adam, Gerhard; Regier, Marc

    2011-06-01

    This study is an evaluation of the diagnostic accuracy of gadolinium-enhanced computed tomography pulmonary angiography (CTPA) for the detection of pulmonary embolism (PE) in comparison with iodine-enhanced CTPA. PE was induced in five anesthetized pigs by administration of blood clots through an 11-F catheter inside the jugular vein. Animals underwent CTPA in breathhold with i.v. bolus injection of 50 ml gadopentetate dimeglumine (0.4 mmol/kg, 4 ml/s). Subsequently, CTPA was performed using the same imaging parameters but under administration of 70 ml nonionic iodinated contrast material (400 mg/ml, 4 ml/s). All images were reconstructed with 1 mm slice thickness. A consensus readout of the iodium-enhanced CTPAs by both radiologists served as reference standard. Gadolinium-enhanced CTPAs were evaluated independently by two experienced radiologists, and differences in detection rate between both contrast agents were assessed on a per embolus basis using the Wilcoxon signed-rank test. Interobserver agreement was determined by calculation of қ values. PE was diagnosed independently by both readers in all five pigs by the use of gadolinium-enhanced CTPA. Out of 60 pulmonary emboli detected in the iodine-enhanced scans, 47 (78.3%; reader 1) and 44 (62.8%; reader 2) emboli were detected by the use of gadolinium. All 13 (100%) emboli in lobar arteries (by both readers) and 26 (reader 1) and 25 (reader 2) out of 27 emboli (96.3% and 92.6%) in segmental arteries were detected by the use of the gadolinium-enhanced CTPA. In subsegmental arteries, only 8 (40%; reader 1) and 6 (30%; reader 2) out of 20 emboli were detected by the gadolinium-enhanced CTPA. By comparing both scans on a per vessel basis (Wilcoxon test), Gd-enhanced CTPA was significantly inferior in emboli detection on subsegmental level (P < 0.0001). The interobserver agreement was excellent on lobar and segmental level (қ = 1.0 and 0.93, respectively), whereas readers only reached moderate agreement for PE evaluation on subsegmental level (қ = 0.56). Compared to conventional CTPA with iodinated contrast media, gadolinium-based contrast agents achieve an equivalent diagnostic accuracy in detection of PE down to segmental level. Gadolinium-enhanced CTPA may be considered as an alternative for the diagnostic workup of acute pulmonary embolism in patients with contraindications to iodinated contrast agents.

  2. Low fingertip temperature rebound measured by digital thermal monitoring strongly correlates with the presence and extent of coronary artery disease diagnosed by 64-slice multi-detector computed tomography.

    PubMed

    Ahmadi, Naser; Nabavi, Vahid; Nuguri, Vivek; Hajsadeghi, Fereshteh; Flores, Ferdinand; Akhtar, Mohammad; Kleis, Stanley; Hecht, Harvey; Naghavi, Morteza; Budoff, Matthew

    2009-10-01

    Previous studies showed strong correlations between low fingertip temperature rebound measured by digital thermal monitoring (DTM) during a 5 min arm-cuff induced reactive hyperemia and both the Framingham Risk Score (FRS), and coronary artery calcification (CAC) in asymptomatic populations. This study evaluates the correlation between DTM and coronary artery disease (CAD) measured by CT angiography (CTA) in symptomatic patients. It also investigates the correlation between CTA and a new index of neurovascular reactivity measured by DTM. 129 patients, age 63 +/- 9 years, 68% male, underwent DTM, CAC and CTA. Adjusted DTM indices in the occluded arm were calculated: temperature rebound: aTR and area under the temperature curve aTMP-AUC. DTM neurovascular reactivity (NVR) index was measured based on increased fingertip temperature in the non-occluded arm. Obstructive CAD was defined as >or=50% luminal stenosis, and normal as no stenosis and CAC = 0. Baseline fingertip temperature was not different across the groups. However, all DTM indices of vascular and neurovascular reactivity significantly decreased from normal to non-obstructive to obstructive CAD [(aTR 1.77 +/- 1.18 to 1.24 +/- 1.14 to 0.94 +/- 0.92) (P = 0.009), (aTMP-AUC: 355.6 +/- 242.4 to 277.4 +/- 182.4 to 184.4 +/- 171.2) (P = 0.001), (NVR: 161.5 +/- 147.4 to 77.6 +/- 88.2 to 48.8 +/- 63.8) (P = 0.015)]. After adjusting for risk factors, the odds ratio for obstructive CAD compared to normal in the lowest versus two upper tertiles of FRS, aTR, aTMP-AUC, and NVR were 2.41 (1.02-5.93), P = 0.05, 8.67 (2.6-9.4), P = 0.001, 11.62 (5.1-28.7), P = 0.001, and 3.58 (1.09-11.69), P = 0.01, respectively. DTM indices and FRS combined resulted in a ROC curve area of 0.88 for the prediction of obstructive CAD. In patients suspected of CAD, low fingertip temperature rebound measured by DTM significantly predicted CTA-diagnosed obstructive disease.

  3. Trabecular bone structure analysis in the osteoporotic spine using a clinical in vivo setup for 64-slice MDCT imaging: comparison to microCT imaging and microFE modeling.

    PubMed

    Issever, Ahi S; Link, Thomas M; Kentenich, Marie; Rogalla, Patrik; Schwieger, Karsten; Huber, Markus B; Burghardt, Andrew J; Majumdar, Sharmila; Diederichs, Gerd

    2009-09-01

    Assessment of trabecular microarchitecture may improve estimation of biomechanical strength, but visualization of trabecular bone structure in vivo is challenging. We tested the feasibility of assessing trabecular microarchitecture in the spine using multidetector CT (MDCT) on intact human cadavers in an experimental in vivo-like setup. BMD, bone structure (e.g., bone volume/total volume = BV/TV; trabecular thickness = Tb.Th; structure model index = SMI) and bone texture parameters were evaluated in 45 lumbar vertebral bodies using MDCT (mean in-plane pixel size, 274 microm(2); slice thickness, 500 microm). These measures were correlated with structure measures assessed with microCT at an isotropic spatial resolution of 16 microm and to microfinite element models (microFE) of apparent modulus and stiffness. MDCT-derived BMD and structure measures showed significant correlations to the density and structure obtained by microCT (BMD, R(2) = 0.86, p < 0.0001; BV/TV, R(2) = 0.64, p < 0.0001; Tb.Th, R(2) = 0.36, p < 0.01). When comparing microCT-derived measures with microFE models, the following correlations (p < 0.001) were found for apparent modulus and stiffness, respectively: BMD (R(2) = 0.58 and 0.66), BV/TV (R(2) = 0.44 and 0.58), and SMI (R(2) = 0.44 and 0.49). However, the overall highest correlation (p < 0.001) with microFE app. modulus (R(2) = 0.75) and stiffness (R(2) = 0.76) was achieved by the combination of QCT-derived BMD with the bone texture measure Minkowski Dimension. In summary, although still limited by its spatial resolution, trabecular bone structure assessment using MDCT is overall feasible. However, when comparing with microFE-derived bone properties, BMD is superior compared with single parameters for microarchitecture, and correlations further improve when combining with texture measures.

  4. New absorbed dose measurement with cylindrical water phantoms for multidetector CT

    NASA Astrophysics Data System (ADS)

    Ohno, Takeshi; Araki, Fujio; Onizuka, Ryota; Hioki, Kazunari; Tomiyama, Yuuki; Yamashita, Yusuke

    2015-06-01

    The aim of this study was to develop new dosimetry with cylindrical water phantoms for multidetector computed tomography (MDCT). The ionization measurement was performed with a Farmer ionization chamber at the center and four peripheral points in the body-type and head-type cylindrical water phantoms. The ionization was converted to the absorbed dose using a 60Co absorbed-dose-to-water calibration factor and Monte Carlo (MC) -calculated correction factors. The correction factors were calculated from MDCT (Brilliance iCT, 64-slice, Philips Electronics) modeled with GMctdospp (IMPS, Germany) software based on the EGSnrc MC code. The spectrum of incident x-ray beams and the configuration of a bowtie filter for MDCT were determined so that calculated photon intensity attenuation curves for aluminum (Al) and calculated off-center ratio (OCR) profiles in air coincided with those measured. The MC-calculated doses were calibrated by the absorbed dose measured at the center in both cylindrical water phantoms. Calculated doses were compared with measured doses at four peripheral points and the center in the phantom for various beam pitches and beam collimations. The calibration factors and the uncertainty of the absorbed dose determined using this method were also compared with those obtained by CTDIair (CT dose index in air). Calculated Al half-value layers and OCRs in air were within 0.3% and 3% agreement with the measured values, respectively. Calculated doses at four peripheral points and the centers for various beam pitches and beam collimations were within 5% and 2% agreement with measured values, respectively. The MC-calibration factors by our method were 44-50% lower than values by CTDIair due to the overbeaming effect. However, the calibration factors for CTDIair agreed within 5% with those of our method after correction for the overbeaming effect. Our method makes it possible to directly measure the absorbed dose for MDCT and is more robust and accurate than the

  5. Multidetector CT Findings of Bowel Transection in Blunt Abdominal Trauma

    PubMed Central

    Cho, Hyun Suk; Hong, Hye-Suk; Park, Mee Hyun; Ha, Hong Il; Yang, Ik; Lee, Yul; Jung, Ah Young; Hwang, Ji-Young

    2013-01-01

    Objective Though a number of CT findings of bowel and mesenteric injuries in blunt abdominal trauma are described in literature, no studies on the specific CT signs of a transected bowel have been published. In the present study we describe the incidence and new CT signs of bowel transection in blunt abdominal trauma. Materials and Methods We investigated the incidence of bowel transection in 513 patients admitted for blunt abdominal trauma who underwent multidetector CT (MDCT). The MDCT findings of 8 patients with a surgically proven complete bowel transection were assessed retrospectively. We report novel CT signs that are unique for transection, such as complete cutoff sign (transection of bowel loop), Janus sign (abnormal dual bowel wall enhancement, both increased and decreased), and fecal spillage. Results The incidence of bowel transection in blunt abdominal trauma was 1.56%. In eight cases of bowel transection, percentage of CT signs unique for bowel transection were as follows: complete cutoff in 8 (100%), Janus sign in 6 (100%, excluding duodenal injury), and fecal spillage in 2 (25%). The combination of complete cutoff and Janus sign were highly specific findings in patients with bowel transection. Conclusion Complete cut off and Janus sign are the unique CT findings to help detect bowel transection in blunt abdominal trauma and recognition of these findings enables an accurate and prompt diagnosis for emergency laparotomy leading to reduced mortality and morbidity. PMID:23901318

  6. Assessment of trabecular bone structure of the calcaneus using multi-detector CT: correlation with microCT and biomechanical testing.

    PubMed

    Diederichs, Gerd; Link, Thomas M; Kentenich, Marie; Schwieger, Karsten; Huber, Markus B; Burghardt, Andrew J; Majumdar, Sharmila; Rogalla, Patrik; Issever, Ahi S

    2009-05-01

    The prediction of bone strength can be improved when determining bone mineral density (BMD) in combination with measures of trabecular microarchitecture. The goal of this study was to assess parameters of trabecular bone structure and texture of the calcaneus by clinical multi-detector row computed tomography (MDCT) in an experimental in situ setup and to correlate these parameters with microCT (microCT) and biomechanical testing. Thirty calcanei in 15 intact cadavers were scanned using three different protocols on a 64-slice MDCT scanner with an in-plane pixel size of 208 microm and 500 microm slice thickness. Bone cores were harvested from each specimen and microCT images with a voxel size of 16 microm were obtained. After image coregistration, trabecular bone structure and texture were evaluated in identical regions on the MDCT images. After data acquisition, uniaxial compression testing was performed. Significant correlations between MDCT- and microCT-derived measures of bone volume fraction (BV/TV), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) were found (range, R(2)=0.19-0.65, p<0.01 or 0.05). The MDCT-derived parameters of volumetric BMD, app. BV/TV, app. Tb.Th and app. Tb.Sp were capable of predicting 60%, 63%, 53% and 25% of the variation in bone strength (p<0.01). When combining those measures with one additional texture index (either GLCM, TOGLCM or MF.euler), prediction of mechanical competence was significantly improved to 86%, 85%, 71% and 63% (p<0.01). In conclusion, this study showed the feasibility of trabecular microarchitecture assessment using MDCT in an experimental setup simulating the clinical situation. Multivariate models of BMD or structural parameters combined with texture indices improved prediction of bone strength significantly and might provide more reliable estimates of fracture risk in patients.

  7. Scenes from the past: initial investigation of early jurassic vertebrate fossils with multidetector CT.

    PubMed

    Bolliger, Stephan A; Ross, Steffen; Thali, Michael J; Hostettler, Bernhard; Menkveld-Gfeller, Ursula

    2012-01-01

    The study of fossils permits the reconstruction of past life on our planet and enhances our understanding of evolutionary processes. However, many fossils are difficult to recognize, being encased in a lithified matrix whose tedious removal is required before examination is possible. The authors describe the use of multidetector computed tomography (CT) in locating, identifying, and examining fossil remains of crocodilians (Mesosuchia) embedded in hard shale, all without removing the matrix. In addition, they describe how three-dimensional (3D) reformatted CT images provided details that were helpful for extraction and preparation. Multidetector CT can help experienced paleontologists localize and characterize fossils in the matrix of a promising rock specimen in a nondestructive manner. Moreover, with its capacity to generate highly accurate 3D images, multidetector CT can help determine whether the fossils warrant extraction and can assist in planning the extraction process. Thus, multidetector CT may well become an invaluable tool in the field of paleoradiology.

  8. Cam-type deformities: Concepts, criteria, and multidetector CT features.

    PubMed

    Mellado, J M; Radi, N

    2015-01-01

    Interpreting imaging studies of a painful hip requires detailed knowledge of the regional anatomy. Some variants of the proximal femur, such as cam-type deformities, can course asymptomatically or cause femoroacetabular impingement. The principal numerical criterion for defining cam-type deformities, the alpha angle, has some limitations. In this article, we review the anatomic variants of the anterior aspect of the proximal femur, focusing on cam-type deformities. Using diagrams and multidetector CT images, we describe the parameters that are useful for characterizing these deformities in different imaging techniques. We also discuss the potential correspondence of imaging findings of cam-type deformities with the terms coined by anatomists and anthropologists to describe these phenomena.

  9. The validity of investigating occult hip fractures using multidetector CT

    PubMed Central

    Williams, Huw L M; Carpenter, Eleanor C; Lyons, Kathleen

    2016-01-01

    Objective: 10% of all hip fractures are occult on plain radiography, requiring further investigation to ascertain the diagnosis. MRI is presently the gold standard investigation, but frequently has disadvantages of time delay, resulting in increased hospital stay and mortality. Our aim was to establish whether multidetector CT (MDCT) is an appropriate first-line investigation of occult femoral neck (NOF) fractures. Methods: From 2013, we elected to use MDCT as the first-line investigation in patients believed to have an NOF fracture with negative plain films. These were reported by consultant musculoskeletal radiologists. We retrospectively analysed the data of consecutive patients presenting to the University Hospital of Wales, over 30 months with a clinical suspicion of a hip fracture. Results: 1443 patients were admitted during the study period. 209 (14.5%) patients had negative plain films requiring further investigation to exclude an NOF fracture, of which 199 patients had a CT. 93 patients had no fracture and 20 patients had isolated greater trochanter fractures. None of these patients progressed to develop an intracapsular femoral neck fracture at 4-month follow-up, although one patient sustained an extracapsular fracture following a high-energy fall whilst admitted. 26 femoral neck fractures were diagnosed on CT, whilst the remaining 60 patients were diagnosed with other pelvic ring fractures. Conclusion: When interpreted by experienced radiologists, MDCT has both sensitivity and specificity of 100%. Advances in knowledge: We recommend the use of MDCT as a safe and appropriate first-line investigation for NOF fractures. PMID:26838948

  10. Classification of lung area using multidetector-row CT images

    NASA Astrophysics Data System (ADS)

    Mukaibo, Tsutomu; Kawata, Yoshiki; Niki, Noboru; Ohmatsu, Hironobu; Kakinuma, Ryutaro; Eguchi, Kenji; Kaneko, Masahiro; Moriyama, Noriyuki

    2002-05-01

    Recently, we can get high quality images in the short time for the progress of X-ray CT scanner. And the three dimensional (3-D) analysis of pulmonary organs using multidetector-row CT (MDCT) images, is expected. This paper presents a method for classifying lung area into each lobe using pulmonary MDCT images of the whole lung area. It is possible to recognize the position of nodule by classifying lung area into these lobes. The structure of lungs differs on the right one and left one. The right lung is divided into three domains by major fissure and minor fissure. And, the left lung is divided into two domains by major fissure. Watching MDCT images carefully, we find that the surroundings of fissures have few blood vessels. Therefore, lung area is classified by extraction of the domain that the distance from pulmonary blood vessels is large and connective search of these extracted domains. These extraction and search are realized by 3-D weighted Hough transform.

  11. Recent technologic advances in multi-detector row cardiac CT.

    PubMed

    Halliburton, Sandra Simon

    2009-11-01

    Recent technical advances in multi-detector row CT have resulted in lower radiation dose, improved temporal and spatial resolution, decreased scan time, and improved tissue differentiation. Lower radiation doses have resulted from the use of pre-patient z collimators, the availability of thin-slice axial data acquisition, the increased efficiency of ECG-based tube current modulation, and the implementation of iterative reconstruction algorithms. Faster gantry rotation and the simultaneous use of two x-ray sources have led to improvements in temporal resolution, and gains in spatial resolution have been achieved through application of the flying x-ray focal-spot technique in the z-direction. Shorter scan times have resulted from the design of detector arrays with increasing numbers of detector rows and through the simultaneous use of two x-ray sources to allow higher helical pitch. Some improvement in tissue differentiation has been achieved with dual energy CT. This article discusses these recent technical advances in detail.

  12. Multidetector CT angiography for acute gastrointestinal bleeding: technique and findings.

    PubMed

    Artigas, José M; Martí, Milagros; Soto, Jorge A; Esteban, Helena; Pinilla, Inmaculada; Guillén, Eugenia

    2013-01-01

    Acute gastrointestinal bleeding is a common reason for emergency department admissions and an important cause of morbidity and mortality. Factors that complicate its clinical management include patient debility due to comorbidities; intermittence of hemorrhage; and multiple sites of simultaneous bleeding. Its management, therefore, must be multidisciplinary and include emergency physicians, gastroenterologists, and surgeons, as well as radiologists for diagnostic imaging and interventional therapy. Upper gastrointestinal tract bleeding is usually managed endoscopically, with radiologic intervention reserved as an alternative to be used if endoscopic therapy fails. Endoscopy is often less successful in the management of acute lower gastrointestinal tract bleeding, where colonoscopy may be more effective. The merits of performing bowel cleansing before colonoscopy in such cases might be offset by the resultant increase in response time and should be weighed carefully against the deficits in visualization and diagnostic accuracy that would result from performing colonoscopy without bowel preparation. In recent years, multidetector computed tomographic (CT) angiography has gained acceptance as a first-line option for the diagnosis and management of lower gastrointestinal tract bleeding. In selected cases of upper gastrointestinal tract bleeding, CT angiography also provides accurate information about the presence or absence of active bleeding, its source, and its cause. This information helps shorten the total diagnostic time and minimizes or eliminates the need for more expensive and more invasive procedures.

  13. Multidetector CT of Surgically Proven Blunt Bowel and Mesenteric Injury.

    PubMed

    Bates, David D B; Wasserman, Michael; Malek, Anita; Gorantla, Varun; Anderson, Stephan W; Soto, Jorge A; LeBedis, Christina A

    2017-01-01

    Blunt traumatic injury is one of the leading causes of morbidity and mortality in the United States. Unintentional injury represents the leading cause of death in the United States for all persons between the ages of 1 and 44 years. In the setting of blunt abdominal trauma, the reported rate of occurrence of bowel and mesenteric injuries ranges from 1% to 5%. Despite the relatively low rate of blunt bowel and mesenteric injury in patients with abdominal and pelvic trauma, delays in diagnosis are associated with increased rates of sepsis, a prolonged course in the intensive care unit, and increased mortality. During the past 2 decades, as multidetector computed tomography (CT) has emerged as an essential tool in emergency radiology, several direct and indirect imaging features have been identified that are associated with blunt bowel and mesenteric injury. The imaging findings in cases of blunt bowel and mesenteric injury can be subtle and may be seen in the setting of multiple complex injuries, such as multiple solid-organ injuries and spinal fractures. Familiarity with the various imaging features of blunt bowel and mesenteric injury, as well as an understanding of their clinical importance with regard to the care of the patient, is essential to making a timely diagnosis. Once radiologists are familiar with the spectrum of findings of blunt bowel and mesenteric injury, they will be able to make timely diagnoses that will lead to improved patient outcomes. (©)RSNA, 2017.

  14. Penetrating wounds to the torso: evaluation with triple-contrast multidetector CT.

    PubMed

    Lozano, J Diego; Munera, Felipe; Anderson, Stephan W; Soto, Jorge A; Menias, Christine O; Caban, Kim M

    2013-01-01

    Penetrating injuries account for a large percentage of visits to emergency departments and trauma centers worldwide. Emergency laparotomy is the accepted standard of care in patients with a penetrating torso injury who are not hemodynamically stable and have a clinical indication for exploratory laparotomy, such as evisceration or gastrointestinal bleeding. Continuous advances in technology have made computed tomography (CT) an indispensable tool in the evaluation of many patients who are hemodynamically stable, have no clinical indication for exploratory laparotomy, and are candidates for conservative treatment. Multidetector CT may depict the trajectory of a penetrating injury and help determine what type of intervention is necessary on the basis of findings such as active arterial extravasation and major vascular, hollow viscus, or diaphragmatic injuries. Because multidetector CT plays an increasing role in the evaluation of patients with penetrating wounds to the torso, the radiologists who interpret these studies should be familiar with the CT findings that mandate intervention.

  15. A new approach to the assessment of lumen visibility of coronary artery stent at various heart rates using 64-slice MDCT

    PubMed Central

    Groen, J. M.; van Ooijen, P. M. A.; Oudkerk, M.

    2007-01-01

    Coronary artery stent lumen visibility was assessed as a function of cardiac movement and temporal resolution with an automated objective method using an anthropomorphic moving heart phantom. Nine different coronary stents filled with contrast fluid and surrounded by fat were scanned using 64-slice multi-detector computed tomography (MDCT) at 50–100 beats/min with the moving heart phantom. Image quality was assessed by measuring in-stent CT attenuation and by a dedicated tool in the longitudinal and axial plane. Images were scored by CT attenuation and lumen visibility and compared with theoretical scoring to analyse the effect of multi-segment reconstruction (MSR). An average increase in CT attenuation of 144 ± 59 HU and average diminished lumen visibility of 29 ± 12% was observed at higher heart rates in both planes. A negative correlation between image quality and heart rate was non-significant for the majority of measurements (P > 0.06). No improvement of image quality was observed in using MSR. In conclusion, in-stent CT attenuation increases and lumen visibility decreases at increasing heart rate. Results obtained with the automated tool show similar behaviour compared with attenuation measurements. Cardiac movement during data acquisition causes approximately twice as much blurring compared with the influence of temporal resolution on image quality. Electronic supplementary material The online version of this article (doi:10.1007/s00330-007-0568-8) contains supplementary material, which is available to authorized users. PMID:17429648

  16. Carotid stenosis evaluation by 64-slice CTA: comparison of NASCET, ECST and CC grading methods.

    PubMed

    Kılıçkap, Gülsüm; Ergun, Elif; Başbay, Elif; Koşar, Pınar; Kosar, Uğur

    2012-06-01

    Purpose is to evaluate the intraobserver and interobserver variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET), European Carotid Surgery Trial (ECST) and Common Carotid (CC) methods, which are used to measure the degree of ICA stenosis, using 64-slice CT angiography and to compare the measurements made by these three methods. 88 cases (111 carotid arteries) were included in the study. Carotid CTA was performed by a 64 slice scanner (Toshiba, Aqullion 64).Two radiologists measured the degree of carotid stenosis by using NASCET, ECST and CC methods. Intraobserver and interobserver variability of each method was determined by intraclass correlation coefficient (ICC), Bland-Altman plots and kappa and linear weighted kappa statistics. The relation between the measurements was assessed by correlation coefficient (with linear and quadratic methods). Correlation coefficients showed that there is linear correlation between the measurements made by the three methods. The degree of stenosis measured with the NASCET method had the lowest value, while the corresponding values measured with the ECST and CC methods were close to each other. ICC and Bland-Altman plots showed high intra and inter observer agreement for NASCET, ECST and CC methods whereas kappa statistics showed moderate to substantial agreement. CC method had slightly higher agreement when compared with the other two methods. Intra and interobserver agreement is high for NASCET, ECST and CC methods however CC method has a slightly higher reproducibility. There is linear correlation between the measurements made by the three methods.

  17. Multidetector CT and postprocessing in planning and assisting in minimally invasive bronchoscopic airway interventions.

    PubMed

    Nair, Arjun; Godoy, Myrna C; Holden, Emma L; Madden, Brendan P; Chua, Felix; Ost, David E; Roos, Justus E; Naidich, David P; Vlahos, Ioannis

    2012-01-01

    A widening spectrum of increasingly advanced bronchoscopic techniques is available for the diagnosis and treatment of various bronchopulmonary diseases. The evolution of computed tomography (CT)-multidetector CT in particular-has paralleled these advances. The resulting development of two-dimensional and three-dimensional (3D) postprocessing techniques has complemented axial CT interpretation in providing more anatomically familiar information to the pulmonologist. Two-dimensional techniques such as multiplanar recontructions and 3D techniques such as virtual bronchoscopy can provide accurate guidance for increasing yield in transbronchial needle aspiration and transbronchial biopsy of mediastinal and hilar lymph nodes. Sampling of lesions located deeper within the lung periphery via bronchoscopic pathways determined at virtual bronchoscopy are also increasingly feasible. CT fluoroscopy for real-time image-guided sampling is now widely available; electromagnetic navigation guidance is being used in select centers but is currently more costly. Minimally invasive bronchoscopic techniques for restoring airway patency in obstruction caused by both benign and malignant conditions include mechanical strategies such as airway stent insertion and ablative techniques such as electrocauterization and cryotherapy. Multidetector CT postprocessing techniques provide valuable information for planning and surveillance of these treatment methods. In particular, they optimize the evaluation of dynamic obstructive conditions such as tracheobronchomalacia, especially with the greater craniocaudal coverage now provided by wide-area detectors. Multidetector CT also provides planning information for bronchoscopic treatment of bronchopleural fistulas and bronchoscopic lung volume reduction for carefully selected patients with refractory emphysema.

  18. 64-Slice Computed Tomographic Angiography for the Diagnosis of Intermediate Risk Coronary Artery Disease

    PubMed Central

    2010-01-01

    Magnetic Resonance Imaging for the Diagnosis of Coronary Artery Disease: An Evidence-Based Analysis Pease note that two related evidence-based analyses of non-invasive cardiac imaging technologies for the assessment of myocardial viability are also available on the MAS website: Positron Emission Tomography for the Assessment of Myocardial Viability: An Evidence-Based Analysis Magnetic Resonance Imaging for the Assessment of Myocardial Viability: an Evidence-Based Analysis The Toronto Health Economics and Technology Assessment Collaborative has also produced an associated economic report entitled: The Relative Cost-effectiveness of Five Non-invasive Cardiac Imaging Technologies for Diagnosing Coronary Artery Disease in Ontario [Internet]. Available from: http://theta.utoronto.ca/reports/?id=7 Objective The objective of this report is to determine the accuracy of computed tomographic angiography (CTA) compared to the more invasive option of coronary angiography (CA) in the detection of coronary artery disease (CAD) in stable (non-emergent) symptomatic patients. CT Angiography CTA is a cardiac imaging test that assesses the presence or absence, as well as the extent, of coronary artery stenosis for the diagnosis of CAD. As such, it is a test of cardiac structure and anatomy, in contrast to the other cardiac imaging modalities that assess cardiac function. It is, however, unclear as to whether cardiac structural features alone, in the absence cardiac function information, are sufficient to determine the presence or absence of intermediate pretest risk of CAD. CTA technology is changing rapidly with increasing scan speeds and anticipated reductions in radiation exposure. Initial scanners based on 4, 8, 16, 32, and 64 slice machines have been available since the end of 2004. Although 320-slice machines are now available, these are not widely diffused and the existing published evidence is specific to 64-slice scanners. In general, CTA allows for 3-dimensional (3D) viewing of the

  19. Relationship between noise, dose, and pitch in cardiac multi-detector row CT.

    PubMed

    Primak, Andrew N; McCollough, Cynthia H; Bruesewitz, Michael R; Zhang, Jie; Fletcher, Joel G

    2006-01-01

    In spiral computed tomography (CT), dose is always inversely proportional to pitch. However, the relationship between noise and pitch (and hence noise and dose) depends on the scanner type (single vs multi-detector row) and reconstruction mode (cardiac vs noncardiac). In single detector row spiral CT, noise is independent of pitch. Conversely, in noncardiac multi-detector row CT, noise depends on pitch because the spiral interpolation algorithm makes use of redundant data from different detector rows to decrease noise for pitch values less than 1 (and increase noise for pitch values > 1). However, in cardiac spiral CT, redundant data cannot be used because such data averaging would degrade the temporal resolution. Therefore, the behavior of noise versus pitch returns to the single detector row paradigm, with noise being independent of pitch. Consequently, since faster rotation times require lower pitch values in cardiac multi-detector row CT, dose is increased without a commensurate decrease in noise. Thus, the use of faster rotation times will improve temporal resolution, not alter noise, and increase dose. For a particular application, the higher dose resulting from faster rotation speeds should be justified by the clinical benefits of the improved temporal resolution.

  20. Dual-energy CT revisited with multidetector CT: review of principles and clinical applications.

    PubMed

    Karçaaltıncaba, Muşturay; Aktaş, Aykut

    2011-09-01

    Although dual-energy CT (DECT) was first conceived in the 1970s, it was not widely used for CT indications. Recently, the simultaneous acquisition of volumetric dual-energy data has been introduced using multidetector CT (MDCT) with two X-ray tubes and rapid kVp switching (gemstone spectral imaging). Two major advantages of DECT are material decomposition by acquiring two image series with different kVp and the elimination of misregistration artifacts. Hounsfield unit measurements by DECT are not absolute and can change depending on the kVp used for an acquisition. Typically, a combination of 80/140 kVp is used for DECT, but for some applications, 100/140 kVp is preferred. In this study, we summarized the clinical applications of DECT and included images that were acquired using the dual-source CT and rapid kVp switching. In general, unenhanced images can be avoided by using DECT for body and neurological applications; iodine can be removed from the image, and a virtual, non-contrast (water) image can be obtained. Neuroradiological applications allow for the removal of bone and calcium from the carotid and brain CT angiography. Thorax applications include perfusion imaging in patients with pulmonary thromboemboli and other chest diseases, xenon ventilation-perfusion imaging and solitary nodule characterization. Cardiac applications include dual-energy cardiac perfusion, viability and cardiac iron detection. The removal of calcific plaques from arteries, bone removal and aortic stent graft evaluation may be achieved in the vascular system. Abdominal applications include the detection and characterization of liver and pancreas masses, the diagnosis of steatosis and iron overload, DECT colonoscopy and CT cholangiography. Urinary system applications are urinary calculi characterization (uric acid vs. non-uric acid), renal cyst characterization and mass characterization. Musculoskeletal applications permit the differentiation of gout from pseudogout and a reduction of

  1. Multidetector CT of blunt traumatic venous injuries in the chest, abdomen, and pelvis.

    PubMed

    Holly, Brian P; Steenburg, Scott D

    2011-01-01

    Venous injuries as a result of blunt trauma are rare. Even though current protocols for multidetector computed tomography (CT) of patients with trauma are designed to evaluate primarily the solid organs and arteries, blunt venous injuries may nevertheless be identified, or at least suspected, on the basis of the multidetector CT findings. Venous injuries are associated with high morbidity and mortality rates. Diagnosis of a possible venous injury is crucial because the physical findings of a venous injury are nonspecific and may be absent. This article aims to make the radiologist aware of various venous injuries caused by blunt trauma and to provide helpful hints to aid in the identification of venous injuries. Multidetector CT technology, in combination with interactive manipulation of the raw dataset, can be useful in the creation of multiplanar reconstructed images and in the identification of a venous injury caused by blunt trauma. Familiarity with direct and indirect signs of venous injuries, as well as with examples of blunt traumatic venous injuries in the chest, abdomen, and pelvis, will help in the diagnosis of these injuries.

  2. Multi-detector CT in the paediatric urinary tract.

    PubMed

    Damasio, M B; Darge, K; Riccabona, M

    2013-07-01

    The use of paediatric multi-slice CT (MSCT) is rapidly increasing worldwide. As technology advances its application in paediatric care is constantly expanding with an increasing need for radiation dose control and appropriate utilization. Recommendations on how and when to use CT for assessment of the paediatric urinary tract appear to be an important issue. Therefore the European Society of Paediatric Radiology (ESPR) uroradiology task force and European Society of Urogenital Radiology (ESUR) paediatric working groups created a proposal for performing renal CT in children that has recently been published. The objective of this paper is to discuss paediatric urinary tract CT (uro-CT) in more detail and depth. The specific aim is not only to offer general recommendations on clinical indications and optimization processes of paediatric CT examination, but also to address various childhood characteristics and phenomena that facilitate understanding the different approach and use of uro-CT in children compared to adults. According to ALARA principles, paediatric uro-CT should only be considered for selected indications provided high-level comprehensive US is not conclusive and alternative non-ionizing techniques such as MR are not available or appropriate. Optimization of paediatric uro-CT protocols (considering lower age-adapted kV and mAs) is mandatory, and the number of phases and acquisition series should be kept as few as possible.

  3. Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware.

    PubMed

    Vande Berg, Bruno; Malghem, Jacques; Maldague, Baudouin; Lecouvet, Frederic

    2006-12-01

    Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

  4. [Multidetector row CT in assessment of coronary artery calcification on hemodialisis].

    PubMed

    Caro, P; Delgado, R; Dapena, F; Núñez, A

    2007-01-01

    Vascular calcification is a strong predictor of cardiovascular and all-cause mortality. Coronary artery calcification is more frequent, more extensive and progresses more rapidly in CKD than in general population. They are also considered a marker of coronary heart disease, with high prevalence and functional significance. It suggests that detection and surveillance may be worthwhile in general clinical practice. New non-invasive image techniques, like Multi-detector row CT, a type of spiral scanner, assess density and volume of calcification at multiple sites and allow quantitative scoring of vascular calcification using calcium scores analogous to those from electron-beam CT. We have assessed and quantified coronary artery calcification with 16 multidetector row CT in 44 patients on hemodialysis and their relationship with several cardiovascular risk factors. Coronary artery calcification prevalence was of 84 % with mean calcium score of 1580 +/- 2010 ( r 0-9844) with calcium score > 400 in 66% of patients. It was usually multiple, affecting more than two vessels in more than 50%. In all but one patient, left anterior descending artery was involved with higher calcium score level at right coronary artery. Advanced age, male, diabetes, smoking, more morbidity, cerebrovascular disease previous, and calcium-binders phosphate and analogous vitamin D treatment would seem to be associated with coronary artery calcification. Coronary artery calcification is very frequent and extensive, usually multiple and associated to modifiable risk factors in hemodialysis patients. Multi-detector-row CT seems an effective, suitable, readily applicable method to assess and quantify coronary artery calcification.

  5. Dedicated multi-detector CT of the esophagus: spectrum of diseases.

    PubMed

    Ba-Ssalamah, Ahmed; Zacherl, Johannes; Noebauer-Huhmann, Iris Melanie; Uffmann, Martin; Matzek, Wolfgang Karl; Pinker, Katja; Herold, Christian; Schima, Wolfgang

    2009-01-01

    Multi-detector computed tomography (CT) offers new opportunities in the imaging of the gastrointestinal tract. Its ability to cover a large volume in a very short scan time, and in a single breath hold with thin collimation and isotropic voxels, allows the imaging of the entire esophagus with high-quality multiplanar reformation and 3D reconstruction. Proper distention of the esophagus and stomach (by oral administration of effervescent granules and water) and optimally timed administration of intravenous contrast material are required to detect and characterize disease. In contrast to endoscopy and double-contrast studies of the upper GI tract, CT provides information about both the esophageal wall and the extramural extent of disease. Preoperative staging of esophageal carcinoma appears to be the main indication for MDCT. In addition, MDCT allows detection of other esophageal malignancies, such as lymphoma and benign esophageal tumors, such as leiomyma. A diagnosis of rupture or fistula of the esophagus can be firmly established using MDCT. Furthermore, miscellaneous esophageal conditions, such as achalasia, esophagitis, diverticula, and varices, are incidental findings and can also be visualized with hydro-multi-detector CT. Multi-detector CT is a valuable tool for the evaluation of esophageal wall disease and serves as an adjunct to endoscopy.

  6. Lymphoplasmacytic sclerosing pancreatitis (autoimmune pancreatitis): evaluation with multidetector CT.

    PubMed

    Kawamoto, Satomi; Siegelman, Stanley S; Hruban, Ralph H; Fishman, Elliot K

    2008-01-01

    Lymphoplasmacytic sclerosing pancreatitis is a form of chronic pancreatitis characterized by a mixed inflammatory infiltrate that centers on the pancreatic ducts. It is a cause of benign pancreatic disease that can clinically mimic pancreatic cancer. Preoperative detection of lymphoplasmacytic sclerosing pancreatitis is important because patients usually respond to steroid therapy. Patients with lymphoplasmacytic sclerosing pancreatitis are often referred for computed tomography (CT) when they are suspected of having a pancreatic or biliary neoplasm; therefore, it is important to search for potential findings suggestive of lymphoplasmacytic sclerosing pancreatitis when typical findings of a pancreatic or biliary neoplasm are not found. Typical CT findings include diffuse or focal enlargement of the pancreas without dilatation of the main pancreatic duct. Focal enlargement is most commonly seen in the head of the pancreas, and the involved pancreas on contrast material-enhanced CT images may be iso-attenuating relative to the rest of the pancreas, or hypo-attenuating, especially during the early postcontrast phase. Thickening and contrast enhancement of the wall of the common bile duct and gallbladder may reflect inflammatory infiltrate and fibrosis associated with lymphoplasmacytic sclerosing pancreatitis. There are several features seen at CT that may help to differentiate lymphoplasmacytic sclerosing pancreatitis from pancreatic cancer, such as diffuse enlargement of the pancreas with minimal peripancreatic stranding in patients with obstructive jaundice, an absence of significant pancreatic atrophy, and an absence of significant main pancreatic duct dilatation. When these findings are encountered, clinical, other imaging, and serologic data should be evaluated.

  7. Multidetector CT of expected findings and complications after contemporary inguinal hernia repair surgery

    PubMed Central

    Tonolini, Massimo

    2016-01-01

    Inguinal hernia repair (IHR) with prosthetic mesh implantation is the most common procedure in general surgery, and may be performed using either an open or laparoscopic approach. This paper provides an overview of contemporary tension-free IHR techniques and materials, and illustrates the expected postoperative imaging findings and iatrogenic injuries. Emphasis is placed on multidetector CT, which represents the ideal modality to comprehensively visualize the operated groin region and deeper intra-abdominal structures. CT consistently depicts seroma, mesh infections, hemorrhages, bowel complications and urinary bladder injuries, and thus generally provides a consistent basis for therapeutic choice. Since radiologists are increasingly requested to investigate suspected iatrogenic complications, this paper aims to provide an increased familiarity with early CT studies after IHR, including complications and normal postoperative appearances such as focal pseudolesions, in order to avoid misinterpretation and inappropriate management. PMID:27460285

  8. Noninvasive imaging of coronary arteries: current and future role of multi-detector row CT.

    PubMed

    Schoenhagen, Paul; Halliburton, Sandra S; Stillman, Arthur E; Kuzmiak, Stacie A; Nissen, Steven E; Tuzcu, E Murat; White, Richard D

    2004-07-01

    While invasive imaging techniques, especially selective conventional coronary angiography, will remain vital to planning and guiding catheter-based and surgical treatment of significantly stenotic coronary lesions, the comprehensive and serial assessment of asymptomatic or minimally symptomatic stages of coronary artery disease (CAD) for preventive purposes will eventually need to rely on noninvasive imaging techniques. Cardiovascular imaging with tomographic modalities, including computed tomography (CT) and magnetic resonance imaging, has great potential for providing valuable information. This review article will describe the current and future role of cardiac CT, and in particular that of multi-detector row CT, for imaging of atherosclerotic and other pathologic changes of the coronary arteries. It will describe how tomographic coronary imaging may eventually supplement traditional angiographic techniques in understanding the patterns of atherosclerotic CAD development.

  9. Virtual anthropology and forensic identification using multidetector CT

    PubMed Central

    Savall, F; Mokrane, F-Z; Rousseau, H; Crubézy, E; Rougé, D; Telmon, N

    2014-01-01

    Virtual anthropology is made possible by modern cross-sectional imaging. Multislice CT (MSCT) can be used for comparative bone and dental identification, reconstructive identification and lesion identification. Comparative identification, the comparison of ante- and post-mortem imaging data, can be performed on both teeth and bones. Reconstructive identification, a considerable challenge for the radiologist, identifies the deceased by determining sex, geographical origin, stature and age at death. Lesion identification combines virtual autopsy and virtual anthropology. MSCT can be useful in palaeopathology, seeking arthropathy, infection, oral pathology, trauma, tumours, haematological disorders, stress indicators or occupational stress in bones and teeth. We examine some of the possibilities offered by this new radiological subspeciality that adds a new dimension to the work of the forensic radiologist. A multidisciplinary approach is crucial and involves communication and data exchange between radiologists, forensic pathologists, anthropologists and radiographers. PMID:24234584

  10. Virtual anthropology and forensic identification using multidetector CT.

    PubMed

    Dedouit, F; Savall, F; Mokrane, F-Z; Rousseau, H; Crubézy, E; Rougé, D; Telmon, N

    2014-04-01

    Virtual anthropology is made possible by modern cross-sectional imaging. Multislice CT (MSCT) can be used for comparative bone and dental identification, reconstructive identification and lesion identification. Comparative identification, the comparison of ante- and post-mortem imaging data, can be performed on both teeth and bones. Reconstructive identification, a considerable challenge for the radiologist, identifies the deceased by determining sex, geographical origin, stature and age at death. Lesion identification combines virtual autopsy and virtual anthropology. MSCT can be useful in palaeopathology, seeking arthropathy, infection, oral pathology, trauma, tumours, haematological disorders, stress indicators or occupational stress in bones and teeth. We examine some of the possibilities offered by this new radiological subspeciality that adds a new dimension to the work of the forensic radiologist. A multidisciplinary approach is crucial and involves communication and data exchange between radiologists, forensic pathologists, anthropologists and radiographers.

  11. Mandibular arteriovenous malformation: A rare life-threatening condition depicted on multidetector CT angiography

    PubMed Central

    Dwivedi, Amit Nandan Dhar; Pandey, Anubha; Kumar, Ishan; Agarwal, Arjit

    2014-01-01

    Arteriovenous malformation (AVM) of the mandible is a rare and potentially life-threatening condition which can lead to massive hemorrhage. The following is a description where a large mandibular AVM presented with torrential bleeding following tooth extraction for caries. An orthopantomogram (OPG) was performed which was suggestive of aneurysmal bone cyst or ameloblastoma. A computed tomography (CT) angiography revealed a large mandibular AVM with submandibular extension. It is important for both clinicians and radiologist to be aware of this type of lesion that can have life-threatening complications. It is important to define the anatomical location and the feeder vessels of the entity in detail preoperatively. This communication highlights the common differential and use of multidetector CT (MDCT) angiography along with other imaging modalities to prevent a fatal hemorrhage and arrive at a correct diagnosis. PMID:24959049

  12. High resolution multidetector CT aided tissue analysis and quantification of lung fibrosis

    NASA Astrophysics Data System (ADS)

    Zavaletta, Vanessa A.; Karwoski, Ronald A.; Bartholmai, Brian; Robb, Richard A.

    2006-03-01

    Idiopathic pulmonary fibrosis (IPF, also known as Idiopathic Usual Interstitial Pneumontis, pathologically) is a progressive diffuse lung disease which has a median survival rate of less than four years with a prevalence of 15-20/100,000 in the United States. Global function changes are measured by pulmonary function tests and the diagnosis and extent of pulmonary structural changes are typically assessed by acquiring two-dimensional high resolution CT (HRCT) images. The acquisition and analysis of volumetric high resolution Multi-Detector CT (MDCT) images with nearly isotropic pixels offers the potential to measure both lung function and structure. This paper presents a new approach to three dimensional lung image analysis and classification of normal and abnormal structures in lungs with IPF.

  13. Normal or abnormal? Demystifying uterine and cervical contrast enhancement at multidetector CT.

    PubMed

    Yitta, Silaja; Hecht, Elizabeth M; Mausner, Elizabeth V; Bennett, Genevieve L

    2011-01-01

    Computed tomography (CT) is not generally advocated as the first-line imaging examination for disorders of the female pelvis. However, multidetector CT is often the modality of choice for evaluating nongynecologic pelvic abnormalities, particularly in emergent settings, in which all the pelvic organs are invariably assessed. Incidental findings of uterine and cervical contrast enhancement in such settings may easily be mistaken for abnormalities, given the broad spectrum of anatomic variants and enhancement patterns that may be seen in the normal uterus and cervix. The authors' review of CT and magnetic resonance (MR) imaging enhancement patterns, augmented by case examples from their clinical radiology practice, provides a solid foundation for understanding the spectrum of normal uterine and cervical appearances and avoiding potential pitfalls in the diagnosis of benign cervical lesions, adenomyosis, infection, malignancy, and postpartum effects. This information should help radiologists more confidently differentiate between normal and abnormal CT findings and, when CT findings are not definitive, offer appropriate recommendations for follow-up ultrasonography or MR imaging.

  14. Influence of z overscanning on normalized effective doses calculated for pediatric patients undergoing multidetector CT examinations

    SciTech Connect

    Tzedakis, Antonis; Damilakis, John; Perisinakis, Kostas; Karantanas, Apostolos; Karabekios, Spiros; Gourtsoyiannis, Nicholas

    2007-04-15

    The purpose of this study was to evaluate the effect of z overscanning on normalized effective dose for pediatric patients undergoing multidetector-computed tomography (CT) examinations. Five commercially available mathematical anthropomorphic phantoms representing newborn, 1-, 5-, 10-, and 15-year-old patients and the Monte Carlo N-Particle (MCNP, version 4C2) radiation transport code were employed in the current study to simulate pediatric CT exposures. For all phantoms, axial and helical examinations at 120 kV tube voltage were simulated. Scans performed at 80 kV were also simulated. Sex-specific normalized effective doses were estimated for four standard CT examinations i.e., head-neck, chest, abdomen-pelvis, and trunk, for all pediatric phantoms. Data for both axial and helical mode acquisition were obtained. In the helical mode, z overscanning was taken into account. The validity of the Monte Carlo results was verified by comparison with dose data obtained using thermoluminescence dosimetry and a physical pediatric anthropomorphic phantom simulating a 10-year-old child. In all cases normalized effective dose values were found to increase with increasing z overscanning. The percentage differences in normalized data between axial and helical scans may reach 43%, 70%, 36%, and 26% for head-neck, chest, abdomen-pelvis, and trunk studies, respectively. Normalized data for female pediatric patients was in general higher compared to male patients for all ages, examined regions, and z overscanning values. For both male and female children, the normalized effective dose values were reduced as the age was increased. For the same typical exposure conditions, dose values decreased when lower tube voltage was used; for a 1-year-old child, for example, the effective dose was 3.8 times lower when 80 kV instead of 120 kV was used. Normalized data for the estimation of effective dose to pediatric patients undergoing standard axial and helical CT examinations on an

  15. Visual claudicatio: diagnosis with 64-slice computed tomography.

    PubMed

    Cademartiri, Filippo; Maffei, Erica; Palumbo, Alessandro; Mollet, Nico R; van der Lugt, Aad; Crisi, Girolamo

    2007-06-01

    We present a case of a 78-year-old male referred presented to our institution with amaurosis fugax after walking 20 steps ("visual claudicatio"). Duplex ultrasound was not able to visualize the carotid arteries. Multislice computed tomography (Sensation 64 Cardiac, Siemens, Germany) of the cerebro-vascular circulation was performed from its origin at the level of the aortic arch to the circle of Willis. The investigation demonstrated a complete occlusion of both common carotid arteries at their origin and a severe origo stenosis of both vertebral arteries. An important collateral circulation of the vertebral arteries through the minor vessels of the neck was also displayed. Both comunicans posterior arteries were small but patent. The intra-cranial arteries were patent. Multislice CT of the cerebro-vascular circulation is an optimal tool for a comprehensive evaluation when duplex ultrasound fails.

  16. Pulmonary arterial hypertension: an imaging review comparing MR pulmonary angiography and perfusion with multidetector CT angiography.

    PubMed

    Junqueira, F P; Lima, C M A O; Coutinho, A C; Parente, D B; Bittencourt, L K; Bessa, L G P; Domingues, R C; Marchiori, E

    2012-11-01

    Pulmonary hypertension (PH) is a progressive disease that leads to substantial morbidity and eventual death. Pulmonary multidetector CT angiography (MDCTA), pulmonary MR angiography (MRA) and MR-derived pulmonary perfusion (MRPP) imaging are non-invasive imaging techniques for the differential diagnosis of PH. MDCTA is considered the gold standard for the diagnosis of pulmonary embolism, one of the most common causes of PH. MRA and MRPP are promising techniques that do not require the use of ionising radiation or iodinated contrast material, and can be useful for patients for whom such material cannot be used. This review compares the imaging aspects of pulmonary MRA and 64-row MDCTA in patients with chronic thromboembolic or idiopathic PH.

  17. Pulmonary arterial hypertension: an imaging review comparing MR pulmonary angiography and perfusion with multidetector CT angiography

    PubMed Central

    Junqueira, F P; Lima, C M A O; Coutinho, A C; Parente, D B; Bittencourt, L K; Bessa, L G P; Domingues, R C; Marchiori, E

    2012-01-01

    Pulmonary hypertension (PH) is a progressive disease that leads to substantial morbidity and eventual death. Pulmonary multidetector CT angiography (MDCTA), pulmonary MR angiography (MRA) and MR-derived pulmonary perfusion (MRPP) imaging are non-invasive imaging techniques for the differential diagnosis of PH. MDCTA is considered the gold standard for the diagnosis of pulmonary embolism, one of the most common causes of PH. MRA and MRPP are promising techniques that do not require the use of ionising radiation or iodinated contrast material, and can be useful for patients for whom such material cannot be used. This review compares the imaging aspects of pulmonary MRA and 64-row MDCTA in patients with chronic thromboembolic or idiopathic PH. PMID:22932061

  18. Bronchial anatomy of left lung: a study of multi-detector row CT.

    PubMed

    Zhao, Xinya; Ju, Yuanrong; Liu, Cheng; Li, Jianfeng; Huang, Min; Sun, Jian; Wang, Tao

    2009-02-01

    Familiarity with prevailing pattern and variations in the bronchial tree is not only essential for the anatomist to explain bronchial variation in bronchial specimens, but also useful for guiding bronchoscopy and instructing pulmonary segmental resection. The purpose of this study was designed to demonstrate various branching patterns of left lung with 3D images, with special attention given to identify the major types at transverse thin-section CT. Two hundred and sixteen patients with routine thorax scans were enrolled. The images of bronchial tree, virtual bronchoscopy were reconstructed using post-processing technique of multi-detector row CT. We attempted to classify the segmental bronchi by interpreting the post-processing images, and identified them in transverse thin-section CT. Our results showed that the segmental bronchial ramifications of the left superior lobe were classified into three types mainly, i.e., common stem of apical and posterior segmental bronchi (64%, 138/216); trifurcation (23%, 50/216); common stem of apical and anterior segmental bronchi (10%, 22/216), and they could be identified at two typical sections of transverse thin-section CT. There were two major types in left basal segmental bronchi, i.e., bifurcation (75%, 163/216), trifurcation (18%, 39/216), and they could also be identified at two typical sections of transverse thin-section CT. In conclusion, our study have offered simplified branching patterns of bronchi and demonstrated various unusual bronchial branching patterns perfectly with 3D images, and have also revealed how to identify the main branching patterns in transverse thin-section CT.

  19. Multidetector CT appearance of the pelvis after cesarean delivery: normal and abnormal acute findings.

    PubMed

    Gui, Benedetta; Danza, Francesco Maria; Valentini, Anna Lia; Laino, Maria Elena; Caruso, Alessandro; Carducci, Brigida; Rodolfino, Elena; Devicienti, Ersilia; Bonomo, Lorenzo

    2016-01-01

    Cesarean section (CS) may have several acute complications that can occur in the early postoperative period. The most common acute complications are hematomas and hemorrhage, infection, ovarian vein thrombosis, uterine dehiscence and rupture. Pelvic hematomas usually occur at specific sites and include bladder flap hematoma (between the lower uterine segment and the bladder) and subfascial or rectus sheath hematoma (rectus sheath or prevescical space). Puerperal hemorrhage can be associated with uterine dehiscence or rupture. Pelvic infections include endometritis, abscess, wound infection, and retained product of conception. Radiologists play an important role in the diagnosis and management of postoperative complications as a result of increasing use of multidetector CT in emergency room. The knowledge of normal and abnormal postsurgical anatomy and findings should facilitate the correct diagnosis so that the best management can be chosen for the patient, avoiding unnecessary surgical interventions and additional treatments. In this article we review the surgical cesarean technique and imaging CT technique followed by description of normal and abnormal post-CS CT findings.

  20. Multidetector CT appearance of the pelvis after cesarean delivery: normal and abnormal acute findings

    PubMed Central

    Gui, Benedetta; Danza, Francesco Maria; Valentini, Anna Lia; Laino, Maria Elena; Caruso, Alessandro; Carducci, Brigida; Rodolfino, Elena; Devicienti, Ersilia; Bonomo, Lorenzo

    2016-01-01

    Cesarean section (CS) may have several acute complications that can occur in the early postoperative period. The most common acute complications are hematomas and hemorrhage, infection, ovarian vein thrombosis, uterine dehiscence and rupture. Pelvic hematomas usually occur at specific sites and include bladder flap hematoma (between the lower uterine segment and the bladder) and subfascial or rectus sheath hematoma (rectus sheath or prevescical space). Puerperal hemorrhage can be associated with uterine dehiscence or rupture. Pelvic infections include endometritis, abscess, wound infection, and retained product of conception. Radiologists play an important role in the diagnosis and management of postoperative complications as a result of increasing use of multidetector CT in emergency room. The knowledge of normal and abnormal postsurgical anatomy and findings should facilitate the correct diagnosis so that the best management can be chosen for the patient, avoiding unnecessary surgical interventions and additional treatments. In this article we review the surgical cesarean technique and imaging CT technique followed by description of normal and abnormal post-CS CT findings. PMID:27756714

  1. Relationship between indexed epicardial fat volume and coronary plaque volume assessed by cardiac multidetector CT

    PubMed Central

    You, Seulgi; Sun, Joo Sung; Park, Seon Young; Baek, Yoolim; Kang, Doo Kyoung

    2016-01-01

    Abstract We explored whether baseline indexed epicardial fat volume (EFVi) and serial changes in EFVi were associated with increase in coronary plaque volume as assessed by multidetector computed tomography. We retrospectively reviewed 87 patients with coronary artery plaque, identified during either baseline or follow-up cardiac computed tomography (CT) examinations. Each plaque volume was measured in volumetric units using a semiautomatic software tool. EFVi was quantified by calculating the total volume of epicardial tissue of CT density −190 to −30 HU, indexed to the body surface area. Clinical cardiovascular risk factors were extracted by medical record review at the time of the cardiac CT examinations. The relationship between EFVi and coronary plaque volume was explored by regression analysis. Although the EFVi did not change significantly from baseline to the time of the follow-up CT (65.7 ± 21.8 vs 66.0 ± 21.8 cm3/m3, P = 0.620), the plaque volumes were increased significantly on the follow-up CT scans. The annual change in EFVi was not accompanied by a parallel change in coronary plaque volume (P = 0.096–0.500). On univariate analysis, smoking, hypercholesterolemia, 10-year coronary heart disease risk, obesity, and baseline EFVi predicted rapid increases in lipid-rich and fibrous plaque volumes. On multivariate analysis, baseline EFVi (odds ratio = 1.029, P = 0.016) was an independent predictor of a rapid increase in lipid-rich plaque volume. EFVi was shown to be an independent predictor of a rapid increase in lipid-rich plaque volume. However, changes in EFVi were not associated with parallel changes in coronary plaque volume. PMID:27399137

  2. Evaluation of accuracy of 3D reconstruction images using multi-detector CT and cone-beam CT

    PubMed Central

    Kim, Mija; YI, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun; Choi, Soon-Chul

    2012-01-01

    Purpose This study was performed to determine the accuracy of linear measurements on three-dimensional (3D) images using multi-detector computed tomography (MDCT) and cone-beam computed tomography (CBCT). Materials and Methods MDCT and CBCT were performed using 24 dry skulls. Twenty-one measurements were taken on the dry skulls using digital caliper. Both types of CT data were imported into OnDemand software and identification of landmarks on the 3D surface rendering images and calculation of linear measurements were performed. Reproducibility of the measurements was assessed using repeated measures ANOVA and ICC, and the measurements were statistically compared using a Student t-test. Results All assessments under the direct measurement and image-based measurements on the 3D CT surface rendering images using MDCT and CBCT showed no statistically difference under the ICC examination. The measurements showed no differences between the direct measurements of dry skull and the image-based measurements on the 3D CT surface rendering images (P>.05). Conclusion Three-dimensional reconstructed surface rendering images using MDCT and CBCT would be appropriate for 3D measurements. PMID:22474645

  3. Contrast enhanced multi-detector CT and MR findings of a well-differentiated pancreatic vipoma.

    PubMed

    Camera, Luigi; Severino, Rosa; Faggiano, Antongiulio; Masone, Stefania; Mansueto, Gelsomina; Maurea, Simone; Fonti, Rosa; Salvatore, Marco

    2014-10-28

    Pancreatic vipoma is an extremely rare tumor accounting for less than 2% of endocrine pancreatic neoplasms with a reported incidence of 0.1-0.6 per million. While cross-sectional imaging findings are usually not specific, exact localization of the tumor by means of either computed tomography (CT) or magnetic resonance (MR) is pivotal for surgical planning. However, cross-sectional imaging findings are usually not specific and further characterization of the tumor may only be achieved by somatostatin-receptor scintigraphy (SRS). We report the case of a 70 years old female with a two years history of watery diarrhoea who was found to have a solid, inhomogeneously enhancing lesion at the level of the pancreatic tail at Gadolinium-enhanced MR (Somatom Trio 3T, Siemens, Germany). The tumor had been prospectively overlooked at a contrast-enhanced multi-detector CT (Aquilion 64, Toshiba, Japan) performed after i.v. bolus injection of only 100 cc of iodinated non ionic contrast media because of a chronic renal failure (3.4 mg/mL) but it was subsequently confirmed by SRS. The patient first underwent a successful symptomatic treatment with somatostatin analogues and was then submitted to a distal pancreasectomy with splenectomy to remove a capsulated whitish tumor which turned out to be a well-differentiated vipoma at histological and immuno-histochemical analysis.

  4. Beam hardening artifacts by dental implants: Comparison of cone-beam and 64-slice computed tomography scanners

    PubMed Central

    Esmaeili, Farzad; Johari, Masume; Haddadi, Pezhman

    2013-01-01

    Background: Cone beam computed tomography (CBCT) is an alternative to a computed tomography (CT) scan, which is appropriate for a wide range of craniomaxillofacial indications. The long-term use of metallic materials in dentistry means that artifacts caused by metallic restorations in the oral cavity should be taken into account when utilizing CBCT and CT scanners. The aim of this study was to quantitatively compare the beam hardening artifacts produced by dental implants between CBCT and a 64-Slice CT scanner. Materials and Methods: In this descriptive study, an implant drilling model similar to the human mandible was used in the present study. The implants (Dentis) were placed in the canine, premolar and molar areas. Three series of scans were provided from the implant areas using Somatom Sensation 64-slice and NewTom VGi (CBCT) CT scanners. Identical images were evaluated by three radiologists. The artifacts in each image were determined based on pre-determined criteria. Kruskal-Wallis test was used to compare mean values; Mann-Whitney U test was used for two-by-two comparisons when there was a statistical significance (P < 0.05). Results: The images of the two scanners had similar resolutions in axial sections (P = 0.299). In coronal sections, there were significant differences in the resolutions of the images produced by the two scanners (P < 0.001), with a higher resolution in the images produced by NewTom VGi scanner. On the whole, there were significant differences between the resolutions of the images produced by the two CT scanners (P < 0.001), with higher resolution in the images produced by NewTom VGi scanner in comparison to those of Somatom Sensation. Conclusion: Given the high quality of the images produced by NewTom VGi and the lower costs in comparison to CT, the use of the images of this scanner in dental procedures is recommended, especially in patients with extensive restorations, multiple prostheses and previous implants. PMID:24019808

  5. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required.

  6. Cirsoid Aneurysm of Coronary Arteries Associated with Arterioventricular Fistula Evaluated by 64-Multidetector CT Coronary Angiography: Depiction of a Case

    SciTech Connect

    Marrone, Gianluca Mamone, Giuseppe; Milazzo, Mariapina; Caruso, Settimo; Baravoglia, Cesar Hernandez; Vitulo, Patrizio; Gridelli, Bruno; Luca, Angelo

    2009-05-15

    A female patient with severe pulmonary hypertension was admitted for lung transplant evaluation. As an incidental finding, the chest CT showed diffuse and dilated coronaries, not detected at previous echocardiography. A coronary CT angiography was then performed using a 64-multidetector computed tomography (MDCT) scanner to better evaluate the coronary tree. The images obtained after postprocessing demonstrated tremendously aneurysmatic and tortuous coronary arteries and the presence of a septal branch deepening into the myocardium and penetrating the right ventricle cavity, forming an abnormal arterioventricular fistula. A causal relation between the aneurysms and the fistula is suspected.

  7. Multidetector CT cystography for imaging colovesical fistulas and iatrogenic bladder leaks.

    PubMed

    Tonolini, Massimo; Bianco, Roberto

    2012-04-01

    Multidetector computed tomography (MDCT) cystography currently represents the modality of choice to image the urinary bladder in traumatized patients. In this review we present our experience with MDCT cystography applications outside the trauma setting, particularly for diagnosing bladder fistulas and leaks. A detailed explanation is provided concerning exam preparation, acquisition technique, image reconstruction and interpretation. Colovesical fistulas most commonly occur as a complication of sigmoid diverticular disease, and often remain occult after extensive diagnostic work-up including cystoscopy and contrast-enhanced CT. We consistently achieved accurate preoperative visualization of colovesical fistulas using MDCT cystography. Urinary leaks and injuries represent a non-negligible occurrence after pelvic surgery, particularly obstetric and gynaecological procedures: in our experience MDCT cystography is useful to investigate iatrogenic bladder leaks or fistulas. In our opinion, MDCT cystography should be recommended as the first line modality for direct visualization or otherwise confident exclusion of both spontaneous enterovesical fistulas and bladder injuries following instrumentation procedures, obstetric or surgical interventions. Main Messages • Explanation of exam preparation, acquisition technique, image reconstruction and interpretation. • Preoperative visualization of colovesical fistulas, usually secondary to sigmoid diverticulitis. • Visualization or exclusion of iatrogenic bladder injuries following instrumentation or surgery.

  8. 64-Slice spiral computed tomography and three-dimensional reconstruction in the diagnosis of cystic pancreatic tumors

    PubMed Central

    WEN, ZHAOXIA; YAO, FENGQING; WANG, YUXING

    2016-01-01

    The present study aimed to describe the characteristics of cystic pancreatic tumors using computed tomography (CT) and to evaluate the diagnostic accuracy (DA) of post-imaging three-dimensional (3D) reconstruction. Clinical and imaging data, including multi-slice spiral CT scans, enhanced scans and multi-faceted reconstruction, from 30 patients with pathologically confirmed cystic pancreatic tumors diagnosed at the Linyi People's Hospital between August 2008 and June 2014 were retrospectively analyzed. Following the injection of Ultravist® 300 contrast agent, arterial, portal venous and parenchymal phase scans were obtained at 28, 60 and 150 sec, respectively, and 3D reconstructions of the CT images were generated. The average age of the patients was 38.4 years (range, 16–77 years), and the cohort included 5 males and 25 females (ratio, 1:5). The patients included 8 cases of mucinous cystadenoma (DA), 80%]; 9 cases of cystadenocarcinoma (DA, 84%); 6 cases of serous cystadenoma (DA, 100%); 3 cases of solid pseudopapillary tumor (DA, 100%); and 4 cases of intraductal papillary mucinous neoplasm (DA, 100%). 3D reconstructions of CT images were generated and, in the 4 cases of intraductal papillary mucinous neoplasm, the tumor was connected to the main pancreatic duct and multiple mural nodules were detected in one of these cases. The DA of the 3D-reconstructed images of cystic pancreatic tumors was 89.3%. The 64-slice spiral CT and 3D-reconstructed CT images facilitated the visualization of cystic pancreatic tumor characteristics, in particular the connections between the tumor and the main pancreatic duct. In conclusion, the 3D reconstruction of multi-slice CT data may provide an important source of information for the surgical team, in combination with the available clinical data. PMID:27073473

  9. Novel ultrahigh resolution data acquisition and image reconstruction for multi-detector row CT

    SciTech Connect

    Flohr, T. G.; Stierstorfer, K.; Suess, C.; Schmidt, B.; Primak, A. N.; McCollough, C. H.

    2007-05-15

    We present and evaluate a special ultrahigh resolution mode providing considerably enhanced spatial resolution both in the scan plane and in the z-axis direction for a routine medical multi-detector row computed tomography (CT) system. Data acquisition is performed by using a flying focal spot both in the scan plane and in the z-axis direction in combination with tantalum grids that are inserted in front of the multi-row detector to reduce the aperture of the detector elements both in-plane and in the z-axis direction. The dose utilization of the system for standard applications is not affected, since the grids are moved into place only when needed and are removed for standard scanning. By means of this technique, image slices with a nominal section width of 0.4 mm (measured full width at half maximum=0.45 mm) can be reconstructed in spiral mode on a CT system with a detector configuration of 32x0.6 mm. The measured 2% value of the in-plane modulation transfer function (MTF) is 20.4 lp/cm, the measured 2% value of the longitudinal (z axis) MTF is 21.5 lp/cm. In a resolution phantom with metal line pair test patterns, spatial resolution of 20 lp/cm can be demonstrated both in the scan plane and along the z axis. This corresponds to an object size of 0.25 mm that can be resolved. The new mode is intended for ultrahigh resolution bone imaging, in particular for wrists, joints, and inner ear studies, where a higher level of image noise due to the reduced aperture is an acceptable trade-off for the clinical benefit brought about by the improved spatial resolution.

  10. Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT.

    PubMed

    Sauerbier, Sebastian; Duttenhoefer, Fabian; Sachlos, Elefterios; Haberstroh, Jörg; Scheifele, Christian; Wrbas, Karl-Thomas; Voss, Pit Jacob; Veigel, Egle; Smedek, Jörg; Ganter, Philip; Tuna, Taskin; Gutwald, Ralf; Palmowski, Moritz

    2013-10-01

    Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

  11. An ancient Roman bowl embedded in a soil sample: surface shaded three dimensional display using data from a multi-detector CT.

    PubMed

    De Maeseneer, M; Buls, N; Cleeren, N; Lenchik, L; De Mey, J

    2006-01-01

    We present an unusual application of multidetector CT and shaded surface rendering in the investigation of a soil sample, containing an ancient Roman bronze bowl. The CT findings were of fundamental importance in helping the archaeologists study the bronze bowl from the soil sample.

  12. A method of estimating conceptus doses resulting from multidetector CT examinations during all stages of gestation

    SciTech Connect

    Damilakis, John; Tzedakis, Antonis; Perisinakis, Kostas; Papadakis, Antonios E.

    2010-12-15

    Purpose: Current methods for the estimation of conceptus dose from multidetector CT (MDCT) examinations performed on the mother provide dose data for typical protocols with a fixed scan length. However, modified low-dose imaging protocols are frequently used during pregnancy. The purpose of the current study was to develop a method for the estimation of conceptus dose from any MDCT examination of the trunk performed during all stages of gestation. Methods: The Monte Carlo N-Particle (MCNP) radiation transport code was employed in this study to model the Siemens Sensation 16 and Sensation 64 MDCT scanners. Four mathematical phantoms were used, simulating women at 0, 3, 6, and 9 months of gestation. The contribution to the conceptus dose from single simulated scans was obtained at various positions across the phantoms. To investigate the effect of maternal body size and conceptus depth on conceptus dose, phantoms of different sizes were produced by adding layers of adipose tissue around the trunk of the mathematical phantoms. To verify MCNP results, conceptus dose measurements were carried out by means of three physical anthropomorphic phantoms, simulating pregnancy at 0, 3, and 6 months of gestation and thermoluminescence dosimetry (TLD) crystals. Results: The results consist of Monte Carlo-generated normalized conceptus dose coefficients for single scans across the four mathematical phantoms. These coefficients were defined as the conceptus dose contribution from a single scan divided by the CTDI free-in-air measured with identical scanning parameters. Data have been produced to take into account the effect of maternal body size and conceptus position variations on conceptus dose. Conceptus doses measured with TLD crystals showed a difference of up to 19% compared to those estimated by mathematical simulations. Conclusions: Estimation of conceptus doses from MDCT examinations of the trunk performed on pregnant patients during all stages of gestation can be made

  13. Multidetector-row CT with a 64-row amorphous silicon flat panel detector

    NASA Astrophysics Data System (ADS)

    Shapiro, Edward G.; Colbeth, Richard E.; Daley, Earl T.; Job, Isaias D.; Mollov, Ivan P.; Mollov, Todor I.; Pavkovich, John M.; Roos, Pieter G.; Star-Lack, Josh M.; Tognina, Carlo A.

    2007-03-01

    A unique 64-row flat panel (FP) detector has been developed for sub-second multidetector-row CT (MDCT). The intent was to explore the image quality achievable with relatively inexpensive amorphous silicon (a-Si) compared to existing diagnostic scanners with discrete crystalline diode detectors. The FP MDCT system is a bench-top design that consists of three FP modules. Each module uses a 30 cm x 3.3 cm a-Si array with 576 x 64 photodiodes. The photodiodes are 0.52 mm x 0.52 mm, which allows for about twice the spatial resolution of most commercial MDCT scanners. The modules are arranged in an overlapping geometry, which is sufficient to provide a full-fan 48 cm diameter scan. Scans were obtained with various detachable scintillators, e.g. ceramic Gd IIO IIS, particle-in-binder Gd IIO IIS:Tb and columnar CsI:Tl. Scan quality was evaluated with a Catphan-500 performance phantom and anthropomorphic phantoms. The FP MDCT scans demonstrate nearly equivalent performance scans to a commercial 16-slice MDCT scanner at comparable 10 - 20 mGy/100mAs doses. Thus far, a high contrast resolution of 15 lp/cm and a low contrast resolution of 5 mm @ 0.3 % have been achieved on 1 second scans. Sub-second scans have been achieved with partial rotations. Since the future direction of MDCT appears to be in acquiring single organ coverage per scan, future efforts are planned for increasing the number of detector rows beyond the current 64- rows.

  14. A new 3-D diagnosis strategy for duodenal malignant lesions using multidetector row CT, CT virtual duodenoscopy, duodenography, and 3-D multicholangiography.

    PubMed

    Sata, N; Endo, K; Shimura, K; Koizumi, M; Nagai, H

    2007-01-01

    Recent advances in multidetector row computed tomography (MD-CT) technology provide new opportunities for clinical diagnoses of various diseases. Here we assessed CT virtual duodenoscopy, duodenography, and three-dimensional (3D) multicholangiography created by MD-CT for clinical diagnosis of duodenal malignant lesions. The study involved seven cases of periduodenal carcinoma (four ampullary carcinomas, two duodenal carcinomas, one pancreatic carcinoma). Biliary contrast medium was administered intravenously, followed by intravenous administration of an anticholinergic agent and oral administration of effervescent granules for expanding the upper gastrointestinal tract. Following intravenous administration of a nonionic contrast medium, an upper abdominal MD-CT scan was performed in the left lateral position. Scan data were processed on a workstation to create CT virtual duodenoscopy, duodenography, 3D multicholangiography, and various postprocessing images, which were then evaluated for their effectiveness as preoperative diagnostic tools. Carcinoma location and extent were clearly demonstrated as defects or colored low-density areas in 3-D multicholangiography images and as protruding lesions in virtual duodenography and duodenoscopy images. These findings were confirmed using multiplanar or curved planar reformation images. In conclusion, CT virtual duodenoscopy, doudenography, 3-D multicholangiography, and various images created by MD-CT alone provided necessary and adequate preoperative diagnostic information.

  15. The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome

    PubMed Central

    Brown, I W; Peebles, C R; Harden, S P; Shambrook, J S

    2014-01-01

    The term “acute aortic syndrome” (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions. PMID:25083552

  16. Estimating radiation dose to organs of patients undergoing conventional and novel multidetector CT exams using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Angel, Erin

    Advances in Computed Tomography (CT) technology have led to an increase in the modality's diagnostic capabilities and therefore its utilization, which has in turn led to an increase in radiation exposure to the patient population. As a result, CT imaging currently constitutes approximately half of the collective exposure to ionizing radiation from medical procedures. In order to understand the radiation risk, it is necessary to estimate the radiation doses absorbed by patients undergoing CT imaging. The most widely accepted risk models are based on radiosensitive organ dose as opposed to whole body dose. In this research, radiosensitive organ dose was estimated using Monte Carlo based simulations incorporating detailed multidetector CT (MDCT) scanner models, specific scan protocols, and using patient models based on accurate patient anatomy and representing a range of patient sizes. Organ dose estimates were estimated for clinical MDCT exam protocols which pose a specific concern for radiosensitive organs or regions. These dose estimates include estimation of fetal dose for pregnant patients undergoing abdomen pelvis CT exams or undergoing exams to diagnose pulmonary embolism and venous thromboembolism. Breast and lung dose were estimated for patients undergoing coronary CTA imaging, conventional fixed tube current chest CT, and conventional tube current modulated (TCM) chest CT exams. The correlation of organ dose with patient size was quantified for pregnant patients undergoing abdomen/pelvis exams and for all breast and lung dose estimates presented. Novel dose reduction techniques were developed that incorporate organ location and are specifically designed to reduce close to radiosensitive organs during CT acquisition. A generalizable model was created for simulating conventional and novel attenuation-based TCM algorithms which can be used in simulations estimating organ dose for any patient model. The generalizable model is a significant contribution of this

  17. Monte Carlo simulations in multi-detector CT (MDCT) for two PET/CT scanner models using MASH and FASH adult phantoms

    NASA Astrophysics Data System (ADS)

    Belinato, W.; Santos, W. S.; Paschoal, C. M. M.; Souza, D. N.

    2015-06-01

    The combination of positron emission tomography (PET) and computed tomography (CT) has been extensively used in oncology for diagnosis and staging of tumors, radiotherapy planning and follow-up of patients with cancer, as well as in cardiology and neurology. This study determines by the Monte Carlo method the internal organ dose deposition for computational phantoms created by multidetector CT (MDCT) beams of two PET/CT devices operating with different parameters. The different MDCT beam parameters were largely related to the total filtration that provides a beam energetic change inside the gantry. This parameter was determined experimentally with the Accu-Gold Radcal measurement system. The experimental values of the total filtration were included in the simulations of two MCNPX code scenarios. The absorbed organ doses obtained in MASH and FASH phantoms indicate that bowtie filter geometry and the energy of the X-ray beam have significant influence on the results, although this influence can be compensated by adjusting other variables such as the tube current-time product (mAs) and pitch during PET/CT procedures.

  18. Diagnostic capability of gadoxetate disodium-enhanced liver MRI for diagnosis of hepatocellular carcinoma: comparison with multi-detector CT.

    PubMed

    Toyota, Naoyuki; Nakamura, Yuko; Hieda, Masashi; Akiyama, Naoko; Terada, Hiroaki; Matsuura, Noriaki; Nishiki, Masayo; Kono, Hirotaka; Kohno, Hiroshi; Irei, Toshimitsu; Yoshikawa, Yukinobu; Kuraoka, Kazuya; Taniyama, Kiyomi; Awai, Kazuo

    2013-09-01

    The purpose of this study was to evaluate the diagnostic capability of gadoxetate disodium (Gd-EOB)-MRI for the detection of hepatocellular carcinoma (HCC) compared with multidetector CT (MDCT). Fifty patients with 57 surgically proven HCCs who underwent Gd-EOB-MRI and MDCT from March 2008 to June 2011 were evaluated. Two observers evaluated MR and CT on a lesion-by-lesion basis. We analyzed sensitivity by grading on a 5-point scale, the degree of arterial enhancement and the differences in histological grades in the diffusion-weighted images (DWI). The results showed that the sensitivity of Gd-EOB-MRI was higher than that of MDCT especially for HCCs that were 1 cm in diameter or smaller. The hepatobiliary phase was useful for the detecting of small HCC. We had few cases in which it was difficult to judge HCC in the arterial enhancement between MRI and MDCT. In the diffusion-weighted image, well differentiated HCC tended to show a low signal intensity, and poorly differentiated HCC tended to show a high signal intensity. In moderately differentiated HCC's, the mean diameter of the high signal intensity group was larger than that of the low signal intensity group (24.5 mm vs. 15.8 mm). In conclusion, Gd-EOB-MRI tended to show higher sensitivity compared to MDCT in the detection of HCC.

  19. The radiological diagnosis of fenestral otosclerosis: the utility of histogram analysis using multidetector row CT.

    PubMed

    Yamashita, Koji; Yoshiura, Takashi; Hiwatashi, Akio; Togao, Osamu; Kikuchi, Kazufumi; Inoguchi, Takashi; Kumazawa, Seiji; Honda, Hiroshi

    2014-12-01

    Bone density measurements using high-resolution CT have been reported to be useful to diagnose fenestral otosclerosis. However, small region of interest (ROI) chosen by less-experienced radiologists may result in false-negative findings. Semi-automatic analysis such as CT histogram analysis may offer improved assessment. The aim of this study was to evaluate the utility of CT histogram analysis in diagnosing fenestral otosclerosis. Temporal bone CT of consecutive patients with otosclerosis and normal controls was retrospectively analyzed. The control group consisted of the normal-hearing contralateral ears of patients with otitis media, cholesteatoma, trauma, facial nerve palsy, or tinnitus. All CT images were obtained using a 64-detector-row CT scanner with 0.5-mm collimation. AROI encompassing 10 × 10 pixels was placed in the bony labyrinth located anterior to the oval window. The mean CT value, variance and entropy were compared between otosclerosis patients and normal controls using Student's t test. The number of pixels below mean minus SD in the control (%Lowcont) and total subjects (%Lowtotal) were also compared. In addition, the area under the receiver operating characteristic curves (AUC) value for the discrimination between otosclerosis patients and normal controls was calculated. 51 temporal bones of 38 patients with otosclerosis and 30 temporal bones of 30 control subjects were included. The mean CT value was significantly lower in otosclerosis cases than in normal controls (p < 0.01). In addition, variance, entropy, %Lowcont and %Lowtotal were significantly higher in otosclerosis cases than in normal controls (p < 0.01, respectively). The AUC values for the mean CT value, %Lowcont and %Lowtotal were 0.751, 0.760 and 0.765, respectively. In conclusion, our results demonstrated that histogram analysis of CT image may be of clinical value in diagnosing otosclerosis.

  20. Variants of the popliteal artery terminal branches as detected by multidetector ct angiography

    PubMed Central

    Oztekin, Pelin Seher; Ergun, Elif; Cıvgın, Esra; Yigit, Hasan; Kosar, Pınar Nercis

    2015-01-01

    Objective To evaluate variants of the popliteal artery (PA) terminal branches with 64-multidetector computed tomographic angiography (64-MD CTA). Materials and Methods A total of 495 extremities (251 right, 244 left) of 253 patients undergoing a 64-MD CTA examination were included in the study. Of these, 242 extremities were evaluated bilaterally, whereas 11 were evaluated unilaterally. The terminal branching pattern of the PA was classified according to the classification scheme proposed by Kim; the distance between the medial tibial plateau and the origin of the anterior tibial artery (A) and the length of the tibioperoneal trunk (B) have been measured and recorded. Results In 459 cases (92.7%) branching of PA occurred distal to the knee joint (Type I); in 18 cases (2.8%) PA branching was superior to the knee joint (Type II); and hypoplasia of the PA branches was found in 27 cases (5.5%) (Type III). Among these types the most frequent branching patterns were Type IA (87.5%), Type IIIA (3.9%), and Type IB (3.8%). The ranges of A and B mean distances were 47.6 mm and 29.6 mm, respectively Conclusion Variations in popliteal artery terminal branching pattern occurred in 7.4% to 17.6% of patients. Pre-surgical detection of these variations with MD CTA may help to reduce the risk of iatrogenic arterial injury by enabling a better surgical treatment plan. PMID:28352741

  1. Volume Changes of Experimental Carotid Sidewall Aneurysms Due to Embolization with Liquid Embolic Agents: A Multidetector CT Angiography Study

    SciTech Connect

    Dudeck, O. Okuducu, A. F.; Jordan, O.; Tesmer, K.; Pech, M.; Weigang, E.; Ruefenacht, D. A.; Doelker, E.; Felix, R.

    2006-12-15

    Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 {+-} 28.9%, whereas a significant shrinkage of 5.6 {+-} 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 {+-} 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm-another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.

  2. National Survey of Radiation Dose and Image Quality in Adult CT Head Scans in Taiwan

    PubMed Central

    Lin, Chung-Jung; Mok, Greta S. P.; Tsai, Mang-Fen; Tsai, Wei-Ta; Yang, Bang-Hung; Tu, Chun-Yuan; Wu, Tung-Hsin

    2015-01-01

    Introduction The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database. Materials and Methods Taiwan’s Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed. Results CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C. Conclusion CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices. PMID:26125549

  3. Can multidetector CT detect the site of gastrointestinal tract injury in trauma? – A retrospective study

    PubMed Central

    Panda, Ananya; Kumar, Atin; Gamanagatti, Shivanand; Das, Ranjita; Paliwal, Swati; Gupta, Amit; Kumar, Subodh

    2017-01-01

    PURPOSE We aimed to assess the performance of computed tomography (CT) in localizing site of traumatic gastrointestinal tract (GIT) injury and determine the diagnostic value of CT signs in site localization. METHODS CT scans of 97 patients with surgically proven GIT or mesenteric injuries were retrospectively reviewed by radiologists blinded to surgical findings. Diagnosis of either GIT or mesenteric injuries was made. In patients with GIT injuries, site of injury and presence of CT signs such as focal bowel wall hyperenhancement, hypoenhancement, wall discontinuity, wall thickening, extramural air, intramural air, perivisceral infiltration, and active vascular contrast leak were evaluated. RESULTS Out of 97 patients, 90 had GIT injuries (70 single site injuries and 20 multiple site injuries) and seven had isolated mesenteric injury. The overall concordance between CT and operative findings for exact site localization was 67.8% (61/90), partial concordance rate was 11.1% (10/90), and discordance rate was 21.1% (19/90). For single site localization, concordance rate was 77.1% (54/70), discordance rate was 21.4% (15/70), and partial concordance rate was 1.4% (1/70). In multiple site injury, concordance rate for all sites of injury was 35% (7/20), partial concordance rate was 45% (9/20), and discordance rate was 20% (4/20). For upper GIT injuries, wall discontinuity was the most accurate sign for localization. For small bowel injury, intramural air and hyperenhancement were the most specific signs for site localization, while for large bowel injury, wall discontinuity and hypoenhancement were the most specific signs. CONCLUSION CT performs better in diagnosing small bowel injury compared with large bowel injury. CT can well predict the presence of multiple site injury but has limited performance in exact localization of all injury sites. PMID:27924777

  4. Update on multidetector coronary CT angiography of coronary stents: in vitro evaluation of 29 different stent types with dual-source CT.

    PubMed

    Maintz, David; Burg, Matthias C; Seifarth, Harald; Bunck, Alexander C; Ozgün, Murat; Fischbach, Roman; Jürgens, Kai Uwe; Heindel, Walter

    2009-01-01

    The aim of this study was to test a large sample of the latest coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in dual-source multidetector row CT (DSCT) in vitro and to provide a CT catalogue of currently used coronary artery stents. Twenty-nine different coronary artery stents (19 steel, 6 cobalt-chromium, 2 tantalum, 1 iron, 1 magnesium) were examined in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70 HU). Stents were imaged in axial orientation with standard parameters: 32 x 0.6 collimation, pitch 0.24, 400 mAs, 120 kV, rotation time 0.33 s. Image reconstructions were obtained with four different convolution kernels (soft, medium-soft, standard high-resolution, stent-dedicated). To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density, and noise were measured. The stent-dedicated kernel offered best average lumen visualization (54 +/- 8.3%) and most realistic lumen attenuation (222 +/- 44 HU) at the expense of increased noise (23.9 +/- 1.9 HU) compared with standard CTA protocols (p < 0.001 for all). The magnesium stent showed the least artifacts with a lumen visibility of 90%. The majority of stents (79%) exhibited a lumen visibility of 50-59%. Less than half of the stent lumen was visible in only six stents. Stent lumen visibility largely varies depending on the stent type. Magnesium is by far more favorable a stent material with regard to CT imaging when compared with the more common materials steel, cobalt-chromium, or tantalum. The magnesium stent exhibits a lumen visibility of 90%, whereas the majority of the other stents exhibit a lumen visibility of 50-59%.

  5. A retrospective comparison of smart prep and test bolus multi-detector CT pulmonary angiography protocols

    SciTech Connect

    Suckling, Tara; Smith, Tony; Reed, Warren

    2013-06-15

    Optimal arterial opacification is crucial in imaging the pulmonary arteries using computed tomography (CT). This poses the challenge of precisely timing data acquisition to coincide with the transit of the contrast bolus through the pulmonary vasculature. The aim of this quality assurance exercise was to investigate if a change in CT pulmonary angiography (CTPA) scanning protocol resulted in improved opacification of the pulmonary arteries. Comparison was made between the smart prep protocol (SPP) and the test bolus protocol (TBP) for opacification in the pulmonary trunk. A total of 160 CTPA examinations (80 using each protocol) performed between January 2010 and February 2011 were assessed retrospectively. CT attenuation coefficients were measured in Hounsfield Units (HU) using regions of interest at the level of the pulmonary trunk. The average pixel value, standard deviation (SD), maximum, and minimum were recorded. For each of these variables a mean value was then calculated and compared for these two CTPA protocols. Minimum opacification of 200 HU was achieved in 98% of the TBP sample but only 90% of the SPP sample. The average CT attenuation over the pulmonary trunk for the SPP was 329 (SD = ±21) HU, whereas for the TBP it was 396 (SD = ±22) HU (P = 0.0017). The TBP also recorded higher maximum (P = 0.0024) and minimum (P = 0.0039) levels of opacification. This study has found that a TBP resulted in significantly better opacification of the pulmonary trunk than the SPP.

  6. A model for quantitative correction of coronary calcium scores on multidetector, dual source, and electron beam computed tomography for influences of linear motion, calcification density, and temporal resolution: A cardiac phantom study

    SciTech Connect

    Greuter, M. J. W.; Groen, J. M.; Nicolai, L. J.; Dijkstra, H.; Oudkerk, M.

    2009-11-15

    Purpose: The objective of this study is to quantify the influence of linear motion, calcification density, and temporal resolution on coronary calcium determination using multidetector computed tomography (MDCT), dual source CT (DSCT), and electron beam tomography (EBT) and to find a quantitative method which corrects for the influences of these parameters using a linear moving cardiac phantom. Methods: On a robotic arm with artificial arteries with four calcifications of increasing density, a linear movement was applied between 0 and 120 mm/s (step of 10 mm/s). The phantom was scanned five times on 64-slice MDCT, DSCT, and EBT using a standard acquisition protocol. The average Agatston, volume, and mass scores were determined for each velocity, calcification, and scanner. Susceptibility to motion was quantified using a cardiac motion susceptibility (CMS) index. Resemblance to EBT and physical volume and mass was quantified using a {Delta} index. Results: Increasing motion artifacts were observed at increasing velocities on all scanners, with increasing severity from EBT to DSCT to 64-slice MDCT. The calcium score showed a linear dependency on motion from which a correction factor could be derived. This correction factor showed a linear dependency on the mean calcification density with a good fit for all three scoring methods and all three scanners (0.73{<=}R{sup 2}{<=}0.95). The slope and offset of this correction factor showed a linear dependency on temporal resolution with a good fit for all three scoring methods and all three scanners (0.83{<=}R{sup 2}{<=}0.98). CMS was minimal for EBT and increasing values were observed for DSCT and highest values for 64-slice MDCT. CMS was minimal for mass score and increasing values were observed for volume score and highest values for Agatston score. For all densities and scoring methods DSCT showed on average the closest resemblance to EBT calcium scores. When using the correction factor, CMS index decreased on average by

  7. Automated characterization of normal and pathologic lung tissue by topological texture analysis of multidetector CT

    NASA Astrophysics Data System (ADS)

    Boehm, H. F.; Fink, C.; Becker, C.; Reiser, M.

    2007-03-01

    Reliable and accurate methods for objective quantitative assessment of parenchymal alterations in the lung are necessary for diagnosis, treatment and follow-up of pulmonary diseases. Two major types of alterations are pulmonary emphysema and fibrosis, emphysema being characterized by abnormal enlargement of the air spaces distal to the terminal, nonrespiratory bronchiole, accompanied by destructive changes of the alveolar walls. The main characteristic of fibrosis is coursening of the interstitial fibers and compaction of the pulmonary tissue. With the ability to display anatomy free from superimposing structures and greater visual clarity, Multi-Detector-CT has shown to be more sensitive than the chest radiograph in identifying alterations of lung parenchyma. In automated evaluation of pulmonary CT-scans, quantitative image processing techniques are applied for objective evaluation of the data. A number of methods have been proposed in the past, most of which utilize simple densitometric tissue features based on the mean X-ray attenuation coefficients expressed in terms of Hounsfield Units [HU]. Due to partial volume effects, most of the density-based methodologies tend to fail, namely in cases, where emphysema and fibrosis occur within narrow spatial limits. In this study, we propose a methodology based upon the topological assessment of graylevel distribution in the 3D image data of lung tissue which provides a way of improving quantitative CT evaluation. Results are compared to the more established density-based methods.

  8. [Comparison of a dental cone beam CT with a multi-detector row CT on effective doses and physical image quality].

    PubMed

    Yoshida, Yutaka; Tokumori, Kenji; Okamura, Kazutoshi; Yoshiura, Kazunori

    2011-01-01

    The purpose of this study was to compare a dental cone beam computed tomography (dental CBCT) and a multi-detector row CT (MDCT) using effective doses and physical image quality. A dental mode (D-mode) and an implant mode (I-mode) were employed for calculating effective doses. Field of view (FOV) size of the MDCT was 150 mm. Three types of images were obtained using 3 different reconstruction functions: FC1 (for abdomen images), FC30 (for internal ear and bone images) and FC81 (for high resolution images). Effective doses obtained with the D-mode and with the I-mode were about 20% and 50% of those obtained with the MDCT, respectively. Resolution properties obtained with the D-mode and I-mode were superior to that of the MDCT in a high frequency range. Noise properties of the D-mode and the I-mode were better than those with FC81. It was found that the dental CBCT has better potential as compared with MDCT in both dental and implant modes.

  9. Split-Bolus Single-Pass Multidetector-Row CT Protocol for Diagnosis of Acute Pulmonary Embolism

    PubMed Central

    Scialpi, Michele; Rebonato, Alberto; Cagini, Lucio; Brunese, Luca; Piscioli, Irene; Pierotti, Luisa; Bellantonio, Lucio; D’Andrea, Alfredo; Rotondo, Antonio

    2016-01-01

    Background: Currently computed tomography pulmonary angiography (CTPA) has become a widely accepted clinical tool in the diagnosis of acute pulmonary embolism (PE). Objectives: To report split-bolus single-pass 64-multidetector-row CT (MDCT) protocol for diagnosis of PE. Patients and Methods: MDCT split-bolus results in 40 patients suspicious of PE were analyzed in terms of image quality of target pulmonary vessels (TPVs) and occurrence and severity of flow-related artifact, flow-related artifact, false filling defect of the pulmonary veins and beam hardening streak artifacts. Dose radiation to patients was calculated. Results: MDCT split-bolus protocol allowed diagnostic images of high quality in all cases. Diagnosis of PE was obtained in 22 of 40 patients. Mean attenuation for target vessels was higher than 250 HU all cases: 361 ± 98 HU in pulmonary artery trunk (PAT); 339 ± 93 HU in right pulmonary artery (RPA); 334 ± 100 HU in left pulmonary artery (LPA). Adequate enhancement was obtained in the right atrium (RA):292 ± 83 HU; right pulmonary vein (RPV): 302 ± 91 HU, and left pulmonary vein (LPV): 291 ± 83 HU. The flow related artifacts and the beam hardening streak artifacts have been detected respectively in 4 and 25 patients. No false filling defect of the pulmonary veins was revealed. Conclusion: MDCT split-bolus technique by simultaneous opacification of pulmonary arteries and veins represents an accurate technique for diagnosis of acute PE, removes the false filling defects of the pulmonary veins, and reduces flow related artifacts. PMID:27110334

  10. Voxel-Based Sensitivity of Flat-Panel CT for the Detection of Intracranial Hemorrhage: Comparison to Multi-Detector CT

    PubMed Central

    Frölich, Andreas M.; Buhk, Jan-Hendrik; Fiehler, Jens; Kemmling, Andre

    2016-01-01

    Objectives Flat-panel CT (FPCT) allows cross-sectional parenchymal, vascular and perfusion imaging within the angiography suite, which could greatly facilitate acute stroke management. We hypothesized that FPCT offers equal diagnostic accuracy compared to multi-detector CT (MDCT) as a primary tool to exclude intracranial hemorrhage. Methods 22 patients with intracranial hematomas who had both MDCT and FPCT performed within 24 hours were retrospectively identified. Patients with visible change in hematoma size or configuration were excluded. Two raters independently segmented hemorrhagic lesions. Data sets and corresponding binary lesion maps were co-registered to compare hematoma volume. Diagnostic accuracy of FPCT to detect hemorrhage was calculated from voxel-wise analysis of lesion overlap compared to reference MDCT. Results Mean hematoma size was similar between MDCT (16.2±8.9 ml) and FPCT (16.1±8.6 ml), with near perfect correlation of hematoma sizes between modalities (ρ = 0.95, p<0.001). Sensitivity and specificity of FPCT to detect hemorrhagic voxels was 61.6% and 99.8% for intraventricular hematomas and 67.7% and 99.5% for all other intracranial hematomas. Conclusions In this small sample containing predominantly cases with subarachnoid hemorrhage, FPCT based assessment of hemorrhagic volume in brain yields acceptable accuracy compared to reference MDCT, albeit with a limited sensitivity on a voxel level. Further assessment and improvement of FPCT is necessary before it can be applied as a primary imaging modality to exclude intracranial hemorrhage in acute stroke patients. PMID:27806106

  11. Crossed Fused Renal Ectopia: Presentations on 99mTc-MAG3 Scan, 99mTc-DMSA SPECT, and Multidetector CT.

    PubMed

    Moon, Eun Ha; Kim, Min-Woo; Kim, Young Jun; Sun, In O

    2015-10-01

    Crossed renal ectopia is an uncommon developmental anomaly in which both kidneys are located on the same side of the body. The present case describes a 20-year-old man who underwent the military entrance physical examination. The ultrasound showed the right kidney in normal site with slightly increased size, but the left kidney was not identified. Tc-MAG3 scan showed a single kidney with 2 ureters, and the orifices of the ureters were connected at both sides of bladder. Tc-DMSA SPECT and contrast-enhanced multidetector CT were performed and revealed crossed fused renal ectopia.

  12. Improving Image Quality of On-Board Cone-Beam CT in Radiation Therapy Using Image Information Provided by Planning Multi-Detector CT: A Phantom Study

    PubMed Central

    Yang, Ching-Ching; Chen, Fong-Lin; Lo, Yeh-Chi

    2016-01-01

    Purpose The aim of this study was to improve the image quality of cone-beam computed tomography (CBCT) mounted on the gantry of a linear accelerator used in radiation therapy based on the image information provided by planning multi-detector CT (MDCT). Methods MDCT-based shading correction for CBCT and virtual monochromatic CT (VMCT) synthesized using the dual-energy method were performed. In VMCT, the high-energy data were obtained from CBCT, while the low-energy data were obtained from MDCT. An electron density phantom was used to investigate the efficacy of shading correction and VMCT on improving the target detectability, Hounsfield unit (HU) accuracy and variation, which were quantified by calculating the contrast-to-noise ratio (CNR), the percent difference (%Diff) and the standard deviation of the CT numbers for tissue equivalent background material, respectively. Treatment plan studies for a chest phantom were conducted to investigate the effects of image quality improvement on dose planning. Results For the electron density phantom, the mean value of CNR was 17.84, 26.78 and 34.31 in CBCT, shading-corrected CBCT and VMCT, respectively. The mean value of %Diff was 152.67%, 11.93% and 7.66% in CBCT, shading-corrected CBCT and VMCT, respectively. The standard deviation within a uniform background of CBCT, shading-corrected CBCT and VMCT was 85, 23 and 15 HU, respectively. With regards to the chest phantom, the monitor unit (MU) difference between the treatment plan calculated using MDCT and those based on CBCT, shading corrected CBCT and VMCT was 6.32%, 1.05% and 0.94%, respectively. Conclusions Enhancement of image quality in on-board CBCT can contribute to daily patient setup and adaptive dose delivery, thus enabling higher confidence in patient treatment accuracy in radiation therapy. Based on our results, VMCT has the highest image quality, followed by the shading corrected CBCT and the original CBCT. The research results presented in this study should be

  13. Pulmonary adenocarcinomas presenting as ground-glass opacities on multidetector CT: three-dimensional computer-assisted analysis of growth pattern and doubling time

    PubMed Central

    Borghesi, Andrea; Farina, Davide; Michelini, Silvia; Ferrari, Matteo; Benetti, Diego; Fisogni, Simona; Tironi, Andrea; Maroldi, Roberto

    2016-01-01

    PURPOSE We aimed to evaluate the growth pattern and doubling time (DT) of pulmonary adenocarcinomas exhibiting ground-glass opacities (GGOs) on multidetector computed tomography (CT). METHODS The growth pattern and DT of 22 pulmonary adenocarcinomas exhibiting GGOs were retrospectively analyzed using three-dimensional semiautomatic software. Analysis of each lesion was based on calculations of volume and mass changes and their respective DTs throughout CT follow-up. Three-dimensional segmentation was performed by a single radiologist on each CT scan. The same observer and another radiologist independently repeated the segmentation at the baseline and the last CT scan to determine the variability of the measurements. The relationships among DTs, histopathology, and initial CT features of the lesions were also analyzed. RESULTS Pulmonary adenocarcinomas presenting as GGOs exhibited different growth patterns: some lesions grew rapidly and some grew slowly, whereas others alternated between periods of growth, stability, or shrinkage. A significant increase in volume and mass that exceeded the coefficient of repeatability of interobserver variability was observed in 72.7% and 84.2% of GGOs, respectively. The volume-DTs and mass-DTs were heterogeneous throughout the follow-up CT scan (range, −4293 to 21928 and −3113 to 17020 days, respectively), and their intra- and interobserver variabilities were moderately high. The volume-DTs and mass-DTs were not correlated with the initial CT features of GGOs; however, they were significantly shorter in invasive adenocarcinomas (P = 0.002 and P = 0.001, respectively). CONCLUSION Pulmonary adenocarcinomas exhibiting GGOs show heterogeneous growth patterns with a trend toward a progressive increase in size. DTs may be useful for predicting tumor aggressiveness. PMID:27682741

  14. 64 slice-coronary computed tomography sensitivity and specificity in the evaluation of coronary artery bypass graft stenosis: A meta-analysis.

    PubMed

    Barbero, Umberto; Iannaccone, Mario; d'Ascenzo, Fabrizio; Barbero, Cristina; Mohamed, Abdirashid; Annone, Umberto; Benedetto, Sara; Celentani, Dario; Gagliardi, Marco; Moretti, Claudio; Gaita, Fiorenzo

    2016-08-01

    A non-invasive approach to define grafts patency and stenosis in the follow-up of coronary artery bypass graft (CABG) patients may be an interesting alternative to coronary angiography. 64-slice-coronary computed tomography is nowadays a diffused non-invasive method that permits an accurate evaluation of coronary stenosis, due to a high temporal and spatial resolution. However, its sensitivity and specificity in CABG evaluation has to be clearly defined, since published studies used different protocols and scanners. We collected all studies investigating patients with stable symptoms and previous CABG and reporting the comparison between diagnostic performances of invasive coronary angiography and 64-slice-coronary computed tomography. As a result, sensitivity and specificity of 64-slice-coronary computed tomography for CABG occlusion were 0.99 (95% CI 0.97-1.00) and 0.99 (95% CI: 0.99-1.00) with an area under the curve (AUC) of 0.99. 64-slice-coronary computed tomography sensitivity and specificity for the presence of any CABG stenosis >50% were 0.98 (95% CI: 0.97-0.99) and 0.98 (95% CI: 0.96-0.98), while AUC was 0.99. At meta-regression, neither the age nor the time from graft implantation had effect on sensitivity and specificity of 64-slice-coronary computed tomography detection of significant CABG stenosis or occlusion. In conclusion 64-slice-coronary computed tomography confirmed its high sensitivity and specificity in CABG stenosis or occlusion evaluation.

  15. The role of 64-slice CT following perfusion with iohexol via the hepatopancreatic ampulla in assessing pancreaticobiliary junctions.

    PubMed

    Guo, Wan-Liang; Bai, Xue-Jie; Huang, Shun-Gen; Fang, Lin; Wang, Jian

    2015-07-01

    The aim of this study was to delineate the structure of the pancreatic and biliary ducts in premature infants using a novel imaging method. The duodenal papillae of 30 premature infant cadavers were dissected. The pancreatic and biliary ducts were visualized using 64-detector multislice spiral computed tomography (MSCT). Contrast agent was injected into the duodenal papilla via the hepatopancreatic ampulla of Vater. MSCT scanning revealed both the pancreatic and biliary ducts as well as the common channel in 18 cases. The bile duct was visualized in the remaining 12 cases. Four patterns of the pancreaticobiliary ductal junction were noted: Y-type (73.3%), U-type (13.3%), V-type (6.7%), and II-type (6.7%). The results showed that MSCT and three-dimensional reconstruction can be used to visualize the junction pattern and common channel of the pancreatic and biliary ducts, and the structure of the surrounding tissue, in premature infants.

  16. Dosimetric characterization and image quality evaluation of the AIRO mobile CT scanner.

    PubMed

    Weir, Victor J; Zhang, Jie; Bruner, Angela P

    2015-01-01

    Radiation dose and image quality from a recently introduced mobile CT imaging system are presented. Radiation dose was measured using a conventional 100 mm pencil ionization chamber and CT polymethylmetacrylate (PMMA) body and head phantoms. Image quality was evaluated with a CATPHAN 500 phantom. Spatial resolution, low contrast resolution, Modulation Transfer Function (MTF), and Normalized Noise Power Spectrum (NNPS) were analyzed. Radiation dose and image quality were compared to those from a multi-detector CT scanner (Siemens Sensation 64). Under identical technique factors radiation dose (mGy/mAs) from the AIRO mobile CT system (AIRO) is higher than that from a 64 slice CT scanner. Based on MTF analysis, both Soft and Standard filters of the AIRO system lost resolution quickly compared to the Sensation 64 slice CT. The Siemens scanner had up to 7 lp/cm for the head FOV and H40 kernel and up to 5 lp/cm at body FOV for the B40f kernel. The Standard kernel in the AIRO system was evaluated to have 3 lp/cm and 4 lp/cm for the body and head FOVs respectively. NNPS of the AIRO shows low frequency noise due to ring-like artifacts which may be caused by detector calibration or lack of artifact reducing image post-processing. Due to a higher dose in terms of mGy/mAs at both head and body FOV, the contrast to noise ratio is higher in the AIRO system than in the Siemens scanner. However detectability of the low contrast objects is poorer in the AIRO due to the presence of ring artifacts in the location of the targets.

  17. Coronary artery calcium measurement with multi-detector row CT: in vitro assessment of effect of radiation dose.

    PubMed

    Hong, Cheng; Bae, Kyongtae T; Pilgram, Thomas K; Suh, Jongdae; Bradley, David

    2002-12-01

    The authors assessed in vitro the effect of radiation dose on coronary artery calcium quantification with multi-detector row computed tomography. A cardiac phantom with calcified cylinders was scanned at various milliampere second settings (20-160 mAs). A clear tendency was found for image noise to decrease as tube current increased (P <.001). No tendency was found for the Agatson score or calcium volume and mass errors to vary with tube current. Calcium measurements were not significantly affected by the choice of tube current. Calcium mass error was strongly correlated with calcium volume error (P <.001). The calcium mass measurement was more accurate and less variable than the calcium volume measurement.

  18. Validity of blood flow measurement using 320 multi-detectors CT and first-pass distribution theory: a phantom study

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Yu, Xuefang; Xu, Shaopeng; Zhou, Kenneth J.

    2015-03-01

    To evaluate the feasibility of measuring the myocardial blood flow using 320 row detector CT by first-pass technique. Heart was simulated with a container that was filled with pipeline of 3mm diameter; coronary artery was simulated with a pipeline of 2 cm diameter and connected with the simulated heart. The simulated coronary artery was connected with a big container with 1500 ml saline and 150ml contrast agent. One pump linking with simulated heart will withdraw with a speed of 10 ml/min, 15 ml/min, 20 ml/min, 25 ml/min and 30 ml/min. First CT scan starts after 30 s of pumpback with certain speed. The second CT scan starts 5 s after first CT scans. CT images processed as follows: The second CT scan images subtract first CT scan images, calculate the increase of CT value of simulated heart and the CT value of the unit volume of simulated coronary artery and then to calculate the total inflow of myocardial blood flow. CT myocardial blood flows were calculated as: 0.94 ml/s, 2.09 ml/s, 2.74 ml/s, 4.18 ml/s, 4.86 ml/s. The correlation coefficient is 0.994 and r2 = 0.97. The method of measuring the myocardial blood flow using 320 row detector CT by 2 scans is feasible. It is possible to develop a new method for quantitatively and functional assessment of myocardial perfusion blood flow with less radiation does.

  19. Comparison between blinded and partially blinded detection of gastric cancer with multidetector CT using surgery and endoscopic submucosal dissection as reference standards.

    PubMed

    Kim, H J; Lee, D H; Ko, Y T

    2010-08-01

    The aim of this study is to compare blinded with partially blinded detection of gastric cancer with multidetector (MD) CT by using surgery and endoscopic submucosal dissection (ESD) as reference standards. 44 patients with gastric cancer underwent MDCT with air as an oral contrast agent. Surgery was performed on 37 patients, ESD on six and surgery after ESD on one. To provide comparison cases of blinded evaluation, 38 MDCT examinations were added for cases where no focal gastric lesion was seen on endoscopy. Two radiologists, blinded to the presence, number and location of the tumours, evaluated axial and axial plus multiplanar reformation (MPR) images of 82 MDCT examinations with or without gastric cancer. For partially blinded evaluation, the same radiologists, blinded to the location and number of tumours, evaluated axial and axial plus MPR images of 44 MDCT examinations of gastric cancer. Differences in assessment were resolved by consensus. 45 gastric cancers were found in surgical and ESD specimens. Detection rates of gastric cancer from axial and axial plus MPR images during blinded evaluation and from axial and axial plus MPR images during partially blinded evaluation were 62% (28/45), 64% (29/45), 64% (29/45) and 71% (32/45), respectively. There was no statistical significance for the comparison between blinded and partially blinded detection rates of gastric cancer. The detection rate of gastric cancer with MDCT during blinded evaluation showed no specific difference compared with the detection rate of gastric cancer with MDCT during partially blinded evaluation.

  20. The Role of Three-Dimensional Multidetector CT Gastrography in the Preoperative Imaging of Stomach Cancer: Emphasis on Detection and Localization of the Tumor

    PubMed Central

    Kim, Jin Woong; Heo, Suk Hee; Lim, Hyo Soon; Lim, Nam Yeol; Park, Young Kyu; Jeong, Yong Yeon; Kang, Heoung Keun

    2015-01-01

    Multidetector CT (MDCT) gastrography has been regarded as a promising technique for the preoperative imaging of gastric cancer. It has the ability to produce various three-dimensional (3D) images. Because 3D reconstruction images are more effective and intuitive for recognizing abnormal changes in the gastric folds and subtle mucosal nodularity than two-dimensional images, 3D MDCT gastrography can enhance the detection rate of early gastric cancer, which, in turn, contributes to the improvement of the accuracy of preoperative tumor (T) staging. In addition, shaded surface display and tissue transition projection images provide a global view of the stomach, with the exact location of gastric cancer, which may replace the need for barium studies. In this article, we discuss technical factors in producing high-quality MDCT gastrographic images and present cases demonstrating the usefulness of MDCT gastrography for the detection and T staging of gastric cancer while emphasizing the significance of preoperative localization of gastric cancer in terms of surgical margin. PMID:25598676

  1. Experimental benchmarking of a Monte Carlo dose simulation code for pediatric CT

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Samei, Ehsan; Yoshizumi, Terry; Colsher, James G.; Jones, Robert P.; Frush, Donald P.

    2007-03-01

    In recent years, there has been a desire to reduce CT radiation dose to children because of their susceptibility and prolonged risk for cancer induction. Concerns arise, however, as to the impact of dose reduction on image quality and thus potentially on diagnostic accuracy. To study the dose and image quality relationship, we are developing a simulation code to calculate organ dose in pediatric CT patients. To benchmark this code, a cylindrical phantom was built to represent a pediatric torso, which allows measurements of dose distributions from its center to its periphery. Dose distributions for axial CT scans were measured on a 64-slice multidetector CT (MDCT) scanner (GE Healthcare, Chalfont St. Giles, UK). The same measurements were simulated using a Monte Carlo code (PENELOPE, Universitat de Barcelona) with the applicable CT geometry including bowtie filter. The deviations between simulated and measured dose values were generally within 5%. To our knowledge, this work is one of the first attempts to compare measured radial dose distributions on a cylindrical phantom with Monte Carlo simulated results. It provides a simple and effective method for benchmarking organ dose simulation codes and demonstrates the potential of Monte Carlo simulation for investigating the relationship between dose and image quality for pediatric CT patients.

  2. Assessment of organ absorbed doses and estimation of effective doses from pediatric anthropomorphic phantom measurements for multi-detector row CT with and without automatic exposure control.

    PubMed

    Brisse, Hervé J; Robilliard, Magalie; Savignoni, Alexia; Pierrat, Noelle; Gaboriaud, Geneviève; De Rycke, Yann; Neuenschwander, Sylvia; Aubert, Bernard; Rosenwald, Jean-Claude

    2009-10-01

    This study was designed to measure organ absorbed doses from multi-detector row computed tomography (MDCT) on pediatric anthropomorphic phantoms, calculate the corresponding effective doses, and assess the influence of automatic exposure control (AEC) in terms of organ dose variations. Four anthropomorphic phantoms (phantoms represent the equivalent of a newborn, 1-, 5-, and 10-y-old child) were scanned with a four-channel MDCT coupled with a z-axis-based AEC system. Two CT torso protocols were compared: a first protocol without AEC and constant tube current-time product and a second protocol with AEC using age-adjusted noise indices. Organ absorbed doses were monitored by thermoluminescent dosimeters (LiF: Mg, Cu, P). Effective doses were calculated according to the tissue weighting factors of the International Commission on Radiological Protection (). For fixed mA acquisitions, organ doses normalized to the volume CT dose index in a 16-cm head phantom (CTDIvol16) ranged from 0.6 to 1.5 and effective doses ranged from 8.4 to 13.5 mSv. For the newborn-equivalent phantom, the AEC-modulated scan showed almost no significant dose variation compared to the fixed mA scan. For the 1-, 5- and 10-y equivalent phantoms, the use of AEC induced a significant dose decrease on chest organs (ranging from 61 to 31% for thyroid, 37 to 21% for lung, 34 to 17% for esophagus, and 39 to 10% for breast). However, AEC also induced a significant dose increase (ranging from 28 to 48% for salivary glands, 22 to 51% for bladder, and 24 to 70% for ovaries) related to the high density of skull base and pelvic bones. These dose increases should be considered before using AEC as a dose optimization tool in children.

  3. Estimating radiation doses from multidetector CT using Monte Carlo simulations: effects of different size voxelized patient models on magnitudes of organ and effective dose.

    PubMed

    DeMarco, J J; Cagnon, C H; Cody, D D; Stevens, D M; McCollough, C H; Zankl, M; Angel, E; McNitt-Gray, M F

    2007-05-07

    The purpose of this work is to examine the effects of patient size on radiation dose from CT scans. To perform these investigations, we used Monte Carlo simulation methods with detailed models of both patients and multidetector computed tomography (MDCT) scanners. A family of three-dimensional, voxelized patient models previously developed and validated by the GSF was implemented as input files using the Monte Carlo code MCNPX. These patient models represent a range of patient sizes and ages (8 weeks to 48 years) and have all radiosensitive organs previously identified and segmented, allowing the estimation of dose to any individual organ and calculation of patient effective dose. To estimate radiation dose, every voxel in each patient model was assigned both a specific organ index number and an elemental composition and mass density. Simulated CT scans of each voxelized patient model were performed using a previously developed MDCT source model that includes scanner specific spectra, including bowtie filter, scanner geometry and helical source path. The scan simulations in this work include a whole-body scan protocol and a thoracic CT scan protocol, each performed with fixed tube current. The whole-body scan simulation yielded a predictable decrease in effective dose as a function of increasing patient weight. Results from analysis of individual organs demonstrated similar trends, but with some individual variations. A comparison with a conventional dose estimation method using the ImPACT spreadsheet yielded an effective dose of 0.14 mSv mAs(-1) for the whole-body scan. This result is lower than the simulations on the voxelized model designated 'Irene' (0.15 mSv mAs(-1)) and higher than the models 'Donna' and 'Golem' (0.12 mSv mAs(-1)). For the thoracic scan protocol, the ImPACT spreadsheet estimates an effective dose of 0.037 mSv mAs(-1), which falls between the calculated values for Irene (0.042 mSv mAs(-1)) and Donna (0.031 mSv mAs(-1)) and is higher relative

  4. Investigation of sinonasal anatomy via low-dose multidetector CT examination in chronic rhinosinusitis patients with higher risk for perioperative complications.

    PubMed

    Fraczek, Marcin; Guzinski, Maciej; Morawska-Kochman, Monika; Krecicki, Tomasz

    2017-02-01

    The aim of the study was to compare visualisation of the surgically relevant anatomical structures via low- and standard-dose multidetector CT protocol in patients with chronic rhinosinusitis (CRS) and higher risk for perioperative complications (i.e. presence of bronchial asthma, history of sinus surgery and advanced nasal polyposis). 135 adult CRS patients were divided randomly into standard-dose (120 kVp, 100 mAs) or low-dose CT groups (120 kVp, 45 mAs). The detectability of the vital anatomical structures (anterior ethmoid artery, optic nerve, cribriform plate and lamina papyracea) was scored using a five-point scale (from excellent to unacceptable) by a radiologist and sinus surgeon. Polyp sizes were quantified endoscopically according to the Lildholdt's scale (LS). Olfactory function was tested with the "Sniffin' Sticks" test. On the low-dose CT images, detectability ranged from 2.42 (better than poor) for cribriform plate among anosmic cases to 4.11 (better than good) for lamina papyracea in cases without nasal polyps. Identification of lamina papyracea on low-dose scans was significantly worse in each group and the same was the case with cribriform plates in patients with advanced polyposis and anosmia. Cribriform plates were the most poorly identified (between poor and average) among all the structures on low-dose images. Identification of anterior ethmoid artery (AEA) with reduced dose was insignificantly worse than with standard-dose examination. The AEA was scored as an average-defined structure and was the second weakest visualised. In conclusion, preoperatively, low-dose protocols may not sufficiently visualise the surgically relevant anatomical structures in patients with CRS and bronchial asthma, advanced nasal polyps (LS > 2) and history of sinus surgery. Low mAs value enables comparable detectability of sinonasal landmarks with standard-dose protocols in patients without analysed risk factors. In the context of planned surgery, the current

  5. Development of adaptive noise reduction filter algorithm for pediatric body images in a multi-detector CT

    NASA Astrophysics Data System (ADS)

    Nishimaru, Eiji; Ichikawa, Katsuhiro; Okita, Izumi; Ninomiya, Yuuji; Tomoshige, Yukihiro; Kurokawa, Takehiro; Ono, Yutaka; Nakamura, Yuko; Suzuki, Masayuki

    2008-03-01

    Recently, several kinds of post-processing image filters which reduce the noise of computed tomography (CT) images have been proposed. However, these image filters are mostly for adults. Because these are not very effective in small (< 20 cm) display fields of view (FOV), we cannot use them for pediatric body images (e.g., premature babies and infant children). We have developed a new noise reduction filter algorithm for pediatric body CT images. This algorithm is based on a 3D post-processing in which the output pixel values are calculated by nonlinear interpolation in z-directions on original volumetric-data-sets. This algorithm does not need the in-plane (axial plane) processing, so the spatial resolution does not change. From the phantom studies, our algorithm could reduce SD up to 40% without affecting the spatial resolution of x-y plane and z-axis, and improved the CNR up to 30%. This newly developed filter algorithm will be useful for the diagnosis and radiation dose reduction of the pediatric body CT images.

  6. Angular on-line tube current modulation in multidetector CT examinations of children and adults: The influence of different scanning parameters on dose reduction

    SciTech Connect

    Papadakis, Antonios E.; Perisinakis, Kostas; Damilakis, John

    2007-07-15

    The purpose of this study was to assess the potential of angular on-line tube current modulation on dose reduction in pediatric and adult patients undergoing multidetector computed tomography (MDCT) examinations. Five physical anthropomorphic phantoms that simulate the average individual as neonate, 1-year-old, 5-year-old, 10-year-old, and adult were employed in the current study. Phantoms were scanned with the use of on-line tube current modulation (TCM). Percent dose reduction (%DR) factors achieved by applying TCM, were determined for standard protocols used for head and neck, shoulder, thorax, thorax and abdomen, abdomen, abdomen and pelvis, pelvis, and whole body examinations. A preliminary study on the application of TCM in MDCT examinations of adult patients was performed to validate the results obtained in anthropomorphic phantoms. Dose reduction was estimated as the percentage difference of the modulated milliamperes for each scan and the preset milliamperes prescribed by the scan protocol. The dose reduction in children was found to be much lower than the corresponding reduction achieved for adults. For helical scans the %DR factors, ranged between 1.6% and 7.4% for the neonate, 2.9% and 8.7% for the 1-year old, 2% and 6% for the 5-year-old, 5% and 10.9% for the 10-year-old, and 10.4% and 20.7% for the adult individual. For sequential scans the corresponding %DR factors ranged between 1.3% and 6.7%, 4.5% and 11%, 4.2% and 6.6%, 6.4% and 12.3%, and 8.9% and 23.3%, respectively. Broader beam collimations are associated with decreased %DR factors, when other scanning parameters are held constant. TCM did not impair image noise. In adult patients, the %DR values were found to be in good agreement with the corresponding results obtained in the anthropomorphic adult phantom. In conclusion, on-line TCM may be considered as a valuable tool for reducing dose in routine CT examinations of pediatric and adult patients. However, the dose reduction achieved with TCM

  7. Coronary CT angiography using 64 detector rows: methods and design of the multi-centre trial CORE-64

    PubMed Central

    Vavere, Andrea L.; Rochitte, Carlos E.; Niinuma, Hiroyuki; Arbab-Zadeh, Armin; Paul, Narinder; Hoe, John; de Roos, Albert; Yoshioka, Kunihiro; Lemos, Pedro A.; Bush, David E.; Lardo, Albert C.; Texter, John; Brinker, Jeffery; Cox, Christopher; Clouse, Melvin E.; Lima, João A. C.

    2012-01-01

    Multislice computed tomography (MSCT) for the noninvasive detection of coronary artery stenoses is a promising candidate for widespread clinical application because of its noninvasive nature and high sensitivity and negative predictive value as found in several previous studies using 16 to 64 simultaneous detector rows. A multi-centre study of CT coronary angiography using 16 simultaneous detector rows has shown that 16-slice CT is limited by a high number of nondiagnostic cases and a high false-positive rate. A recent meta-analysis indicated a significant interaction between the size of the study sample and the diagnostic odds ratios suggestive of small study bias, highlighting the importance of evaluating MSCT using 64 simultaneous detector rows in a multi-centre approach with a larger sample size. In this manuscript we detail the objectives and methods of the prospective “CORE-64” trial (“Coronary Evaluation Using Multidetector Spiral Computed Tomography Angiography using 64 Detectors”). This multi-centre trialwas unique in that it assessed the diagnostic performance of 64-slice CT coronary angiography in nine centres worldwide in comparison to conventional coronary angiography. In conclusion, the multi-centre, multi-institutional and multi-continental trial CORE-64 has great potential to ultimately assess the per-patient diagnostic performance of coronary CT angiography using 64 simultaneous detector rows. PMID:18998142

  8. [Valvular heart disease: multidetector computed tomography evaluation].

    PubMed

    Franco, A; Fernández-Pérez, G C; Tomás-Mallebrera, M; Badillo-Portugal, S; Orejas, M

    2014-01-01

    Heart valve disease is a clinical problem that has been studied with classical imaging techniques like echocardiography and MRI. Technological advances in CT make it possible to obtain static and dynamic images that enable not only a morphological but also a functional analysis in many cases. Although it is currently indicated only in patients with inconclusive findings at echocardiography and MRI or those in whom these techniques are contraindicated, multidetector CT makes it possible to diagnose stenosis or regurgitation through planimetry, to evaluate and quantify valvular calcium, and to show the functional repercussions of these phenomena on the rest of the structures of the heart. Given that multidetector CT is being increasingly used in the diagnosis of ischemic heart disease, we think it is interesting for radiologists to know its potential for the study of valvular disease.

  9. Common carotid artery pseudoaneurysm after neck dissection: colour Doppler ultrasound and multidetector computed tomography findings.

    PubMed

    Flor, N; Sardanelli, F; Ghilardi, G; Tentori, A; Franceschelli, G; Felisati, G; Cornalba, G P

    2007-05-01

    Common carotid artery pseudoaneurysm is a rare disease, which has been previously unreported in association with neck dissection. We describe the Doppler ultrasound and multidetector computed tomography (CT) findings of a case of carotid pseudoaneurysm, one month after pharyngolaryngectomy with bilateral neck dissection. Multidetector CT confirmed the diagnosis made on the basis of Doppler ultrasound; the high image quality of axial and three-dimensional reconstructions avoided the need for pre-operative conventional angiography. In the presence of a pulsatile cervical mass after neck surgery, pseudoaneurysm of the carotid artery should be included in the differential diagnosis, and multidetector CT can be the sole pre-operative diagnostic imaging modality.

  10. Diagnostic accuracy of 16-slice multidetector-row CT for detection of in-stent restenosis vs detection of stenosis in nonstented coronary arteries.

    PubMed

    Kefer, Joelle M; Coche, Emmanuel; Vanoverschelde, Jean-Louis J; Gerber, Bernhard L

    2007-01-01

    The purpose of this study was to assess the diagnostic accuracy of 16-slice multidetector-row computed tomography (MDCT) for detecting in-stent restenosis. Fifty patients with 69 previously implanted coronary stents underwent 16-slice MDCT before quantitative coronary angiography (QCA). Diagnostic accuracy of MDCT for detection of in-stent restenosis defined as >50% lumen diameter stenosis (DS) in stented and nonstented coronary segments >1.5-mm diameter was computed using QCA as reference. According to QCA, 18/69 (25%) stented segments had restenosis. In addition, 33/518 (6.4%) nonstented segments had >50% DS. In-stent restenosis was correctly identified on MDCT images in 12/18 stents, and absence of restenosis was correctly identified in 50/51 stents. Stenosis in native coronary arteries was correctly identified in 22/33 segments and correctly excluded in 482/485 segments. Thus, sensitivity (67% vs 67% p=1.0), specificity (98% vs 99%, p=0.96) and overall diagnostic accuracy (90% vs 97%, p=0.68) was similarly high for detecting in-stent restenosis as for detecting stenosis in nonstented coronary segments. MDCT has similarly high diagnostic accuracy for detecting in-stent restenosis as for detecting coronary artery disease in nonstented segments. This suggests that MDCT could be clinically useful for identification of restenosis in patients after coronary stenting.

  11. Three-dimensional volume-rendered multidetector CT imaging of the posterior inferior pancreaticoduodenal artery: its anatomy and role in diagnosing extrapancreatic perineural invasion

    PubMed Central

    Giacomini, Craig; Brooke Jeffrey, R.; Willmann, Juergen K.; Olcott, Eric

    2013-01-01

    Abstract Extrapancreatic perineural spread in pancreatic adenocarcinoma contributes to poor outcomes, as it is known to be a major contributor to positive surgical margins and disease recurrence. However, current staging classifications have not yet taken extrapancreatic perineural spread into account. Four pathways of extrapancreatic perineural spread have been described that conveniently follow small defined arterial pathways. Small field of view three-dimensional (3D) volume-rendered multidetector computed tomography (MDCT) images allow visualization of small peripancreatic vessels and thus perineural invasion that may be associated with them. One such vessel, the posterior inferior pancreaticoduodenal artery (PIPDA), serves as a surrogate for extrapancreatic perineural spread by pancreatic adenocarcinoma arising in the uncinate process. This pictorial review presents the normal and variant anatomy of the PIPDA with 3D volume-rendered MDCT imaging, and emphasizes its role as a vascular landmark for the diagnosis of extrapancreatic perineural invasion from uncinate adenocarcinomas. Familiarity with the anatomy of PIPDA will allow accurate detection of extrapancreatic perineural spread by pancreatic adenocarcinoma involving the uncinate process, and may potentially have important staging implications as neoadjuvant therapy improves. PMID:24434918

  12. The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Gu, J.; Bednarz, B.; Caracappa, P. F.; Xu, X. G.

    2009-05-01

    The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as

  13. The development, validation and application of a multi-detector CT (MDCT) scanner model for assessing organ doses to the pregnant patient and the fetus using Monte Carlo simulations.

    PubMed

    Gu, J; Bednarz, B; Caracappa, P F; Xu, X G

    2009-05-07

    The latest multiple-detector technologies have further increased the popularity of x-ray CT as a diagnostic imaging modality. There is a continuing need to assess the potential radiation risk associated with such rapidly evolving multi-detector CT (MDCT) modalities and scanning protocols. This need can be met by the use of CT source models that are integrated with patient computational phantoms for organ dose calculations. Based on this purpose, this work developed and validated an MDCT scanner using the Monte Carlo method, and meanwhile the pregnant patient phantoms were integrated into the MDCT scanner model for assessment of the dose to the fetus as well as doses to the organs or tissues of the pregnant patient phantom. A Monte Carlo code, MCNPX, was used to simulate the x-ray source including the energy spectrum, filter and scan trajectory. Detailed CT scanner components were specified using an iterative trial-and-error procedure for a GE LightSpeed CT scanner. The scanner model was validated by comparing simulated results against measured CTDI values and dose profiles reported in the literature. The source movement along the helical trajectory was simulated using the pitch of 0.9375 and 1.375, respectively. The validated scanner model was then integrated with phantoms of a pregnant patient in three different gestational periods to calculate organ doses. It was found that the dose to the fetus of the 3 month pregnant patient phantom was 0.13 mGy/100 mAs and 0.57 mGy/100 mAs from the chest and kidney scan, respectively. For the chest scan of the 6 month patient phantom and the 9 month patient phantom, the fetal doses were 0.21 mGy/100 mAs and 0.26 mGy/100 mAs, respectively. The paper also discusses how these fetal dose values can be used to evaluate imaging procedures and to assess risk using recommendations of the report from AAPM Task Group 36. This work demonstrates the ability of modeling and validating an MDCT scanner by the Monte Carlo method, as well as

  14. Consideration of the Pathological Features of Pediatric Congenital Heart Diseases Which Are Ideally Suitable for Diagnosing With Multidetector-row CT

    PubMed Central

    Hayabuchi, Yasunobu; Inoue, Miki; Watanabe, Noriko; Sakata, Miho; Ohnishi, Tatsuya; Kagami, Shoji

    2011-01-01

    Background A lots of articles published regarding the usefulness of multidetector-row computed tomography (MDCT) in children with congenital heart disease (CHD) mostly describe that it can be an alternative to the invasive catheterization and angiography. The unique diagnostic features of this imaging modality have been largely ignored or disregarded. We described the pathological conditions that cannot be diagnosed by conventional angiography with cardiac catheterization but can be accurately diagnosed by MDCT. Methods We retrospectively reviewed non-ECG-gated MDCT images acquired from 452 children and young adults with CHD between 2005 and 2010 in our institute. In this article, we focused on the diagnostic advantages of MDCT, and indicated five pathological conditions. (1) When Blalock-Taussig shunt total occlusion prevents catheter insertion into the artificial vessel and angiography is ruled out, the peripheral pulmonary artery during the peripheral pulmonary artery can be imaged and diagnosed using MDCT based on blood flow supplied from many small collateral vessels originating from the aorta. (2) The location and protrusion of the device in the vessel after coil embolization to treat patent ductus arteriosus can be accurately visualized by virtual endoscopy using MDCT. (3) Calcification of patches, synthetic blood vessels, and other prostheses that is indistinct on conventional angiograms is clear on MDCT. (4) Simultaneous MDCT observations of the anatomical relationships between arterial and venous systems on the same image can clarify the detail diagnosis for surgical treatment. (5) Compression of the airways by the great vessels and pulmonary segmental emphysematous change can be diagnosed by MDCT. Results and Conclusions Among patients with CHD, MDCT is useful not only as a non-invasive alternative to conventional angiography, but also as a tool for specific morphological diagnoses. In the future, it will be necessary to accumulate experience in the

  15. Multi-detector thoracic CT findings in cerebro-costo-mandibular syndrome: rib gaps and failure of costo-vertebral separation.

    PubMed

    Watson, Tom Anthony; Arthurs, Owen John; Muthialu, Nagarajan; Calder, Alistair Duncan

    2014-02-01

    Cerebro-costo-mandibular syndrome (CCMS) describes a triad of mandibular hypoplasia, brain dysfunction and posterior rib defects ("rib gaps"). We present the CT imaging for a 2-year-old girl with CCMS that highlights the rib gap defects and shows absent transverse processes with abnormal fusion of the ribs directly to the vertebral bodies. We argue that this is likely to relate to abnormal lateral sclerotome development in embryology, with the failure of normal costo-vertebral junctions compounding impaired thoracic function. The case also highlights the use of CT for specific indications in skeletal dysplasia.

  16. [Significance of abdominal wall CT-angiography in planning DIEA perforator flaps, TRAM flaps and SIEA flaps].

    PubMed

    Fansa, H; Schirmer, S; Frerichs, O; Gehl, H B

    2011-04-01

    Muscle sparing TRAM flaps and DIEA perforator flaps are standard procedures for breast reconstruction. Recently CT-angiography has been established to evaluate perforator vessels pre-operatively. CT-angiography was introduced to our department in July 2009. In a retrospective analysis data of the last 20 patients (altogether 22 flaps) before CT-angiography introduction and the following 20 (also 22 flaps) patients after introduction of CT-angiography were analysed with regard to the ratio of TRAM to DIEP flaps, and the time required to raise the flaps. The same surgeon raised all flaps. As different surgeons performed dissection of the recipient site, anastomoses, and insertion of flaps, and patients received primary (with sentinel or complete lymphadenctomy) or secondary reconstructions, only the time required harvesting the flap was compared. Thus other influences on raising the flap were eliminated. DIEP flaps were harvested with one single perforator. If perfusion or was considered not to be safe via one single perforator a muscle sparing TRAM flap (ms2) was raised. Angiography was performed using a 64-slice multi-detector CT scanner. CT-angiography did not lead to an increased rate of DIEP flaps in relation to ms2-TRAM flaps. Harvesting time of all flap types with CT-angiography on average was 121 min, without CT-angiography 135 min. This was not significantly different. However, separate analysis of DIEP flaps and ms2-TRAM flaps revealed a significant advantage of CT-angiography based harvesting of DIEP flaps of 26 min: with CT-angiography 101 min vs. 127 min without CT-angiography (p<0.028). There were no significant differences for ms2-TRAM flaps. All scans showed course and branching, diameter and size of the inferior epigastric artery. If evident the superficial inferior epigastric artery (SIEA) was marked. Dosage was 292 mGy-606 mGy×cm dependent on body weight. CTDI was 6.8-14.7 mGy. CT-angiography is a reproducible and observer independent procedure

  17. Multidetector computed tomography angiography of the abdomen.

    PubMed

    Güven, Koray; Acunaş, Bülent

    2004-10-01

    Multidetector computed tomography (MDCT) angiography has provided excellent opportunities for advancement of computed tomography (CT) technology and clinical applications. It has a wide range of applications in the abdomen including vascular pathologies either occlusive or aneurysmal; enables the radiologist to produce vascular mapping that clearly show tumor invasion of vasculature and the relationship of vessels to mass lesions. MDCTA can be used in preoperative planning for hepatic resection, preoperative evaluation and planning for liver transplantation. MDCTA can also provide extremely valuable information in the evaluation of ischemic bowel disease, active Crohn disease, the extent and location of collateral vessels in cirrhosis.

  18. Effect of Low Tube Voltage on Image Quality, Radiation Dose, and Low-Contrast Detectability at Abdominal Multidetector CT: Phantom Study

    PubMed Central

    Tang, Kun; Wang, Ling; Li, Rui; Lin, Jie; Zheng, Xiangwu; Cao, Guoquan

    2012-01-01

    Purpose. To investigate the effect of low tube voltage (80 kV) on image quality, radiation dose, and low-contrast detectability (LCD) at abdominal computed tomography (CT). Materials and Methods. A phantom containing low-contrast objects was scanned with a CT scanner at 80 and 120 kV, with tube current-time product settings at 150–650 mAs. The differences between image noise, contrast-to-noise ratio (CNR), and scores of LCD obtained with 80 kV at 150–650 mAs and those obtained with 120 kV at 300 mAs were compared respectively. Results. The image noise substantially increased with low tube voltage. However, with identical dose, use of 80 kV resulted in higher CNR compared with CNR at 120 kV. There were no statistically significant difference in CNR and scores of LCD between 120 kV at 300 mAs and 80 kV at 550–650 mAs (P > 0.05). The relative dose delivered at 80 kV ranged from 58% at 550 mAs to 68% at 650 mAs. Conclusion. With a reduction of the tube voltage from 120 kV to 80 kV at abdominal CT, the radiation dose can be reduced by 32% to 42% without degradation of CNR and LCD. PMID:22619490

  19. Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging?

    PubMed

    Coursey, Courtney A; Nelson, Rendon C; Boll, Daniel T; Paulson, Erik K; Ho, Lisa M; Neville, Amy M; Marin, Daniele; Gupta, Rajan T; Schindera, Sebastian T

    2010-01-01

    Dual-energy CT provides information about how substances behave at different energies, the ability to generate virtual unenhanced datasets, and improved detection of iodine-containing substances on low-energy images. Knowing how a substance behaves at two different energies can provide information about tissue composition beyond that obtainable with single-energy techniques. The term K edge refers to the spike in attenuation that occurs at energy levels just greater than that of the K-shell binding because of the increased photoelectric absorption at these energy levels. K-edge values vary for each element, and they increase as the atomic number increases. The energy dependence of the photoelectric effect and the variability of K edges form the basis of dual-energy techniques, which may be used to detect substances such as iodine, calcium, and uric acid crystals. The closer the energy level used in imaging is to the K edge of a substance such as iodine, the more the substance attenuates. In the abdomen and pelvis, dual-energy CT may be used in the liver to increase conspicuity of hypervascular lesions; in the kidneys, to distinguish hyperattenuating cysts from enhancing renal masses and to characterize renal stone composition; in the adrenal glands, to characterize adrenal nodules; and in the pancreas, to differentiate between normal and abnormal parenchyma.

  20. The relevance of image quality indices for dose optimization in abdominal multi-detector row CT in children: experimental assessment with pediatric phantoms

    NASA Astrophysics Data System (ADS)

    Brisse, H. J.; Brenot, J.; Pierrat, N.; Gaboriaud, G.; Savignoni, A.; DeRycke, Y.; Neuenschwander, S.; Aubert, B.; Rosenwald, J.-C.

    2009-04-01

    This study assessed and compared various image quality indices in order to manage the dose of pediatric abdominal MDCT protocols and to provide guidance on dose reduction. PMMA phantoms representing average body diameters at birth, 1 year, 5 years, 10 years and 15 years of age were scanned in a four-channel MDCT with a standard pediatric abdominal CT protocol. Image noise (SD, standard deviation of CT number), noise derivative (ND, derivative of the function of noise with respect to dose) and contrast-to-noise ratio (CNR) were measured. The 'relative' low-contrast detectability (rLCD) was introduced as a new quantity to adjust LCD to the various phantom diameters on the basis of the LCD1% assessed in a Catphan® phantom and a constant central absorbed dose. The required variations of CTDIvol16 with respect to phantom size were analyzed in order to maintain each image quality index constant. The use of a fixed SD or CNR level leads to major dose ratios between extreme patient sizes (factor 22.7 to 44 for SD, 31.7 to 51.5 for CNR2.8%), whereas fixed ND and rLCD result in acceptable dose ratios ranging between factors of 2.9 and 3.9 between extreme phantom diameters. For a 5-9 mm rLCD1%, adjusted ND values range between -0.84 and -0.11 HU mGy-1. Our data provide guidance on dose reduction on the basis of patient dimensions and the required rLCD (e.g., to get a constant 7 mm rLCD1% for abdominal diameters of 10, 13, 16, 20 and 25 cm, tube current-time product should be adjusted in order to obtain CTDIvol16 values of 6.2, 7.2, 8.8, 11.6 and 17.7 mGy, respectively).

  1. The relevance of image quality indices for dose optimization in abdominal multi-detector row CT in children: experimental assessment with pediatric phantoms.

    PubMed

    Brisse, H J; Brenot, J; Pierrat, N; Gaboriaud, G; Savignoni, A; De Rycke, Y; Neuenschwander, S; Aubert, B; Rosenwald, J-C

    2009-04-07

    This study assessed and compared various image quality indices in order to manage the dose of pediatric abdominal MDCT protocols and to provide guidance on dose reduction. PMMA phantoms representing average body diameters at birth, 1 year, 5 years, 10 years and 15 years of age were scanned in a four-channel MDCT with a standard pediatric abdominal CT protocol. Image noise (SD, standard deviation of CT number), noise derivative (ND, derivative of the function of noise with respect to dose) and contrast-to-noise ratio (CNR) were measured. The 'relative' low-contrast detectability (rLCD) was introduced as a new quantity to adjust LCD to the various phantom diameters on the basis of the LCD(1%) assessed in a Catphan phantom and a constant central absorbed dose. The required variations of CTDIvol(16) with respect to phantom size were analyzed in order to maintain each image quality index constant. The use of a fixed SD or CNR level leads to major dose ratios between extreme patient sizes (factor 22.7 to 44 for SD, 31.7 to 51.5 for CNR(2.8%)), whereas fixed ND and rLCD result in acceptable dose ratios ranging between factors of 2.9 and 3.9 between extreme phantom diameters. For a 5-9 mm rLCD1(%), adjusted ND values range between -0.84 and -0.11 HU mGy(-1). Our data provide guidance on dose reduction on the basis of patient dimensions and the required rLCD (e.g., to get a constant 7 mm rLCD(1%) for abdominal diameters of 10, 13, 16, 20 and 25 cm, tube current-time product should be adjusted in order to obtain CTDIvol(16) values of 6.2, 7.2, 8.8, 11.6 and 17.7 mGy, respectively).

  2. The effect of z overscanning on radiation burden of pediatric patients undergoing head CT with multidetector scanners: A Monte Carlo study

    SciTech Connect

    Tzedakis, Antonis; Perisinakis, Kostas; Raissaki, Maria; Damilakis, John

    2006-07-15

    The purpose of this study was to investigate the effect of z overscanning on eye lens dose and effective dose received by pediatric patients undergoing head CT examinations. A pediatric patient study was carried out to obtain the exposure parameters and data regarding the eye lens position with respect to imaged volume boundaries. This information was used to simulate CT exposures by Monte Carlo code. The Monte Carlo N-Particle (MCNP, version 4C2) radiation transport code and five mathematical anthropomorphic phantoms representing newborn, 1-, 5-, 10-, and 15-year-old patient, were employed in the current study. To estimate effective dose, the weighted computed tomography dose index was calculated by cylindrical polymethyl-methacrylate phantoms of 9.7, 13.1, 15.4, 16.1, and 16.9 cm in diameter representing the pediatric head of newborn, 1-, 5-, 10-, and 15-year-old individuals, respectively. The validity of the Monte Carlo calculated approach was verified by comparison with dose data obtained using physical pediatric anthropomorphic phantoms and thermoluminescence dosimetry. For all patients studied, the eye lenses were located in the region -1 to 3 cm from the first slice of the imaged volume. Doses from axial scans were always lower than those from corresponding helical examinations. The percentage differences in normalized eye lens absorbed dose between contiguous axial and helical examinations with pitch=1 were found to be up to 10.9%, when the eye lenses were located inside the region to be imaged. When the eye lenses were positioned 0-3 cm far from the first slice of region to be imaged, the normalized dose to the lens from contiguous axial examinations was up to 11 times lower than the corresponding values from helical mode with pitch=1. The effective dose from axial examinations was up to 24% lower than corresponding values from helical examinations with pitch=1. In conclusion, it is more dose efficient to use axial mode acquisition rather than helical scan

  3. Transcatheter Arterial Embolization Therapy for a Hypoplastic Pelvic Kidney with a Single Vaginal Ectopic Ureter to Control Incontinence: The Usefulness of Three-Dimensional CT Angiography Using Multidetector-Row Helical CT

    SciTech Connect

    Kudoh, Kouichi Kadota, Masataka; Nakayama, Yoshiharu; Imuta, Masanori; Yasuda, Tsuyoshi; Yamashita, Yasuyuki; Inadome, Akito; Yoshida, Masaki; Ueda, Shouichi

    2003-09-15

    A girl with continuous urinary incontinence was successfully treated by angiographic embolization of a hypoplastic pelvic kidney with a single unilateral vaginal ectopic opening of the ureter. For this intervention, CT angiography was useful for detecting the corresponding renal artery of the hypoplastic kidney.

  4. Patient-specific dose estimation for pediatric chest CT

    SciTech Connect

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

    2008-12-15

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

  5. Multidetector CT of hepatic artery pathologies.

    PubMed

    Karaosmanoglu, D; Erol, B; Karcaaltincaba, M

    2012-01-01

    The hepatic artery can be involved by a variety of pathology and diseases.Today MDCT enables high quality imaging of the hepatic artery using axial, MIP and volume rendered images. We illustrate MDCT findings of anatomical variations, aneurysm, dilatation, dissection, arteriovenous fistula, thrombosis and stenosis. Aneurysms can be saccular, fusiform and multiple and may develop due to atherosclerosis, vasculitis, trauma and biopsy. Dilatation of hepatic artery can be seen in portal hypertension, Osler-Weber-Rendu disease and hemangiomatosis. Hepatic artery can be occluded after trauma and transplantation. Dissection develops due to atherosclerosis, Marfan and Ehler Danlos syndromes and during pregnancy. Arteriovenous fistula can be congenital and acquired. We conclude that various hepatic artery pathologies can be confidently diagnosed by MDCT.

  6. Cardiac Computed Tomography (Multidetector CT, or MDCT)

    MedlinePlus

    ... Graft (CABG) Surgery Atherosclerosis Coronary Artery Disease (CAD) Heart Attack • Home • About Heart Attacks • Warning Signs of a ... Heart Attack • Heart Attack Tools & Resources • Support Network Heart Attack Tools & Resources What Is a Heart Attack? How ...

  7. Comparison of the Diagnostic Image Quality of the Canine Maxillary Dentoalveolar Structures Obtained by Cone Beam Computed Tomography and 64-Multidetector Row Computed Tomography.

    PubMed

    Soukup, Jason W; Drees, Randi; Koenig, Lisa J; Snyder, Christopher J; Hetzel, Scott; Miles, Chanda R; Schwarz, Tobias

    2015-01-01

    The objective of this blinded study was to validate the use of cone beam computed tomography (C) for imaging of the canine maxillary dentoalveolar structures by comparing its diagnostic image quality with that of 64-multidetector row CT Sagittal slices of a tooth-bearing segment of the maxilla of a commercially purchased dog skull embedded in methylmethacrylate were obtained along a line parallel with the dental arch using a commercial histology diamond saw. The slice of tooth-bearing bone that best depicted the dentoalveolar structures was chosen and photographed. The maxillary segment was imaged with cone beam CT and 64-multidetector row CT. Four blinded evaluators compared the cone beam CT and 64-multidetector row CT images and image quality was scored as it related to the anatomy of dentoalveolar structures. Trabecular bone, enamel, dentin, pulp cavity, periodontal ligament space, and lamina dura were scored In addition, a score depicting the evaluators overall impression of the image was recorded. Images acquired with cone beam CT were found to be significantly superior in image quality to images acquired with 64-multidetector row CT overall, and in all scored categories. In our study setting cone beam CT was found to be a valid and clinically superior imaging modality for the canine maxillary dentoalveolar structures when compared to 64-multidetector row CT.

  8. Associations Between Cardio-Ankle Vascular Index and Aortic Structure and Sclerosis Using Multidetector Computed Tomography.

    PubMed

    Horinaka, Shigeo; Yagi, Hiroshi; Fukushima, Hiromichi; Shibata, Yoshimasa; Takeshima, Hiroshi; Ishimitsu, Toshihiko

    2017-04-01

    Aortic pulse wave velocity (PWV) has been accepted as the gold standard for arterial stiffness measurement. However, PWV depends on blood pressure (BP). To eliminate the BP dependency of PWV, the cardio-ankle vascular index (CAVI) was developed. This study aimed to define the relationship between CAVI and aortic atherosclerosis or structure on multidetector computed tomography (MDCT). Patients with (n = 49) or without (n = 49) coronary artery disease were studied. The lumen and vessel diameters and wall thickness were calculated from the cross-sectional area at the pulmonary bifurcation level by 64-slice MDCT. The CAVI was measured within 3 days before MDCT. Multivariate analysis showed that the vessel diameter of the ascending and descending aorta on MDCT depends on age, body surface area, and diastolic BP. The CAVI significantly correlated with the vessel diameter ( r = .453) and wall thickness ( r = .387) of the thoracic descending aorta ( P < .001, respectively). The CAVI was an independent predictor of the descending aortic wall thickness on multiple stepwise regression analysis. These data suggest that CAVI, a simple index, is useful for evaluating thoracic aortic atherosclerosis.

  9. A novel method of estimating effective dose from the point dose method: a case study—parathyroid CT scans

    NASA Astrophysics Data System (ADS)

    Januzis, Natalie; Nguyen, Giao; Hoang, Jenny K.; Lowry, Carolyn; Yoshizumi, Terry T.

    2015-02-01

    The purpose of this study was to validate a novel approach of applying a partial volume correction factor (PVCF) using a limited number of MOSFET detectors in the effective dose (E) calculation. The results of the proposed PVCF method were compared to the results from both the point dose (PD) method and a commercial CT dose estimation software (CT-Expo). To measure organ doses, an adult female anthropomorphic phantom was loaded with 20 MOSFET detectors and was scanned using the non-contrast and 2 phase contrast-enhanced parathyroid imaging protocols on a 64-slice multi-detector computed tomography scanner. E was computed by three methods: the PD method, the PVCF method, and the CT-Expo method. The E (in mSv) for the PD method, the PVCF method, and CT-Expo method was 2.6  ±  0.2, 1.3  ±  0.1, and 1.1 for the non-contrast scan, 21.9  ±  0.4, 13.9  ±  0.2, and 14.6 for the 1st phase of the contrast-enhanced scan, and 15.5  ±  0.3, 9.8  ±  0.1, and 10.4 for the 2nd phase of the contrast-enhanced scan, respectively. The E with the PD method differed from the PVCF method by 66.7% for the non-contrast scan, by 44.9% and by 45.5% respectively for the 1st and 2nd phases of the contrast-enhanced scan. The E with PVCF was comparable to the results from the CT-Expo method with percent differences of 15.8%, 5.0%, and 6.3% for the non-contrast scan and the 1st and 2nd phases of the contrast-enhanced scan, respectively. To conclude, the PVCF method estimated E within 16% difference as compared to 50-70% in the PD method. In addition, the results demonstrate that E can be estimated accurately from a limited number of detectors.

  10. Comparison of in vivo cone-beam and multidetector computed tomographic scans by three-dimensional merging software.

    PubMed

    Rostetter, Claudio; Metzler, Philipp; Schenkel, Jan S; Seifert, Burkhardt; Luebbers, Heinz-Theo

    2015-12-01

    In dentomaxillofacial radiology, cone-beam computed tomography (CT) is used to give fast and high-resolution 3-dimensional images of bone with a low dose of radiation. However, its use for quantitative measurement of bone density based on absolute values (Hounsfield units, HU) as in multidetector CT is still controversial. We know of no in vivo study of 3-dimensional merging software that will reliably match identical bone areas of cone-beam and multidetector CT datasets. We studied 19 multidetector, and 19 cone-beam, CT scans of the skull. The two datasets were fused, corresponding points were identified for measurement, and we compared mean density. We used linear regression to analyse the relation between the two different scanning methods, and studied a total of 4180 measurements. The mean time interval between scans was 5.2 (4.7) months. Mean R(2) over all measurements was 0.63 (range 0.22 - 0.79) with a mean internal consistency (Cronbach's α) of 0.86 (range 0.61 - 0.93). The strongest linearity, seen at the left mastoid, was R(2)=0.79 with high internal consistency (Cronbach's α 0.89), and the weakest was at the left zygomatic bone with R(2)=0.22 and Cronbach's α=0.61. Measurements of bone density based on cone-beam and multidetector CT scans generated in vivo showed high and reproducible internal consistency but poor linearity.

  11. Analysis of the topological properties of the proximal femur on a regional scale: evaluation of multi-detector CT-scans for the assessment of biomechanical strength using local Minkowski functionals in 3D

    NASA Astrophysics Data System (ADS)

    Boehm, H. F.; Link, T. M.; Monetti, R. A.; Kuhn, V.; Eckstein, F.; Raeth, C. W.; Reiser, M.

    2006-03-01

    In our recent studies on the analysis of bone texture in the context of Osteoporosis, we could already demonstrate the great potential of the topological evaluation of bone architecture based on the Minkowski Functionals (MF) in 2D and 3D for the prediction of the mechanical strength of cubic bone specimens depicted by high resolution MRI. Other than before, we now assess the mechanical characteristics of whole hip bone specimens imaged by multi-detector computed tomography. Due to the specific properties of the imaging modality and the bone tissue in the proximal femur, this requires to introduce a new analysis method. The internal architecture of the hip is functionally highly specialized to withstand the complex pattern of external and internal forces associated with human gait. Since the direction, connectivity and distribution of the trabeculae changes considerably within narrow spatial limits it seems most reasonable to evaluate the femoral bone structure on a local scale. The Minkowski functionals are a set of morphological descriptors for the topological characterization of binarized, multi-dimensional, convex objects with respect to shape, structure, and the connectivity of their components. The MF are usually used as global descriptors and may react very sensitively to minor structural variations which presents a major limitation in a number of applications. The objective of this work is to assess the mechanical competence of whole hip bone specimens using parameters based on the MF. We introduce an algorithm that considers the local topological aspects of the bone architecture of the proximal femur allowing to identify regions within the bone that contribute more to the overall mechanical strength than others.

  12. Advances and perspectives in lung cancer imaging using multidetector row computed tomography.

    PubMed

    Coche, Emmanuel

    2012-10-01

    The introduction of multidetector row computed tomography (CT) into clinical practice has revolutionized many aspects of the clinical work-up. Lung cancer imaging has benefited from various breakthroughs in computing technology, with advances in the field of lung cancer detection, tissue characterization, lung cancer staging and response to therapy. Our paper discusses the problems of radiation, image visualization and CT examination comparison. It also reviews the most significant advances in lung cancer imaging and highlights the emerging clinical applications that use state of the art CT technology in the field of lung cancer diagnosis and follow-up.

  13. Effect of Radiation Dose Reduction and Reconstruction Algorithm on Image Noise, Contrast, Resolution, and Detectability of Subtle Hypoattenuating Liver Lesions at Multidetector CT: Filtered Back Projection versus a Commercial Model-based Iterative Reconstruction Algorithm.

    PubMed

    Solomon, Justin; Marin, Daniele; Roy Choudhury, Kingshuk; Patel, Bhavik; Samei, Ehsan

    2017-02-07

    Purpose To determine the effect of radiation dose and iterative reconstruction (IR) on noise, contrast, resolution, and observer-based detectability of subtle hypoattenuating liver lesions and to estimate the dose reduction potential of the IR algorithm in question. Materials and Methods This prospective, single-center, HIPAA-compliant study was approved by the institutional review board. A dual-source computed tomography (CT) system was used to reconstruct CT projection data from 21 patients into six radiation dose levels (12.5%, 25%, 37.5%, 50%, 75%, and 100%) on the basis of two CT acquisitions. A series of virtual liver lesions (five per patient, 105 total, lesion-to-liver prereconstruction contrast of -15 HU, 12-mm diameter) were inserted into the raw CT projection data and images were reconstructed with filtered back projection (FBP) (B31f kernel) and sinogram-affirmed IR (SAFIRE) (I31f-5 kernel). Image noise (pixel standard deviation), lesion contrast (after reconstruction), lesion boundary sharpness (average normalized gradient at lesion boundary), and contrast-to-noise ratio (CNR) were compared. Next, a two-alternative forced choice perception experiment was performed (16 readers [six radiologists, 10 medical physicists]). A linear mixed-effects statistical model was used to compare detection accuracy between FBP and SAFIRE and to estimate the radiation dose reduction potential of SAFIRE. Results Compared with FBP, SAFIRE reduced noise by a mean of 53% ± 5, lesion contrast by 12% ± 4, and lesion sharpness by 13% ± 10 but increased CNR by 89% ± 19. Detection accuracy was 2% higher on average with SAFIRE than with FBP (P = .03), which translated into an estimated radiation dose reduction potential (±95% confidence interval) of 16% ± 13. Conclusion SAFIRE increases detectability at a given radiation dose (approximately 2% increase in detection accuracy) and allows for imaging at reduced radiation dose (16% ± 13), while maintaining low

  14. Prospective study evaluating the relative sensitivity of 18F-NaF PET/CT for detecting skeletal metastases from renal cell carcinoma in comparison to multidetector CT and 99mTc-MDP bone scintigraphy, using an adaptive trial design

    PubMed Central

    Gerety, E. L.; Lawrence, E. M.; Wason, J.; Yan, H.; Hilborne, S.; Buscombe, J.; Cheow, H. K.; Shaw, A. S.; Bird, N.; Fife, K.; Heard, S.; Lomas, D. J.; Matakidou, A.; Soloviev, D.; Eisen, T.; Gallagher, F. A.

    2015-01-01

    Background The detection of occult bone metastases is a key factor in determining the management of patients with renal cell carcinoma (RCC), especially when curative surgery is considered. This prospective study assessed the sensitivity of 18F-labelled sodium fluoride in conjunction with positron emission tomography/computed tomography (18F-NaF PET/CT) for detecting RCC bone metastases, compared with conventional imaging by bone scintigraphy or CT. Patients and methods An adaptive two-stage trial design was utilized, which was stopped after the first stage due to statistical efficacy. Ten patients with stage IV RCC and bone metastases were imaged with 18F-NaF PET/CT and 99mTc-labelled methylene diphosphonate (99mTc-MDP) bone scintigraphy including pelvic single photon emission computed tomography (SPECT). Images were reported independently by experienced radiologists and nuclear medicine physicians using a 5-point scoring system. Results Seventy-seven lesions were diagnosed as malignant: 100% were identified by 18F-NaF PET/CT, 46% by CT and 29% by bone scintigraphy/SPECT. Standard-of-care imaging with CT and bone scintigraphy identified 65% of the metastases reported by 18F-NaF PET/CT. On an individual patient basis, 18F-NaF PET/CT detected more RCC metastases than 99mTc-MDP bone scintigraphy/SPECT or CT alone (P = 0.007). The metabolic volumes, mean and maximum standardized uptake values (SUVmean and SUVmax) of the malignant lesions were significantly greater than those of the benign lesions (P < 0.001). Conclusions 18F-NaF PET/CT is significantly more sensitive at detecting RCC skeletal metastases than conventional bone scintigraphy or CT. The detection of occult bone metastases could greatly alter patient management, particularly in the context when standard-of-care imaging is negative for skeletal metastases. PMID:26202597

  15. Bladder trauma: multidetector computed tomography cystography.

    PubMed

    Ishak, Charbel; Kanth, Nalini

    2011-08-01

    Multidetector computed tomography (MDCT) cystography is rapidly becoming the most recommended study for evaluation of the bladder for suspected trauma. This article reviews the bladder trauma with emphasis on the application of MDCT cystography to traumatic bladder injuries using a pictorial essay based on images collected in our level I trauma center.

  16. CHIMERA Multidetector at Laboratori Nazionali del Sud

    SciTech Connect

    Aiello, S.; Anzalone, A.; Baldo, M.; Barna, R.; Campisi, M.g.; Cardella, G.; Cavallaro, Sl., Amico, V.D.; De Filippo, E.; DePasquale, D.; Femino, S.; Geraci, E.; Giustolisi, F.; Guazzoni, P.; Iacono-Manno, C.M.; Italiano, A.; Lanzalone, G.; Lanzano, G.; LoNigro, S.; Lombardo, U.; Manfredi, G.; Pagano, A.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Sambataro, S.; Sperduto, M.L.; Sutera, C.M.; Zetta, L.

    2000-12-31

    The installation of CHIMERA multidetector, designed in order to study central collisions in heavy ion reactions at intermediate energy, is going on at LNS and the first experiment with the forward part (688 telescopes) is running since May 1999. The aim of this contribution is to present the status of the project.

  17. Validation of a paediatric thyroid phantom using different multidetector computed tomography models

    NASA Astrophysics Data System (ADS)

    Alsabbagh, M.; Ng, L. Y.; Tajuddin, A. A.; Manap, M. A.; Zainon, R.

    2016-03-01

    The aim of this study was to compare the attenuation values of a fabricated paediatric thyroid phantom material using different MDCT models. A paediatric thyroid phantom was designed to mimic the shape and size of a paediatric patient with an age of 9 years using high- density Polyethylene as the phantom material. The fabricated phantom was scanned using two different multidetector CT scanners (16- and 128-row detectors). The CT numbers were evaluated and the mass attenuation coefficients (μ/ρ) of the phantom material were obtained at each applied energy from each scanner. The results were compared with the tables of the National Institute of Standards and Technology (NIST). The CTs of 16- and 128-row detectors showed that the obtained attenuation values are very similar to the NIST's values. However, the CT of the 128-row detectors showed a slightly much closer match to the NIST's values. This refers to the type and quality of the electronic connections between the detectors. Furthermore, the type and number of detectors (16- and 128-detectors) could affect the details and quality of the output images. The results show that different multidetector CTs can be used to validate the phantom and determine the mass attenuation coefficients of its material.

  18. Comparison of the diagnostic accuracy of FBP, ASiR, and MBIR reconstruction during CT angiography in the evaluation of a vessel phantom with calcified stenosis in a distal superficial femoral artery in a cadaver extremity

    PubMed Central

    Tsukada, Jitsuro; Yamada, Minoru; Yamada, Yoshitake; Yamazaki, Shun; Imanishi, Nobuaki; Tamura, Kentaro; Hashimoto, Masahiro; Nakatsuka, Seishi; Jinzaki, Masahiro

    2016-01-01

    Abstract Purpose: To investigate whether adaptive statistical iterative reconstruction (ASiR) or model-based iterative reconstruction (MBIR) improves the diagnostic performance of computed tomography angiography (CTA) for small-vessel calcified lesions relative to filtered back projection (FBP) using cadaver extremities and a calcified stenosis phantom. Methods: A cadaver was used in accordance with our institutional regulations, and a calcified stenosis phantom simulating 4 grades of stenosis was prepared. The phantom was inserted within the distal superficial femoral artery of the cadaver leg. Ten CT images per reconstruction type and stenosis grade were acquired using a 64-slice multidetector-row CTA. As an objective measurement, the first and second derivatives of the CT value function profiles were calculated. As a subjective measurement, 2 blinded reviewers measured the stenosis ratio using a quantitative scale. The Wilcoxon rank-sum test was used to evaluate the data. Results: Objective measurements of both 25% and 50% stenosis differed significantly (P < 0.01) between MBIR (25/50%: 25.80/50.30 ± 3.88/3.86%) and FBP (25/50%: 35.60/83.80 ± 3.44/26.10%), whereas significant differences were not observed between ASiR and FBP. Reviewer 2's subjective measurements of 25% stenosis differed significantly (P < 0.01) between MBIR (35.13 ± 3.25%) and ASiR (40.89 ± 3.14%), and the measurements of 50% stenosis differed significantly (P < 0.01) between MBIR (reviewers 1/2, 62.36/54.78 ± 2.78/4.96%) and FBP (reviewers 1/2, 62.36/74.84 ± 2.78/18.10%). Significant differences in the subjective measurements were not observed between ASiR and FBP. Conclusion: MBIR improves the diagnostic performance of CTA for small-vessel calcified lesions relative to FBP. PMID:27399123

  19. State-of-the-art in CT hardware and scan modes for cardiovascular CT

    PubMed Central

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J.; Gentry, Ralph; George, Richard T.; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm. Guy

    2013-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and the coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography (SCCT) Basic and Emerging Sciences and Technology (BEST) Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging. PMID:22551595

  20. State-of-the-art in CT hardware and scan modes for cardiovascular CT.

    PubMed

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J; Gentry, Ralph; George, Richard T; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm Guy

    2012-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography Basic and Emerging Sciences and Technology Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging.

  1. [Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms].

    PubMed

    Casula, E; Lonjedo, E; Cerverón, M J; Ruiz, A; Gómez, J

    2014-01-01

    The increase in the frequency of abdominal aortic aneurysms (AAA) and the widely accepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alternative to conventional surgery make it necessary for radiologists to have thorough knowledge of the pre- and post-treatment findings. The high image quality provided by multidetector computed tomography (MDCT) enables CT angiography to play a fundamental role in the study of AAA and in planning treatment. The objective of this article is to review the cases of AAA in which CT angiography was the main imaging technique, so that radiologists will be able to detect the signs related to this disease, to diagnose it, to plan treatment, and to detect complications in the postoperative period.

  2. Diagnostic Yield of Multidetector Computed Tomography in Patients with Acute Spondylodiscitis.

    PubMed

    Rausch, Vanessa Hanna; Bannas, Peter; Schoen, Gerhard; Froelich, Andreas; Well, Lennart; Regier, Marc; Adam, Gerhard; Henes, Frank Oliver Gerhard

    2017-03-01

    Purpose To determine the value of multidetector computed tomography (MDCT) in patients with acute spondylodiscitis. Methods and Materials For data acquisition, we searched our radiological database for all patients who had undergone magnetic resonance imaging (MRI) for suspected spondylodiscitis between 2007 and 2015 (n = 325). For further analyses, we included all patients (n = 67) who initially underwent MDCT prior to MRI. Overall accuracy, sensitivity, specificity and positive and negative predictive values were calculated for MDCT and, separately, for contrast-enhanced CT (CECT, n = 36) and for non-enhanced CT (NECT, n = 31). MRI together with clinical evaluation served as the standard of reference.

  3. SU-E-I-21: Dosimetric Characterization and Image Quality Evaluation of the AIRO Mobile CT Scanner

    SciTech Connect

    Weir, V; Zhang, J; Bruner, A

    2015-06-15

    Purpose: The AIRO Mobile CT system was recently introduced which overcomes the limitations from existing CT, CT fluoroscopy, and intraoperative O-arm. With an integrated table and a large diameter bore, the system is suitable for cranial, spine and trauma procedures, making it a highly versatile intraoperative imaging system. This study is to investigate radiation dose and image quality of the AIRO and compared with those from a routine CT scanner. Methods: Radiation dose was measured using a conventional 100mm pencil ionization chamber and CT polymethylmetacrylate (PMMA) body and head phantoms. Image quality was evaluated with a CATPHAN 500 phantom. Spatial resolution, low contrast resolution (CNR), Modulation Transfer Function (MTF), and Normalized Noise Power Spectrum (NNPS) were analyzed. Results: Under identical technique conditions, radiation dose (mGy/mAs) from the AIRO mobile CT system (AIRO) is higher than that from a 64 slice CT scanner. MTFs show that both Soft and Standard filters of the AIRO system lost resolution quickly compared to the Sensation 64 slice CT. With the Standard kernel, the spatial resolutions of the AIRO system are 3lp/cm and 4lp/cm for the body and head FOVs, respectively. NNPSs show low frequency noise due to ring-like artifacts. Due to a higher dose in terms of mGy/mAs at both head and body FOV, CNR of the AIRO system is higher than that of the Siemens scanner. However detectability of the low contrast objects is poorer in the AIRO due to the presence of ring artifacts in the location of the targets. Conclusion: For image guided surgery applications, the AIRO has some advantages over a routine CT scanner due to its versatility, large bore size, and acceptable image quality. Our evaluation of the physical performance helps its future improvements.

  4. [CT - diagnosis and differential diagnosis of inflammatory acute intestinal conditions].

    PubMed

    Wiesner, W

    2011-08-24

    Multidetector-row CT has shown over the past years that it is able to provide reliable diagnoses in various acute intestinal conditions. The presented article provides an overview of primary and secondary inflammatory acute intestinal pathologies and their differential diagnoses.

  5. Association of Neutrophil-to-Lymphocyte Ratio with the Severity and Morphology of Coronary Atherosclerotic Plaques Detected by Multidetector Computerized Tomography

    PubMed Central

    Ateş, Ahmet Hakan; Aytemir, Kudret; Koçyiğit, Duygu; Yalcin, Muhammed Ulvi; Gürses, Kadri Murat; Yorgun, Hikmet; Canpolat, Uğur; Hazırolan, Tuncay; Özer, Necla

    2016-01-01

    Background Studies have demonstrated a consistent relationship between white blood cell (WBC) counts and coronary artery disease (CAD). The neutrophil/lymphocyte ratio (NLR) has been considered as a potential marker for identifying individuals under risk of CAD and associated events. In this study, we aimed to evaluate whether NLR was associated with the severity and morphology of coronary atherosclerotic plaques shown by multidetector computed tomography (MDCT). Methods Our study population consisted of 684 patients who underwent dual-source 64 slice MDCT for the assessment of CAD. Coronary arteries were evaluated on a 16-segment basis and critical coronary plaque was described as luminal narrowing > 50%, whereas plaque morphology was assessed on a per segment basis. Total WBC, neutrophil and lymphocyte counts were determined using commercially available assay kits. Results WBC count [7700 (6400-8800) vs. 6800 (5700-7900), p < 0.05] and NLR [2.40 (1.98-3.07) vs. 1.86 (1.50-2.38), p < 0.001] were found to be higher in patients with critical stenosis than in those without. In the binary logistic regression analysis, NLR was a predictor of critical stenosis (odds ratio, 1.68; 95% confidence interval, 1.39-2.03, p < 0.001). NLR levels differed among plaque morphology subtypes (p < 0.05) and was significantly higher in non-calcified plaque (NCP) compared to mixed plaque (MP) and calcified plaque (CP) (p < 0.05). In the multinomial logistic regression analysis, NLR was found to be an independent predictor of NCP, MP and CP (p < 0.001). Conclusions These data show that NLR is associated with both the severity and morphology of coronary atherosclerotic disease. PMID:27899854

  6. Research on radiation exposure from CT part of hybrid camera and diagnostic CT

    NASA Astrophysics Data System (ADS)

    Solný, Pavel; Zimák, Jaroslav

    2014-11-01

    Research on radiation exposure from CT part of hybrid camera in seven different Departments of Nuclear Medicine (DNM) was conducted. Processed data and effective dose (E) estimations led to the idea of phantom verification and comparison of absorbed doses and software estimation. Anonymous data from about 100 examinations from each DNM was gathered. Acquired data was processed and utilized by dose estimation programs (ExPACT, ImPACT, ImpactDose) with respect to the type of examination and examination procedures. Individual effective doses were calculated using enlisted programs. Preserving the same procedure in dose estimation process allows us to compare the resulting E. Some differences and disproportions during dose estimation led to the idea of estimated E verification. Consequently, two different sets of about 100 of TLD 100H detectors were calibrated for measurement inside the Aldersnon RANDO Anthropomorphic Phantom. Standard examination protocols were examined using a 2 Slice CT- part of hybrid SPECT/CT. Moreover, phantom exposure from body examining protocol for 32 Slice and 64 Slice diagnostic CT scanner was also verified. Absorbed dose (DT,R) measured using TLD detectors was compared with software estimation of equivalent dose HT values, computed by E estimation software. Though, only limited number of cavities for detectors enabled measurement within the regions of lung, liver, thyroid and spleen-pancreas region, some basic comparison is possible.

  7. Dynamic multidetector computed tomography findings of hepatocellular carcinoma of hepatitis B virus-positive and -negative patients

    PubMed Central

    2014-01-01

    Background The objective of this study was to retrospectively investigate and compare multidetector computed tomography findings of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV)-positive and -negative patients. Methods Triphasic (arterial, portal venous, and delayed phases) dynamic multidetector computed tomography (CT) was performed in 83 patients with HCC, 48 of whom were HBV-positive. The diagnosis of HCC was established with typical CT imaging findings (68 patients) or histopathological evaluation (15 patients). Distribution of solitary, multiple, and diffuse HCC, portal/hepatic vein thrombosis, metastasis, and patients with high alpha-fetoprotein levels in the HBV-positive and -negative groups were compared using the Kolmogorov–Smirnov test. Lesion size, alpha-fetoprotein levels, arterial, portal, delayed enhancement, and washout of lesions were compared using the Student’s t-test. Results Hypervascular tumors were observed in 72 (87%) patients, and hypovascular tumors were found in 11 (13%) patients. The mean alpha-fetoprotein value of HBV-positive patients with HCC was significantly higher than the mean alpha-fetoprotein value of HBV-negative patients (P < 0.05). Portal/hepatic vein thrombosis and metastasis were more frequently observed in HBV-positive patients (P < 0.05). The frequencies of solitary, multiple, and diffuse lesions in HBV-positive and -negative patients were not significantly different (P > 0.05). The mean diameters, arterial, portal, and delayed phase attenuations, and washout of HCC were not significantly different (P > 0.05). Conclusions Multidetector CT imaging findings of HCC in HBV-positive and -negative patients are alike. Portal/hepatic vein thrombosis and metastasis are more frequently observed in HBV-positive patients. Alpha-fetoprotein levels are higher in HBV-positive patients. PMID:25608603

  8. Visualisation of the Bonebridge by means of CT and CBCT

    PubMed Central

    2013-01-01

    Background With the Bonebridge, a new bone-anchored hearing aid has been available since March 2012. The objective of the study was to analyse the visualisation of the implant itself as well as its impact on the representation of the bony structures of the petrosal bone in CT, MRI and cone beam CT (CBCT). Methods The Bonebridge was implanted unilaterally in two completely prepared human heads. The radiological imaging by means of CBCT, 64-slice CT, 1.5-T and 3.0-T MRI was conducted both preoperatively and postoperatively. The images were subsequently evaluated from both the ENT medical and nd radiological perspectives. Results As anticipated, no visualisation of the implant or of the petrosal bones could be realised on MRI because of the interactive technology and the magnet artefact. In contrast, an excellent evaluability of the implant itself as well as of the surrounding neurovascular structures (sinus sigmoideus, skull base, middle ear, inner ear, inner auditory canal) was exhibited in both the CT and in the CBCT. Conclusion The Bonebridge can be excellently imaged with the radiological imaging technologies of CT and CBCT. In the process, CBCT shows discrete advantages in comparison with CT. No relevant restrictions in image quality in the evaluation of the bony structures of the petrosal bones could be seen. PMID:24004903

  9. Morphometric analysis of sex differences in contemporary Japanese pelves using multidetector computed tomography.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2015-12-01

    Sex estimation of decomposed or skeletal remains is clearly important in forensic contexts. Recently, contemporary population-specific data has been obtained using multidetector computed tomography (MDCT) scanning. The main purpose of this study was to investigate skeletal pelvic dimorphism in a contemporary Japanese forensic sample and to quantify the accuracy of sex estimation using various pelvic measurements obtained from three-dimensional (3D) CT images. This study used a total of 208 cadavers (104 males, 104 females) of which postmortem CT scanning and subsequent forensic autopsy were conducted between December 2011 and August 2014. Eleven measurements of each pelvis were obtained from 3D CT reconstructed images that extracted only bone data. The measurements were analyzed using descriptive statistics and discriminant function analyses. All except one measurement were dimorphic in terms of sex differences. Univariate discriminant function analyses using these measurements provided sex classification accuracy rates of 62.0-98.1%. The subpubic angle was found to contribute most significantly to accurate sex estimation. Multivariate discriminant functions yielded sex prediction accuracy rates of 63.9-98.1%. In conclusion, the pelvic measurements obtained from 3D CT images of a contemporary Japanese population successfully demonstrated sexual dimorphism and may be useful for the estimation of skeletal sex in the field of forensic anthropology.

  10. CT angiography in the abdomen: a pictorial review and update.

    PubMed

    Liu, Peter S; Platt, Joel F

    2014-02-01

    The development of multidetector CT technology and helical scanning techniques has revolutionized the use of CT for primary diagnostic evaluation of the abdominal vasculature, particularly the arterial system. CT angiography has numerous benefits relative to conventional catheter angiography, and has largely replaced catheter-based techniques in many clinical algorithms. This pictorial review and update will cover important technical principles related to modern CT angiography (including contrast delivery and dose considerations), discuss relevant anatomy and variants, and illustrate numerous arterial conditions related to the abdominal aorta and branch vessels.

  11. Strategies for reduction of radiation dose in cardiac multislice CT.

    PubMed

    Paul, Jean-François; Abada, Hicham T

    2007-08-01

    Because cardiac computed tomography (CT) (mainly coronary CT angiography) is a very promising technique, used more and more for coronary artery evaluation, the benefits and risks of this new low-invasive technique must be balanced. Radiation dose is a major concern for coronary CT angiography, especially in case of repeated examinations or in particular subgroups of patients (for example young female patients). Radiation dose to patient tends to increase from 16- to 64-slice CT. Radiation exposure in ECG-gated acquisitions may reach up to 40 mSv; considerable differences are attributable to the performance of CT machines, to technical dose-sparing tools, but also to radiological habits. Setting radiation dose at the lowest level possible should be a constant goal for the radiologist. Current technological tools are detailed in regard to their efficiency. Optimisation is necessary, by a judicious use of technological tools and also by individual adaptation of kV or mAs. This paper reviews the different current strategies for radiation dose reduction, keeping image quality constant. Data from the literature are discussed, and future technological developments are considered in regards to radiation dose reduction. The particular case of paediatric patients with congenital heart disease is also addressed.

  12. Is multidetector computed tomography comparable to magnetic resonance imaging for assessment of lumbar foraminal stenosis?

    PubMed

    Kang, Woo Young; Ahn, Joong Mo; Lee, Joon Woo; Lee, Eugene; Bae, Yun Jung; Seo, Jiwoon; Kim, Junghoon; Kang, Heung Sik

    2017-02-01

    Background Both multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) are used for assessment of lumbar foraminal stenosis (LFS). Therefore, it is relevant to assess agreement between these imaging modalities. Purpose To determine intermodality, inter-, and intra-observer agreement for assessment of LFS on MDCT and MRI. Material and Methods A total of 120 foramina in 20 patients who visited our institution in January and February 2014 were evaluated by six radiologists with different levels of experience. Radiologists evaluated presence and severity of LFS on sagittal CT and MR images according to a previously published LFS grading system. Intermodality agreement was analyzed by using weighted kappa statistics, while inter- and intra-observer agreement were analyzed by using intraclass correlation coefficients (ICCs) and kappa statistics. Results Overall intermodality agreement was moderate to good (kappa, 0.478-0.765). In particular, two professors and one fellow tended to overestimate the degree of LFS on CT compared with MRI. For inter-observer agreement of all six observers, ICCs indicated excellent agreement for both CT (0.774) and MRI (0.771), while Fleiss' kappa values showed moderate agreement for CT (0.482) and MRI (0.575). There was better agreement between professors and fellows compared with residents. For intra-observer agreement, ICCs indicated excellent agreement, while kappa values showed good to excellent agreement for both CT and MRI. Conclusion MDCT was comparable to MRI for diagnosis and assessment of LFS, especially for experienced observers. However, there was a tendency to overestimate the degree of LFS on MDCT compared with MRI.

  13. Managing patient dose in multi-detector computed tomography(MDCT). ICRP Publication 102.

    PubMed

    Valentin, J

    2007-01-01

    Computed tomography (CT) technology has changed considerably in recent years with the introduction of increasing numbers of multiple detector arrays. There are several parameters specific to multi-detector computed tomography (MDCT) scanners that increase or decrease patient dose systematically compared to older single detector computed tomography (SDCT) scanners. This document briefly reviews the MDCT technology, radiation dose in MDCT, including differences from SDCT and factors that affect dose, radiation risks, and the responsibilities for patient dose management. The document recommends that users need to understand the relationship between patient dose and image quality and be aware that image quality in CT is often higher than that necessary for diagnostic confidence. Automatic exposure control (AEC) does not totally free the operator from selection of scan parameters, and awareness of individual systems is important. Scanning protocols cannot simply be transferred between scanners from different manufacturers and should be determined for each MDCT. If the image quality is appropriately specified by the user, and suited to the clinical task, there will be a reduction in patient dose for most patients. Understanding of some parameters is not intuitive and the selection of image quality parameter values in AEC systems is not straightforward. Examples of some clinical situation shave been included to demonstrate dose management, e.g. CT examinations of the chest, the heart for coronary calcium quantification and non-invasive coronary angiography, colonography, the urinary tract, children, pregnant patients, trauma cases, and CT guided interventions. CT is increasingly being used to replace conventional x-ray studies and it is important that patient dose is given careful consideration, particularly with repeated or multiple examinations.

  14. A Modular and Compact Multidetector System Based on Monolithic Telescopes

    SciTech Connect

    Figuera, P.; Cardella, G.; Di Pietro, A.; Papa, M.; Tian, W.; Amorini, F.; Musumarra, A.; Pappalardo, G.; Rizzo, F.; Tudisco, S.; Fallica, G.; Valvo, G.

    2004-02-27

    The characteristics of a new multidetector based on the use of Monolithic Silicon Telescopes are presented. Using suitable ion implantation techniques, the {delta}E and residual energy stages of the telescopes have been integrated on a single Si chip, obtaining a typical thickness for the {delta}E stage of the order of 2{mu}m.

  15. Advances of multidetector computed tomography in the characterization and staging of renal cell carcinoma

    PubMed Central

    Tsili, Athina C; Argyropoulou, Maria I

    2015-01-01

    Renal cell carcinoma (RCC) accounts for approximately 90%-95% of kidney tumors. With the widespread use of cross-sectional imaging modalities, more than half of RCCs are detected incidentally, often diagnosed at an early stage. This may allow the planning of more conservative treatment strategies. Computed tomography (CT) is considered the examination of choice for the detection and staging of RCC. Multidetector CT (MDCT) with the improvement of spatial resolution and the ability to obtain multiphase imaging, multiplanar and three-dimensional reconstructions in any desired plane brought about further improvement in the evaluation of RCC. Differentiation of RCC from benign renal tumors based on MDCT features is improved. Tumor enhancement characteristics on MDCT have been found closely to correlate with the histologic subtype of RCC, the nuclear grade and the cytogenetic characteristics of clear cell RCC. Important information, including tumor size, localization, and organ involvement, presence and extent of venous thrombus, possible invasion of adjacent organs or lymph nodes, and presence of distant metastases are provided by MDCT examination. The preoperative evaluation of patients with RCC was improved by depicting the presence or absence of renal pseudocapsule and by assessing the possible neoplastic infiltration of the perirenal fat tissue and/or renal sinus fat compartment. PMID:26120380

  16. Multidetector row computed tomography evaluation of potential living laparoscopic renal donors: the story so far.

    PubMed

    Namasivayam, Saravanan; Kalra, Mannudeep K; Small, William C; Torres, William E; Mittal, Pardeep K

    2006-01-01

    Renal transplantation is the treatment of choice for end-stage renal disease. Living related kidney donation is the major source of renal grafts due to limited availability of cadaveric kidneys. Open nephrectomy was used to harvest donor kidneys. However, the laparoscopic approach is associated with less postoperative pain and quick recovery. So, most centers now prefer a laparoscopic approach to explant donor kidneys. Laparoscopic approach is technically challenging due to limited operative visibility. Hence, accurate preoperative detection of renal arterial and venous anomalies is imperative to avoid inadvertent vascular injury and bleeding. The preoperative workup of renal donors includes clinical evaluation, laboratory tests, and imaging. Traditionally, the renal donors were evaluated with conventional imaging techniques, which included renal catheter angiography and intravenous urography. However, conventional imaging is invasive, expensive, and less accurate for evaluation of complex renal venous anomalies, small calculi, and diffuse or focal renal parenchymal lesions. The introduction of multidetector row computed tomography (MDCT) revolutionized the CT technology by enabling isotropic resolution with faster scan coverage in a single, short breath-hold. Consequently, MDCT has now replaced conventional imaging for comprehensive imaging of potential living renal donors. MDCT is a minimally invasive technique that can accurately detect urolithiasis, renal arterial and venous anomalies, renal parenchymal lesions, and urinary tract anomalies. Renal vascular anomalies detected by MDCT can help the surgeon in planning donor nephrectomy. MDCT with three-dimensional CT angiography enables accurate preoperative renal vascular mapping. This article reviews the role of MDCT in preoperative evaluation of potential laparoscopic renal donors.

  17. CT Enterography

    MedlinePlus

    ... obstructions and Crohn’s disease. CT scanning is fast, painless, noninvasive and accurate. CT enterography is better able ... the benefits vs. risks? Benefits CT scanning is painless, noninvasive and accurate. A major advantage of CT ...

  18. Flat-panel volume CT: fundamental principles, technology, and applications.

    PubMed

    Gupta, Rajiv; Cheung, Arnold C; Bartling, Soenke H; Lisauskas, Jennifer; Grasruck, Michael; Leidecker, Christianne; Schmidt, Bernhard; Flohr, Thomas; Brady, Thomas J

    2008-01-01

    Flat-panel volume computed tomography (CT) systems have an innovative design that allows coverage of a large volume per rotation, fluoroscopic and dynamic imaging, and high spatial resolution that permits visualization of complex human anatomy such as fine temporal bone structures and trabecular bone architecture. In simple terms, flat-panel volume CT scanners can be thought of as conventional multidetector CT scanners in which the detector rows have been replaced by an area detector. The flat-panel detector has wide z-axis coverage that enables imaging of entire organs in one axial acquisition. Its fluoroscopic and angiographic capabilities are useful for intraoperative and vascular applications. Furthermore, the high-volume coverage and continuous rotation of the detector may enable depiction of dynamic processes such as coronary blood flow and whole-brain perfusion. Other applications in which flat-panel volume CT may play a role include small-animal imaging, nondestructive testing in animal survival surgeries, and tissue-engineering experiments. Such versatility has led some to predict that flat-panel volume CT will gain importance in interventional and intraoperative applications, especially in specialties such as cardiac imaging, interventional neuroradiology, orthopedics, and otolaryngology. However, the contrast resolution of flat-panel volume CT is slightly inferior to that of multidetector CT, a higher radiation dose is needed to achieve a comparable signal-to-noise ratio, and a slower scintillator results in a longer scanning time.

  19. Precision of dosimetry-related measurements obtained on current multidetector computed tomography scanners

    SciTech Connect

    Mathieu, Kelsey B.; McNitt-Gray, Michael F.; Zhang, Di; Kim, Hyun J.; Cody, Dianna D.

    2010-08-15

    Purpose: Computed tomography (CT) intrascanner and interscanner variability has not been well characterized. Thus, the purpose of this study was to examine the within-run, between-run, and between-scanner precision of physical dosimetry-related measurements collected over the course of 1 yr on three different makes and models of multidetector row CT (MDCT) scanners. Methods: Physical measurements were collected using nine CT scanners (three scanners each of GE VCT, GE LightSpeed 16, and Siemens Sensation 64 CT). Measurements were made using various combinations of technical factors, including kVp, type of bowtie filter, and x-ray beam collimation, for several dosimetry-related quantities, including (a) free-in-air CT dose index (CTDI{sub 100,air}); (b) calculated half-value layers and quarter-value layers; and (c) weighted CT dose index (CTDI{sub w}) calculated from exposure measurements collected in both a 16 and 32 cm diameter CTDI phantom. Data collection was repeated at several different time intervals, ranging from seconds (for CTDI{sub 100,air} values) to weekly for 3 weeks and then quarterly or triannually for 1 yr. Precision of the data was quantified by the percent coefficient of variation (%CV). Results: The maximum relative precision error (maximum %CV value) across all dosimetry metrics, time periods, and scanners included in this study was 4.33%. The median observed %CV values for CTDI{sub 100,air} ranged from 0.05% to 0.19% over several seconds, 0.12%-0.52% over 1 week, and 0.58%-2.31% over 3-4 months. For CTDI{sub w} for a 16 and 32 cm CTDI phantom, respectively, the range of median %CVs was 0.38%-1.14% and 0.62%-1.23% in data gathered weekly for 3 weeks and 1.32%-2.79% and 0.84%-2.47% in data gathered quarterly or triannually for 1 yr. Conclusions: From a dosimetry perspective, the MDCT scanners tested in this study demonstrated a high degree of within-run, between-run, and between-scanner precision (with relative precision errors typically well

  20. SU-E-I-19: Optimization of Low Contrast Detectability Across Two CT Manufacturers

    SciTech Connect

    Mahmood, U; Dauer, L; Erdi, Y

    2015-06-15

    Purpose: Our goal was to evaluate low contrast detectability (LCD) for abdominal CT protocols across two CT scanner manufacturers, while producing a similar noise texture and CTDIvol for acquired images. Methods: A CIRS tissue equivalent LCD phantom containing three columns of 7 spherical targets, ranging from 10 mm to 2.4 mm, that are 5, 10, and 20 HU below the background matrix (HUBB) was scanned using two a GE HD750 64 slice scanner and a Siemens Somatom Definition AS 64 slice scanner. Protocols were designed to deliver a CTDIvol of 12.26 mGy and images were reconstructed with FBP, ASIR and Sapphire. Comparisons were made with those algorithms that had matching noise power spectrum peaks (NPS). NPS information was extracted from a previously published article that matched NPS peak frequencies across manufacturers by calculating the NPS from uniform phantom images reconstructed with several IR algorithms. Results: The minimum detectable lesion size in the 20 HUBB and 10 HUBB column was 6.3 mm, and 10 mm in the 5 HUBB column for the GE HD 750 scanner. The minimum detectable lesion size in the 20 HUBB column was 4.8 mm, in the 10 HUBB column, 9.5 mm, and the 5 HUBB column, 10 mm for the Siemens Somatom Definition AS. Conclusion: Reducing radiation dose while improving or maintaining LCD is possible with application of IR. However, there are several different IR algorithms, with each generating a different resolution and noise texture. In multi-manufacturer settings, matching only the CTDIvol between manufacturers may Result in a loss of clinically relevant information.

  1. Organ doses to adult patients for chest CT

    SciTech Connect

    Huda, Walter; Sterzik, Alexander; Tipnis, Sameer; Schoepf, U. Joseph

    2010-02-15

    Purpose: The goal of this study was to estimate organ doses for chest CT examinations using volume computed tomography dose index (CTDI{sub vol}) data as well as accounting for patient weight. Methods: A CT dosimetry spreadsheet (ImPACT CT patient dosimetry calculator) was used to compute organ doses for a 70 kg patient undergoing chest CT examinations, as well as volume computed tomography dose index (CTDI{sub vol}) in a body CT dosimetry phantom at the same CT technique factors. Ratios of organ dose to CTDI{sub vol} (f{sub organ}) were generated as a function of anatomical location in the chest for the breasts, lungs, stomach, red bone marrow, liver, thyroid, liver, and thymus. Values of f{sub organ} were obtained for x-ray tube voltages ranging from 80 to 140 kV for 1, 4, 16, and 64 slice CT scanners from two vendors. For constant CT techniques, we computed ratios of dose in water phantoms of differing diameter. By modeling patients of different weights as equivalent water cylinders of different diameters, we generated factors that permit the estimation of the organ doses in patients weighing between 50 and 100 kg who undergo chest CT examinations relative to the corresponding organ doses received by a 70 kg adult. Results: For a 32 cm long CT scan encompassing the complete lungs, values of f{sub organ} ranged from 1.7 (thymus) to 0.3 (stomach). Organs that are directly in the x-ray beam, and are completely irradiated, generally had f{sub organ} values well above 1 (i.e., breast, lung, heart, and thymus). Organs that are not completely irradiated in a total chest CT scan generally had f{sub organ} values that are less than 1 (e.g., red bone marrow, liver, and stomach). Increasing the x-ray tube voltage from 80 to 140 kV resulted in modest increases in f{sub organ} for the heart (9%) and thymus (8%), but resulted in larger increases for the breast (19%) and red bone marrow (21%). Adult patient chests have been modeled by water cylinders with diameters between

  2. CT enterography with polyethylene glycol solution vs CT enteroclysis in small bowel disease

    PubMed Central

    Minordi, L M; Vecchioli, A; Mirk, P; Bonomo, L

    2011-01-01

    Objective The aim of the study is to compare CT enterography with polyethylene glycol solution (PEG-CT) with CT enteroclysis (CT-E) in patients with suspected small bowel disease. Methods 145 patients underwent abdominal contrast-enhanced 16-row multidetector CT after administration of 2000 ml of PEG by mouth (n = 75) or after administration of 2000 ml of methylcellulose by nasojejunal tube (n = 70). Small bowel distension, luminal and extraluminal findings were evaluated and compared with small bowel follow-through examination in 60 patients, double contrast enema in 50, surgery in 25 and endoscopy in 35. Statistical evaluation was carried out by χ2 testing. For both techniques we have also calculated the effective dose and the equivalent dose in a standard patient. Results Crohn's disease was diagnosed in 64 patients, neoplasms in 16, adhesions in 6. Distension of the jejunum was better with CT-E than PEG-CT (p<0.05: statistically significant difference). No significant difference was present for others sites (p>0.05). Evaluation of pathological ileal loops was good with both techniques. The values of sensitivity, specificity and diagnostic accuracy were respectively 94%, 100% and 96% with CT-E, and 93%, 94% and 93% with PEG-CT. The effective dose for PEG-CT was less than the dose for the CT-E (34.7 mSv vs 39.91 mSv). Conclusion PEG-CT shows findings of Crohn's disease as well as CT-E does, although CT-E gives better bowel distension, especially in the jejunum, and has higher specificity than PEG-CT. PMID:20959377

  3. SU-E-P-11: Comparison of Image Quality and Radiation Dose Between Different Scanner System in Routine Abdomen CT

    SciTech Connect

    Liao, S; Wang, Y; Weng, H

    2015-06-15

    Purpose To evaluate image quality and radiation dose of routine abdomen computed tomography exam with the automatic current modulation technique (ATCM) performed in two different brand 64-slice CT scanners in our site. Materials and Methods A retrospective review of routine abdomen CT exam performed with two scanners; scanner A and scanner B in our site. To calculate standard deviation of the portal hepatic level with a region of interest of 12.5 mm x 12.5mm represented to the image noise. The radiation dose was obtained from CT DICOM image information. Using Computed tomography dose index volume (CTDIv) to represented CT radiation dose. The patient data in this study were with normal weight (about 65–75 Kg). Results The standard deviation of Scanner A was smaller than scanner B, the scanner A might with better image quality than scanner B. On the other hand, the radiation dose of scanner A was higher than scanner B(about higher 50–60%) with ATCM. Both of them, the radiation dose was under diagnostic reference level. Conclusion The ATCM systems in modern CT scanners can contribute a significant reduction in radiation dose to the patient. But the reduction by ATCM systems from different CT scanner manufacturers has slightly variation. Whatever CT scanner we use, it is necessary to find the acceptable threshold of image quality with the minimum possible radiation exposure to the patient in agreement with the ALARA principle.

  4. Multidetector computed tomography analysis of benign and malignant nodules in patients with chronic lymphocytic thyroiditis.

    PubMed

    Zhu, Caisong; Liu, Wei; Yang, Jun; Yang, Jing; Shao, Kangwei; Yuan, Lixin; Chen, Hairong; Lu, Wei; Zhu, Ying

    2016-07-01

    The aim of the present study was to compare the multidetector computed tomography (MDCT) features of benign and malignant nodules in patients with chronic lymphocytic thyroiditis (CLT). MDCT findings, including the size, solid percentage, calcification, margin, capsule, anteroposterior-transverse diameter ratio as well as the mode and the degree of enhancement of 137 thyroid nodules in 127 CLT cases were retrospectively analyzed. Furthermore, the correlation between MDCT findings and pathological results combined with the CT perfusion imaging was analyzed for the differences between benign and malignant nodules. A total of 77.5% (31/40) of malignant nodules were completely solid, and 33% (32/97) of benign nodules were predominantly cystic. Compared with the benign nodules, micro-calcification and internal calcification were more frequently observed in the malignant nodules (P<0.05). MDCT features such as ill-defined margin, absence of capsule or incomplete capsule or homogeneous enhancement were more likely to be present in the malignant nodules (P<0.05). Nevertheless, no significant difference was observed in the enhancement degree at arterial or venous phase between benign and malignant nodules (P>0.05). MDCT features are useful in differentiating the benign and malignant nodules in CLT patients, and it may be essential for a radiologist to review the MDCT characteristics of nodules in the clinical practice.

  5. New insights on COPD imaging via CT and MRI

    PubMed Central

    Sverzellati, N; Molinari, F; Pirronti, T; Bonomo, L; Spagnolo, P; Zompatori, M

    2007-01-01

    Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD. PMID:18229568

  6. Sixty-four-slice CT angiography to determine the three dimensional relationships of vascular and soft tissue wounds in lower extremity war time injuries.

    PubMed

    Smith, Jennifer M; Fox, Charles J; Brazaitis, Michael P; Via, Kathy; Garcia, Roman; Feuerstein, Irwin M

    2010-01-01

    This article analyzes the use and benefits of the 64-slice CT scanner in determining the 3D relationships of vascular and soft tissue wounds in lower extremity war time injuries. A brief overview of CT scanning is given as well as the techniques used to produce the images needed for diagnosis. The series follows two similar cases of war time injury patients at the Walter Reed Army Medical Center. The first case is a 30-year-old active duty male, who presented with multiple trauma from a motor vehicle accident because of an improvised explosive device (IED) blast, sustaining substantial lower extremity injuries. The second case is a 34-year-old active duty male, who presented with multiple trauma blast injuries. Both cases were of interest because the vasculature was found to be very close to the surface of the wound, which put the arteries at risk for rupture and for iatrogenic injury during repeated debridements.

  7. [The different manifestations of pulmonary aspergillosis: multidetector computed tomography findings].

    PubMed

    Koren Fernández, L; Alonso Charterina, S; Alcalá-Galiano Rubio, A; Sánchez Nistal, M A

    2014-01-01

    Pulmonary aspergillosis is a fungal infection usually caused by inhaling Aspergillus fumigatus spores. However, when we talk about aspergillosis, we normally refer to the spectrum of clinical and radiological findings that depend directly on the patient's immune status, on the prior existence of lung disease, and on the virulence of the infective organism. There are four types of pulmonary aspergillosis (aspergilloma, allergic bronchopulmonary aspergillosis, chronic necrotizing pulmonary aspergillosis, and invasive aspergillosis), and each type has its own distinct radiologic findings. We review the signs of pulmonary aspergillosis on multidetector computed tomography and we correlate them with patients' symptoms and immune responses. Likewise, we discuss the differential diagnoses.

  8. Multidetector Computer Tomography: Evaluation of Blunt Chest Trauma in Adults

    PubMed Central

    Matos, António P.; Mascarenhas, Vasco; Herédia, Vasco

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall. PMID:25295188

  9. Multidetector computer tomography: evaluation of blunt chest trauma in adults.

    PubMed

    Palas, João; Matos, António P; Mascarenhas, Vasco; Herédia, Vasco; Ramalho, Miguel

    2014-01-01

    Imaging plays an essential part of chest trauma care. By definition, the employed imaging technique in the emergency setting should reach the correct diagnosis as fast as possible. In severe chest blunt trauma, multidetector computer tomography (MDCT) has become part of the initial workup, mainly due to its high sensitivity and diagnostic accuracy of the technique for the detection and characterization of thoracic injuries and also due to its wide availability in tertiary care centers. The aim of this paper is to review and illustrate a spectrum of characteristic MDCT findings of blunt traumatic injuries of the chest including the lungs, mediastinum, pleural space, and chest wall.

  10. From the RSNA refresher courses: CT angiography: clinical applications in the abdomen.

    PubMed

    Fishman, E K

    2001-10-01

    The development of spiral computed tomography (CT) and subsequently multidetector CT has provided unparalleled opportunities for advancement of CT technology and clinical applications. One of the most influential developments has been CT angiography, which is the use of thin-section CT combined with postprocessing of imaging data by using a variety of three-dimensional reconstruction techniques to produce vascular maps that equal or exceed those provided by classic angiography in many applications. In the evaluation of pancreatic disease, the use of multidetector CT angiography enables the radiologist to produce vascular maps that clearly show tumor invasion of vasculature and the relationship of vessels to pancreatic masses. Anatomic areas for which the three-dimensional display is especially helpful include the confluence of the portal vein and the superior mesenteric vein and the more distal portions of the portal vein. Preliminary studies indicate that CT angiography may prove beneficial in the evaluation of ischemic bowel and active Crohn disease. CT angiography has proved extremely valuable for applications such as preoperative planning for hepatic resection, preoperative evaluation and planning for liver transplantation, pretreatment planning for patients considered for hepatic arterial infusion chemotherapy, and pretreatment evaluation of portal vein patency for a variety of reasons. CT angiography can also provide supplemental information in patients with cirrhosis, upper gastrointestinal tract bleeding due to varices, or primary extrahepatic neoplasms.

  11. Spontaneous left main coronary artery dissection complicated by pseudoaneurysm formation in pregnancy: role of CT coronary angiography.

    PubMed

    Rahman, Shahid; Abdul-Waheed, Mohammed; Helmy, Tarek; Huffman, Lynn C; Koshal, Vipin; Guitron, Julian; Merrill, Walter H; Lewis, David F; Dunlap, Stephanie; Shizukuda, Yukitaka; Weintraub, Neal L; Meyer, Christopher; Cilingiroglu, Mehmet

    2009-04-01

    We report a case of a 26-year-old female, who presented at 34 weeks of an uncomplicated pregnancy with an acute ST elevation anterior wall myocardial infarction. Cardiac catheterization suggested a left main coronary artery dissection with pseudoaneurysm formation. The patient's course was complicated by congestive heart failure. She was initially managed conservatively by a multidisciplinary team including heart failure specialists, obstetricians, and cardiovascular surgeons. 4 days after admission, her LMC was imaged by dual-source 64 slice Cardiac computed tomography, coronary dissection was identified extending to the lumen, and the presence of pseudoaneurysm was confirmed. She underwent subsequently a staged procedure, which included placement of an intra-aortic balloon pump, cesarean section, and coronary artery bypass grafting. This case illustrates the utility of coronary artery CT imaging to assess the complexity and stability of coronary artery dissections, thereby helping to determine the need for, and timing of revascularization procedures.

  12. SU-E-I-23: A General KV Constrained Optimization of CNR for CT Abdominal Imaging

    SciTech Connect

    Weir, V; Zhang, J

    2015-06-15

    Purpose: While Tube current modulation has been well accepted for CT dose reduction, kV adjusting in clinical settings is still at its early stage. This is mainly due to the limited kV options of most current CT scanners. kV adjusting can potentially reduce radiation dose and optimize image quality. This study is to optimize CT abdomen imaging acquisition based on the assumption of a continuous kV, with the goal to provide the best contrast to noise ratio (CNR). Methods: For a given dose (CTDIvol) level, the CNRs at different kV and pitches were measured with an ACR GAMMEX phantom. The phantom was scanned in a Siemens Sensation 64 scanner and a GE VCT 64 scanner. A constrained mathematical optimization was used to find the kV which led to the highest CNR for the anatomy and pitch setting. Parametric equations were obtained from polynomial fitting of plots of kVs vs CNRs. A suitable constraint region for optimization was chosen. Subsequent optimization yielded a peak CNR at a particular kV for different collimations and pitch setting. Results: The constrained mathematical optimization approach yields kV of 114.83 and 113.46, with CNRs of 1.27 and 1.11 at the pitch of 1.2 and 1.4, respectively, for the Siemens Sensation 64 scanner with the collimation of 32 x 0.625mm. An optimized kV of 134.25 and 1.51 CNR is obtained for a GE VCT 64 slice scanner with a collimation of 32 x 0.625mm and a pitch of 0.969. At 0.516 pitch and 32 x 0.625 mm an optimized kV of 133.75 and a CNR of 1.14 was found for the GE VCT 64 slice scanner. Conclusion: CNR in CT image acquisition can be further optimized with a continuous kV option instead of current discrete or fixed kV settings. A continuous kV option is a key for individualized CT protocols.

  13. Multidetector Computed Tomography for Congenital Anomalies of the Aortic Arch: Vascular Rings.

    PubMed

    García-Guereta, Luis; García-Cerro, Estefanía; Bret-Zurita, Montserrat

    2016-07-01

    The development of multidetector computed tomography has triggered a revolution in the study of the aorta and other large vessels and has replaced angiography in the diagnosis of congenital anomalies of the aortic arch, particularly vascular rings. The major advantage of multidetector computed tomography is that it permits clear 3-dimensional assessment of not only vascular structures, but also airway and esophageal compression. The current update aims to summarize the embryonic development of the aortic arch and the developmental anomalies leading to vascular ring formation and to discuss the current diagnostic and therapeutic role of multidetector computed tomography in this field.

  14. Multidetector computed tomography findings in deaths with severe burns.

    PubMed

    Levy, Angela D; Harcke, Howard T; Getz, John M; Mallak, Craig T

    2009-06-01

    This study compared autopsy with postmortem multidetector computed tomography (MDCT) findings in charred remains. Seventeen consecutive male subjects (mean age, 29.4 years) who perished in a fire-related event resulting in charred remains underwent total body MDCT immediately prior to routine autopsy that included serum carboxyhemoglobin measurement. MDCT showed all thermal tissue changes (skin and subcutaneous fat loss, skeletal muscle retraction, pugilistic attitude, cortical fractures, bone and organ destruction, thermal epidural hematoma, and thermal amputation) and established all fracture patterns that were lethal, but autopsy added the fire as a contributory cause of death when there was carboxyhemoglobin elevation. MDCT had limited value in determination of lethal vascular and visceral injuries. MDCT is an effective complement to autopsy in the setting of charred remains and may serve to augment a limited autopsy. This may be particularly useful in mass casualty scenarios.

  15. Toroid cavity/coil NMR multi-detector

    DOEpatents

    Gerald, II, Rex E.; Meadows, Alexander D.; Gregar, Joseph S.; Rathke, Jerome W.

    2007-09-18

    An analytical device for rapid, non-invasive nuclear magnetic resonance (NMR) spectroscopy of multiple samples using a single spectrometer is provided. A modified toroid cavity/coil detector (TCD), and methods for conducting the simultaneous acquisition of NMR data for multiple samples including a protocol for testing NMR multi-detectors are provided. One embodiment includes a plurality of LC resonant circuits including spatially separated toroid coil inductors, each toroid coil inductor enveloping its corresponding sample volume, and tuned to resonate at a predefined frequency using a variable capacitor. The toroid coil is formed into a loop, where both ends of the toroid coil are brought into coincidence. Another embodiment includes multiple micro Helmholtz coils arranged on a circular perimeter concentric with a central conductor of the toroid cavity.

  16. Enhanced security for multi-detector quantum random number generators

    NASA Astrophysics Data System (ADS)

    Marangon, Davide G.; Vallone, Giuseppe; Zanforlin, Ugo; Villoresi, Paolo

    2016-11-01

    Quantum random number generators (QRNG) represent an advanced solution for randomness generation, which is essential in every cryptographic application. In this context, integrated arrays of single-photon detectors have promising applications as QRNGs based on the spatial detection of photons. For the employment of QRNGs in cryptography, it is necessary to have efficient methods to evaluate the so-called quantum min-entropy that corresponds to the amount of the true extractable quantum randomness from the QRNG. Here, we present an efficient method that allows the estimation of the quantum min-entropy for a multi-detector QRNG. In particular, we consider a scenario in which an attacker can control the efficiency of the detectors and knows the emitted number of photons. Eventually, we apply the method to a QRNG with 103 detectors.

  17. 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 ...

  18. Relevance of MTF and NPS in quantitative CT: towards developing a predictable model of quantitative performance

    NASA Astrophysics Data System (ADS)

    Chen, Baiyu; Richard, Samuel; Samei, Ehsan

    2012-03-01

    The quantification of lung nodule volume based on CT images provides valuable information for disease diagnosis and staging. However, the precision of the quantification is protocol, system, and technique dependent and needs to be evaluated for each specific case. To efficiently investigate the quantitative precision and find an optimal operating point, it is important to develop a predictive model based on basic system parameters. In this study, a Fourier-based metric, the estimability index (e') was proposed as such a predictor, and validated across a variety of imaging conditions. To first obtain the ground truth of quantitative precision, an anthropomorphic chest phantom with synthetic spherical nodules were imaged on a 64 slice CT scanner across a range of protocols (five exposure levels and two reconstruction algorithms). The volumes of nodules were quantified from the images using clinical software, with the precision of the quantification calculated for each protocol. To predict the precision, e' was calculated for each protocol based on several Fourier-based figures of merit, which modeled the characteristic of the quantitation task and the imaging condition (resolution, noise, etc.) of a particular protocol. Results showed a strong correlation (R2=0.92) between the measured and predicted precision across all protocols, indicating e' as an effective predictor of the quantitative precision. This study provides a useful framework for quantification-oriented optimization of CT protocols.

  19. Clinical significance of multidetector-row computed tomography in breast surgery.

    PubMed

    Doihara, Hiroyoshi; Fujita, Takeo; Takabatake, Daisuke; Takahashi, Hirotoshi; Ogasawara, Yutaka; Shimizu, Nobuyoshi

    2006-01-01

    Several reports support the association of higher ipsilateral breast tumor recurrence rates with positive or intermediate margins compared with negative pathologic margins. Precise evaluation of tumor extension and adequate surgical margin are important factors affecting tumor recurrence after breast-conserving surgery (BCS). Many studies have reported the utility of magnetic resonance imaging (MRI) for diagnosing the tumor extension of breast cancer, but few have evaluated the utility of multidetector-row computed tomography (MDCT). The results of this study show the clinical significance of MDCT for detecting cancer extension and demonstrate the clinical role of MDCT in BCS. Subjects comprised 136 patients grouped into two categories based on whether or not tumor extension was evaluated with MDCT preoperatively. The positive surgical margin rate and breast conservation rate were analyzed in each group and the clinical role of MDCT in BCS was evaluated. Moreover, evaluation of intraductal extension was done both with MDCT and histologically, and computed tomography (CT)-pathologic correlations were examined retrospectively. Finally, the margin-positive cases were analyzed in relation to their clinical characteristics. Sensitivity, specificity, positive predictive value, and negative predictive value for detection of the intraductal component were 71.8%, 85.7%, 82.1%, and 76.9%, respectively. The positive surgical margin rate and conservation rate are 7.46% and 81.9%, respectively, for those who were diagnosed with MDCT preoperatively; their corresponding rates without MDCT were 16.67% and 67.9%. Most margin-positive patients have remarkable lymphatic space invasion. Positive surgical margins were often recognized toward the nipple. For diagnosing the intraductal extension, MDCT shows sufficient diagnosability. Moreover, MDCT can provide appropriate information for the determination of adequate surgical margins and contribute to increases in breast conservation

  20. CT of Normal Developmental and Variant Anatomy of the Pediatric Skull: Distinguishing Trauma from Normality.

    PubMed

    Idriz, Sanjin; Patel, Jaymin H; Ameli Renani, Seyed; Allan, Rosemary; Vlahos, Ioannis

    2015-01-01

    The use of computed tomography (CT) in clinical practice has been increasing rapidly, with the number of CT examinations performed in adults and children rising by 10% per year in England. Because the radiology community strives to reduce the radiation dose associated with pediatric examinations, external factors, including guidelines for pediatric head injury, are raising expectations for use of cranial CT in the pediatric population. Thus, radiologists are increasingly likely to encounter pediatric head CT examinations in daily practice. The variable appearance of cranial sutures at different ages can be confusing for inexperienced readers of radiologic images. The evolution of multidetector CT with thin-section acquisition increases the clarity of some of these sutures, which may be misinterpreted as fractures. Familiarity with the normal anatomy of the pediatric skull, how it changes with age, and normal variants can assist in translating the increased resolution of multidetector CT into more accurate detection of fractures and confident determination of normality, thereby reducing prolonged hospitalization of children with normal developmental structures that have been misinterpreted as fractures. More important, the potential morbidity and mortality related to false-negative interpretation of fractures as normal sutures may be avoided. The authors describe the normal anatomy of all standard pediatric sutures, common variants, and sutural mimics, thereby providing an accurate and safe framework for CT evaluation of skull trauma in pediatric patients.

  1. Low-dose CT for quantitative analysis in acute respiratory distress syndrome

    DTIC Science & Technology

    2013-08-31

    few studies on pulmonary emphysema [22-24], that showed that quantification of hyperinflated tissue is not affected by a reduction of tube current...Pulmonary emphysema : radiation dose and section thickness at multidetector CT quantification--comparison with macroscopic and microscopic...pulmonary emphysema using a low-dose technique. Radiol Med 2002, 104:13-24. 24. Nishio M, Matsumoto S, Ohno Y, Sugihara N, Inokawa H, Yoshikawa T

  2. ESTIMATION OF CARDIAC CT ANGIOGRAPHY RADIATION DOSE TOWARD THE ESTABLISHMENT OF NATIONAL DIAGNOSTIC REFERENCE LEVEL FOR CCTA IN IRAN.

    PubMed

    Hosseini Nasab, Seyed Mohammad Bagher; Shabestani-Monfared, Ali; Deevband, Mohammad Reza; Paydar, Reza; Nabahati, Mehrdad

    2016-08-29

    In recent years, with the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography (CCTA) has emerged as a useful diagnostic imaging modality as a non-invasive assessment of coronary heart disease. CT produces a larger radiation dose than other imaging tests and cardiac CT involves higher radiation dose with the advances in the spatial and temporal resolution. The aims of this study are patient dose assessment and establishment of national diagnostic reference level for CCTA in Iran. A questionnaire was sent to CCTA centers. Data for patient and CT protocols were obtained. The volumetric CT dose index (CTDIvol), dose length product (DLP) and total DLP were considered in the 32 cm standard body phantom. Calculation of estimated effective dose (ED) was obtained by multiplying the DLP by a conversion factor [k = 0.014 mSv (mGy·cm)(-1)]. Mean value of CTDIvol and DLP for CCTA was 50 mGy and 825 mGy·cm. The third quartile (75th) of the distribution of mean CTDIvol (66.54 mGy) and DLP (1073 mGy·cm) values was expressed as the diagnostic reference level (DRL) for CCTA in Iran. The median of ED was 10.26 mSv and interquartile range of ED was 7.08-15.03 mSv. A large variety in CTDIvol and DLP among CT scanner and different sites due to variability in CT parameter is noted. It seems that training could help to reduce patient's dose.

  3. Multi-detector CT assessment in pulmonary hypertension: techniques, systematic approach to interpretation and key findings.

    PubMed

    Lewis, Gareth; Hoey, Edward T D; Reynolds, John H; Ganeshan, Arul; Ment, Jerome

    2015-06-01

    Pulmonary arterial hypertension (PAH) may be suspected based on the clinical history, physical examination and electrocardiogram findings but imaging is usually central to confirming the diagnosis, establishing a cause and guiding therapy. The diagnostic pathway of PAH involves a variety of complimentary investigations of which computed tomography pulmonary angiography (CTPA) has established a central role both in helping identify an underlying cause for PAH and assessing resulting functional compromise. In particular CTPA is considered as the gold standard technique for the diagnosis of thromboembolic disease. This article reviews the CTPA evaluation in PAH, describing CTPA techniques, a systematic approach to interpretation and spectrum of key imaging findings.

  4. Multidetector CT and histological features of benign mesenchymoma of the infratemporal space: a rare case report

    PubMed Central

    Kelkar, CA; Desai, RS; Kambadakone, A; Shetty, SJ

    2013-01-01

    Benign mesenchymoma is a soft tissue neoplasm composed of an admixture of two or more benign mesenchymal components in addition to fibrous tissue. A rare case of benign mesenchymoma of the infratemporal space in a 14-year-old boy is presented. In this case report we discuss the salient imaging and histopathological features of this rare entity. PMID:22282510

  5. Neurologic applications of whole-brain volumetric multidetector computed tomography.

    PubMed

    Snyder, Kenneth V; Mokin, Maxim; Bates, Vernice E

    2014-02-01

    The introduction of computed tomography (CT) scanning in the 1970s revolutionized the way clinicians could diagnose and treat stroke. Subsequent advances in CT technology significantly reduced radiation dose, reduced metallic artifact, and achieved speeds that enable dynamic functional studies. The recent addition of whole-brain volumetric CT perfusion technology has given clinicians a powerful tool to assess parenchymal perfusion parameters as well as visualize dynamic changes in blood vessel flow throughout the brain during a single cardiac cycle. This article reviews clinical applications of volumetric multimodal CT that helped to guide and manage care.

  6. SU-E-T-541: Measurement of CT Density Model Variations and the Impact On the Accuracy of Monte Carlo (MC) Dose Calculation in Stereotactic Body Radiation Therapy for Lung Cancer

    SciTech Connect

    Xiang, H; Li, B; Behrman, R; Russo, G; Kachnic, L; Lu, H; Fernando, H

    2015-06-15

    Purpose: To measure the CT density model variations between different CT scanners used for treatment planning and impact on the accuracy of MC dose calculation in lung SBRT. Methods: A Gammex electron density phantom (RMI 465) was scanned on two 64-slice CT scanners (GE LightSpeed VCT64) and a 16-slice CT (Philips Brilliance Big Bore CT). All three scanners had been used to acquire CT for CyberKnife lung SBRT treatment planning. To minimize the influences of beam hardening and scatter for improving reproducibility, three scans were acquired with the phantom rotated 120° between scans. The mean CT HU of each density insert, averaged over the three scans, was used to build the CT density models. For 14 patient plans, repeat MC dose calculations were performed by using the scanner-specific CT density models and compared to a baseline CT density model in the base plans. All dose re-calculations were done using the same plan beam configurations and MUs. Comparisons of dosimetric parameters included PTV volume covered by prescription dose, mean PTV dose, V5 and V20 for lungs, and the maximum dose to the closest critical organ. Results: Up to 50.7 HU variations in CT density models were observed over the baseline CT density model. For 14 patient plans examined, maximum differences in MC dose re-calculations were less than 2% in 71.4% of the cases, less than 5% in 85.7% of the cases, and 5–10% for 14.3% of the cases. As all the base plans well exceeded the clinical objectives of target coverage and OAR sparing, none of the observed differences led to clinically significant concerns. Conclusion: Marked variations of CT density models were observed for three different CT scanners. Though the differences can cause up to 5–10% differences in MC dose calculations, it was found that they caused no clinically significant concerns.

  7. 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 ...

  8. 64-MULTIDETECTOR COMPUTED TOMOGRAPHIC ANGIOGRAPHY OF THE CANINE CORONARY ARTERIES

    PubMed Central

    Drees, Randi; Frydrychowicz, Alex; Reeder, Scott B.; Pinkerton, Marie E.; Johnson, Rebecca

    2012-01-01

    Canine coronary artery angiography (CTA) was performed in four anesthetized healthy dogs using 64-multi-detector computed tomography. Esmolol, a β-1 adrenergic receptor antagonist, and sodium nitroprusside, an arteriolar and venous dilator, were administered to enhance visualization of the coronary arteries by reducing heart rate and creating vasodilation. The left main coronary artery with its three main branches and the right coronary artery were visualized and subdivided in 13 segments for evaluation. Optimal reconstruction interval, expressed as percentage of the R-to-R interval, was determined at 5% in 2.9%, 35% in 1%, 75% in 21.2%, 85% in 43.3%, and 95% in 31.7% of the segments. Overall image quality was good in 41.3% of the segments and excellent in 14.4%. There was blur in 98.1%, motion in 17.3%, and stair step in 6.7% of the evaluated segments, but these artifacts did not interfere with anatomic depiction of the arteries. Cross-sectional anatomy of the coronary arteries as evaluated from the coronary CTA agreed well with gross anatomic evaluation and published information. The use of esmolol did not lead to the target heart rate of 60–65 beats/min. Nitroprusside had no significant effect on visualized length or diameter of the coronary artery branches. Coronary CTA is useful for the anatomic depiction of coronary artery branches in the dog. PMID:21521398

  9. CT-automatic exposure control devices: What are their performances?

    NASA Astrophysics Data System (ADS)

    Gutierrez, Daniel; Schmidt, Sabine; Denys, Alban; Schnyder, Pierre; Bochud, François O.; Verdun, Francis R.

    2007-10-01

    PurposeTo avoid unnecessary exposure to the patients, constructors have developed tube current modulation algorithms. The purpose of this work is to assess the performance of computed tomography (CT) tube current modulation concerning patient dose and image noise in MSCT scanners. Material and methodsA conical PMMA phantom with elliptical cross-section, to vary the thickness of the irradiated object in a monotonous way, and an anthropomorphic chest phantom were scanned under similar conditions on a general electrics (GE) LightSpeed VCT (64 slices) scanner. Noise measurements were made by calculating the standard deviation of the CT-number on a homogeneous ROI in both phantoms. The dose was estimated with the parameters read in the DICOM header of each studied image. ResultsThe study has shown that most of the time, constant noise levels (noise index) can be obtained by a variation of the mA. Nevertheless, this adaptation can be not fast enough when the variation of the attenuation changes is rapid. Thus, an adaptation length up to 5 cm was obtained. A 18% dose reduction can be achieved (mean of 9.9%) by switching from z-axis modulation algorithm to xyz-axis modulation option. However, exposure in the chest area can be higher with current modulation than without, when trying to keep an image noise level constant in thoraco-abdominal investigations. ConclusionCurrent modulation algorithms can produce inadequate quality images due to problems with tube current stabilization when a sudden attenuation variation takes place as at the start of a scanning sequence. As expected, rotational ( xyz-axis) modulation performs better than only z-axis modulation algorithm. The use of automatic exposure control (AEC) can lead to an increase of the dose if the maximum allowed current is not properly set in thoraco-abdominal acquisitions.

  10. 3D Printing of CT Dataset: Validation of an Open Source and Consumer-Available Workflow.

    PubMed

    Bortolotto, Chandra; Eshja, Esmeralda; Peroni, Caterina; Orlandi, Matteo A; Bizzotto, Nicola; Poggi, Paolo

    2016-02-01

    The broad availability of cheap three-dimensional (3D) printing equipment has raised the need for a thorough analysis on its effects on clinical accuracy. Our aim is to determine whether the accuracy of 3D printing process is affected by the use of a low-budget workflow based on open source software and consumer's commercially available 3D printers. A group of test objects was scanned with a 64-slice computed tomography (CT) in order to build their 3D copies. CT datasets were elaborated using a software chain based on three free and open source software. Objects were printed out with a commercially available 3D printer. Both the 3D copies and the test objects were measured using a digital professional caliper. Overall, the objects' mean absolute difference between test objects and 3D copies is 0.23 mm and the mean relative difference amounts to 0.55 %. Our results demonstrate that the accuracy of 3D printing process remains high despite the use of a low-budget workflow.

  11. Coronary artery imaging with multidetector computed tomography: a call for an evidence-based, multidisciplinary approach.

    PubMed

    Schoenhagen, Paul; Stillman, Arthur E; Garcia, Mario J; Halliburton, Sandra S; Tuzcu, E Murat; Nissen, Steven E; Modic, Michael T; Lytle, Bruce W; Topol, Eric J; White, Richard D

    2006-05-01

    Modern multidetector computed tomography systems are capable of a comprehensive assessment of the cardiovascular system, including noninvasive assessment of coronary anatomy. Multidetector computed tomography is expected to advance the role of noninvasive imaging for coronary artery disease, but clinical experience is still limited. Clinical guidelines are necessary to standardize scanner technology and appropriate clinical applications for coronary computed tomographic angiography. Further evaluation of this evolving technology will benefit from cooperation between different medical specialties, imaging scientists, and manufacturers of multidetector computed tomography systems, supporting multidisciplinary teams focused on the diagnosis and treatment of early and advanced stages of coronary artery disease. This cooperation will provide the necessary education, training, and guidelines for physicians and technologists assuring standard of care for their patients.

  12. Usefulness of 40-slice multidetector row computed tomography to detect coronary disease in patients prior to cardiac valve surgery.

    PubMed

    Pouleur, Anne-Catherine; le Polain de Waroux, Jean-Benoît; Kefer, Joëlle; Pasquet, Agnès; Coche, Emmanuel; Vanoverschelde, Jean-Louis; Gerber, Bernhard L

    2007-12-01

    Preoperative identification of significant coronary artery disease (CAD) in patients prior to valve surgery requires systematic invasive coronary angiography. The purpose of this current prospective study was to evaluate whether exclusion of CAD by multi-detector CT (MDCT) might potentially avoid systematic cardiac catheterization in these patients. Eighty-two patients (53 males, 62 +/- 13 years) scheduled to undergo valve surgery underwent 40-slice MDCT before invasive quantitative coronary angiography (QCA). According to QCA, 15 patients had CAD (5 one-vessel, 6 two-vessel and 4 three-vessel disease). The remaining 67 patients had no CAD. On a per-vessel basis, MDCT correctly identified 27/29 (sensitivity 93%) vessels with and excluded 277/299 vessels (specificity 93%) without CAD. On a per-patient basis, MDCT correctly identified 14/15 patients with (sensitivity 93%) and 60/67 patients without CAD (specificity 90%). Positive and negative predictive values of MDCT were 67% and 98%. Performing invasive angiography only in patients with abnormal MDCT might have avoided QCA in 60/82 (73%). MDCT could be potentially useful in the preoperative evaluation of patients with valve disease. By selecting only those patients with coronary lesions to undergo invasive coronary angiography, it could avoid cardiac catheterization in a large number of patients without CAD.

  13. MULTIDETECTOR-ROW COMPUTED TOMOGRAPHY PATTERNS OF BRONCHOESPHAGEAL ARTERY HYPERTROPHY AND SYSTEMIC-TO-PULMONARY FISTULA IN DOGS.

    PubMed

    Ledda, Gianluca; Caldin, Marco; Mezzalira, Giorgia; Bertolini, Giovanna

    2015-01-01

    Anomalies involving arterial branches in the lungs are one of the causes of hemoptysis in humans and dogs. Congenital and acquired patterns of bronchoesophageal artery hypertrophy have been reported in humans based on CT characteristics. The purpose of this retrospective study was to describe clinical, echocardiographic, and multidetector computed tomography features of bronchoesophageal artery hypertrophy and systemic-to-pulmonary arterial communications in a sample of 14 dogs. Two main vascular patterns were identified in dogs that resembled congenital and acquired conditions reported in humans. Pattern 1 appeared as an aberrant origin of the right bronchoesophageal artery, normal origin of the left one, and enlargement of both the bronchial and esophageal branches that formed a dense network terminating in a pulmonary artery through an orifice. Pattern 2 appeared as a normal origin of both right and left bronchoesophageal arteries, with an enlarged and tortuous course along the bronchi to the periphery of the lung, where they communicated with subsegmental pulmonary arteries. Dogs having Pattern 1 also had paraesophageal and esophageal varices, with the latter being confirmed by videoendoscopy examination. Authors conclude that dogs with Pattern 1 should be differentiated from dogs with other congenital vascular systemic-to-pulmonary connections. Dogs having Pattern 2 should be evaluated for underlying pleural or pulmonary diseases. Bronchoesophageal artery hypertrophy can be accompanied by esophageal venous engorgement and should be included in the differential diagnosis for esophageal and paraesophageal varices in dogs.

  14. Development and performance evaluation of an experimental fine pitch detector multislice CT scanner

    SciTech Connect

    Imai, Yasuhiro; Nukui, Masatake; Ishihara, Yotaro; Fujishige, Takashi; Ogata, Kentaro; Moritake, Masahiro; Kurochi, Haruo; Ogata, Tsuyoshi; Yahata, Mitsuru; Tang Xiangyang

    2009-04-15

    The authors have developed an experimental fine pitch detector multislice CT scanner with an ultrasmall focal spot x-ray tube and a high-density matrix detector through current CT technology. The latitudinal size of the x-ray tube focal spot was 0.4 mm. The detector dimension was 1824 channels (azimuthal direction)x32 rows (longitudinal direction) at row width of 0.3125 mm, in which a thinner reflected separator surrounds each detector cell coupled with a large active area photodiode. They were mounted on a commercial 64-slice CT scanner gantry while the scan field of view (50 cm) and gantry rotation speed (0.35 s) can be maintained. The experimental CT scanner demonstrated the spatial resolution of 0.21-0.22 mm (23.8-22.7 lp/cm) with the acrylic slit phantom and in-plane 50%-MTF 9.0 lp/cm and 10%-MTF 22.0 lp/cm. In the longitudinal direction, it demonstrated the spatial resolution of 0.24 mm with the high-resolution insert of the CATPHAN phantom and 0.34 mm as the full width at half maximum of the slice sensitivity profile. In low-contrast detectability, 3 mm at 0.3% was visualized at the CTDI{sub vol} of 47.2 mGy. Two types of 2.75 mm diameter vessel phantoms with in-stent stenosis at 25%, 50%, and 75% stair steps were scanned, and the reconstructed images can clearly resolve the stenosis at each case. The experimental CT scanner provides high-resolution imaging while maintaining low-contrast detectability, demonstrating the potentiality for clinical applications demanding high spatial resolution, such as imaging of inner ear, lung, and bone, or low-contrast detectability, such as imaging of coronary artery.

  15. Validation of multi-detector computed tomography as a non-invasive method for measuring ovarian volume in macaques (Macaca fascicularis).

    PubMed

    Jones, Jeryl C; Appt, Susan E; Werre, Stephen R; Tan, Joshua C; Kaplan, Jay R

    2010-06-01

    The purpose of this study was to validate low radiation dose, contrast-enhanced, multi-detector computed tomography (MDCT) as a non-invasive method for measuring ovarian volume in macaques. Computed tomography scans of four known-volume phantoms and nine mature female cynomolgus macaques were acquired using a previously described, low radiation dose scanning protocol, intravenous contrast enhancement, and a 32-slice MDCT scanner. Immediately following MDCT, ovaries were surgically removed and the ovarian weights were measured. The ovarian volumes were determined using water displacement. A veterinary radiologist who was unaware of actual volumes measured ovarian CT volumes three times, using a laptop computer, pen display tablet, hand-traced regions of interest, and free image analysis software. A statistician selected and performed all tests comparing the actual and CT data. Ovaries were successfully located in all MDCT scans. The iliac arteries and veins, uterus, fallopian tubes, cervix, ureters, urinary bladder, rectum, and colon were also consistently visualized. Large antral follicles were detected in six ovaries. Phantom mean CT volume was 0.702+/-SD 0.504 cc and the mean actual volume was 0.743+/-SD 0.526 cc. Ovary mean CT volume was 0.258+/-SD 0.159 cc and mean water displacement volume was 0.257+/-SD 0.145 cc. For phantoms, the mean coefficient of variation for CT volumes was 2.5%. For ovaries, the least squares mean coefficient of variation for CT volumes was 5.4%. The ovarian CT volume was significantly associated with actual ovarian volume (ICC coefficient 0.79, regression coefficient 0.5, P=0.0006) and the actual ovarian weight (ICC coefficient 0.62, regression coefficient 0.6, P=0.015). There was no association between the CT volume accuracy and mean ovarian CT density (degree of intravenous contrast enhancement), and there was no proportional or fixed bias in the CT volume measurements. Findings from this study indicate that MDCT is a valid non

  16. Prediction of Small Bowel Obstruction Caused by Bezoars Using Risk Factor Categories on Multidetector Computed Tomographic Findings

    PubMed Central

    Kuang, Lian-qin; Cheng, Cheng

    2016-01-01

    Objectives. The aim of this study was to detect factors associated with small bowel obstruction (SBO) caused by bezoars on multidetector computed tomographic findings. Methods. We retrospectively reviewed 61 patients who had bezoars in the small bowels on MDCT. The patients were divided into SBO patients group and non-SBO patients group. The mean values of the diameter, volume, and CT attenuation as well as location and characteristics of the bezoars were compared between the two groups. Multivariate analysis was performed to determine factors associated with SBO. Results. There were 32 patients (52.5%) in the SBO group and 29 patients (47.5%) in the non-SBO group. The bezoars in the SBO group had greater values of each mean diameter and mean volume than those in the non-SBO group (3.2 ± 0.5 cm versus 1.6 ± 0.7 cm, P < 0.0001, 14.9 ± 6.4 cm3 versus 2.5 ± 2.7 cm3, P < 0.0001, resp.) and had a lower CT attenuation than the non-SBO group (55.5 ± 23.4 versus 173.0 ± 68.0, P < 0.0001). The SBO group had higher prevalence of phytobezoar appearance (75.0% versus 10.3%, P < 0.0001). Major diameters of bezoar and phytobezoar were significant independent risk factors associated with SBO (odds ratio = 36.09, 8.26, resp., and P = 0.0004, 0.044, resp.). Conclusions. Major diameter of bezoar or phytobezoar is a potential risk factor associated with SBO. PMID:27403434

  17. Evaluation of posterior clinoid process pneumatization by multidetector computed tomography.

    PubMed

    Burulday, Veysel; Akgül, Mehmet Hüseyin; Muluk, Nuray Bayar; Ozveren, Mehmet Faik; Kaya, Ahmet

    2016-10-21

    In the present study, we investigated the types and ratio of posterior clinoid process (PCP) pneumatization in paranasal sinus multidetector computed tomography (MDCT). Paranasal MDCT images of 541 subjects (227 males, 314 females), between 15 and 65 years old, were included into the study. Pneumatization of anterior clinoid process and pneumatization types (I, II, or III) were evaluated in the males and females. PCP pneumatization was detected in 20.7 % of the males and 11.5 % of the females. Right, left, and bilateral PCP pneumatizations were detected in 7.9, 5.7, and 7.0 % of the males and 2.9, 3.2, and 4.5 % of the females, respectively. PCP pneumatization of the males is significantly higher than the females. The most detected type of pneumatization was type I (61.2 %) for all groups. In right, left, and bilateral pneumatizations separately, type I pneumatization was the most detected pneumatization type with the ratio of the 70.4, 65.2, and 50.0 %, respectively. In males, type I (61.7 %), and similarly in females, type I (60.6 %) pneumatization were detected more. Type II and type III pneumatizations were detected in decreasing order in both groups. In younger subjects, pneumatization of posterior clinoid process was found as higher, and in older subjects, PCP pneumatization was found as lower. Sclerosis process related to the aging may be responsible for the lower pneumatization ratios in older subjects. Structure of the surrounding regions of PCP is important for surgical procedures related to cavernous sinus, basilar apex aneurysms, and mass lesions. Preoperative radiological examinations are useful for operative planning. Any anomalies to PCP can cause unnecessary injury to the neurovascular complex structure around the cavernous sinus or postclinoidectomy CSF fistulas. Posterior clinoidectomies should be avoided in patients with type III PCP pneumatization to prevent CSF fistulas.

  18. Patient doses using multidetector computed tomography scanners in Kenya.

    PubMed

    Korir, G K; Wambani, J S; Korir, I K

    2012-08-01

    Assessment of patient dose attributed to multislice computed tomography (CT) examination. A questionnaire method was developed and used in recording the patient dose and scanning parameters for the head, chest, abdomen and lumbar spine examinations. The patient doses due to brain, chest and abdomen examination were above the international diagnostic reference levels (DRLs) by factors of between one and four. The study demonstrated that the use of multislice CT elevates patient radiation dose, justifying the need for local optimised scanning protocols and the use of institutional DRL for dose management without affecting diagnostic image quality.

  19. SU-E-I-25: Determining Tube Current, Tube Voltage and Pitch Suitable for Low- Dose Lung Screening CT

    SciTech Connect

    Williams, K; Matthews, K

    2014-06-01

    Purpose: The quality of a computed tomography (CT) image and the dose delivered during its acquisition depend upon the acquisition parameters used. Tube current, tube voltage, and pitch are acquisition parameters that potentially affect image quality and dose. This study investigated physicians' abilities to characterize small, solid nodules in low-dose CT images for combinations of current, voltage and pitch, for three CT scanner models. Methods: Lung CT images was acquired of a Data Spectrum anthropomorphic torso phantom with various combinations of pitch, tube current, and tube voltage; this phantom was used because acrylic beads of various sizes could be placed within the lung compartments to simulate nodules. The phantom was imaged on two 16-slice scanners and a 64-slice scanner. The acquisition parameters spanned a range of estimated CTDI levels; the CTDI estimates from the acquisition software were verified by measurement. Several experienced radiologists viewed the phantom lung CT images and noted nodule location, size and shape, as well as the acceptability of overall image quality. Results: Image quality for assessment of nodules was deemed unsatisfactory for all scanners at 80 kV (any tube current) and at 35 mA (any tube voltage). Tube current of 50 mA or more at 120 kV resulted in similar assessments from all three scanners. Physician-measured sphere diameters were closer to actual diameters for larger spheres, higher tube current, and higher kV. Pitch influenced size measurements less for larger spheres than for smaller spheres. CTDI was typically overestimated by the scanner software compared to measurement. Conclusion: Based on this survey of acquisition parameters, a low-dose CT protocol of 120 kV, 50 mA, and pitch of 1.4 is recommended to balance patient dose and acceptable image quality. For three models of scanners, this protocol resulted in estimated CTDIs from 2.9–3.6 mGy.

  20. Study of statistical properties of hybrid statistic in coherent multidetector compact binary coalescences search

    NASA Astrophysics Data System (ADS)

    Haris, K.; Pai, Archana

    2016-05-01

    In this article, we revisit the coherent gravitational wave search problem of compact binary coalescences with multidetector network consisting of advanced interferometers like LIGO-Virgo. Based on the loss of the optimal multidetector signal-to-noise ratio (SNR), we construct a hybrid statistic as a best of maximum-likelihood-ratio (MLR) statistic tuned for face-on and face-off binaries. The statistical properties of the hybrid statistic is studied. The performance of this hybrid statistic is compared with that of the coherent MLR statistic for generic inclination angles. Owing to the single synthetic data stream, the hybrid statistic gives few false alarms compared to the multidetector MLR statistic and small fractional loss in the optimum SNR for a large range of binary inclinations. We demonstrate that, for a LIGO-Virgo network and binary inclination ɛ <7 0 ° and ɛ >11 0 ° , the hybrid statistic captures more than 98% of the network optimum matched filter SNR with a low false alarm rate. The Monte Carlo exercise with two distributions of incoming inclination angles—namely, U [cos ɛ ] and a more realistic distribution proposed by B. F. Schutz [Classical Quantum Gravity 28, 125023 (2011)]—are performed with the hybrid statistic and give approximately 5% and 7% higher detection probabilities, respectively, compared to the two stream multidetector MLR statistic for a fixed false alarm probability of 1 0-5.

  1. SU-F-207-16: CT Protocols Optimization Using Model Observer

    SciTech Connect

    Tseng, H; Fan, J; Kupinski, M

    2015-06-15

    Purpose: To quantitatively evaluate the performance of different CT protocols using task-based measures of image quality. This work studies the task of size and the contrast estimation of different iodine concentration rods inserted in head- and body-sized phantoms using different imaging protocols. These protocols are designed to have the same dose level (CTDIvol) but using different X-ray tube voltage settings (kVp). Methods: Different concentrations of iodine objects inserted in a head size phantom and a body size phantom are imaged on a 64-slice commercial CT scanner. Scanning protocols with various tube voltages (80, 100, and 120 kVp) and current settings are selected, which output the same absorbed dose level (CTDIvol). Because the phantom design (size of the iodine objects, the air gap between the inserted objects and the phantom) is not ideal for a model observer study, the acquired CT images are used to generate simulation images with four different sizes and five different contracts iodine objects. For each type of the objects, 500 images (100 x 100 pixels) are generated for the observer study. The observer selected in this study is the channelized scanning linear observer which could be applied to estimate the size and the contrast. The figure of merit used is the correct estimation ratio. The mean and the variance are estimated by the shuffle method. Results: The results indicate that the protocols with 100 kVp tube voltage setting provides the best performance for iodine insert size and contrast estimation for both head and body phantom cases. Conclusion: This work presents a practical and robust quantitative approach using channelized scanning linear observer to study contrast and size estimation performance from different CT protocols. Different protocols at same CTDIvol setting could Result in different image quality performance. The relationship between the absorbed dose and the diagnostic image quality is not linear.

  2. Musculoskeletal applications of flat-panel volume CT.

    PubMed

    Reichardt, Benjamin; Sarwar, Ammar; Bartling, Soenke H; Cheung, Arnold; Grasruck, Michael; Leidecker, Christianne; Bredella, Miriam A; Brady, Thomas J; Gupta, Rajiv

    2008-12-01

    Flat-panel volume computed tomography (fpVCT) is a recent development in imaging. We discuss some of the musculoskeletal applications of a high-resolution flat-panel CT scanner. FpVCT has four main advantages over conventional multidetector computed tomography (MDCT): high-resolution imaging; volumetric coverage; dynamic imaging; omni-scanning. The overall effective dose of fpVCT is comparable to that of MDCT scanning. Although current fpVCT technology has higher spatial resolution, its contrast resolution is slightly lower than that of MDCT (5-10HU vs. 1-3HU respectively). We discuss the efficacy and potential utility of fpVCT in various applications related to musculoskeletal radiology and review some novel applications for pediatric bones, soft tissues, tumor perfusion, and imaging of tissue-engineered bone growth. We further discuss high-resolution CT and omni-scanning (combines fluoroscopic and tomographic imaging).

  3. Implementation and characterization of a 320-slice volumetric CT scanner for simulation in radiation oncology

    SciTech Connect

    Coolens, C.; Breen, S.; Purdie, T. G.; Owrangi, A.; Publicover, J.; Bartolac, S.; Jaffray, D. A.

    2009-11-15

    Purpose: Effective target definition and broad employment of treatment response assessment with dynamic contrast-enhanced CT in radiation oncology requires increased speed and coverage for use within a single bolus injection. To this end, a novel volumetric CT scanner (Aquilion One, Toshiba, Tochigi Pref., Japan) has been installed at the Princess Margaret Hospital for implementation into routine CT simulation. This technology offers great advantages for anatomical and functional imaging in both scan speed and coverage. The aim of this work is to investigate the system's imaging performance and quality as well as CT quantification accuracy which is important for radiotherapy dose calculations. Methods: The 320-slice CT scanner uses a 160 mm wide-area (2D) solid-state detector design which provides the possibility to acquire a volumetric axial length of 160 mm without moving the CT couch. This is referred to as ''volume'' and can be scanned with a rotation speed of 0.35-3 s. The scanner can also be used as a 64-slice CT scanner and perform conventional (axial) and helical acquisitions with collimation ranges of 1-32 and 16-32 mm, respectively. Commissioning was performed according to AAPM Reports TG 66 and 39 for both helical and volumetric imaging. Defrise and other cone-beam image analysis tests were performed. Results: Overall, the imaging spatial resolution and geometric efficiency (GE) were found to be very good (>10 lp/mm, <1 mm spatial integrity and GE{sub 160mm}=85%) and within the AAPM guidelines as well as IEC recommendations. Although there is evidence of some cone-beam artifacts when scanning the Defrise phantom, image quality was found to be good and sufficient for treatment planning (soft tissue noise <10 HU). Measurements of CT number stability and contrast-to-noise values across the volume indicate clinically acceptable scan accuracy even at the field edge. Conclusions: Initial experience with this exciting new technology confirms its accuracy for

  4. An improved analytical model for CT dose simulation with a new look at the theory of CT dose

    SciTech Connect

    Dixon, Robert L.; Munley, Michael T.; Bayram, Ersin

    2005-12-15

    Gagne [Med. Phys. 16, 29-37 (1989)] has previously described a model for predicting the sensitivity and dose profiles in the slice-width (z) direction for CT scanners. The model, developed prior to the advent of multidetector CT scanners, is still widely used; however, it does not account for the effect of anode tilt on the penumbra or include the heel effect, both of which are increasingly important for the wider beams (up to 40 mm) of contemporary, multidetector scanners. Additionally, it applied only on (or near) the axis of rotation, and did not incorporate the photon energy spectrum. The improved model described herein transcends all of the aforementioned limitations of the Gagne model, including extension to the peripheral phantom axes. Comparison of simulated and measured dose data provides experimental validation of the model, including verification of the superior match to the penumbra provided by the tilted-anode model, as well as the observable effects on the cumulative dose distribution. The initial motivation for the model was to simulate the quasiperiodic dose distribution on the peripheral, phantom axes resulting from a helical scan series in order to facilitate the implementation of an improved method of CT dose measurement utilizing a short ion chamber, as proposed by Dixon [Med. Phys. 30, 1272-1280 (2003)]. A more detailed set of guidelines for implementing such measurements is also presented in this paper. In addition, some fundamental principles governing CT dose which have not previously been clearly enunciated follow from the model, and a fundamental (energy-based) quantity dubbed 'CTDI-aperture' is introduced.

  5. Three-dimensional image reconstruction of an anorectal malformation with multidetector-row helical computed tomography technology.

    PubMed

    Watanabe, Yoshio; Ando, Hisami; Seo, Takahiko; Kaneko, Kentaro; Katsuno, Shinsuke; Shinohara, Tsuyoshi; Mori, Kensaku; Toriwaki, Junichiro

    2003-05-01

    The presentation of the surgical anatomy of anorectal malformation by standard anatomical figures is not suitable for individual anorectoplasty. It is essential to understand the anatomy of the pelvic muscle (striated muscle complex: SMC) including the external anal sphincter and their three-dimensional (3D) configuration in each patient. Thus, we studied the SMC three-dimensionally with multidetector-row helical computed tomography (MRH-CT) preoperatively, and evaluated its usefulness. Fourteen patients with anorectal malformations before anorectoplasty (types: high n=6, intermediate n=2, low n=6) and two patients without anorectal malformations as controls (total: male n=8, female n=8) were investigated. An image of pelvic region was prepared with a slice thickness of 0.5 mm and a reconstruction pitch of 0.5 mm. A 3D reconstruction on a conventional personal computer (PC) was made with a volume rendering method, and assisted by our own software. The SMC was analyzed with three modified modes of 3D reconstruction corresponding to the surrounding tissues. A length of the parasagittal muscle, and both the sagittal and transverse width of the vertical fibers in the SMC at the connection to the parasagittal muscle were measured on a 3D image and then compared among three different types and controls. To eliminate variations in age, a length index was used to allow comparison. The 3D configuration of the SMC was different in every case. The arranged image mode, which displayed the SMC and the pelvic bones simultaneously, enabled to use conventional knowledge in cysto-urethrography. The length of the parasagittal muscle was longest in the high type but the width of the vertical fibers was smallest. Anatomical figures of the SMC including the external anal sphincter were clearly demonstrated on a PC in every anorectal malformation by our program. A 3D reconstruction image provides positional information on the SMC for the body surface and pelvic bone at the same time

  6. SU-E-I-62: Assessing Radiation Dose Reduction and CT Image Optimization Through the Measurement and Analysis of the Detector Quantum Efficiency (DQE) of CT Images Using Different Beam Hardening Filters

    SciTech Connect

    Collier, J; Aldoohan, S; Gill, K

    2014-06-01

    Purpose: Reducing patient dose while maintaining (or even improving) image quality is one of the foremost goals in CT imaging. To this end, we consider the feasibility of optimizing CT scan protocols in conjunction with the application of different beam-hardening filtrations and assess this augmentation through noise-power spectrum (NPS) and detector quantum efficiency (DQE) analysis. Methods: American College of Radiology (ACR) and Catphan phantoms (The Phantom Laboratory) were scanned with a 64 slice CT scanner when additional filtration of thickness and composition (e.g., copper, nickel, tantalum, titanium, and tungsten) had been applied. A MATLAB-based code was employed to calculate the image of noise NPS. The Catphan Image Owl software suite was then used to compute the modulated transfer function (MTF) responses of the scanner. The DQE for each additional filter, including the inherent filtration, was then computed from these values. Finally, CT dose index (CTDIvol) values were obtained for each applied filtration through the use of a 100 mm pencil ionization chamber and CT dose phantom. Results: NPS, MTF, and DQE values were computed for each applied filtration and compared to the reference case of inherent beam-hardening filtration only. Results showed that the NPS values were reduced between 5 and 12% compared to inherent filtration case. Additionally, CTDIvol values were reduced between 15 and 27% depending on the composition of filtration applied. However, no noticeable changes in image contrast-to-noise ratios were noted. Conclusion: The reduction in the quanta noise section of the NPS profile found in this phantom-based study is encouraging. The reduction in both noise and dose through the application of beam-hardening filters is reflected in our phantom image quality. However, further investigation is needed to ascertain the applicability of this approach to reducing patient dose while maintaining diagnostically acceptable image qualities in a

  7. Automatic detection of plaques with severe stenosis in coronary vessels of CT angiography

    NASA Astrophysics Data System (ADS)

    Dinesh, M. S.; Devarakota, Pandu; Kumar, Jitendra

    2010-03-01

    Coronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of coronary arteries and is the leading cause of death worldwide. Computed tomography angiography (CTA) has been proved to be very useful for accurate noninvasive diagnosis and quantification of plaques. However, the existing methods to measure the stenosis in the plaques are not accurate enough in mid and distal segments where the vessels become narrower. To alleviate this, we propose a method that consists of three stages namely, automatic extraction of coronary vessels; vessels straightening; lumen extraction and stenosis evaluation. In the first stage, the coronary vessels are segmented using a parametric approach based on circular vessel model at each point on the centerline. It is assumed that centerline information is available in advance. Vessel straightening in the second stage performs multi-planar reformat (MPR) to straighten the curved vessels. MPR view of a vessel helps to visualize and measure the plaques better. On the straightened vessel, lumen and vessel wall are segregated using a nearest neighbor classification. To detect the plaques with severe stenosis in the vessel lumen, we propose a "Diameter Luminal Stenosis" method for analyzing the smaller segments of the vessel. Proposed measurement technique identifies the segments that have plaques and reports the top three severely stenosed segments. Proposed algorithm is applied on 24 coronary vessels belonging to multiple cases acquired from Sensation 64 - slice CT and initial results are promising.

  8. SU-E-CAMPUS-J-06: The Impact of CT-Scan Energy On Range Uncertainty in Proton Therapy Planning

    SciTech Connect

    Grantham, K; Li, H; Zhao, T; Klein, E

    2014-06-15

    Purpose: To investigate the impact of tube potential (kVp) on the CTnumber (HU) to proton stopping power ratio (PSPR) conversion table; the range uncertainty and the dosimetric change introduced by a mismatch in kVp between the CT and the HU to PSPR table used to calculate dose are analyzed. Methods: A CIRS CT-ED phantom was scanned with a Philips Brilliance 64-slice scanner under 90kVp and 120kVp tube potentials. Two HU to PSPR curves were then created. Using Eclipse (Varian) a treatment plan was created for a single beam in a water phantom (HU=0) passing through a wedge-shaped heterogeneity (HU=1488). The dose was recalculated by changing only the HU to PSPR table used in the dose calculation. The change in range (the distal 90% isodose line) relative to a distal structure was recorded as a function of heterogeneity thickness in the beam. To show the dosimetric impact of a mismatch in kVp between the CT and the HU to PSPR table, we repeated this procedure using a clinical plan comparing DVH data. Results: The HU to PSPR tables diverge for low-density bone and higher density structures. In the phantom plan, the divergence of the tables results in a change in range of ~1mm per cm of bone in the beam path for the HU used. For the clinical plan, a mismatch in kVp showed a 28% increase in mean dose to the brainstem along with a 10% increase in maximum dose to the brainstem center. Conclusion: A mismatch in kVp between the CT and the HU to PSPR table can introduce significant uncertainty in the proton beam range. For dense bone, the measured range uncertainty is about 1mm per cm of bone in the beam. CT-scan energy verification should be employed, particularly when high-density media is in the proton beam path.

  9. CT Colonography (Virtual Colonoscopy)

    MedlinePlus

    ... Z CT Colonography Computed tomography (CT) colonography or virtual colonoscopy uses special x-ray equipment to examine ... and blood vessels. CT colonography, also known as virtual colonoscopy, uses low dose radiation CT scanning to ...

  10. Hypercortisolism Is Associated With Increased Coronary Arterial Atherosclerosis: Analysis of Noninvasive Coronary Angiography Using Multidetector Computerized Tomography

    PubMed Central

    Neary, Nicola M.; Booker, O. Julian; Abel, Brent S.; Matta, Jatin R.; Muldoon, Nancy; Sinaii, Ninet; Pettigrew, Roderic I.; Nieman, Lynnette K.

    2013-01-01

    Background: Observational studies show that glucocorticoid therapy and the endogenous hypercortisolism of Cushing's syndrome (CS) are associated with increased rates of cardiovascular morbidity and mortality. However, the causes of these findings remain largely unknown. Objective: To determine whether CS patients have increased coronary atherosclerosis. Design: A prospective case-control study was performed. Setting: Subjects were evaulated in a clinical research center. Subjects: Fifteen consecutive patients with ACTH-dependent CS, 14 due to an ectopic source and 1 due to pituitary Cushing's disease were recruited. Eleven patients were studied when hypercortisolemic; 4 patients were eucortisolemic due to medication (3) or cyclic hypercortisolism (1). Fifteen control subjects with at least one risk factor for cardiac disease were matched 1:1 for age, sex, and body mass index. Primary outcome variables: Agatston score a measure of calcified plaque and non-calcified coronary plaque volume were quantified using a multidetector CT (MDCT) coronary angiogram scan. Additional variables included fasting lipids, blood pressure, history of hypertension or diabetes, and 24-hour urine free cortisol excretion. Results: CS patients had significantly greater noncalcified plaque volume and Agatston score (noncalcified plaque volume [mm3] median [interquartile ranges]: CS 49.5 [31.4, 102.5], controls 17.9 [2.6, 25.3], P < .001; Agatston score: CS 70.6 [0, 253.1], controls 0 [0, 7.6]; P < .05). CS patients had higher systolic and diastolic blood pressures than controls (systolic: CS 143 mm Hg [135, 173]; controls, 134 [123, 136], P < .02; diastolic CS: 86 [80, 99], controls, 76 [72, 84], P < .05). Conclusions: Increased coronary calcifications and noncalcified coronary plaque volumes are present in patients with active or previous hypercortisolism. Increased atherosclerosis may contribute to the increased rates of cardiovascular morbidity and mortality in patients with

  11. Utilisation of PACS to monitor patient CT doses.

    PubMed

    AlSuwaidi, J S; Bayoumi, M; Al Shibli, N; Sulaiman, H; Urrahman, T; AlYarah, M

    2011-09-01

    In the past 5 y, the number of computed tomography (CT) studies has doubled at Dubai Health Authority hospitals. This situation, along with patient's overdoses reported internationally, has prompted action to establish a system to manage patient doses incurred due to medical imaging practices. In this work, the authors aim to homogenise dose reporting to monitor radiation dose levels and facilitate the establishment of local and national dose reference levels. The two hospitals enrolled in this study are equipped with three CT systems (two 4 slices and one 64 slices). Through the Picture Archive and Communication Systems (PACS) tracking system, it is mandatory to fill CT patient doses in radiology information system (RIS). Dose length product (mGy cm) was recorded for 2502 adult and 178 paediatric patients. All patients' dosimetry data were collected from the RIS by Cogonos statistical software. The PACS data were reviewed to exclude incomplete data. Average and range of effective doses for adult and paediatric patients were calculated using an appropriate weighting factor. Individual accumulated effective doses for adult and paediatric patients were calculated for 4s-scanner-1 only. Adult average effective doses for the head (1482 exams) were 1.23 ± 0.58, 2.84 ± 0.83 and 2.98 ± 1.103 mSv, the chest (545 exams) were 5.39 ± 1.63, 21.85 ± 5.63 and 18.19 ± 3.22 mSv and for the abdomen and pelvis (1183 exams) were 10.85 ± 4.26, 25.66 ± 8.83 and 26.46 ± 13.75 mSv for 4s-scanner-1, 4s-scanner-2 and 64 s, respectively. The paediatric average effective dose for the head (127 exams) was 1.77 ± 0.82 mSv, for the chest (22 exams) was 3.3 ± 1.29 mSv and for the abdomen and pelvis (27 exams) was 6.16 ± 2.64 mSv. Results of individual accumulated effective doses for adult and paediatric patients were presented. PACS dose reporting facilitated dosimetry clinical auditing. Effective doses obtained in this work demonstrated that the results of one scanner were within

  12. Value and Accuracy of Multidetector Computed Tomography in Obstructive Jaundice

    PubMed Central

    Mathew, Rishi Philip; Moorkath, Abdunnisar; Basti, Ram Shenoy; Suresh, Hadihally B.

    2016-01-01

    Summary Background Objective; To find out the role of MDCT in the evaluation of obstructive jaundice with respect to the cause and level of the obstruction, and its accuracy. To identify the advantages of MDCT with respect to other imaging modalities. To correlate MDCT findings with histopathology/surgical findings/Endoscopic Retrograde CholangioPancreatography (ERCP) findings as applicable. Material/Methods This was a prospective study conducted over a period of one year from August 2014 to August 2015. Data were collected from 50 patients with clinically suspected obstructive jaundice. CT findings were correlated with histopathology/surgical findings/ERCP findings as applicable. Results Among the 50 people studied, males and females were equal in number, and the majority belonged to the 41–60 year age group. The major cause for obstructive jaundice was choledocholithiasis. MDCT with reformatting techniques was very accurate in picking a mass as the cause for biliary obstruction and was able to differentiate a benign mass from a malignant one with high accuracy. There was 100% correlation between the CT diagnosis and the final diagnosis regarding the level and type of obstruction. MDCT was able to determine the cause of obstruction with an accuracy of 96%. Conclusions MDCT with good reformatting techniques has excellent accuracy in the evaluation of obstructive jaundice with regards to the level and cause of obstruction. PMID:27429673

  13. SU-F-207-01: Comparison of Beam Characteristics and Organ Dose From Four Commercial Multidetector Computed Tomography Scanners

    SciTech Connect

    Ohno, T; Araki, F

    2015-06-15

    Purpose: To compare dosimetric properties and patient organ doses from four commercial multidetector CT (MDCT) using Monte Carlo (MC) simulation based on the absorbed dose measured using a Farmer chamber and cylindrical water phantoms according to AAPM TG-111. Methods: Four commercial MDCT were modeled using the GMctdospp (IMPS, Germany) based on the EGSnrc user code. The incident photon spectrum and bowtie filter for MC simulations were determined so that calculated values of aluminum half-value layer (Al-HVL) and off-center ratio (OCR) profile in air agreed with measured values. The MC dose was calibrated from absorbed dose measurements using a Farmer chamber and cylindrical water phantoms. The dose distributions of head, chest, and abdominal scan were calculated using patient CT images and mean organ doses were evaluated from dose volume histograms. Results: The HVLs at 120 kVp of Brilliance, LightSpeed, Aquilion, and SOMATOM were 9.1, 7.5, 7.2, and 8.7 mm, respectively. The calculated Al-HVLs agreed with measurements within 0.3%. The calculated and measured OCR profiles agreed within 5%. For adult head scans, mean doses for eye lens from Brilliance, LightSpeed, Aquilion, and SOMATOM were 21.7, 38.5, 47.2 and 28.4 mGy, respectively. For chest scans, mean doses for lung from Brilliance, LightSpeed, Aquilion, and SOMATOM were 21.1, 26.1, 35.3 and 24.0 mGy, respectively. For adult abdominal scans, the mean doses for liver from Brilliance, LightSpeed, Aquilion, and SOMATOM were 16.5, 21.3, 22.7, and 18.0 mGy, respectively. The absorbed doses increased with decreasing Al-HVL. The organ doses from Aquilion were two greater than those from Brilliance in head scan. Conclusion: MC dose distributions based on absorbed dose measurement in cylindrical water phantom are useful to evaluate individual patient organ doses.

  14. Differentiation of Lymphoma Presenting as Retroperitoneal Mass and Retroperitoneal Fibrosis: Evaluation with Multidetector-row Computed Tomography

    PubMed Central

    Zhang, Shuai; Chen, Min; Li, Chun-Mei; Song, Guo-Dong; Liu, Ying

    2017-01-01

    Background: Retroperitoneal fibrosis (RPF) and lymphoma presenting as retroperitoneal mass may closely resemble each other and misdiagnosis may occur. This study investigated the differential imaging features of RPF and lymphoma which presented as a retroperitoneal soft tissue using multidetector-row computed tomography (MDCT). Methods: The 42 consecutive patients were included in this retrospective review, including 19 RPF patients (45.2%; including 13 males and 6 females; mean age: 56.7 ± 6.2 years) and 23 patients with lymphoma (54.8%; including 14 males and 9 females; mean age: 57.4 ± 12.3 years). An array of qualitative computed tomography (CT) features of lesions in 42 consecutive patients with newly diagnosed untreated RPF and lymphoma were retrospectively analyzed. The quantitative size of the lesion at the para-aortic region and attenuation in the precontrast, arterial, and portal phases were calculated in regions of interest and compared between the patients with newly diagnosed untreated RPF and with lymphoma. Receiver operating characteristic curve analysis was used to assess the potential diagnostic value of each quantitative parameter. Inter-reader concordance was also calculated. Results: Mean ages between patients with RPF and lymphoma were not significantly different (56.7 ± 6.2 years vs. 57.4 ± 12.3 years P = 0.595). Compared to those in patients with lymphoma, homogeneous enhancement (65.2% vs. 94.7%, P = 0.027) and pelvic extension (52.2% vs. 89.5%, P = 0.017) were significantly more common while the involvement of additional nodes (78.3% vs. 5.3%, P < 0.001), suprarenal extension (60.9% vs. 15.8%, P = 0.004), and aortic displacement (43.5% vs. 5.3%, P = 0.006) were significantly less common in patients with RPF. Lesion size at the para-aorta was significantly greater in patients with lymphoma, compared with RPF patients (3.9 ± 1.2 cm vs. 1.8 ± 0.6 cm; P < 0.001). The attenuation values in three phases were not significantly different

  15. SU-E-I-57: Evaluation and Optimization of Effective-Dose Using Different Beam-Hardening Filters in Clinical Pediatric Shunt CT Protocol

    SciTech Connect

    Gill, K; Aldoohan, S; Collier, J

    2014-06-01

    Purpose: Study image optimization and radiation dose reduction in pediatric shunt CT scanning protocol through the use of different beam-hardening filters Methods: A 64-slice CT scanner at OU Childrens Hospital has been used to evaluate CT image contrast-to-noise ratio (CNR) and measure effective-doses based on the concept of CT dose index (CTDIvol) using the pediatric head shunt scanning protocol. The routine axial pediatric head shunt scanning protocol that has been optimized for the intrinsic x-ray tube filter has been used to evaluate CNR by acquiring images using the ACR approved CT-phantom and radiation dose CTphantom, which was used to measure CTDIvol. These results were set as reference points to study and evaluate the effects of adding different filtering materials (i.e. Tungsten, Tantalum, Titanium, Nickel and Copper filters) to the existing filter on image quality and radiation dose. To ensure optimal image quality, the scanner routine air calibration was run for each added filter. The image CNR was evaluated for different kVps and wide range of mAs values using above mentioned beam-hardening filters. These scanning protocols were run under axial as well as under helical techniques. The CTDIvol and the effective-dose were measured and calculated for all scanning protocols and added filtration, including the intrinsic x-ray tube filter. Results: Beam-hardening filter shapes energy spectrum, which reduces the dose by 27%. No noticeable changes in image low contrast detectability Conclusion: Effective-dose is very much dependent on the CTDIVol, which is further very much dependent on beam-hardening filters. Substantial reduction in effective-dose is realized using beam-hardening filters as compare to the intrinsic filter. This phantom study showed that significant radiation dose reduction could be achieved in CT pediatric shunt scanning protocols without compromising in diagnostic value of image quality.

  16. Investigation of temporal resolution required for CT coronary angiography

    NASA Astrophysics Data System (ADS)

    Ohashi, Kazuya; Ichikawa, Katsuhiro; Kawai, Tatsuya; Shibamoto, Yuta

    2012-03-01

    Sub-second multi-detector computed tomography systems (MDCTs) offer great potentials for improving cardiac imaging. However, since the temporal resolution of such CT systems is not sufficient, blurring and artifacts produced by fast cardiac motion are still problematic. The purposes of this study were to investigate the accurate method for measurement of temporal resolution (TR) of the cardiac CT and required TR for obtaining better CT coronary angiography (CTCA). We employed a dual source CT system (Somatom Definition, Siemens), which has various temporal resolution modes (83, 125, and 165 msec) for electro-cardiogram (ECG)-gated scanning. The temporal sensitivity profiles (TSPs) were measured by a new method using temporal impulse generated by metal ball (impulse method). The CTCA images of 200 patients with heart rates (HRs) ranging from 36 to 117 beat per minute (bpm) were visually evaluated using a 4-point scale. The 165-msec TR mode, which is mostly available on recent MDCTs, showed a sufficient image quality only at low HR (<= 60 bpm) for all 3 arteries. The image quality of 125-msec TR mode was acceptable at low to intermediate HRs (< 80 bpm) for LADs and LCXs, and insufficient for the RCAs in cases with HR more than 71 bpm. The 83-msec TR mode demonstrated excellent image quality except for cases with very quick motion of the RCAs at a high HR (>80 bpm).

  17. ASSESSMENT OF EFFECTIVE DOSE FROM CONE BEAM CT IMAGING IN SPECT/CT EXAMINATION IN COMPARISON WITH OTHER MODALITIES.

    PubMed

    Tonkopi, Elena; Ross, Andrew A

    2016-12-01

    The aim of this study was to assess radiation dose from the cone beam computed tomography (CBCT) component of single photon emission tomography/computed tomography (SPECT/CT) examinations and to compare it with the radiopharmaceutical related dose as well as dose from multidetector computed tomography (MDCT). Effective dose (ED) from computed tomography (CT) was estimated using dose-length product values and anatomy-specific conversion factors. The contribution from the SPECT component was evaluated using ED per unit administered activity for the radiopharmaceuticals listed in the International Commission on Radiological Protection Publications 80 and 106. With the exception of cardiac studies (0.11 mSv), the CBCT dose (3.96-6.04 mSv) was similar to that from the radiopharmaceutical accounting for 29-56 % of the total ED from the examination. In comparison with MDCT examinations, the CBCT dose was 48 and 42 % lower for abdomen/pelvis and chest/abdomen/pelvis scans, respectively, while in the chest the CBCT scan resulted in higher dose (23 %). Radiation dose from the CT component should be taken into consideration when evaluating total SPECT/CT patient dose.

  18. Abdominal CT scan

    MedlinePlus

    Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... 2016:chap 133. Radiologyinfo.org. Computed tomography (CT) - abdomen and pelvis. Updated June 16, 2016. www.radiologyinfo. ...

  19. Computed Tomography (CT) - Spine

    MedlinePlus

    ... test used to help diagnose—or rule out—spinal column damage in injured patients. CT scanning is fast, ... CT is to detect—or to rule out—spinal column damage in patients who have been injured. CT ...

  20. The Role of Multidetector Computed Tomography in the Early Diagnosis of Invasive Pulmonary Aspergillosis in Patients with Febrile Neutropenia Undergoing Hematopoietic Stem Cell Transplantation

    PubMed Central

    Çiledağ, Nazan; Arda, Kemal; Arıbaş, Bilgin Kadri; Tekgündüz, Ali Irfan Emre; Altuntaş, Fevzi

    2012-01-01

    Objective: To evaluate vessel involvement and the role of multidetector computed tomography (MDCT) in the earlydiagnosis of invasive pulmonary aspergillosis (IPA) in patients with febrile neutropenia and antibiotic-resistant feverundergoing autologous bone morrow transplantation. Material and Methods: In all, 74 pulmonary MDCT examinations in 37 consecutive hematopoietic stem celltransplantation patients with febrile neutropenia and clinically suspected IPA were retrospectively evaluated. Results: Diagnosis of IPA was based on Fungal Infections Cooperative Group, and National Institute of Allergy andInfectious Diseases Mycoses Study Consensus Group criteria. In all, 0, 14, and 11 patients were diagnosed as proven,probable, and possible IPA, respectively. Among the 25 patients accepted as probable and possible IPA, all had pulmonaryMDCT findings consistent with IPA. The remaining 12 patients were accepted as having fever of unknown origin (FUO)and had patent vessels based on MDCT findings.In the patients with probable and possible IPA, 72 focal pulmonary lesions were observed; in 41 of the 72 (57%) lesionsvascular occlusion was noted and the CT halo sign was observed in 25 of these 41 (61%) lesions. Resolution of feveroccurred following antifungal therapy in 19 (76%) of the 25 patients with probable and possible IPA. In all, 6 (25%)of the patients diagnosed as IPA died during follow-up. Transplant-related mortality 100 d post transplant in patientswith IPA and FUO was 24% and 0%, respectively. Conclusion: In conclusion, MDCT has a potential role in the early diagnosis of IPA via detection of vessel occlusion. PMID:24744620

  1. Optic Strut and Para-clinoid Region – Assessment by Multi-detector Computed Tomography with Multiplanar and 3 Dimensional Reconstructions

    PubMed Central

    Ravikiran, S.R.; Kumar, Ashvini; Chavadi, Channabasappa; Pulastya, Sanyal

    2015-01-01

    Purpose To evaluate thickness, location and orientation of optic strut and anterior clinoid process and variations in paraclinoid region, solely based on multidetector computed tomography (MDCT) images with multiplanar (MPR) and 3 dimensional (3D) reconstructions, among Indian population. Materials and Methods Ninety five CT scans of head and paranasal sinuses patients were retrospectively evaluated with MPR and 3D reconstructions to assess optic strut thickness, angle and location, variations like pneumatisation, carotico-clinoid foramen and inter-clinoid osseous ridge. Results Mean optic strut thickness was 3.64mm (±0.64), optic strut angle was 42.67 (±6.16) degrees. Mean width and length of anterior clinoid process were 10.65mm (±0.79) and 11.20mm (±0.95) respectively. Optic strut attachment to sphenoid body was predominantly sulcal as in 52 cases (54.74%) and was most frequently attached to anterior 2/5th of anterior clinoid process, seen in 93 sides (48.95%). Pneumatisation of optic strut occurred in 23 sides. Carotico-clinoid foramen was observed in 42 cases (22.11%), complete foramen in 10 cases (5.26%), incomplete foramen in 24 cases (12.63%) and contact type in 8 cases (4.21%). Inter-clinoid osseous bridge was seen unilaterally in 4 cases. Conclusion The study assesses morphometric features and anatomical variations of paraclinoid region using MDCT 3D and multiplanar reconstructions in Indian population. PMID:26557589

  2. Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

    SciTech Connect

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P.

    2011-01-15

    Purpose: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. Methods: The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDI{sub vol}) and the effective dose derived from the dose-length product (DLP). Results: The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller

  3. SU-E-I-17: Evaluation of Commercially Available Extension Plates for the ACR CT Accreditation Phantom

    SciTech Connect

    Greene-Donnelly, K; Ogden, K

    2015-06-15

    Purpose: To evaluate the impact of commercially available extension plates on Hounsfield Unit (HU) values in the ACR CT accreditation phantom (Model 464, Gammex Inc., Middleton, Wi). The extension plates are intended to improve water HU values in scanners where the traditional solution involves scanning the phantom with an adjacent water or CTDI phantom. Methods: The Model 464 phantom was scanned on 9 different CT scanners at 8 separate sites representing 16 and 64 slice MDCT technology from four CT manufacturers. The phantom was scanned with and without the extension plates (Gammex 464 EXTPLT-KIT) in helical and axial modes. A water phantom was also scanned to verify water HU calibration. Technique was 120 kV tube potential, 350 mAs, and 210 mm display field of view. Slice thickness and reconstruction algorithm were based on site clinical protocols. The widest available beam collimation was used. Regions of interest were drawn on the HU test objects in Module 1 of the phantom and mean values recorded. Results: For all axial mode scans, water HU values were within limits with or without the extension plates. For two scanners (both Lightspeed VCT, GE Medical Systems, Waukesha WI), axial mode bone HU values were above the specified range both with and without the extension plates though they were closer to the specified range with the plates installed. In helical scan mode, two scanners (both GE Lightspeed VCT) had water HU values above the specified range without the plates installed. With the plates installed, the water HU values were within range for all scanners in all scan modes. Conclusion: Using the plates, the Lightspeed VCT scanners passed the water HU test when scanning in helical mode. The benefit of the extension plates was evident in helical mode scanning with GE scanners using a nominal 4 cm beam. Disclosure: The extension plates evaluated in this work were provided free of charge to the authors. The authors have no other financial interest in Gammex

  4. Multidetector computed tomography of pediatric large airway diseases: state-of-the-art.

    PubMed

    Lee, Edward Y; Greenberg, S Bruce; Boiselle, Phillip M

    2011-09-01

    Advances in multidetector computed tomography (MDCT) technology have given rise to improvements in the noninvasive and comprehensive assessment of the large airways in pediatric patients. Superb two-dimensional and three-dimensional reconstruction MDCT images have revolutionized the display of large airways and enhanced the ability to diagnose large airway diseases in children. The 320-MDCT scanner, which provides combined detailed anatomic and dynamic functional information assessment of the large airways, is promising for the assessment of dynamic large airway disease such as tracheobronchomalacia. This article discusses imaging techniques and clinical applications of MDCT for assessing large airway diseases in pediatric patients.

  5. ISEE-C HKH high energy cosmic rays. [multidetector particle telescope experiment

    NASA Technical Reports Server (NTRS)

    Greiner, D. E.; Bieser, F. S.; Heckman, H. H.

    1978-01-01

    The paper describes the ISEE-C multidetector cosmic ray telescope experiment. The HKH particle identifier sensor array is designed to identify the charge and mass of incident cosmic ray nuclei from H-1 to Ni-64 over the energy range of approximately 20 to 500 MeV/nucleon. Particle identification is based on the multiple energy loss technique. The scientific aspects of the experiment are briefly reviewed and consideration is given to the flight hardware, including sensors, event encoding, buffer memory, redundancy and commandability, and packaging.

  6. Absence of a sphenoid wing in neurofibromatosis type 1 disease: imaging with multidetector computed tomography.

    PubMed

    Onbas, Omer; Aliagaoglu, Cihangir; Calikoglu, Cagatay; Kantarci, Mecit; Atasoy, Mustafa; Alper, Fatih

    2006-01-01

    Neurofibromatosis type 1 disease is characterized by pigmented cutaneous lesions and generalized tumors of a neural crest origin and it may affect all the systems of the human body. Sphenoid dysplasia is one of the characteristics of this syndrome and it occurs in 5-10% of the cases; further, abnormalities of the sphenoid wings are often considered pathognomonic. However, complete agenesis of a sphenoid wing is very rare. We report here on an unusual case of neurofibromatosis type 1 disease with the associated absence of a sphenoid wing that was diagnosed by using multidetector computed tomography.

  7. Extraperitoneal Rupture of a Bladder Diverticulum and the Role of Multidetector Computed Tomography Cystography.

    PubMed

    Kodama, Koichi; Takase, Yasukazu; Saito, Katsuhiko

    2016-11-01

    Nontraumatic rupture of the bladder is less widely recognized than traumatic rupture, with a challenging early diagnosis due to high variability in clinical presentations. We report a case of extraperitoneal rupture of a bladder diverticulum in a patient with diabetes mellitus who presented with paralytic ileus. Despite conservative management, the patient developed sepsis requiring surgical treatment. Urinary tract infection and bladder outlet obstruction were considered to be potential mechanisms of the rupture. Multidetector computed tomography cystography should be used as the first-line modality when evaluating for a suspected bladder rupture, even in patients with nontraumatic bladder rupture.

  8. Identification of Cardiac and Aortic Injuries in Trauma with Multi-detector Computed Tomography.

    PubMed

    Shergill, Arvind K; Maraj, Tishan; Barszczyk, Mark S; Cheung, Helen; Singh, Navneet; Zavodni, Anna E

    2015-01-01

    Blunt and penetrating cardiovascular (CV) injuries are associated with a high morbidity and mortality. Rapid detection of these injuries in trauma is critical for patient survival. The advent of multi-detector computed tomography (MDCT) has led to increased detection of CV injuries during rapid comprehensive scanning of stabilized major trauma patients. MDCT has the ability to acquire images with a higher temporal and spatial resolution, as well as the capability to create multiplanar reformats. This pictorial review illustrates several common and life-threatening traumatic CV injuries from a regional trauma center.

  9. Identification of Cardiac and Aortic Injuries in Trauma with Multi-detector Computed Tomography

    PubMed Central

    Shergill, Arvind K; Maraj, Tishan; Barszczyk, Mark S; Cheung, Helen; Singh, Navneet; Zavodni, Anna E

    2015-01-01

    Blunt and penetrating cardiovascular (CV) injuries are associated with a high morbidity and mortality. Rapid detection of these injuries in trauma is critical for patient survival. The advent of multi-detector computed tomography (MDCT) has led to increased detection of CV injuries during rapid comprehensive scanning of stabilized major trauma patients. MDCT has the ability to acquire images with a higher temporal and spatial resolution, as well as the capability to create multiplanar reformats. This pictorial review illustrates several common and life-threatening traumatic CV injuries from a regional trauma center. PMID:26430541

  10. Tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography: association with N categories

    PubMed Central

    Li, Hang; Chen, Xiao-li; Li, Jun-ru; Li, Zhen-lin; Chen, Tian-wu; Pu, Hong; Yin, Long-lin; Xu, Guo-hui; Li, Zhen-wen; Reng, Jing; Zhou, Peng; Cheng, Zhu-zhong; Cao, Ying

    2016-01-01

    OBJECTIVE: To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories. MATERIALS AND METHODS: A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories. RESULTS: The gross tumor volume could predict regional lymph node metastasis (p<0.0001) in the univariate analysis, and the multivariate analyses indicated that the gross tumor volume was an independent risk factor for regional lymph node metastasis (p=0.005, odds ratio=1.364). The Mann-Whitney U test showed that the gross tumor volume could distinguish N0 from the N1-N3 categories, N0-N1 from N2-N3, and N0-N2 from N3 (all p<0.0001). In the T1-T4a categories, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 12.3 cm3), N0-N1 from N2-N3 (cutoff, 16.6 cm3), and N0-N2 from N3 (cutoff, 24.6 cm3). In the T4a category, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 15.8 cm3), N0-N1 from N2-N3 (cutoff, 17.8 cm3), and N0-N2 from N3 (cutoff, 24 cm3). CONCLUSION: The gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict regional lymph node metastasis and N categories. PMID:27166769

  11. SU-E-I-27: Estimating KERMA Area Product for CT Localizer Images

    SciTech Connect

    Ogden, K; Greene-Donnelly, K; Bennett, R; Thorpe, M

    2015-06-15

    Purpose: To estimate the free-in-air KERMA-Area Product (KAP) incident on patients due to CT localizer scans for common CT exams. Methods: In-plane beam intensity profiles were measured in localizer acquisition mode using OSLs for a 64 slice MDCT scanner (Lightspeed VCT, GE Medical Systems, Waukesha WI). The z-axis beam width was measured as a function of distance from isocenter. The beam profile and width were used to calculate a weighted average air KERMA per unit mAs as a function of intercepted x-axis beam width for objects symmetric about the localizer centerline.Patient areas were measured using manually drawn regions and divided by localizer length to determine average width. Data were collected for 50 head exams (lateral localizer only), 15 head/neck exams, 50 chest exams, and 50 abdomen/pelvis exams. Mean patient widths and acquisition techniques were used to calculate the weighted average free-in-air KERMA, which was multiplied by the patient area to estimate KAP. Results: Scan technique was 120 kV tube voltage, 10 mA current, and table speed of 10 cm/s. The mean ± standard deviation values of KAP were 120 ± 11.6, 469 ± 62.6, 518 ± 45, and 763 ± 93 mGycm{sup 2} for head, head/neck, chest, and abdomen/pelvis exams, respectively. For studies with AP and lateral localizers, the AP/lateral area ratio was 1.20, 1.33, and 1.24 for the head/neck, chest, and abdomen/pelvis exams, respectively. However, the AP/lateral KAP ratios were 1.12, 1.08, and 1.07, respectively. Conclusion: Calculation of KAP in CT localizers is complicated by the non-uniform intensity profile and z-axis beam width. KAP values are similar to those for simple radiographic exams such as a chest radiograph and represent a small fraction of the x-ray exposure at CT. However, as CT doses are reduced the localizer contribution will be a more significant fraction of the total exposure.

  12. Contribution of diffusion weighted MRI to diagnosis and staging in gastric tumors and comparison with multi-detector computed tomography

    PubMed Central

    Fatih Özbay, Mehmet; Çallı, İskan; Doğan, Erkan; Çelik, Sebahattin; Batur, Abdussamet; Bora, Aydın; Yavuz, Alpaslan; Bulut, Mehmet Deniz; Özgökçe, Mesut; Çetin Kotan, Mehmet

    2017-01-01

    Abstract Background Diagnostic performance of Diffusion-Weighted magnetic resonance Imaging (DWI) and Multi-Detector Computed Tomography (MDCT) for TNM (Tumor, Lymph node, Metastasis) staging of gastric cancer was compared. Patients and methods We used axial T2-weighted images and DWI (b-0,400 and b-800 s/mm2) protocol on 51 pre-operative patients who had been diagnosed with gastric cancer. We also conducted MDCT examinations on them. We looked for a signal increase in the series of DWI images. The depth of tumor invasion in the stomach wall (tumor (T) staging), the involvement of lymph nodes (nodal (N) staging), and the presence or absence of metastases (metastatic staging) in DWI and CT images according to the TNM staging system were evaluated. In each diagnosis of the tumors, sensitivity, specificity, positive and negative accuracy rates of DWI and MDCT examinations were found through a comparison with the results of the surgical pathology, which is the gold standard method. In addition to the compatibilities of each examination with surgical pathology, kappa statistics were used. Results Sensitivity and specificity of DWI and MDCT in lymph node staging were as follows: N1: DWI: 75.0%, 84.6%; MDCT: 66.7%, 82%;N2: DWI: 79.3%, 77.3%; MDCT: 69.0%, 68.2%; N3: DWI: 60.0%, 97.6%; MDCT: 50.0%, 90.2%. The diagnostic tool DWI seemed more compatible with the gold standard method (surgical pathology), especially in the staging of lymph node, when compared to MDCT. On the other hand, in T staging, the results of DWI and MDCT were better than the gold standard when the T stage increased. However, DWI did not demonstrate superiority to MDCT. The sensitivity and specificity of both imaging techniques for detecting distant metastasis were 100%. Conclusions The diagnostic accuracy of DWI for TNM staging in gastric cancer before surgery is at a comparable level with MDCT and adding DWI to routine protocol of evaluating lymph nodes metastasis might increase diagnostic accuracy

  13. Advances in post-mortem CT-angiography

    PubMed Central

    Grimm, J; Dominguez, A; Vanhaebost, J; Mangin, P

    2014-01-01

    Performing a post-mortem multidetector CT (MDCT) scan has already become routine in some institutes of forensic medicine. To better visualize the vascular system, different techniques of post-mortem CT-angiography have been explored, which can essentially be divided into partial- and whole-body angiography techniques. Probably the most frequently applied technique today is the so-called multiphase post-mortem CT-angiography (MPMCTA) a standardized method for investigating the vessels of the head, thorax and abdomen. Different studies exist, describing its use for medicolegal investigations, and its advantages as well as its artefacts and pitfalls. With the aim to investigate the performance of PMCTA and to develop and validate techniques, an international working group was created in 2012 called the “Technical Working Group Post-mortem Angiography Methods” (TWGPAM). Beyond its primary perspective, the goals of this group include creating recommendations for the indication of the investigation and for the interpretation of the images and to distribute knowledge about PMCTA. This article provides an overview about the different approaches that have been developed and tested in recent years and an update about ongoing research in this field. It will explain the technique of MPMCTA in detail and give an outline of its indications, application, advantages and limitations. PMID:24234582

  14. [PET/CT for diagnostics and therapy stratification of lung cancer].

    PubMed

    Kratochwil, C; Haberkorn, U; Giesel, F L

    2010-08-01

    With the introduction of positron emission tomography (PET) and more recently the hybrid systems PET/CT, the management of cancer patients in the treatment strategy has changed tremendously. The combination of PET with multidetector CT scanning enables the integration of metabolic and high resolution morphological image information. PET/CT is nowadays an established modality for tumor detection, characterization, staging and response monitoring. The increased installation of PET/CT systems worldwide and also the increased scientific publications underline the importance of this imaging modality. PET/CT is particular the imaging modality of choice in lung cancer staging and re-staging (T, N and M staging). The possible increased success of surgery in lung cancer patients and also the expected reduction in additional invasive diagnostics lead to benefits for both the individual patient and the healthcare system. In this review article PET and PET/CT is presented for diagnostic and therapeutic stratification in lung cancer. The fundamentals of glucose metabolism, staging, tumor recurrence and therapeutic monitoring are presented.

  15. Search for continuous gravitational waves: Metric of the multidetector F-statistic

    SciTech Connect

    Prix, Reinhard

    2007-01-15

    We develop a general formalism for the parameter-space metric of the multidetector F-statistic, which is a matched-filtering detection statistic for continuous gravitational waves. We find that there exists a whole family of F-statistic metrics, parametrized by the (unknown) amplitude parameters of the gravitational wave. The multidetector metric is shown to be expressible in terms of noise-weighted averages of single-detector contributions, which implies that the number of templates required to cover the parameter space does not scale with the number of detectors. Contrary to using a longer observation time, combining detectors of similar sensitivity is therefore the computationally cheapest way to improve the sensitivity of coherent wide-parameter searches for continuous gravitational waves. We explicitly compute the F-statistic metric family for signals from isolated spinning neutron stars, and we numerically evaluate the quality of different metric approximations in a Monte Carlo study. The metric predictions are tested against the measured mismatches and we identify regimes in which the local metric is no longer a good description of the parameter-space structure.

  16. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations*

    PubMed Central

    de Mello Júnior, Carlos Fernando; Araujo Neto, Severino Aires; de Carvalho Junior, Arlindo Monteiro; Rebouças, Rafael Batista; Negromonte, Gustavo Ramalho Pessoa; de Oliveira, Carollyne Dantas

    2016-01-01

    Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations. PMID:27403020

  17. Multidetector computed tomography angiography of the renal arteries: normal anatomy and its variations.

    PubMed

    de Mello Júnior, Carlos Fernando; Araujo Neto, Severino Aires; de Carvalho Junior, Arlindo Monteiro; Rebouças, Rafael Batista; Negromonte, Gustavo Ramalho Pessoa; de Oliveira, Carollyne Dantas

    2016-01-01

    Conventional angiography is still considered the gold standard for the study of the anatomy and of vascular diseases of the abdomen. However, the advent of multidetector computed tomography and techniques of digital image reconstruction has provided an alternative means of performing angiography, without the risks inherent to invasive angiographic examinations. Therefore, within the field of radiology, there is an ever-increasing demand for deeper knowledge of the anatomy of the regional vasculature and its variations. Variations in the renal vascular system are relatively prevalent in the venous and arterial vessels. For various conditions in which surgical planning is crucial to the success of the procedure, knowledge of this topic is important. The aim of this study was to familiarize the general radiologist with variations in the renal vascular system. To that end, we prepared a pictorial essay comprising multidetector computed tomography images obtained in a series of cases. We show patterns representative of the most common anatomical variations in the arterial blood supply to the kidneys, calling attention to the nomenclature, as well as to the clinical and surgical implications of such variations.

  18. On the relationship of minimum detectable contrast to dose and lesion size in abdominal CT

    NASA Astrophysics Data System (ADS)

    Zhou, Yifang; Scott, Alexander, II; Allahverdian, Janet; Lee, Christina; Kightlinger, Blake; Azizyan, Avetis; Miller, Joseph

    2015-10-01

    CT dose optimization is typically guided by pixel noise or contrast-to-noise ratio that does not delineate low contrast details adequately. We utilized the statistically defined low contrast detectability to study its relationship to dose and lesion size in abdominal CT. A realistically shaped medium sized abdomen phantom was customized to contain a cylindrical void of 4 cm diameter. The void was filled with a low contrast (1% and 2%) insert containing six groups of cylindrical targets ranging from 1.2 mm to 7 mm in size. Helical CT scans were performed using a Siemens 64-slice mCT and a GE Discovery 750 HD at various doses. After the subtractions between adjacent slices, the uniform sections of the filtered backprojection reconstructed images were partitioned to matrices of square elements matching the sizes of the targets. It was verified that the mean values from all the elements in each matrix follow a Gaussian distribution. The minimum detectable contrast (MDC), quantified by the mean signal to background difference equal to the distribution’s standard deviation multiplied by 3.29, corresponding to 95% confidence level, was found to be related to the phantom specific dose and the element size by a power law (R^2  >  0.990). Independent readings on the 5 mm and 7 mm targets were compared to the measured contrast to the MDC ratios. The results showed that 93% of the cases were detectable when the measured contrast exceeds the MDC. The correlation of the MDC to the pixel noise and target size was also identified and the relationship was found to be the same for the scanners in the study. To quantify the impact of iterative reconstructions to the low contrast detectability, the noise structure was studied in a similar manner at different doses and with different ASIR blending fractions. The relationship of the dose to the blending fraction and low contrast detectability is presented.

  19. Clinical application of in vivo treatment delivery verification based on PET/CT imaging of positron activity induced at high energy photon therapy

    NASA Astrophysics Data System (ADS)

    Janek Strååt, Sara; Andreassen, Björn; Jonsson, Cathrine; Noz, Marilyn E.; Maguire, Gerald Q., Jr.; Näfstadius, Peder; Näslund, Ingemar; Schoenahl, Frederic; Brahme, Anders

    2013-08-01

    The purpose of this study was to investigate in vivo verification of radiation treatment with high energy photon beams using PET/CT to image the induced positron activity. The measurements of the positron activation induced in a preoperative rectal cancer patient and a prostate cancer patient following 50 MV photon treatments are presented. A total dose of 5 and 8 Gy, respectively, were delivered to the tumors. Imaging was performed with a 64-slice PET/CT scanner for 30 min, starting 7 min after the end of the treatment. The CT volume from the PET/CT and the treatment planning CT were coregistered by matching anatomical reference points in the patient. The treatment delivery was imaged in vivo based on the distribution of the induced positron emitters produced by photonuclear reactions in tissue mapped on to the associated dose distribution of the treatment plan. The results showed that spatial distribution of induced activity in both patients agreed well with the delivered beam portals of the treatment plans in the entrance subcutaneous fat regions but less so in blood and oxygen rich soft tissues. For the preoperative rectal cancer patient however, a 2 ± (0.5) cm misalignment was observed in the cranial-caudal direction of the patient between the induced activity distribution and treatment plan, indicating a beam patient setup error. No misalignment of this kind was seen in the prostate cancer patient. However, due to a fast patient setup error in the PET/CT scanner a slight mis-position of the patient in the PET/CT was observed in all three planes, resulting in a deformed activity distribution compared to the treatment plan. The present study indicates that the induced positron emitters by high energy photon beams can be measured quite accurately using PET imaging of subcutaneous fat to allow portal verification of the delivered treatment beams. Measurement of the induced activity in the patient 7 min after receiving 5 Gy involved count rates which were about

  20. TH-C-18A-11: Investigating the Minimum Scan Parameters Required to Generate Free-Breathing Fast-Helical CT Scans Without Motion-Artifacts

    SciTech Connect

    Thomas, D; Neylon, J; Dou, T; Jani, S; Lamb, J; Low, D; Tan, J

    2014-06-15

    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 motion 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

  1. Applying an animal model to quantify the uncertainties of an image-based 4D-CT algorithm

    NASA Astrophysics Data System (ADS)

    Pierce, Greg; Wang, Kevin; Battista, Jerry; Lee, Ting-Yim

    2012-06-01

    The purpose of this paper is to use an animal model to quantify the spatial displacement uncertainties and test the fundamental assumptions of an image-based 4D-CT algorithm in vivo. Six female Landrace cross pigs were ventilated and imaged using a 64-slice CT scanner (GE Healthcare) operating in axial cine mode. The breathing amplitude pattern of the pigs was varied by periodically crimping the ventilator gas return tube during the image acquisition. The image data were used to determine the displacement uncertainties that result from matching CT images at the same respiratory phase using normalized cross correlation (NCC) as the matching criteria. Additionally, the ability to match the respiratory phase of a 4.0 cm subvolume of the thorax to a reference subvolume using only a single overlapping 2D slice from the two subvolumes was tested by varying the location of the overlapping matching image within the subvolume and examining the effect this had on the displacement relative to the reference volume. The displacement uncertainty resulting from matching two respiratory images using NCC ranged from 0.54 ± 0.10 mm per match to 0.32 ± 0.16 mm per match in the lung of the animal. The uncertainty was found to propagate in quadrature, increasing with number of NCC matches performed. In comparison, the minimum displacement achievable if two respiratory images were matched perfectly in phase ranged from 0.77 ± 0.06 to 0.93 ± 0.06 mm in the lung. The assumption that subvolumes from separate cine scan could be matched by matching a single overlapping 2D image between to subvolumes was validated. An in vivo animal model was developed to test an image-based 4D-CT algorithm. The uncertainties associated with using NCC to match the respiratory phase of two images were quantified and the assumption that a 4.0 cm 3D subvolume can by matched in respiratory phase by matching a single 2D image from the 3D subvolume was validated. The work in this paper shows the image-based 4D-CT

  2. Statistical model based iterative reconstruction (MBIR) in clinical CT systems: Experimental assessment of noise performance

    SciTech Connect

    Li, Ke; Tang, Jie; Chen, Guang-Hong

    2014-04-15

    Purpose: To reduce radiation dose in CT imaging, the statistical model based iterative reconstruction (MBIR) method has been introduced for clinical use. Based on the principle of MBIR and its nonlinear nature, the noise performance of MBIR is expected to be different from that of the well-understood filtered backprojection (FBP) reconstruction method. The purpose of this work is to experimentally assess the unique noise characteristics of MBIR using a state-of-the-art clinical CT system. Methods: Three physical phantoms, including a water cylinder and two pediatric head phantoms, were scanned in axial scanning mode using a 64-slice CT scanner (Discovery CT750 HD, GE Healthcare, Waukesha, WI) at seven different mAs levels (5, 12.5, 25, 50, 100, 200, 300). At each mAs level, each phantom was repeatedly scanned 50 times to generate an image ensemble for noise analysis. Both the FBP method with a standard kernel and the MBIR method (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for CT image reconstruction. Three-dimensional (3D) noise power spectrum (NPS), two-dimensional (2D) NPS, and zero-dimensional NPS (noise variance) were assessed both globally and locally. Noise magnitude, noise spatial correlation, noise spatial uniformity and their dose dependence were examined for the two reconstruction methods. Results: (1) At each dose level and at each frequency, the magnitude of the NPS of MBIR was smaller than that of FBP. (2) While the shape of the NPS of FBP was dose-independent, the shape of the NPS of MBIR was strongly dose-dependent; lower dose lead to a “redder” NPS with a lower mean frequency value. (3) The noise standard deviation (σ) of MBIR and dose were found to be related through a power law of σ ∝ (dose){sup −β} with the component β ≈ 0.25, which violated the classical σ ∝ (dose){sup −0.5} power law in FBP. (4) With MBIR, noise reduction was most prominent for thin image slices. (5) MBIR lead to better noise spatial

  3. [Examination of the effectiveness of heart rate control using intravenous β-blocker in 64-slice coronary computed tomography angiography].

    PubMed

    Yamaguchi, Takayoshi; Takahashi, Daichi; Nakagawa, Shingo; Morita, Mari; Noda, Rie; Nakamura, Yoko; Igarashi, Keiichi

    2012-01-01

    The purpose of this study is to clarify the effectiveness of the use of β-blocker in coronary computed tomography angiography (CCTA). In 1783 patients, heart rate was controlled by propranolol injection to patients with heart rates of 61 bpm or more. As a result, the scan heart rate (58.8±6.5 bpm) decreased significantly compared with the initial heart rate (72.7±9.4 bpm). Prospective gating method was used by 61.9% including 64.3% of the intravenous β-blocker injection group. Moreover, daily use of oral β-blocker had influence on reduction of the scan heart rate (daily use group: 60.1±6.5 bpm vs. unuse group: 58.5±6.3 bpm p<0.01). When we evaluated the image quality of CCTA by the score, the improvement of the score was obviously admitted by 65 bpm or less of the scan heart rate. The ratio of scan heart rate that was controlled by 65 bpm or less was decreased in the initial heart rate groups that were 81 bpm or more. The incidence of adverse reactions by the propranolol injection was few, and these instances only involved slight symptoms. Therefore, heart rate control with the use of β-blocker is useful for the image quality improvement of CCTA. This form of treatment can be safely enforced.

  4. A Novel Fast Helical 4D-CT Acquisition Technique to Generate Low-Noise Sorting Artifact–Free Images at User-Selected Breathing Phases

    SciTech Connect

    Thomas, David; Lamb, James; White, Benjamin; Jani, Shyam; Gaudio, Sergio; Lee, Percy; Ruan, Dan; McNitt-Gray, Michael; Low, Daniel

    2014-05-01

    Purpose: To develop a novel 4-dimensional computed tomography (4D-CT) technique that exploits standard fast helical acquisition, a simultaneous breathing surrogate measurement, deformable image registration, and a breathing motion model to remove sorting artifacts. Methods and Materials: Ten patients were imaged under free-breathing conditions 25 successive times in alternating directions with a 64-slice CT scanner using a low-dose fast helical protocol. An abdominal bellows was used as a breathing surrogate. Deformable registration was used to register the first image (defined as the reference image) to the subsequent 24 segmented images. Voxel-specific motion model parameters were determined using a breathing motion model. The tissue locations predicted by the motion model in the 25 images were compared against the deformably registered tissue locations, allowing a model prediction error to be evaluated. A low-noise image was created by averaging the 25 images deformed to the first image geometry, reducing statistical image noise by a factor of 5. The motion model was used to deform the low-noise reference image to any user-selected breathing phase. A voxel-specific correction was applied to correct the Hounsfield units for lung parenchyma density as a function of lung air filling. Results: Images produced using the model at user-selected breathing phases did not suffer from sorting artifacts common to conventional 4D-CT protocols. The mean prediction error across all patients between the breathing motion model predictions and the measured lung tissue positions was determined to be 1.19 ± 0.37 mm. Conclusions: The proposed technique can be used as a clinical 4D-CT technique. It is robust in the presence of irregular breathing and allows the entire imaging dose to contribute to the resulting image quality, providing sorting artifact–free images at a patient dose similar to or less than current 4D-CT techniques.

  5. NETL CT Imaging Facility

    ScienceCinema

    None

    2016-07-12

    NETL's CT Scanner laboratory is equipped with three CT scanners and a mobile core logging unit that work together to provide characteristic geologic and geophysical information at different scales, non-destructively.

  6. Body CT (CAT Scan)

    MedlinePlus

    ... may increase the risk of an unusual adverse effect. Women should always inform their physician and the CT ... of data to create two-dimensional cross-sectional images of your body, which are then displayed on a monitor. CT ...

  7. Virtual monochromatic spectral imaging with fast kilovoltage switching: reduction of metal artifacts at CT.

    PubMed

    Pessis, Eric; Campagna, Raphaël; Sverzut, Jean-Michel; Bach, Fabienne; Rodallec, Mathieu; Guerini, Henri; Feydy, Antoine; Drapé, Jean-Luc

    2013-01-01

    With arthroplasty being increasingly used to relieve joint pain, imaging of patients with metal implants can represent a significant part of the clinical work load in the radiologist's daily practice. Computed tomography (CT) plays an important role in the postoperative evaluation of patients who are suspected of having metal prosthesis-related problems such as aseptic loosening, bone resorption or osteolysis, infection, dislocation, metal hardware failure, or periprosthetic bone fracture. Despite advances in detector technology and computer software, artifacts from metal implants can seriously degrade the quality of CT images, sometimes to the point of making them diagnostically unusable. Several factors may help reduce the number and severity of artifacts at multidetector CT, including decreasing the detector collimation and pitch, increasing the kilovolt peak and tube charge, and using appropriate reconstruction algorithms and section thickness. More recently, dual-energy CT has been proposed as a means of reducing beam-hardening artifacts. The use of dual-energy CT scanners allows the synthesis of virtual monochromatic spectral (VMS) images. Monochromatic images depict how the imaged object would look if the x-ray source produced x-ray photons at only a single energy level. For this reason, VMS imaging is expected to provide improved image quality by reducing beam-hardening artifacts.

  8. Focused assessment with sonography for trauma (FAST) versus multidetector computed tomography in hemodynamically stable emergency patients.

    PubMed

    Fornell Pérez, R

    2017-02-10

    This critically appraised topic (CAT) study aims to evaluate the quality and extent of the scientific evidence that supports the use of focused assessment with sonography for trauma (FAST) versus multidetector computed tomography (MDCT) in hemodynamically stable trauma patients in the emergency room. An efficient search of the literature yielded several recent articles with a high level of evidence. The CAT study concludes that FAST is an acceptable initial imaging test in hemodynamically stable patients, although its performance is limited in certain circumstances. The decision whether to use MDCT should be determined by evaluating the patient's degree of instability and the distance to the MDCT scanner. Nevertheless, few articles address the question of the distance to MDCT scanners in emergency departments.

  9. Computed tomography angiography: state-of-the-art imaging using multidetector-row technology.

    PubMed

    Napoli, Alessandro; Fleischmann, Dominik; Chan, Frandics P; Catalano, Carlo; Hellinger, Jeffrey C; Passariello, Roberto; Rubin, Geoffrey D

    2004-01-01

    Multidetector-row computed tomography (MDCT) is an essential diagnostic modality for many clinical algorithms. This is particularly true with regard to the evaluation of cardiovascular disease. As a result of increased image acquisition speed, improved spatial resolution, and greater scan volume, MDCT angiography (computed tomography angiography [CTA]) has become an excellent noninvasive imaging technique, replacing intra-arterial digital subtraction angiography for most vascular territories. The clinical success of CTA depends on precise synchronization of image acquisition with optimal vascular enhancement. As technology continuously evolves, however, this task can be challenging. It remains important to have a fundamental knowledge of the principles behind technical parameters and contrast medium administration. This article reviews these essential principles, followed by an overview of current clinical applications.

  10. Collimated prompt gamma TOF measurements with multi-slit multi-detector configurations

    NASA Astrophysics Data System (ADS)

    Krimmer, J.; Chevallier, M.; Constanzo, J.; Dauvergne, D.; De Rydt, M.; Dedes, G.; Freud, N.; Henriquet, P.; La Tessa, C.; Létang, J. M.; Pleskač, R.; Pinto, M.; Ray, C.; Reithinger, V.; Richard, M. H.; Rinaldi, I.; Roellinghoff, F.; Schuy, C.; Testa, E.; Testa, M.

    2015-01-01

    Longitudinal prompt-gamma ray profiles have been measured with a multi-slit multi-detector configuration at a 75 MeV/u 13C beam and with a PMMA target. Selections in time-of-flight and energy have been applied in order to discriminate prompt-gamma rays produced in the target from background events. The ion ranges which have been extracted from each individual detector module agree amongst each other and are consistent with theoretical expectations. In a separate dedicated experiment with 200 MeV/u 12C ions the fraction of inter-detector scattering has been determined to be on the 10%-level via a combination of experimental results and simulations. At the same experiment different collimator configurations have been tested and the shielding properties of tungsten and lead for prompt-gamma rays have been measured.

  11. [Evaluation of cardiac tumors by multidetector computed tomography and magnetic resonance imaging].

    PubMed

    Mercado-Guzman, Marcela P; Meléndez-Ramírez, Gabriela; Castillo-Castellon, Francisco; Kimura-Hayama, Eric

    Cardiac tumors, are a rare pathology (0.002-0.3%) in all age groups, however, they have a clinic importance, due the affected organ. They are classified in primary (benign or malignant) and secondary (metastasis) types. Among primary type, mixoma, is the most common benign tumor, and sarcoma represents most of the malignant injuries. Cardiac metastasis are more frequent than primary tumors. Clinic effects of cardiac tumors are unspecific and vary according their location, size and agresivity. The use of Multidetector Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) assist on the location, sizing, anatomical relationships and the compromise of adyacents structures, besides, MRI is useful for tissue characterization of the tumor. Due to the previous reasons, studies based on noninvasive cardiovascular imaging, have an important role on the characterization of these lesions and the differential diagnosis among them.

  12. An Unusual Left Ventricular Outflow Pseudoaneurysm: Usefulness of Echocardiography and Multidetector Computed Tomography for Surgical Repair

    SciTech Connect

    Da Col, Uberto; Ramoni, Enrico Di Bella, Isidoro; Ragni, Temistocle

    2009-01-15

    Left ventricular outflow tract (LVOT) pseudoaneurysm is a rare but potentially lethal complication, mainly after aortic root endocarditis or surgery. Usually it originates from a dehiscence in the mitral-aortic intervalvular fibrosa and it arises posteriorly to the aortic root. Due to these anatomical features, its imaging assessment is challenging and surgical repair requires complex procedures. An unusual case of LVOT pseudoaneurysm is described. It was detected by transthoracic ecocardiography 7 months after aortic root replacement for acute endocarditis. Multidetector computed tomography (MDCT) confirmed the presence of a pouch located between the aortic root and the right atrium. Computed tomography also detected the origin of the pseudoaneurysm from the muscular interventricular septum of the LVOT, rather below the aortic valve plane. It was repaired with an extracardiac surgical approach, sparing the aortic root bioprosthesis previously implanted. The high-resolution three-dimensional details provided by the preoperative MDCT allowed us to plan a simple and effective surgical strategy.

  13. TU-EF-204-10: A Preliminary Study Evaluating Calculation Variations of Local Noise Power Spectra for CT Simulation in Radiation Therapy

    SciTech Connect

    Dolly, S; Chen, H; Anastasio, M; Mutic, S; Li, H

    2015-06-15

    Purpose: Local noise power spectrum (NPS) properties are significantly affected by calculation variables and CT acquisition and reconstruction parameters, but a thoughtful analysis of these effects is absent. In this study, we performed a complete analysis of the effects of calculation and imaging parameters on the NPS. Methods: The uniformity module of a Catphan phantom was scanned with a Philips Brilliance 64-slice CT simulator using various scanning protocols. Images were reconstructed using both FBP and iDose4 reconstruction algorithms. From these images, local NPS were calculated for regions of interest (ROI) of varying locations and sizes, using four image background removal methods. Additionally, using a predetermined ground truth, NPS calculation accuracy for various calculation parameters was compared for computer simulated ROIs. A complete analysis of the effects of calculation, acquisition, and reconstruction parameters on the NPS was conducted. Results: The local NPS varied with ROI size and image background removal method, particularly at low spatial frequencies. The image subtraction method was the most accurate according to the computer simulation study, and was also the most effective at removing low frequency background components in the acquired data. However, first-order polynomial fitting using residual sum of squares and principle component analysis provided comparable accuracy under certain situations. Similar general trends were observed when comparing the NPS for FBP to that of iDose4 while varying other calculation and scanning parameters. However, while iDose4 reduces the noise magnitude compared to FBP, this reduction is spatial-frequency dependent, further affecting NPS variations at low spatial frequencies. Conclusion: The local NPS varies significantly depending on calculation parameters, image acquisition parameters, and reconstruction techniques. Appropriate local NPS calculation should be performed to capture spatial variations of

  14. Accurate estimation of global and regional cardiac function by retrospectively gated multidetector row computed tomography: comparison with cine magnetic resonance imaging.

    PubMed

    Belge, Bénédicte; Coche, Emmanuel; Pasquet, Agnès; Vanoverschelde, Jean-Louis J; Gerber, Bernhard L

    2006-07-01

    Retrospective reconstruction of ECG-gated images at different parts of the cardiac cycle allows the assessment of cardiac function by multi-detector row CT (MDCT) at the time of non-invasive coronary imaging. We compared the accuracy of such measurements by MDCT to cine magnetic resonance (MR). Forty patients underwent the assessment of global and regional cardiac function by 16-slice MDCT and cine MR. Left ventricular (LV) end-diastolic and end-systolic volumes estimated by MDCT (134+/-51 and 67+/-56 ml) were similar to those by MR (137+/-57 and 70+/-60 ml, respectively; both P=NS) and strongly correlated (r=0.92 and r=0.95, respectively; both P<0.001). Consequently, LV ejection fractions by MDCT and MR were also similar (55+/-21 vs. 56+/-21%; P=NS) and highly correlated (r=0.95; P<0.001). Regional end-diastolic and end-systolic wall thicknesses by MDCT were highly correlated (r=0.84 and r=0.92, respectively; both P<0.001), but significantly lower than by MR (8.3+/-1.8 vs. 8.8+/-1.9 mm and 12.7+/-3.4 vs. 13.3+/-3.5 mm, respectively; both P<0.001). Values of regional wall thickening by MDCT and MR were similar (54+/-30 vs. 51+/-31%; P=NS) and also correlated well (r=0.91; P<0.001). Retrospectively gated MDCT can accurately estimate LV volumes, EF and regional LV wall thickening compared to cine MR.

  15. Cone beam CT for dental and maxillofacial imaging: dose matters.

    PubMed

    Pauwels, Ruben

    2015-07-01

    The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiographs, a routine or excessive use of CBCT would lead to a substantial increase of the collective patient dose. The potential use of CBCT for paediatric patients (e.g. developmental disorders, trauma and orthodontic treatment planning) further increases concern regarding its proper application. This paper provides an overview of justification and optimisation issues in dental and maxillofacial CBCT. The radiation dose in CBCT will be briefly reviewed. The European Commission's Evidence Based Guidelines prepared by the SEDENTEXCT Project Consortium will be summarised, and (in)appropriate use of CBCT will be illustrated for various dental applications.

  16. Synchrotron-based Micro-CT Imaging of the Human Lung Acinus

    PubMed Central

    Litzlbauer, Horst Detlef; Korbel, Kathrin; Kline, Timothy L.; Jorgensen, Steven M.; Eaker, Diane R.; Bohle, Rainer M.; Ritman, Erik L.; Langheinrich, Alexander C.

    2012-01-01

    Structural data about the human lung fine structure are mainly based on stereological methods applied to serial sections. As these methods utilize 2D images, which are often not contiguous, they suffer from inaccuracies which are overcome by analysis of 3D micro-CT images of the never-sectioned specimen. The purpose of our study was to generate a complete data set of the intact 3-dimensional architecture of the human acinus using high-resolution synchrotron-based micro-CT (synMCT). A human lung was inflation-fixed by formaldehyde ventilation and then scanned in a 64-slice CT over its apex to base extent. Lung samples (8-mm diameter, 10-mm height, n = 12) were punched out, stained with osmium tetroxide, and scanned using synMCT at (4μm)3 voxel size. The lung functional unit (acinus, n = 8) was segmented from the 3D tomographic image using an automated tree-analysis software program. Morphometric data of the lung were analyzed by ANOVA. Intraacinar airways branching occurred over 11 generations. The mean acinar volume was 131.3 ± 29.2 mm3 (range 92.5 – 171.3 mm3) and the mean acinar surface was calculated with 1012 ± 26 cm2. The airway internal diameter (starting from the bronchiolus terminalis) decreases distally from 0.66 ± 0.04 mm to 0.34 ± 0.06 mm (p < 0.001) and remains constant after the 7th generation (p < 0.5). The length of each generation ranges between 0.52 – 0.93 mm and did not show significant differences between the second and 11th generation. The branching angle between daughter branches varies between 113–134° without significant differences between the generations (p < 0.3). This study demonstrates the feasibility of quantitating the 3D structure of the human acinus at the spatial resolution readily achievable using synMCT. PMID:20687188

  17. Practical considerations for noise power spectra estimation for clinical CT scanners.

    PubMed

    Dolly, Steven; Chen, Hsin-Chen; Anastasio, Mark; Mutic, Sasa; Li, Hua

    2016-05-01

    Local noise power spectra (NPS) have been commonly calculated to represent the noise properties of CT imaging systems, but their properties are significantly affected by the utilized calculation schemes. In this study, the effects of varied calculation parameters on the local NPS were analyzed, and practical suggestions were provided regarding the estimation of local NPS for clinical CT scanners. The uniformity module of a Catphan phantom was scanned with a Philips Brilliance 64 slice CT simulator with varied scanning protocols. Images were reconstructed using FBP and iDose(4) iterative reconstruction with noise reduction levels 1, 3, and 6. Local NPS were calculated and compared for varied region of interest (ROI) locations and sizes, image background removal methods, and window functions. Additionally, with a predetermined NPS as a ground truth, local NPS calculation accuracy was compared for computer simulated ROIs, varying the aforementioned parameters in addition to ROI number. An analysis of the effects of these varied calculation parameters on the magnitude and shape of the NPS was conducted. The local NPS varied depending on calculation parameters, particularly at low spatial frequencies below ∼0.15 mm-1. For the simulation study, NPS calculation error decreased exponentially as ROI number increased. For the Catphan study the NPS magnitude varied as a function of ROI location, which was better observed when using smaller ROI sizes. The image subtraction method for background removal was the most effective at reducing low-frequency background noise, and produced similar results no matter which ROI size or window function was used. The PCA background removal method with a Hann window function produced the closest match to image subtraction, with an average percent difference of 17.5%. Image noise should be analyzed locally by calculating the NPS for small ROI sizes. A minimum ROI size is recommended based on the chosen radial bin size and image pixel

  18. Practical considerations for noise power spectra estimation for clinical CT scanners.

    PubMed

    Dolly, Steven; Chen, Hsin-Chen; Anastasio, Mark; Mutic, Sasa; Li, Hua

    2016-05-08

    Local noise power spectra (NPS) have been commonly calculated to represent the noise properties of CT imaging systems, but their properties are significantly affected by the utilized calculation schemes. In this study, the effects of varied calculation parameters on the local NPS were analyzed, and practical suggestions were provided regarding the estimation of local NPS for clinical CT scanners. The uniformity module of a Catphan phantom was scanned with a Philips Brilliance 64 slice CT simulator with varied scanning protocols. Images were reconstructed using FBP and iDose4 iterative reconstruction with noise reduction levels 1, 3, and 6. Local NPS were calculated and compared for varied region of interest (ROI) locations and sizes, image background removal methods, and window functions. Additionally, with a predetermined NPS as a ground truth, local NPS calculation accuracy was compared for computer simulated ROIs, varying the aforementioned parameters in addition to ROI number. An analysis of the effects of these varied calculation parameters on the magnitude and shape of the NPS was conducted. The local NPS varied depending on calculation parameters, particularly at low spatial frequencies below ~ 0.15 mm-1. For the simulation study, NPS calculation error decreased exponentially as ROI number increased. For the Catphan study the NPS magnitude varied as a function of ROI location, which was better observed when using smaller ROI sizes. The image subtraction method for background removal was the most effective at reducing low-frequency background noise, and produced similar results no matter which ROI size or window function was used. The PCA background removal method with a Hann window function produced the closest match to image subtraction, with an average percent difference of 17.5%. Image noise should be analyzed locally by calculating the NPS for small ROI sizes. A minimum ROI size is recommended based on the chosen radial bin size and image pixel

  19. Synchrotron-Based Micro-CT Imaging of the Human Lung Acinus

    SciTech Connect

    Litzlbauer, H.; Korbel, K; Kline, T; Jorgensen, S; Eaker, D; Bohle, R; Ritman, E; Langheinrich, A

    2010-01-01

    Structural data about the human lung fine structure are mainly based on stereological methods applied to serial sections. As these methods utilize 2D images, which are often not contiguous, they suffer from inaccuracies which are overcome by analysis of 3D micro-CT images of the never-sectioned specimen. The purpose of our study was to generate a complete data set of the intact three-dimensional architecture of the human acinus using high-resolution synchrotron-based micro-CT (synMCT). A human lung was inflation-fixed by formaldehyde ventilation and then scanned in a 64-slice CT over its apex to base extent. Lung samples (8-mm diameter, 10-mm height, N = 12) were punched out, stained with osmium tetroxide, and scanned using synMCT at (4 {micro}m){sup 3} voxel size. The lung functional unit (acinus, N = 8) was segmented from the 3D tomographic image using an automated tree-analysis software program. Morphometric data of the lung were analyzed by ANOVA. Intra-acinar airways branching occurred over 11 generations. The mean acinar volume was 131.3 {+-} 29.2 mm{sup 3} (range, 92.5-171.3 mm{sup 3}) and the mean acinar surface was calculated with 1012 {+-} 26 cm{sup 2}. The airway internal diameter (starting from the bronchiolus terminalis) decreases distally from 0.66 {+-} 0.04 mm to 0.34 {+-} 0.06 mm (P < 0.001) and remains constant after the seventh generation (P < 0.5). The length of each generation ranges between 0.52 and 0.93 mm and did not show significant differences between the second and eleventh generation. The branching angle between daughter branches varies between 113-degree and 134-degree without significant differences between the generations (P < 0.3). This study demonstrates the feasibility of quantitating the 3D structure of the human acinus at the spatial resolution readily achievable using synMCT.

  20. Quadricuspid pulmonary valve in an adult patient identified by transthoracic echocardiography and multi-detector computed tomography.

    PubMed

    Jung, Soo-Yeon

    2015-01-01

    Quadricuspid pulmonary valve is a rare congenital heart disease. It is infrequently associated with significant clinical complications and tends to be clinically silent. Because of its benign nature, it has been diagnosed mainly post mortem. Its diagnosis by transthoracic echocardiography is very difficult because of the anatomical features. We describe a case of quadricuspid pulmonary valve diagnosed by transthoracic echocardiography and electrocardiography-gated multi-detector row computed tomography.

  1. Comparison of Intraoperative Portable CT Scanners in Skull Base and Endoscopic Sinus Surgery: Single Center Case Series

    PubMed Central

    Conley, David B.; Tan, Bruce; Bendok, Bernard R.; Batjer, H. Hunt; Chandra, Rakesh; Sidle, Douglas; Rahme, Rudy J.; Adel, Joseph G.; Fishman, Andrew J.

    2011-01-01

    Precise and safe management of complex skull base lesions can be enhanced by intraoperative computed tomography (CT) scanning. Surgery in these areas requires real-time feedback of anatomic landmarks. Several portable CT scanners are currently available. We present a comparison of our clinical experience with three portable scanners in skull base and craniofacial surgery. We present clinical case series and the participants were from the Northwestern Memorial Hospital. Three scanners are studied: one conventional multidetector CT (MDCT), two digital flat panel cone-beam CT (CBCT) devices. Technical considerations, ease of use, image characteristics, and integration with image guidance are presented for each device. All three scanners provide good quality images. Intraoperative scanning can be used to update the image guidance system in real time. The conventional MDCT is unique in its ability to resolve soft tissue. The flat panel CBCT scanners generally emit lower levels of radiation and have less metal artifact effect. In this series, intraoperative CT scanning was technically feasible and deemed useful in surgical decision-making in 75% of patients. Intraoperative portable CT scanning has significant utility in complex skull base surgery. This technology informs the surgeon of the precise extent of dissection and updates intraoperative stereotactic navigation. PMID:22470270

  2. Characterizing string-of-pearls colloidal silica by multidetector hydrodynamic chromatography and comparison to multidetector size-exclusion chromatography, off-line multiangle static light scattering, and transmission electron microscopy.

    PubMed

    Brewer, Amandaa K; Striegel, André M

    2011-04-15

    The string-of-pearls-type morphology is ubiquitous, manifesting itself variously in proteins, vesicles, bacteria, synthetic polymers, and biopolymers. Characterizing the size and shape of analytes with such morphology, however, presents a challenge, due chiefly to the ease with which the "strings" can be broken during chromatographic analysis or to the paucity of information obtained from the benchmark microscopy and off-line light scattering methods. Here, we address this challenge with multidetector hydrodynamic chromatography (HDC), which has the ability to determine, simultaneously, the size, shape, and compactness and their distributions of string-of-pearls samples. We present the quadruple-detector HDC analysis of colloidal string-of-pearls silica, employing static multiangle and quasielastic light scattering, differential viscometry, and differential refractometry as detection methods. The multidetector approach shows a sample that is broadly polydisperse in both molar mass and size, with strings ranging from two to five particles, but which also contains a high concentration of single, unattached "pearls". Synergistic combination of the various size parameters obtained from the multiplicity of detectors employed shows that the strings with higher degrees of polymerization have a shape similar to the theory-predicted shape of a Gaussian random coil chain of nonoverlapping beads, while the strings with lower degrees of polymerization have a prolate ellipsoidal shape. The HDC technique is contrasted experimentally with multidetector size-exclusion chromatography, where, even under extremely gentle conditions, the strings still degraded during analysis. Such degradation is shown to be absent in HDC, as evidenced by the fact that the molar mass and radius of gyration obtained by HDC with multiangle static light scattering detection (HDC/MALS) compare quite favorably to those determined by off-line MALS analysis under otherwise identical conditions. The

  3. Coronary artery calcium score: influence of reconstruction interval at 16-detector row CT with retrospective electrocardiographic gating.

    PubMed

    Schlosser, Thomas; Hunold, Peter; Schmermund, Axel; Kühl, Hilmar; Waltering, Kai-Uwe; Debatin, Jörg F; Barkhausen, Jörg

    2004-11-01

    In 30 patients, Agatston and volumetric scores were assessed by using retrospectively gated multi-detector row computed tomography (CT). For each patient, 10 data sets were created at different times and were evenly spaced throughout the cardiac cycle. For each reconstruction, patients were assigned a percentile that described the level of cardiovascular risk. Nineteen (63%) of 30 patients could be assigned to more than one risk group depending on the reconstruction interval used. Agatston and volumetric scores both proved highly dependent on the reconstruction interval used (coefficient of variation, < or =63.1%) even with the most advanced CT scanners. Accurate and reproducible quantification of coronary calcium seems to require analysis of multiple reconstructions.

  4. [Two-dimensional and three-dimensional CT diagnosis of alimentary tract].

    PubMed

    Shiraga, N

    2001-10-01

    The recent development of multidetector-row CT(MDCT) has made it possible to obtain three-dimensional images of the alimentary tract that offer new diagnostic potential. In its two-dimensional diagnosis of the alimentary tract, MDCT has also changed the concept of the oral contrast agent. Before MDCT, we routinely used a positive contrast agent to distinguish the stomach and intestine from other organs and masses. The excellent slice profile acquired by MDCT can distinguish the alimentary tract and depict abnormal findings without the use of a positive contrast agent. With the use of an intravenous contrast medium, the alimentary tract itself, alimentary tumors, and inflammatory disease are well demarcated with water and air. Moreover, the combination of two-dimensional and three-dimensional diagnostic images makes it possible to detect and assess early gastric and colonic cancers as conventional gastroscopy and colonoscopy. Although the lack of texture information is one of the disadvantages of three-dimensional CT, three-dimensional CT diagnosis of the alimentary tract is less invasive and more objective than conventional studies. Advances in three-dimensional imaging with isotropic data sets will lead to the use of two-dimensional and three-dimensional CT diagnosis as one of the standard examinations of the alimentary tract.

  5. A new cubic phantom for PET/CT dosimetry: Experimental and Monte Carlo characterization

    SciTech Connect

    Belinato, Walmir; Silva, Rogerio M.V.; Souza, Divanizia N.; Santos, William S.; Caldas, Linda V.E.

    2015-07-01

    In recent years, positron emission tomography (PET) associated with multidetector computed tomography (MDCT) has become a diagnostic technique widely disseminated to evaluate various malignant tumors and other diseases. However, during PET/CT examinations, the doses of ionizing radiation experienced by the internal organs of patients may be substantial. To study the doses involved in PET/CT procedures, a new cubic phantom of overlapping acrylic plates was developed and characterized. This phantom has a deposit for the placement of the fluorine-18 fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) solution. There are also small holes near the faces for the insertion of optically stimulated luminescence dosimeters (OSLD). The holes for OSLD are positioned at different distances from the {sup 18}F-FDG deposit. The experimental results were obtained in two PET/CT devices operating with different parameters. Differences in the absorbed doses were observed in OSLD measurements due to the non-orthogonal positioning of the detectors inside the phantom. This phantom was also evaluated using Monte Carlo simulations, with the MCNPX code. The phantom and the geometrical characteristics of the equipment were carefully modeled in the MCNPX code, in order to develop a new methodology form comparison of experimental and simulated results, as well as to allow the characterization of PET/CT equipments in Monte Carlo simulations. All results showed good agreement, proving that this new phantom may be applied for these experiments. (authors)

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  7. Hybrid SPECT/CT Imaging in the Evaluation of Coronary Stenosis: Role in Diabetic Patients

    PubMed Central

    Romagnoli, Andrea; Schillaci, Orazio; Arganini, Chiara; Gaspari, Eleonora; Ricci, Aurora; Morosetti, Daniele; Coco, Irene; Crusco, Sonia; Calabria, Ferdinando; Sperandio, Massimiliano; Simonetti, Giovanni

    2013-01-01

    Purpose. Our purpose was to combine the results of the MDCT (multidetector computed tomography) morphological data and the SPECT (single-photon emission computed tomography) data using hybrid imaging to overcome the limits of the MDCT in the evaluation of coronary stenosis in diabetic patients with large amount of calcium in the coronary arteries. Method and Materials. 120 diabetic patients underwent MDCT examination and SPECT examination. We evaluated 324 coronary arteries. After the examinations, we merged CT and SPECT images. Results. CT evaluation: 52 (32.8%) coronaries with stenosis ≥ 50%, 228 (70.4%) with stenosis < 50%, and 44 (13.6%) with a doubtful evaluation. SPECT evaluation: 80 (24.7%) areas with hypoperfusion, 232 (71.6%) with normal perfusion, and 12 (3.7%) with a doubtful evaluation. Of 324 coronary arteries and corresponding areas, the hybrid SPECT/CT evaluation showed 92 (28.4%) areas with hypoperfusion, and 232 (71.6%) with normal perfusion. Conclusion. Hybrid CT/SPECT imaging could be useful in the detection of significant coronary stenosis in patients with large amount of coronary calcifications. PMID:24959556

  8. Surgical interventions with fatal outcome: utility of multi-phase postmortem CT angiography.

    PubMed

    Zerlauth, J-B; Doenz, F; Dominguez, A; Palmiere, C; Uské, A; Meuli, R; Grabherr, S

    2013-02-10

    Cases of fatal outcome after surgical intervention are autopsied to determine the cause of death and to investigate whether medical error caused or contributed to the death. For medico-legal purposes, it is imperative that autopsy findings are documented clearly. Modern imaging techniques such as multi-detector computed tomography (MDCT) and postmortem CT angiography, which is used for vascular system imaging, are useful tools for determining cause of death. The aim of this study was to determine the utility of postmortem CT angiography for the medico-legal death investigation. This study investigated 10 medico-legal cases with a fatal outcome after surgical intervention using multi-phase postmortem whole body CT angiography. A native CT scan was performed as well as three angiographic phases (arterial, venous, and dynamic) using a Virtangio(®) perfusion device and the oily contrast agent, Angiofil(®). The results of conventional autopsy were compared to those from the radiological investigations. We also investigated whether the radiological findings affected the final interpretation of cause-of-death. Causes of death were hemorrhagic shock, intracerebral hemorrhage, septic shock, and a combination of hemorrhage and blood aspiration. The diagnoses were made by conventional autopsy as well as by postmortem CT angiography. Hemorrhage played an important role in eight of ten cases. The radiological exam revealed the exact source of bleeding in seven of the eight cases, whereas conventional autopsy localized the source of bleeding only generally in five of the seven cases. In one case, neither conventional autopsy nor CT angiography identified the source of hemorrhage. We conclude that postmortem CT angiography is extremely useful for investigating deaths following surgical interventions. This technique helps document autopsy findings and allows a second examination if it is needed; specifically, it detects and visualizes the sources of hemorrhages in detail, which

  9. CT angiography - chest

    MedlinePlus

    Computed tomography angiography - thorax; CTA - lungs; Pulmonary embolism - CTA chest; Thoracic aortic aneurysm - CTA chest; Venous thromboembolism - CTA lung; Blood clot - CTA lung; Embolus - CTA lung; CT ...

  10. Evaluation of exposure dose reduction in multislice CT coronary angiography (MS-CTA) with prospective ECG-gated helical scan

    NASA Astrophysics Data System (ADS)

    Ota, Takamasa; Tsuyuki, Masaharu; Okumura, Miwa; Sano, Tomonari; Kondo, Takeshi; Takase, Shinichi

    2008-03-01

    A novel low-dose ECG-gated helical scan method to investigate coronary artery diseases was developed. This method uses a high pitch for scanning (based on the patient's heart rate) and X-rays are generated only during the optimal cardiac phases. The dose reduction was obtained using a two-level approach: 1) To use a 64-slice CT scanner (Aquilion, Toshiba, Otawara, Tochigi, Japan) with a scan speed of 0.35 s/rot. to helically scan the heart at a high pitch based on the patient's heart rate. By changing the pitch from the conventional 0.175 to 0.271 for a heart rate of 60 bpm, the exposure dose was reduced to 65%. 2) To employ tube current gating that predicts the timing of optimal cardiac phases from the previous cardiac cycle and generates X-rays only during the required cardiac phases. The combination of high speed scanning with a high pitch and appropriate X-ray generation only in the cardiac phases from 60% to 90% allows the exposure dose to be reduced to 5.6 mSv for patients with a heart rate lower than 65 bpm. This is a dose reduction of approximately 70% compared to the conventional scanning method recommended by the manufacturer when segmental reconstruction is considered. This low-dose protocol seamlessly allows for wide scan ranges (e.g., aortic dissection) with the benefits of ECG-gated helical scanning: smooth continuity for longitudinal direction and utilization of data from all cardiac cycles.

  11. WE-B-207-02: CT Lung Cancer Screening and the Medical Physicist: A Dosimetry Summary of CT Participants in the National Lung Cancer Screening Trial (NLST)

    SciTech Connect

    Lee, C.

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  12. Evaluation of cardiovascular anomalies in patients with asymptomatic turner syndrome using multidetector computed tomography.

    PubMed

    Lee, Sun Hee; Jung, Ji Mi; Song, Min Seob; Choi, Seok jin; Chung, Woo Yeong

    2013-08-01

    Turner syndrome is well known to be associated with significant cardiovascular abnormalities. This paper studied the incidence of cardiovascular abnormalities in asymptomatic adolescent patients with Turner syndrome using multidetector computed tomography (MDCT) instead of echocardiography. Twenty subjects diagnosed with Turner syndrome who had no cardiac symptoms were included. Blood pressure and electrocardiography (ECG) was checked. Cardiovascular abnormalities were checked by MDCT. According to the ECG results, 11 had a prolonged QTc interval, 5 had a posterior fascicular block, 3 had a ventricular conduction disorder. MDCT revealed vascular abnormalities in 13 patients (65%). Three patients had an aberrant right subclavian artery, 2 had dilatation of left subclavian artery, and others had an aortic root dilatation, aortic diverticulum, and abnormal left vertebral artery. As for venous abnormalities, 3 patients had partial anomalous pulmonary venous return and 2 had a persistent left superior vena cava. This study found cardiovascular abnormalities in 65% of asymptomatic Turner syndrome patients using MDCT. Even though, there are no cardiac symptoms in Turner syndrome patients, a complete evaluation of the heart with echocardiography or MDCT at transition period to adults must be performed.

  13. Colonic perforation by a transmural and transvalvular migrated retained sponge: multi-detector computed tomography findings.

    PubMed

    Camera, Luigi; Sagnelli, Marco; Guadagno, Paolo; Mainenti, Pier Paolo; Marra, Teresa; Scotto di Santolo, Maria; Fei, Landino; Salvatore, Marco

    2014-04-21

    Transmural migrated retained sponges usually impact at the level of the ileo-cecal valve leading to a small bowel obstruction. Once passed through the ileo-cecal valve, a retained sponge can be propelled forward by peristaltic activity and eliminated with feces. We report the case of a 52-year-old female with a past surgical history and recurrent episodes of abdominal pain and constipation. On physical examination, a generalized resistance was observed with tenderness in the right flank. Contrast-enhanced multi-detector computed tomography findings were consistent with a perforated right colonic diverticulitis with several out-pouchings at the level of the ascending colon and evidence of free air in the right parieto-colic gutter along with an air-fluid collection within the mesentery. In addition, a ring-shaped hyperdense intraluminal material was also noted. At surgery, the ascending colon appeared irregularly thickened and folded with a focal wall interruption and a peri-visceral abscess at the level of the hepatic flexure, but no diverticula were found. A right hemi-colectomy was performed and on dissection of the surgical specimen a retained laparotomy sponge was found in the bowel lumen.

  14. A case of bilateral tracheal bronchus: report of a rare association in multidetector computed tomography bronchoscopy.

    PubMed

    Wooten, Candace; Doros, Caius; Miclaus, Gratian D; Matusz, Petru; Loukas, Marios

    2015-08-01

    Bilateral tracheal bronchus is a rare variation of the tracheobronchial tree. We present a 1-year 7-month-old male patient who presented with sepsis following endotracheal intubation. Upon review of multidetector computed tomography images, the patient was diagnosed with displaced bilateral tracheal bronchus. Imaging showed a right-sided anomalous bronchus arising 0.9 cm proximal to the carina. The left-sided anomalous bronchus arose 0.7 cm proximal to the carina, mimicking a tracheal trifurcation. When viewed together, the close proximity of both the right and left tracheal bronchi to the carina created a distinct tracheal quadrifurcation. This rare anatomic variation was additionally associated with an anorectal malformation (anal atresia). Unrecognized tracheal bronchus in patients undergoing endotracheal intubation can lead to serious complications. While bilateral tracheal bronchus is described in the literature, we are unaware of any case similar to this patient presentation. We present and analyze this unusual case of bilateral tracheal bronchus. The anatomy and clinical significance of this variation is then discussed.

  15. A Structural and Functional Assessment of the Lung via Multidetector-Row Computed Tomography

    PubMed Central

    Hoffman, Eric A.; Simon, Brett A.; McLennan, Geoffrey

    2006-01-01

    With advances in multidetector-row computed tomography (MDCT), it is now possible to image the lung in 10 s or less and accurately extract the lungs, lobes, and airway tree to the fifth- through seventh-generation bronchi and to regionally characterize lung density, texture, ventilation, and perfusion. These methods are now being used to phenotype the lung in health and disease and to gain insights into the etiology of pathologic processes. This article outlines the application of these methodologies with specific emphasis on chronic obstructive pulmonary disease. We demonstrate the use of our methods for assessing regional ventilation and perfusion and demonstrate early data that show, in a sheep model, a regionally intact hypoxic pulmonary vasoconstrictor (HPV) response with an apparent inhibition of HPV regionally in the presence of inflammation. We present the hypothesis that, in subjects with pulmonary emphysema, one major contributing factor leading to parenchymal destruction is the lack of a regional blunting of HPV when the regional hypoxia is related to regional inflammatory events (bronchiolitis or alveolar flooding). If maintaining adequate blood flow to inflamed lung regions is critical to the nondestructive resolution of inflammatory events, the pathologic condition whereby HPV is sustained in regions of inflammation would likely have its greatest effect in the lung apices where blood flow is already reduced in the upright body posture. PMID:16921136

  16. Structural Comparison between the Right and Left Atrial Appendages Using Multidetector Computed Tomography

    PubMed Central

    Shinoda, Koichi; Fukuoka, Daisuke; Torii, Ryo; Watanabe, Tsuneo; Nakano, Takashi

    2016-01-01

    The three-dimensional (3D) structures of the right atrial appendage (RAA) and left atrial appendage (LAA) were compared to clarify why thrombus formation less frequently occurs in RAA than in LAA. Morphological differences between RAA and LAA of 34 formalin-preserved cadaver hearts were investigated. Molds of RAA and LAA specimens were made and the neck areas, volumes of the atrial appendages (AA), and amount of pectinate muscles (PMs) were analyzed using multidetector computed tomography. In RAA, most PMs were connected to one another and formed a “dendritic” appearance and the inner surface area was smaller than in LAA. RAA had smaller volumes and larger neck areas than LAA. The ratios of the neck area/volume were larger and the amounts of PMs were smaller in RAA than in LAA. The volumes, neck areas, and amount of PMs of RAA were significantly correlated with those of LAA. According to the 3D structure, RAA appears to be suited for a more favorable blood flow, which may explain why the thrombus formation is less common in RAA than in LAA. Examining not only LAA but also RAA by transesophageal echocardiography may be useful in high-risk patients of thrombus formation in LAA because the volume, neck area, and amount of PMs of LAA reflect the shape of RAA. PMID:27900330

  17. Trabecular bone class mapping across resolutions: translating methods from HR-pQCT to clinical CT

    NASA Astrophysics Data System (ADS)

    Valentinitsch, Alexander; Fischer, Lukas; Patsch, Janina M.; Bauer, Jan; Kainberger, Franz; Langs, Georg; DiFranco, Matthew

    2015-03-01

    Quantitative assessment of 3D bone microarchitecture in high-resolution peripheral quantitative computed tomography (HR-pQCT) has shown promise in fracture risk assessment and biomechanics, but is limited to the distal radius and tibia. Trabecular microarchitecture classes (TMACs), based on voxel-wise clustering texture and structure tensor features in HRpQCT, is extended in this paper to quantify trabecular bone classes in clinical multi-detector CT (MDCT) images. Our comparison of TMACs in 12 cadaver radii imaged using both HRpQCT and MDCT yields a mean Dice score of up to 0.717+/-0.40 and visually concordant bone quality maps. Further work to develop clinically viable bone quantitative imaging using HR-pQCT validation could have a significant impact on overall bone health assessment.

  18. Computed Tomography (CT) -- Sinuses

    MedlinePlus

    ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the ...

  19. Stature estimation from skull measurements using multidetector computed tomographic images: A Japanese forensic sample.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2016-01-01

    The aim of this study was to assess the correlation between stature and cranial measurements in a contemporary Japanese population, using three-dimensional (3D) computed tomographic (CT) images. A total of 228 cadavers (123 males, 105 females) underwent postmortem CT scanning and subsequent forensic autopsy between May 2011 and April 2015. Five cranial measurements were taken from 3D CT reconstructed images that extracted only cranial data. The correlations between stature and each of the cranial measurements were assessed with Pearson product-moment correlation coefficients. Simple and multiple regression analyses showed significant correlations between stature and cranial measurements. In conclusion, cranial measurements obtained from 3D CT images may be useful for forensic estimation of the stature of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available.

  20. Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art

    PubMed Central

    Stradiotti, P.; Curti, A.; Castellazzi, G.

    2009-01-01

    The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available new techniques that can help minimizing the severe beam-hardening artifacts. The presence of artifacts at CT from metal hardware is related to image reconstruction algorithm (filter), tube current (in mA), X-ray kilovolt peak, pitch, hardware composition, geometry (shape), and location. MRI imaging has been used safely in patients with orthopaedic metallic implants because most of these implants do not have ferromagnetic properties and have been fixed into position. However, on MRI imaging metallic implants may produce geometric distortion, the so-called susceptibility artifact. In conclusion, although 140 kV and high milliamperage second exposures are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. MRI artifacts can be minimized by positioning optimally and correctly the examined anatomy part with metallic implants in the magnet and by choosing fast spin-echo sequences, and in some cases also STIR sequences, with an anterior to posterior frequency-encoding direction and the smallest voxel size. PMID:19437043

  1. Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art.

    PubMed

    Stradiotti, P; Curti, A; Castellazzi, G; Zerbi, A

    2009-06-01

    The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available new techniques that can help minimizing the severe beam-hardening artifacts. The presence of artifacts at CT from metal hardware is related to image reconstruction algorithm (filter), tube current (in mA), X-ray kilovolt peak, pitch, hardware composition, geometry (shape), and location. MRI imaging has been used safely in patients with orthopaedic metallic implants because most of these implants do not have ferromagnetic properties and have been fixed into position. However, on MRI imaging metallic implants may produce geometric distortion, the so-called susceptibility artifact. In conclusion, although 140 kV and high milliamperage second exposures are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. MRI artifacts can be minimized by positioning optimally and correctly the examined anatomy part with metallic implants in the magnet and by choosing fast spin-echo sequences, and in some cases also STIR sequences, with an anterior to posterior frequency-encoding direction and the smallest voxel size.

  2. Determination of Single-Kidney Glomerular Filtration Rate in Human Subjects by Using CT

    PubMed Central

    Kwon, Soon Hyo; Saad, Ahmed; Herrmann, Sandra M.; Textor, Stephen C.

    2015-01-01

    Purpose To test the hypothesis that computed tomography (CT)–derived measurements of single-kidney glomerular filtration rate (GFR) obtained in human subjects with 64-section CT agree with those obtained with iothalamate clearance, a rigorous reference standard. Materials and Methods The institutional review board approved this HIPAA-compliant study, and written informed consent was obtained. Ninety-six patients (age range, 51–73 years; 46 men, 50 women) with essential (n = 56) or renovascular (n = 40) hypertension were prospectively studied in controlled conditions (involving sodium intake and renin-angiotensin blockade). Single-kidney perfusion, volume, and GFR were measured by using multidetector CT time-attenuation curves and were compared with GFR measured by using iothalamate clearance, as assigned to the right and left kidney according to relative volumes. The reproducibility of CT GFR over a 3-month period (n = 21) was assessed in patients with renal artery stenosis who were undergoing stable medical treatment. Statistical analysis included the t test, Wilcoxon signed rank test, linear regression, and Bland-Altman analysis. Results CT GFR values were similar to those of iothalamate clearance (mean ± standard deviation, 38.2 mL/min ± 18 vs 41.6 mL/min ± 17; P = .062). Stenotic kidney CT GFR in patients with renal artery stenosis was lower than contralateral kidney GFR or essential hypertension single-kidney GFR (mean, 23.1 mL/min ± 13 vs 36.9 mL/min ± 17 [P = .0008] and 45.2 mL/min ± 16 [P = .019], respectively), as was iothalamate clearance (mean, 26.9 mL/min ± 14 vs 38.5 mL/min ± 15 [P = .0004] and 49.0 mL/min ± 14 [P = .001], respectively). CT GFR correlated well with iothalamate GFR (linear regression, CT GFR = 0.88*iothalamate GFR, r2 = 0.89, P < .0001), and Bland-Altman analysis was used to confirm the agreement. CT GFR was also moderately reproducible in medically treated patients with renal artery stenosis (concordance coefficient

  3. 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.

  4. MO-E-17A-08: Attenuation-Based Size Adjusted, Scanner-Independent Organ Dose Estimates for Head CT Exams: TG 204 for Head CT

    SciTech Connect

    McMillan, K; Bostani, M; Cagnon, C; McNitt-Gray, M; Zankl, M; DeMarco, J

    2014-06-15

    Purpose: AAPM Task Group 204 described size specific dose estimates (SSDE) for body scans. The purpose of this work is to use a similar approach to develop patient-specific, scanner-independent organ dose estimates for head CT exams using an attenuation-based size metric. Methods: For eight patient models from the GSF family of voxelized phantoms, dose to brain and lens of the eye was estimated using Monte Carlo simulations of contiguous axial scans for 64-slice MDCT scanners from four major manufacturers. Organ doses were normalized by scannerspecific 16 cm CTDIvol values and averaged across all scanners to obtain scanner-independent CTDIvol-to-organ-dose conversion coefficients for each patient model. Head size was measured at the first slice superior to the eyes; patient perimeter and effective diameter (ED) were measured directly from the GSF data. Because the GSF models use organ identification codes instead of Hounsfield units, water equivalent diameter (WED) was estimated indirectly. Using the image data from 42 patients ranging from 2 weeks old to adult, the perimeter, ED and WED size metrics were obtained and correlations between each metric were established. Applying these correlations to the GSF perimeter and ED measurements, WED was calculated for each model. The relationship between the various patient size metrics and CTDIvol-to-organ-dose conversion coefficients was then described. Results: The analysis of patient images demonstrated the correlation between WED and ED across a wide range of patient sizes. When applied to the GSF patient models, an exponential relationship between CTDIvol-to-organ-dose conversion coefficients and the WED size metric was observed with correlation coefficients of 0.93 and 0.77 for the brain and lens of the eye, respectively. Conclusion: Strong correlation exists between CTDIvol normalized brain dose and WED. For the lens of the eye, a lower correlation is observed, primarily due to surface dose variations. Funding

  5. SU-F-207-14: Low Contrast Detectability (LCD) at Different Diagnostic Reference Levels for Adult Abdominal CT Procedures

    SciTech Connect

    Mahmood, U; Erdi, Y

    2015-06-15

    Purpose Using diagnostic reference levels (DRL) to optimize CT protocols has potential to reduce radiation dose and meet regulatory requirements. However, DRL’s tend to be misconstrued as dose limits, are typically designed for specific patient populations, and are assumed to have acceptable image quality (AIQ) associated with them. To determine the image quality that is associated with established DRL’s for adult abdominal CT studies, a LCD phantom study was employed. Methods: A CT phantom (CIRS) containing three columns of 7 spherical targets, ranging from 10mm to 2.4 mm, that are 5, 10, and 20 HU below the background (HUBB) matrix was scanned with a GE HD750 64 slice scanner. The phantom was scanned at the NEXT 2006 25th CTDIvol of 12 mGy, the NCRP 172 achievable dose (AD) CTDIvol of 17 mGy and 75th CTDIvol of 25 mGy and at the ACR recommended CTDIvol of 25 mGy. It was also scanned at a CTDIvol 20% greater than the AD at 20 mGy and the ACR maximum threshold of 30 mGy. Results: At the NEXT 2006 25th percentile CTDIvol of 12 mGy, a 6.3 mm low contrast lesion was detectable in the 20 HUBB; 6.3 mm in the 10 HUBB and 10 mm in the 5 HUBB column. Increasing the CTDIvol to the NCRP 172 AD of 17 mGy, an additional 4.8 mm lesion was visualized in the 20 HUBB column. At 20 mGy, an additional 4.8 mm lesion was detectable in the 10 HUBB column. No further lesions were visible between 20 and 30 mGy. However, conspicuity of all lesions increased with each additional step up in CTDI. Conclusion: Optimizing radiation dose to achieve AIQ is a critical aspect of any dose optimization committee. Hence, judicious monitoring of radiation exposure to patients has to be balanced with diagnostic image quality.

  6. Lung Motion Model Validation Experiments, Free-Breathing Tissue Densitometry, and Ventilation Mapping using Fast Helical CT Imaging

    NASA Astrophysics Data System (ADS)

    Dou, Hsiang-Tai

    The uncertainties due to respiratory motion present significant challenges to accurate characterization of cancerous tissues both in terms of imaging and treatment. Currently available clinical lung imaging techniques are subject to inferior image quality and incorrect motion estimation, with consequences that can systematically impact the downstream treatment delivery and outcome. The main objective of this thesis is the development of the techniques of fast helical computed tomography (CT) imaging and deformable image registration for the radiotherapy applications in accurate breathing motion modeling, lung tissue density modeling and ventilation imaging. Fast helical CT scanning was performed on 64-slice CT scanner using the shortest available gantry rotation time and largest pitch value such that scanning of the thorax region amounts to just two seconds, which is less than typical breathing cycle in humans. The scanning was conducted under free breathing condition. Any portion of the lung anatomy undergoing such scanning protocol would be irradiated for only a quarter second, effectively removing any motion induced image artifacts. The resulting CT data were pristine volumetric images that record the lung tissue position and density in a fraction of the breathing cycle. Following our developed protocol, multiple fast helical CT scans were acquired to sample the tissue positions in different breathing states. To measure the tissue displacement, deformable image registration was performed that registers the non-reference images to the reference one. In modeling breathing motion, external breathing surrogate signal was recorded synchronously with the CT image slices. This allowed for the tissue-specific displacement to be modeled as parametrization of the recorded breathing signal using the 5D lung motion model. To assess the accuracy of the motion model in describing tissue position change, the model was used to simulate the original high-pitch helical CT scan

  7. Multidetector computed tomography angiography of the celiac trunk and hepatic arterial system: normal anatomy and main variants *

    PubMed Central

    Araujo Neto, Severino Aires; de Mello Júnior, Carlos Fernando; Franca, Henrique Almeida; Duarte, Cláudia Martina Araújo; Borges, Rafael Farias; de Magalhães, Ana Guardiana Ximenes

    2016-01-01

    Although digital angiography remains as the gold standard for imaging the celiac arterial trunk and hepatic arteries, multidetector computed tomography in association with digital images processing by software resources represents a useful tool particularly attractive for its non invasiveness. Knowledge of normal anatomy as well as of its variations is helpful in images interpretation and to address surgical planning on a case-by-case basis. The present essay illustrates several types of anatomical variations of celiac trunk, hepatic artery and its main branches, by means of digitally reconstructed computed tomography images, correlating their prevalence in the population with surgical implications. PMID:26929461

  8. Using the 320-Multidetector Computed Tomography scanner for four-dimensional functional assessment of the elbow joint.

    PubMed

    Goh, Yin Peng; Lau, Kenneth K

    2012-02-01

    As described in this case report, the use of the 320-Multidetector Computed Tomography scanner (Aquilion One, Toshiba Medical Systems, Japan) to produce continuous 3-dimensional images in real time, over a distance of 16 cm in the z-axis, proved to aid in the diagnosis of a patient's restrictive elbow joint. This state-of-the-art scanner allows fast and noninvasive dynamic-kinematic functional evaluation of the elbow joint in vivo. It will also be applicable to kinematic studies of other joints.

  9. Multidetector computed tomography angiography of the celiac trunk and hepatic arterial system: normal anatomy and main variants.

    PubMed

    Araujo Neto, Severino Aires; de Mello Júnior, Carlos Fernando; Franca, Henrique Almeida; Duarte, Cláudia Martina Araújo; Borges, Rafael Farias; de Magalhães, Ana Guardiana Ximenes

    2016-01-01

    Although digital angiography remains as the gold standard for imaging the celiac arterial trunk and hepatic arteries, multidetector computed tomography in association with digital images processing by software resources represents a useful tool particularly attractive for its non invasiveness. Knowledge of normal anatomy as well as of its variations is helpful in images interpretation and to address surgical planning on a case-by-case basis. The present essay illustrates several types of anatomical variations of celiac trunk, hepatic artery and its main branches, by means of digitally reconstructed computed tomography images, correlating their prevalence in the population with surgical implications.

  10. Multidetector computed tomography in the evaluation of pediatric acute abdominal pain in the emergency department.

    PubMed

    Lin, Wei-Ching; Lin, Chien-Heng

    2016-06-01

    The accurate diagnosis of pediatric acute abdominal pain is one of the most challenging tasks in the emergency department (ED) due to its unclear clinical presentation and non-specific findings in physical examinations, laboratory data, and plain radiographs. The objective of this study was to evaluate the impact of abdominal multidetector computed tomography (MDCT) performed in the ED on pediatric patients presenting with acute abdominal pain. A retrospective chart review of children aged <18 years with acute abdominal pain who visited the emergency department and underwent MDCT between September 2004 and June 2007 was conducted. Patients with a history of trauma were excluded. A total of 156 patients with acute abdominal pain (85 males and 71 females, age 1-17 years; mean age 10.9 ± 4.6 years) who underwent abdominal MDCT in the pediatric ED during this 3-year period were enrolled in the study. One hundred and eighteen patients with suspected appendicitis underwent abdominal MDCT. Sixty four (54.2%) of them had appendicitis, which was proven by histopathology. The sensitivity of abdominal MDCT for appendicitis was found to be 98.5% and the specificity was 84.9%. In this study, the other two common causes of nontraumatic abdominal emergencies were gastrointestinal tract (GI) infections and ovarian cysts. The most common etiology of abdominal pain in children that requires imaging with abdominal MDCT is appendicitis. MDCT has become a preferred and invaluable imaging modality in evaluating uncertain cases of pediatric acute abdominal pain in ED, in particular for suspected appendicitis, neoplasms, and gastrointestinal abnormalities.

  11. Multidetector Computed Tomography and Magnetic Resonance Imaging Evaluation of Craniovertebral junction Abnormalities

    PubMed Central

    Dhadve, Rajshree U.; Garge, Shaileshkumar S.; Vyas, Pooja D.; Thakker, Nirav R.; Shah, Sonali H.; Jaggi, Sunila T.; Talwar, Inder A.

    2015-01-01

    Background: Craniovertebral junction (CVJ) abnormalities constitute an important group of treatable neurological disorders with diagnostic dilemma. Their precise diagnosis, identification of probable etiology, and pretreatment evaluation significantly affects prognosis and quality of life of patients. Aims: The study was to classify various craniovertebral junction disorders according to their etiology and to define the importance of precise diagnosis for pretreatment evaluation with multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods: This is a prospective observational study of 62 patients referred to our department between October 2012 and September 2014. All patients suspected to have a craniovertebral junction disorder were included in the study, from all age groups and both genders. Detailed clinical history was taken. Radiographs of cervical spine were collected if available. All patients were subjected to MDCT and/or MRI. Results: In our study of 62 patients; 39 were males and 23 were females, with male to female ratio of 1.6:1. Most common age group was 2nd -3rd decade (19 patients, 30.64%). Developmental anomalies (33 patients, 53.22%) were the most common etiology group followed by traumatic (10 patients, 16.12%), degenerative (eight patients, 12.90%), infective (four patients, 6.45%), inflammatory and neoplastic (three patients each, 4.8%), and no cause found in one patient. Conclusions: CVJ abnormalities constitute an important group of treatable neurological disorders, especially in certain ethnic groups and are approached with much caution by clinicians. Thus, it is essential that radiologists should be able to make a precise diagnosis of craniovertebral junction abnormalities, classify them into etiological group, and rule out important mimickers on MDCT and/or MRI, as this information ultimately helps determine the management of such abnormalities, prognosis, and quality of life of patients. PMID

  12. Ultra-high resolution flat-panel volume CT: fundamental principles, design architecture, and system characterization.

    PubMed

    Gupta, Rajiv; Grasruck, Michael; Suess, Christoph; Bartling, Soenke H; Schmidt, Bernhard; Stierstorfer, Karl; Popescu, Stefan; Brady, Tom; Flohr, Thomas

    2006-06-01

    Digital flat-panel-based volume CT (VCT) represents a unique design capable of ultra-high spatial resolution, direct volumetric imaging, and dynamic CT scanning. This innovation, when fully developed, has the promise of opening a unique window on human anatomy and physiology. For example, the volumetric coverage offered by this technology enables us to observe the perfusion of an entire organ, such as the brain, liver, or kidney, tomographically (e.g., after a transplant or ischemic event). By virtue of its higher resolution, one can directly visualize the trabecular structure of bone. This paper describes the basic design architecture of VCT. Three key technical challenges, viz., scatter correction, dynamic range extension, and temporal resolution improvement, must be addressed for successful implementation of a VCT scanner. How these issues are solved in a VCT prototype and the modifications necessary to enable ultra-high resolution volumetric scanning are described. The fundamental principles of scatter correction and dose reduction are illustrated with the help of an actual prototype. The image quality metrics of this prototype are characterized and compared with a multi-detector CT (MDCT).

  13. CT Angiography (CTA)

    MedlinePlus

    ... CT Angiography? Angiography is a minimally invasive medical test that helps physicians diagnose and treat medical conditions. Angiography uses one of three imaging technologies and, in most cases, a contrast material injection ...

  14. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... scanners can perform the exam without stopping.) A computer creates separate images of the body area, called ...

  15. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... scanners can perform the exam without stopping.) A computer creates separate images of the arm area, called ...

  16. Computed Tomography (CT) -- Sinuses

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  17. Computed Tomography (CT) -- Head

    MedlinePlus Videos and Cool Tools

    ... to urinate; however, this is actually a contrast effect and subsides quickly. When you enter the CT scanner room, special light lines may be seen projected onto your body, and are used to ensure that you are ...

  18. Thoracic spine CT scan

    MedlinePlus

    ... Narrowing of the spine ( spinal stenosis ) Scoliosis Tumor Risks Risks of CT scans include: Exposure to radiation ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  19. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  20. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  1. Body CT (CAT Scan)

    MedlinePlus

    ... lives. CT has been shown to be a cost-effective imaging tool for a wide range of ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  2. Cardiac CT Scan

    MedlinePlus

    ... CT Scan Related Topics Aneurysm Coronary Calcium Scan Coronary Heart Disease Heart Attack Pulmonary Embolism Send a link to ... imaging test can help doctors detect or evaluate coronary heart disease, calcium buildup in the coronary arteries, problems with ...

  3. WE-B-207-00: CT Lung Cancer Screening Part 1

    SciTech Connect

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  4. CT of pituitary abscess

    SciTech Connect

    Fong, T.C.; Johns, R.D.; Long, M.; Myles, S.T.

    1985-06-01

    Pituitary abscess is a rare condition, with only 50 cases reported in the literature. Of those, 29 cases were well documented for analysis. Preoperative diagnosis of pituitary abscess is difficult. The computed tomographic (CT) appearance of pituitary abscess was first described in 1983; the abscess was depicted by axial images with coronal reconstruction. The authors recently encountered a case of pituitary abscess documented by direct coronal CT of the sella turcica.

  5. Construction of a multimodal CT-video chest model

    NASA Astrophysics Data System (ADS)

    Byrnes, Patrick D.; Higgins, William E.

    2014-03-01

    Bronchoscopy enables a number of minimally invasive chest procedures for diseases such as lung cancer and asthma. For example, using the bronchoscope's continuous video stream as a guide, a physician can navigate through the lung airways to examine general airway health, collect tissue samples, or administer a disease treatment. In addition, physicians can now use new image-guided intervention (IGI) systems, which draw upon both three-dimensional (3D) multi-detector computed tomography (MDCT) chest scans and bronchoscopic video, to assist with bronchoscope navigation. Unfortunately, little use is made of the acquired video stream, a potentially invaluable source of information. In addition, little effort has been made to link the bronchoscopic video stream to the detailed anatomical information given by a patient's 3D MDCT chest scan. We propose a method for constructing a multimodal CT-video model of the chest. After automatically computing a patient's 3D MDCT-based airway-tree model, the method next parses the available video data to generate a positional linkage between a sparse set of key video frames and airway path locations. Next, a fusion/mapping of the video's color mucosal information and MDCT-based endoluminal surfaces is performed. This results in the final multimodal CT-video chest model. The data structure constituting the model provides a history of those airway locations visited during bronchoscopy. It also provides for quick visual access to relevant sections of the airway wall by condensing large portions of endoscopic video into representative frames containing important structural and textural information. When examined with a set of interactive visualization tools, the resulting fused data structure provides a rich multimodal data source. We demonstrate the potential of the multimodal model with both phantom and human data.

  6. Multimaterial Decomposition Algorithm for the Quantification of Liver Fat Content by Using Fast-Kilovolt-Peak Switching Dual-Energy CT: Experimental Validation.

    PubMed

    Hyodo, Tomoko; Hori, Masatoshi; Lamb, Peter; Sasaki, Kosuke; Wakayama, Tetsuya; Chiba, Yasutaka; Mochizuki, Teruhito; Murakami, Takamichi

    2017-02-01

    Purpose To assess the ability of fast-kilovolt-peak switching dual-energy computed tomography (CT) by using the multimaterial decomposition (MMD) algorithm to quantify liver fat. Materials and Methods Fifteen syringes that contained various proportions of swine liver obtained from an abattoir, lard in food products, and iron (saccharated ferric oxide) were prepared. Approval of this study by the animal care and use committee was not required. Solid cylindrical phantoms that consisted of a polyurethane epoxy resin 20 and 30 cm in diameter that held the syringes were scanned with dual- and single-energy 64-section multidetector CT. CT attenuation on single-energy CT images (in Hounsfield units) and MMD-derived fat volume fraction (FVF; dual-energy CT FVF) were obtained for each syringe, as were magnetic resonance (MR) spectroscopy measurements by using a 1.5-T imager (fat fraction [FF] of MR spectroscopy). Reference values of FVF (FVFref) were determined by using the Soxhlet method. Iron concentrations were determined by inductively coupled plasma optical emission spectroscopy and divided into three ranges (0 mg per 100 g, 48.1-55.9 mg per 100 g, and 92.6-103.0 mg per 100 g). Statistical analysis included Spearman rank correlation and analysis of covariance. Results Both dual-energy CT FVF (ρ = 0.97; P < .001) and CT attenuation on single-energy CT images (ρ = -0.97; P < .001) correlated significantly with FVFref for phantoms without iron. Phantom size had a significant effect on dual-energy CT FVF after controlling for FVFref (P < .001). The regression slopes for CT attenuation on single-energy CT images in 20- and 30-cm-diameter phantoms differed significantly (P = .015). In sections with higher iron concentrations, the linear coefficients of dual-energy CT FVF decreased and those of MR spectroscopy FF increased (P < .001). Conclusion Dual-energy CT FVF allows for direct quantification of fat content in units of volume percent. Dual-energy CT FVF was larger in 30

  7. Accessible or Inaccessible? Diagnostic Efficacy of CT-Guided Core Biopsies of Head and Neck Masses

    SciTech Connect

    Cunningham, Jane D. McCusker, Mark W.; Power, Sarah; PearlyTi, Joanna; Thornton, John; Brennan, Paul; Lee, Michael J.; O’Hare, Alan; Looby, Seamus

    2015-04-15

    PurposeTissue sampling of lesions in the head and neck is challenging due to complex regional anatomy and sometimes necessitates open surgical biopsy. However, many patients are poor surgical candidates due to comorbidity. Thus, we evaluated the use of CT guidance for establishing histopathological diagnosis of head and neck masses.MethodsAll consecutive patients (n = 22) who underwent CT-guided core biopsy of head or neck masses between April 2009 and August 2012 were retrospectively reviewed using the departmental CT interventional procedures database. The indication for each biopsy performed was to establish or exclude a diagnosis of neoplasia in patients with suspicious head or neck lesions found on clinical examination or imaging studies. Patients received conscious sedation and 18 G, semiautomated core needle biopsies were performed by experienced neuroradiologists using 16-slice multidetector row CT imaging guidance (Somatom Definition Siemens Medical Solutions, Germany). Histopathology results of each biopsy were analysed.ResultsSixteen of 22 biopsies that were performed (73 %) yielded a pathological diagnosis. Anatomic locations biopsied included: masticator (n = 7), parapharyngeal (n = 3), parotid (n = 3), carotid (n = 3), perivertebral (n = 3), pharyngeal (n = 2), and retropharyngeal (n = 1) spaces. Six biopsies (27 %) were nondiagnostic due to inadequate tissue sampling, particularly small biopsy sample size and failure to biopsy the true sampling site due to extensive necrosis. No major complications were encountered.ConclusionsThe use of CT guidance to perform core biopsies of head and neck masses is an effective means of establishing histopathological diagnosis and reduces the need for diagnostic open surgical biopsy and general anaesthesia.

  8. Three-dimensional visualization of composite fillings for dental identification using CT images

    PubMed Central

    Sakuma, A; Saitoh, H; Makino, Y; Inokuchi, G; Hayakawa, M; Yajima, D; Iwase, H

    2012-01-01

    Objectives This study aimed to discriminate between enamel and composite resins by differences in Hounsfield units shown on 16 section multidetector CT (MDCT) images taken of unidentified bodies. Methods First, we determined the Hounsfield units of composite resins in 15 extracted human teeth. We then filled a single cavity prepared in each of the teeth with one of five different types of composite resins, and scanned the teeth using our routine post-mortem CT protocol for the head and neck. Obtained data were transferred to a radiological workstation and reconstructed. Furthermore, post-mortem CT images of the head of three unidentified bodies were reconstructed in the same manner. Results Four types of composite resins containing radio-opaque fillers showed a constant value of 4000 HU, and one radiolucent composite resin showed values in the range of 660–800 HU in the extracted teeth. Pixels at 4000 HU indicated that the composite resins were selected and visualized as three-dimensional colour images. Composite resins could be visualized on reconstructed images of the three unidentified bodies, and the sites visualized matched those noted on the forensic dental charts. Conclusions Discriminating enamel and composite resins containing radio-opaque materials was difficult because of their similar Hounsfield unit values. However, we did succeed in visualizing the composite resins despite limitations of the CT scale. CT reconstructed images can contribute to dental identification, particularly in cases where it is difficult to detect composite resins on external investigation, and these images can be prepared during routine dental identification work. PMID:22868297

  9. A measurement-based generalized source model for Monte Carlo dose simulations of CT scans

    NASA Astrophysics Data System (ADS)

    Ming, Xin; Feng, Yuanming; Liu, Ransheng; Yang, Chengwen; Zhou, Li; Zhai, Hezheng; Deng, Jun

    2017-03-01

    The goal of this study is to develop a generalized source model for accurate Monte Carlo dose simulations of CT scans based solely on the measurement data without a priori knowledge of scanner specifications. The proposed generalized source model consists of an extended circular source located at x-ray target level with its energy spectrum, source distribution and fluence distribution derived from a set of measurement data conveniently available in the clinic. Specifically, the central axis percent depth dose (PDD) curves measured in water and the cone output factors measured in air were used to derive the energy spectrum and the source distribution respectively with a Levenberg–Marquardt algorithm. The in-air film measurement of fan-beam dose profiles at fixed gantry was back-projected to generate the fluence distribution of the source model. A benchmarked Monte Carlo user code was used to simulate the dose distributions in water with the developed source model as beam input. The feasibility and accuracy of the proposed source model was tested on a GE LightSpeed and a Philips Brilliance Big Bore multi-detector CT (MDCT) scanners available in our clinic. In general, the Monte Carlo simulations of the PDDs in water and dose profiles along lateral and longitudinal directions agreed with the measurements within 4%/1 mm for both CT scanners. The absolute dose comparison using two CTDI phantoms (16 cm and 32 cm in diameters) indicated a better than 5% agreement between the Monte Carlo-simulated and the ion chamber-measured doses at a variety of locations for the two scanners. Overall, this study demonstrated that a generalized source model can be constructed based only on a set of measurement data and used for accurate Monte Carlo dose simulations of patients’ CT scans, which would facilitate patient-specific CT organ dose estimation and cancer risk management in the diagnostic and therapeutic radiology.

  10. Role of (68)Ga-DOTATATE PET/CT in patients with multiple endocrine neoplasia type 1 (MEN1).

    PubMed

    Lastoria, Secondo; Marciello, Francesca; Faggiano, Antongiulio; Aloj, Luigi; Caracò, Corradina; Aurilio, Michela; D'Ambrosio, Laura; Di Gennaro, Francesca; Ramundo, Valeria; Camera, Luigi; De Luca, Leonardo; Fonti, Rosa; Napolitano, Vincenzo; Colao, Annamaria

    2016-06-01

    Multiple endocrine neoplasia type 1 (MEN1) is a hereditary syndrome predisposing to many endocrine and neuroendocrine tumors (NET). Conventional imaging (CI) cannot provide satisfactory results for all the different types of MEN1-related tumors. Objective of this prospective observational study was to evaluate the role of (68)Ga-DOTATATE PET/CT in MEN1 compared to CI. Diagnostic performance of (68)Ga-DOTATATE PET/CT for the detection of NET was evaluated as well as the prognostic role of SUVmax. Eighteen patients with genetically confirmed MEN1 were evaluated by (68)Ga-DOTATATE PET/CT, endoscopic ultrasounds, multidetector-row computed tomography, magnetic resonance imaging, and hormone/markers serum measurements. Four MEN1-related tumor sites (pancreas, pituitary, parathyroids, adrenals) were considered. Sensitivity and specificity of (68)Ga-DOTATATE PET/CT for the detection of NET were calculated. There was (68)Ga-DOTATATE PET/CT uptake in 11/11 patients with pancreatic lesions, in 9/12 with pituitary adenoma, in 5/15 with parathyroid enlargements, and in 5/7 with adrenal lesions. (68)Ga-DOTATATE PET/CT showed sensitivity and specificity of 100 and 100 % in pancreas, 75 and 83 % in pituitary, 28 and 100 % in parathyroids, and 62.5 and 100 % in adrenals, respectively. Compared with CI, no significant difference in sensitivity for pancreas, pituitary, and adrenals was found, while CI had a better sensitivity for parathyroids (p = 0.002). On the ROC analysis, progression of pancreatic lesions was significantly associated to SUVmax <12.3 (p < 0.05). (68)Ga-DOTATATE PET/CT is greatly helpful in the work-up of MEN1 providing a panoramic view of MEN1-related lesions. There is also a prognostic role of (68)Ga-PET in patients with MEN1-pancreatic lesions.

  11. Criteria for establishing shielding of multi-detector computed tomography (MDCT) rooms.

    PubMed

    Verdun, F R; Aroua, A; Baechler, S; Schmidt, S; Trueb, P R; Bochud, F O

    2010-01-01

    The aim of this work is to compare two methods used for determining the proper shielding of computed tomography (CT) rooms while considering recent technological advances in CT scanners. The approaches of the German Institute for Standardisation and the US National Council on Radiation Protection and Measurements were compared and a series of radiation measurements were performed in several CT rooms at the Lausanne University Hospital. The following three-step procedure is proposed for assuring sufficient shielding of rooms hosting new CT units with spiral mode acquisition and various X-ray beam collimation widths: (1) calculate the ambient equivalent dose for a representative average weekly dose length product at the position where shielding is required; (2) from the maximum permissible weekly dose at the location of interest, calculate the transmission factor F that must be taken to ensure proper shielding and (3) convert the transmission factor into a thickness of lead shielding. A similar approach could be adopted to use when designing shielding for fluoroscopy rooms, where the basic quantity would be the dose area product instead of the load of current (milliampere-minute).

  12. Stature estimation in a contemporary Japanese population based on clavicular measurements using multidetector computed tomography.

    PubMed

    Torimitsu, Suguru; Makino, Yohsuke; Saitoh, Hisako; Sakuma, Ayaka; Ishii, Namiko; Yajima, Daisuke; Inokuchi, Go; Motomura, Ayumi; Chiba, Fumiko; Yamaguchi, Rutsuko; Hashimoto, Mari; Hoshioka, Yumi; Iwase, Hirotaro

    2017-03-08

    The aims of this study was to assess the correlation between stature and clavicular measurements in a contemporary Japanese population using three-dimensional (3D) computed tomographic (CT) images, and to establish regression equations for predicting stature. A total of 249 cadavers (131 males, 118 females) underwent postmortem CT scanning and subsequent forensic autopsy between October 2011 and May 2016 in our department. Four clavicular variables (linear distances between the superior margins of the left and right sternal facets to the anterior points of the left and right acromial ends and between the superior margins of the left and right sternal facets to the left and right conoid tubercles) were measured using 3D CT reconstructed images that extracted only bone data. The correlations between stature and each of the clavicular measurements were assessed with Pearson product-moment correlation coefficients. These clavicular measurements correlated significantly with stature in both sexes. The lowest standard error of estimation value in all, male, and female subjects was 3.62cm (r(2)=0.836), 3.55cm (r(2)=0.566), and 3.43cm (r(2)=0.663), respectively. In conclusion, clavicular measurements obtained from 3D CT images may be useful for stature estimation of Japanese individuals, particularly in cases where better predictors, such as long bones, are not available.

  13. The combined evaluation of interim contrast-enhanced computerized tomography (CT) and FDG-PET/CT predicts the clinical outcomes and may impact on the therapeutic plans in patients with aggressive non-Hodgkin's lymphoma.

    PubMed

    Yang, Deok-Hwan; Min, Jung-Joon; Jeong, Yong Yeon; Ahn, Jae-Sook; Kim, Yeo-Kyeoung; Cho, Sang-Hee; Chung, Ik-Joo; Bom, Hee-Seung; Kim, Hyeoung-Joon; Lee, Je-Jung

    2009-05-01

    We investigated the concomitant interim response of patients with aggressive non-Hodgkin's lymphoma (NHL) using multi-detector row computerized tomography (CT) and (18)F-fluoro-2-deoxy-D: -glucose-positron emission tomography (PET)/CT for prediction of clinical outcomes. One hundred six newly diagnosed patients with aggressive NHL were enrolled. Both the CT and PET/CT were serially performed at the time of diagnosis and after three to four cycles of chemotherapy (interim). The patients were categorized into four different responsive groups according to the interim PET/CT and CT: (1) complete metabolic response (CMR)-complete response unconfirmed (CRu), (2) CMR-partial response (PR), (3) partial metabolic response (PMR)-Cru, and (4) PMR-PR. Fifty-five patients with CMR-CRu, 20 patients with CMR-PR, seven patients with PMR-Cru, and 23 patients with PMR-PR were distributed. In addition, one patient experienced a disease progression. There was a significant difference in relapse rates between PET/CT-positive (67.3%) and PET/CT-negative patients (17.3%; P < 0.01). Also, there was a significant difference between patients with PMR-PR (32.0% and 26.1%) and CMR-CRu (89.3% and 80.0%) for 3-year overall survival (OS) and event-free survival (EFS), respectively. A multivariate analysis revealed that high international prognostic index (> or =3) at diagnosis, T-cell phenotype, and PMR-PR in interim PET/CT and CT were independent prognostic significances for OS. Moreover, bulky disease (>10 cm), T-cell phenotype, and PMR-PR showed significant associations for EFS. PMR-PR in interim response was the predictive prognostic determinant for both OS and EFS, with a hazard ratio of 3.93 (1.61-9.60) and 3.60 (1.62-7.98), respectively. The combined evaluation of interim PET/CT and CT was found to be a significant predictor of disease progression, OS, and EFS.

  14. CT of abdominal tuberculosis

    SciTech Connect

    Epstein, B.M.; Mann, J.H.

    1982-11-01

    Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms of peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.

  15. CT Perfusion of the Head

    MedlinePlus

    ... the machine as the actual CT scanning is performed. Depending on the type of CT scan, the machine may make several passes. The contrast material will then be injected through an intravenous line ( ...

  16. Evaluation of patient dose using a virtual CT scanner: Applications to 4DCT simulation and Kilovoltage cone-beam imaging

    NASA Astrophysics Data System (ADS)

    DeMarco, J. J.; McNitt-Gray, M. F.; Cagnon, C. H.; Angel, E.; Agazaryan, N.; Zankl, M.

    2008-02-01

    This work evaluates the effects of patient size on radiation dose from simulation imaging studies such as four-dimensional computed tomography (4DCT) and kilovoltage cone-beam computed tomography (kV-CBCT). 4DCT studies are scans that include temporal information, frequently incorporating highly over-sampled imaging series necessary for retrospective sorting as a function of respiratory phase. This type of imaging study can result in a significant dose increase to the patient due to the slower table speed as compared with a conventional axial or helical scan protocol. Kilovoltage cone-beam imaging is a relatively new imaging technique that requires an on-board kilovoltage x-ray tube and a flat-panel detector. Instead of porting individual reference fields, the kV tube and flat-panel detector are rotated about the patient producing a cone-beam CT data set (kV-CBCT). To perform these investigations, we used Monte Carlo simulation methods with detailed models of adult patients and virtual source models of multidetector computed tomography (MDCT) scanners. The GSF family of three-dimensional, voxelized patient models, were implemented as input files using the Monte Carlo code MCNPX. The adult patient models represent a range of patient sizes and have all radiosensitive organs previously identified and segmented. Simulated 4DCT scans of each voxelized patient model were performed using a multi-detector CT source model that includes scanner specific spectra, bow-tie filtration, and helical source path. Standard MCNPX tally functions were applied to each model to estimate absolute organ dose based upon an air-kerma normalization measurement for nominal scanner operating parameters.

  17. The effect of CT scanner parameters and 3D volume rendering techniques on the accuracy of linear, angular, and volumetric measurements of the mandible

    PubMed Central

    Whyms, B.J.; Vorperian, H.K.; Gentry, L.R.; Schimek, E.M.; Bersu, E.T.; Chung, M.K.

    2013-01-01

    Objectives This study investigates the effect of scanning parameters on the accuracy of measurements from three-dimensional multi-detector computed tomography (3D-CT) mandible renderings. A broader range of acceptable parameters can increase the availability of CT studies for retrospective analysis. Study Design Three human mandibles and a phantom object were scanned using 18 combinations of slice thickness, field of view, and reconstruction algorithm and three different threshold-based segmentations. Measurements of 3D-CT models and specimens were compared. Results Linear and angular measurements were accurate, irrespective of scanner parameters or rendering technique. Volume measurements were accurate with a slice thickness of 1.25 mm, but not 2.5 mm. Surface area measurements were consistently inflated. Conclusions Linear, angular and volumetric measurements of mandible 3D-CT models can be confidently obtained from a range of parameters and rendering techniques. Slice thickness is the primary factor affecting volume measurements. These findings should also apply to 3D rendering using cone-beam-CT. PMID:23601224

  18. Technical aspects of CT angiography.

    PubMed

    Kuszyk, B S; Fishman, E K

    1998-10-01

    The basic tasks of spiral CT acquisition, image processing, and image display are the foundations underlying CT angiography regardless of the anatomic region of interest. Volume rendering is a rapidly emerging image processing technique for creating three-dimensional (3D) images from CT datasets, which has important advantages over other 3D rendering techniques including maximum intensity projection and surface rendering. This articles reviews the techniques that are commonly used in CT angiography and key considerations for optimization.

  19. Seventh-generation CT

    NASA Astrophysics Data System (ADS)

    Besson, G. M.

    2016-03-01

    A new dual-drum CT system architecture has been recently introduced with the potential to achieve significantly higher temporal resolution than is currently possible in medical imaging CT. The concept relies only on known technologies; in particular rotation speeds several times higher than what is possible today could be achieved leveraging typical x-ray tube designs and capabilities. However, the architecture lends itself to the development of a new arrangement of x-ray sources in a toroidal vacuum envelope containing a rotating cathode ring and a (optionally rotating) shared anode ring to potentially obtain increased individual beam power as well as increase total exposure per rotation. The new x-ray source sub-system design builds on previously described concepts and could make the provision of multiple conventional high-power cathodes in a CT system practical by distributing the anode target between the cathodes. In particular, relying on known magnetic-levitation technologies, it is in principle possible to more than double the relative speed of the electron-beam with respect to the target, thus potentially leading to significant individual beam power increases as compared to today's state-of-the-art. In one embodiment, the proposed design can be naturally leveraged by the dual-drum CT concept previously described to alleviate the problem of arranging a number of conventional rotating anode-stem x-ray tubes and power conditioners on the limited space of a CT gantry. In another embodiment, a system with three cathodes is suggested leveraging the architecture previously proposed by Franke.

  20. Congenital Variants and Anomalies of the Pancreas and Pancreatic Duct: Imaging by Magnetic Resonance Cholangiopancreaticography and Multidetector Computed Tomography

    PubMed Central

    Erden, Ayşe; Türkoğlu, Mehmet Akif; Yener, Özlem

    2013-01-01

    Though congenital anomalies of the pancreas and pancreatic duct are relatively uncommon and they are often discovered as an incidental finding in asymptomatic patients, some of these anomalies may lead to various clinical symptoms such as recurrent abdominal pain, nausea and vomiting. Recognition of these anomalies is important because these anomalies may be a surgically correctable cause of recurrent pancreatitis or the cause of gastric outlet obstruction. An awareness of these anomalies may help in surgical planning and prevent inadvertent ductal injury. The purpose of this article is to review normal pancreatic embryology, the appearance of ductal anatomic variants and developmental anomalies of the pancreas, with emphasis on magnetic resonance cholangiopancreaticography and multidetector computed tomography. PMID:24265565

  1. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    SciTech Connect

    Li, Ke; Chen, Guang-Hong; Garrett, John; Ge, Yongshuai

    2014-07-15

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDI{sub vol} =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than

  2. Minimizing artifacts resulting from respiratory and cardiac motion by optimization of the transmission scan in cardiac PET/CT

    SciTech Connect

    Nye, Jonathon A.; Esteves, Fabio; Votaw, John R.

    2007-06-15

    The introduction of positron emission/computed tomography (PET/CT) systems coupled with multidetector CT arrays has greatly increased the amount of clinical information in myocardial perfusion studies. The CT acquisition serves the dual role of providing high spatial anatomical detail and attenuation correction for PET. However, the differences between the interaction of respiratory and cardiac cycles in the CT and PET acquisitions presents a challenge when using the CT to determine PET attenuation correction. Three CT attenuation correction protocols were tested for their ability to produce accurate emission images: gated, a step mode acquisition covering the diastolic heart phase; normal, a high-pitch helical CT; and slow, a low-pitch, low-temporal-resolution helical CT. The amount of cardiac tissue in the emission image that overlaid lung tissue in the transmission image was used as the measure of mismatch between acquisitions. Phantom studies simulating misalignment of the heart between the transmission and emission sequences were used to correlate the amount of mismatch with the artificial defect changes in the emission image. Consecutive patients were studied prospectively with either paired gated (diastolic phase, 120 kVp, 280 mA, 2.6 s) and slow CT (0.562:1 pitch, 120 kVp, Auto-mA, 16 s) or paired normal (0.938:1 pitch, 120 kVp, Auto-mA, 4.8 s) and slow CT protocols, prior to a Rb-82 perfusion study. To determine the amount of mismatch, the transmission and emission images were converted to binary representations of attenuating tissue and cardiac tissue and overlaid using their native registration. The number of cardiac tissue pixels from the emission image present in the CT lung field yielded the magnitude of misalignment represented in terms of volume, of where a small volume indicates better registration. Acquiring a slow CT improved registration between the transmission and emission acquisitions compared to the gated and normal CT protocols. The volume

  3. A Study of Internal Thoracic Arteriovenous Principal Perforators by Using Multi-detector Row Computed Tomography Angiography

    PubMed Central

    Hashikawa, Kazunobu; Sakakibara, Shunsuke; Onishi, Hiroyuki; Terashi, Hiroto

    2016-01-01

    Objective: There are numerous reports of perforating branches from the intercostal spaces of the internal thoracic vessels. These branches have varying diameters, and a main perforating branch, the principal perforator, most often found in the second or third intercostal space. We report different results based on multi-detector row computed tomography. Methods: We evaluated 121 sides from 70 women scheduled for breast reconstruction with free lower abdominal skin flaps who underwent preoperative multi-detector row computed tomographic scan between June 2008 and June 2015. For primary reconstruction, we analyzed both sides, and for 1-sided secondary reconstruction, we analyzed only the unaffected side. We evaluated both early arterial phase and late venous phase 5-mm horizontal, cross-sectional, and volume-rendering images for perforation sites and internal thoracic arteriovenous perforating branches’ intercostal space thickness. We analyzed differences in thickness between the internal thoracic arteries and veins and symmetry in cases involving both sides. Results: Venous principal perforators nearly always perforated the same intercostal spaces as accompanying veins of arterial principal perforators (99.2%), forming arteriovenous principal perforators. We found 49 principal perforators in the first intercostal space (37.4%), 52 in the second intercostal space (39.7%), 23 in the third intercostal space (17.6%), 6 in the fourth intercostal space (4.6%), and 1 in the fifth intercostal space (0.7%). Of the 51 cases in which we studied both sides, 25 cases (49%) had principal perforators with bilateral symmetry. Conclusions: In contrast to findings from past reports, we found that internal thoracic arteriovenous principal perforators were often present in almost the same numbers in the first and second intercostal spaces. PMID:26958104

  4. Evaluation of Enteroneovesical Fistula by 64-Detector CT Enterography: A Case Report

    PubMed Central

    Algin, Oktay; Metin, Melike Rusen; Karaoglanoglu, Mustafa

    2015-01-01

    Enterovesical fistula is an abnormal communication between the bladder and the intestine. The accurate localization of leakage is important for accurate treatment planning. Some imaging techniques can not demonstrate the fistula; therefore, choosing the appropriate imaging technique is necessary. CT enterography (CTE) is a new technique for evaluation of the small bowel and the entire abdomen. CTE examination with multi-detector CT (MDCT) enables us to get excellent quality reformatted images with high spatial resolution. We report a patient with neobladder and enteroneovesical fistula. We showed the exact location of the fistula and its’ association with the bowels and neobladder by CTE. The aim of this report is to show that CTE can be a new and effective modality in the detection of enteroneovesical fistulas and to discuss the efficacy of CTE in the detection and evaluation of enterovesical fistula referring to the literature. In conclusion, CTE may be a useful, sensitive, effective, and non-invasive technique for the evaluation of enteroneovesical fistula, leakage from the anastomose sides, and other extraintestinal complications such as urinary tract obstruction or abscess formation. PMID:26060558

  5. Automatic vessel extraction and abdominal aortic stent planning in multislice CT

    NASA Astrophysics Data System (ADS)

    Subramanyan, Krishna; Smith, Dava; Varma, Jay; Chandra, Shalabh

    2002-05-01

    The abdominal aorta is the most common site for an aneurysm, which may lead to hemorrhage and death, to develop. The aim of this study was to develop a semi-automated method to de-lineate the vessels and detect the center-line of these vessels to make measurements necessary for stent design from multi-detector computed tomograms. We developed a robust method of tracking the aortic vessel tree with branches from a user selected seed point along the vessel path using scale space approaches, central transformation measures, vessel direction findings, iterative corrections and a priori information in determining the vessel branches. Fifteen patients were scanned with contrast on Mx8000 CT scanner (Philips Medical Systems), with a 3.2 mm thickness, 1.5 mm slice spacing, and a stack of 512x512x320 volume data sets were reconstructed. The algorithm required an initial user input to locate the vessel seen in axial CT slice. Next, the automated image processing took approximately two minutes to compute the centerline and borders of the aortic vessel tree. The results between the manually and automatically generated vessel diameters were compared and statistics were computed. We observed our algorithm was consistent (less than 0.01 S.D) and similar (less than 0.1 S.D) to manual results.

  6. Can a revised paediatric radiation dose reduction CT protocol be applied and still maintain anatomical delineation, diagnostic confidence and overall imaging quality?

    PubMed Central

    Siriwanarangsun, P; Tanaanantarak, P; Krisanachinda, A

    2014-01-01

    Objective: To compare multidetector CT (MDCT) radiation doses between default settings and a revised dose reduction protocol and to determine whether the diagnostic confidence can be maintained with imaging quality made under the revised protocol in paediatric head, chest and abdominal CT studies. Methods: The study retrospectively reviewed head, chest, abdominal and thoracoabdominal MDCT studies, comparing 231 CT studies taken before (Phase 1) and 195 CT studies taken after (Phase 2) the implemented revised protocol. Image quality was assessed using a five-point grading scale based on anatomical criteria, diagnostic confidence and overall quality. Image noise and dose–length product (DLP) were collected and compared. Results: The relative dose reductions between Phase 1 and Phase 2 were statistically significant in 35%, 51% and 54% (p < 0.001) of head, chest and abdominal CT studies, respectively. There were no statistically significant differences in overall image quality score comparisons in the head (p = 0.3), chest (p = 0.7), abdominal (p = 0.7) and contiguous thoracic (p = 0.1) and abdominal (p = 0.2) CT studies, with the exception of anatomical quality in definition of bronchial walls and delineation of intrahepatic portal branches in thoracoabdominal CTs, and diagnostic confidence in mass lesion in head CTs, liver lesion (>1 cm), splanchnic venous thrombosis, pancreatitis in abdominal CTs, and emphysema and aortic dissection in thoracoabdominal CTs. Conclusion: Paediatric CT radiation doses can be significantly reduced from manufacturer's default protocol while still maintaining anatomical delineation, diagnostic confidence and overall imaging quality. Advances in knowledge: Revised paediatric CT protocol can provide a half DLP reduction while preserving overall imaging quality. PMID:24959737

  7. Automatic detection of ureter lesions in CT urography

    NASA Astrophysics Data System (ADS)

    Exell, Trevor; Hadjiiski, Lubomir; Chan, Heang-Ping; Cha, Kenny H.; Caoili, Elaine M.; Cohan, Richard H.; Wei, Jun; Zhou, Chuan

    2016-03-01

    We are developing a CAD system for automated detection of ureter abnormalities in multi-detector row CT urography (CTU). Our CAD system consists of two stages. The first stage automatically tracks the ureter via the previously proposed COmbined Model-guided Path-finding Analysis and Segmentation System (COMPASS). The second stage consists of lesion enhancement filtering, adaptive thresholding, edge extraction, and noise removal. With IRB approval, 36 cases were collected from patient files, including 15 cases (17 ureters with 32 lesions) for training, and 10 abnormal cases (11 ureters with 17 lesions) and 11 normal cases (22 ureters) for testing. All lesions were identified by experienced radiologists on the CTU images and COMPASS was able to track the ureters in 100% of the cases. The average lesion size was 5.1 mm (range: 2.1 mm - 21.9 mm) for the training set and 6.1 mm (range: 2.0 mm - 18.9 mm) for the test set. The average conspicuity was 4.1 (range: 2 to 5) and 3.9 (range: 1 to 5) on a scale of 1 to 5 (5 very subtle), for the training and test sets, respectively. The system achieved 90.6% sensitivity at 2.41 (41/17) FPs/ureter for the training set and 70.6% sensitivity at 2 (44/22) FPs/normal ureter for the test set. These initial results demonstrate the feasibility of the CAD system to track the ureter and detect ureter cancer of medium conspicuity and relatively small sizes.

  8. Prospectively versus retrospectively ECG-gated 256-slice coronary CT angiography: image quality and radiation dose over expanded heart rates.

    PubMed

    Hou, Yang; Yue, Yong; Guo, Wenli; Feng, Guoqiang; Yu, Tao; Li, Guangwei; Vembar, Mani; Olszewski, Mark E; Guo, Qiyong

    2012-01-01

    To compare image quality and radiation dose estimates for coronary computed tomography angiography (CCTA) obtained with a prospectively gated transaxial (PGT) CT technique and a retrospectively gated helical (RGH) CT technique using a 256-slice multidetector CT (MDCT) scanner and establish an upper limit of heart rate to achieve reliable diagnostic image quality using PGT. 200 patients (135 males, 65 females) with suspected coronary artery disease (CAD) underwent CCTA on a 256-slice MDCT scanner. The PGT patients were enrolled prospectively from January to June, 2009. For each PGT patient, we found the paired ones in retrospective-gating patients database and randomly selected one patient in these match cases and built up the RGH group. Image quality for all coronary segments was assessed and compared between the two groups using a 4-point scale (1: non-diagnostic; 4: excellent). Effective radiation doses were also compared. The average heart rate ± standard deviation (HR ± SD) between the two groups was not significantly different (PGT: 64.6 ± 12.9 bpm, range 45-97 bpm; RGH: 66.7 ± 10.9 bpm, range 48-97 bpm, P = 0.22). A receiver-operating characteristic (ROC) analysis determined a cutoff HR of 75 bpm up to which diagnostic image quality could be achieved using the PGT technique (P < 0.001). There were no significant differences in assessable coronary segments between the two groups for HR ≤ 75 bpm (PGT: 99.9% [961 of 962 segments]; RGH: 99.8% [1038 of 1040 segments]; P = 1.0). At HR > 75 bpm, the performance of the PGT technique was affected, resulting in a moderate reduction of percentage assessable coronary segments using this approach (PGT: 95.5% [323 of 338 segments]; RGH: 98.5% [261 of 265 segments]; P = 0.04). The mean estimated effective radiation dose for the PGT group was 3.0 ± 0.7 mSv, representing reduction of 73% compared to that of the RGH group (11.1 ± 1.6 mSv) (P < 0.001). Prospectively-gated axial coronary computed tomography using a 256

  9. Optimization of acquisition and contrast injection protocol for C-arm CT imaging in transcatheter aortic valve implantation: initial experience in a swine model.

    PubMed

    Numburi, Uma D; Kapadia, Samir R; Schoenhagen, Paul; Tuzcu, E Murat; von Roden, Martin; Halliburton, Sandra S

    2013-02-01

    To determine the optimal C-arm computed tomography (CT) protocol for transcatheter aortic valve implantation (TAVI) in swine. In 6 swine, C-arm CT was performed using 5-s ungated acquisition during sinus rhythm with aortic root (Method 1) or peripheral (Method 2) injection, and during rapid ventricular pacing with root injection (Method 3). Additionally, 24-s ECG-gated acquisitions were performed during sinus rhythm with root (Method 4) or peripheral (Method 5) injection. Aortic root enhancement, presence of artifacts and contrast volumes were compared for all methods. Aortic root measurements were also compared between C-arm CT and multidetector-row computed tomography (MDCT). The best C-arm CT image set was identified and used to predict optimal angiographic projection angles during TAVI; predictions were compared to those from MDCT. Methods 1, 3, 4, and 5 yielded sufficient root enhancement with mild or moderate artifacts and aortic annulus, sinotubular junction, and mid-ascending aorta diameters similar to MDCT. Ungated C-arm CT (Methods 1, 3) required less contrast than ECG-gated C-arm CT (Methods 4, 5). Method 3 was optimal yielding images with high attenuation, few artifacts (2.0), and root measurements similar to MDCT using minimal contrast (36 mL). Predicted angiographic projections from Method 3 were similar to MDCT. Ungated C-arm CT during rapid pacing with aortic root injection required minimal contrast, yielded high attenuation and few artifacts, and aortic root measurements and predicted angiographic planes similar to those from MDCT.

  10. Geographic Distribution of CT, MRI and PET Devices in Japan: A Longitudinal Analysis Based on National Census Data

    PubMed Central

    Matsumoto, Masatoshi; Koike, Soichi; Kashima, Saori; Awai, Kazuo

    2015-01-01

    Background Japan has the most CT and MRI scanners per unit population in the world; however, the geographic distribution of these technologies is currently unknown. Moreover, nothing is known of the cause-effect relationship between the number of diagnostic imaging devices and their geographic distribution. Methods Data on the number of CT, MRI and PET devices and that of their utilizations in all 1829 municipalities of Japan was generated, based on the Static Survey of Medical Institutions conducted by the government. The inter-municipality equity of the number of devices or utilizations was evaluated with Gini coefficient. Results Between 2005 and 2011, the number of CT, MRI and PET devices in Japan increased by 47% (8789 to 12945), 19% (5034 to 5990) and 70% (274 to 466), respectively. Gini coefficient of the number of devices was largest for PET and smallest for CT (p for PET-MRI difference <0.001; MRI-CT difference <0.001). For all three modalities, Gini coefficient steadily decreased (p for 2011-2005 difference: <0.001 for CT; 0.003 for MRI; and <0.001 for PET). The number of devices in old models (single-detector CT, MRI<1.5 tesla, and conventional PET) decreased, while that in new models (multi-detector CT, MRI≥1.5 tesla, and PET-CT) increased. Gini coefficient of the old models increased or remained unchanged (increase rate of 9%, 3%, and -1%; p for 2011-2008 difference <0.001, 0.072, and 0.562, respectively), while Gini coefficient of the new models decreased (-10%, -9%, and -10%; p for 2011-2008 difference <0.001, <0.001, and <0.001 respectively). Similar results were observed in terms of utilizations. Conclusions The more abundant a modality, the more equal the modality’s distribution. Any increase in the modality made its distribution more equal. The geographic distribution of the diagnostic imaging technology in Japan appears to be affected by spatial competition derived from a market force. PMID:25946125

  11. Chronic osteomyelitis examined by CT

    SciTech Connect

    Wing, V.W.; Jeffrey, R.B. Jr.; Federle, M.P.; Helms, C.A.; Trafton, P.

    1985-01-01

    CT examination of 25 patients who had acute exacerbations of chronic osteomyelitis allowed for the correct identification of single or multiple sequestra in 14 surgical patients. Plain radiographs were equivocal for sequestra in seven of these patients, because the sequestra were too small or because diffuse bony sclerosis was present. CT also demonstrated a foreign body and five soft tissue abscesses not suspected on the basis of plain radiographs. CT studies, which helped guide the operative approach, were also useful in treating those patients whose plain radiographs were positive for sequestra. The authors review the potential role of CT in evaluating patients with chronic osteomyelitis.

  12. Four- and Eight-Channel Aortoiliac CT Angiography: A Comparative Study

    SciTech Connect

    Karcaaltincaba, Musturay Foley, Dennis

    2005-04-15

    Purpose. To compare performance parameters, contrast material load and radiation dose in a patient cohort having aortoiliac CT angiography using 4- and 8-channel multidetector CT (MDCT) systems. Methods. Eighteen patients with abdominal aortic aneurysms underwent initial 4-channel and follow-up 8-channel MDCT angiography. Both the 4- and 8-channel MDCT systems utilized a matrix detector of 16 x 1.25 mm rows. Scan coverage included the abdominal aorta and iliac arteries to the level of the proximal femoral arteries. For 4-channel MDCT, nominal slice thickness and beam pitch were 1.25 mm and 1.5, respectively, and for 8-channel MDCT they were 1.25 mm and 1.35 or 1.65 respectively. Scan duration, iodinated contrast material load and mean aortoiliac attenuation were compared retrospectively. Comparative radiation dose measurements for 4- and 8-channel MDCT were obtained using a multiple scan average dose technique on an abdominal phantom. Results. Compared with 4-channel MDCT, 8-channel MDCT aortoiliac angiography was performed with equivalent collimation, decreased contrast load (mean 45% decrease: 144 ml versus 83 ml of 300 mg iodine/ml contrast material) and decreased acquisition time (mean 51% shorter: 34.4 sec versus 16.9 sec) without a significant change in mean aortic enhancement (299 HU versus 300 HU, p > 0.05). Radiation dose was 2 rad for the 4-channel system and 2/1.5 rad for the 8-channel system at 1.35/1.65 pitch respectively. Conclusion. Compared with 4-channel MDCT, aortoiliac CT angiography with 8-channel MDCT produces equivalent z-axis resolution with decreased contrast load and acquisition time without increased radiation exposure.

  13. TU-G-204-09: The Effects of Reduced- Dose Lung Cancer Screening CT On Lung Nodule Detection Using a CAD Algorithm

    SciTech Connect

    Young, S; Lo, P; Kim, G; Hsu, W; Hoffman, J; Brown, M; McNitt-Gray, M

    2015-06-15

    Purpose: While Lung Cancer Screening CT is being performed at low doses, the purpose of this study was to investigate the effects of further reducing dose on the performance of a CAD nodule-detection algorithm. Methods: We selected 50 cases from our local database of National Lung Screening Trial (NLST) patients for which we had both the image series and the raw CT data from the original scans. All scans were acquired with fixed mAs (25 for standard-sized patients, 40 for large patients) on a 64-slice scanner (Sensation 64, Siemens Healthcare). All images were reconstructed with 1-mm slice thickness, B50 kernel. 10 of the cases had at least one nodule reported on the NLST reader forms. Based on a previously-published technique, we added noise to the raw data to simulate reduced-dose versions of each case at 50% and 25% of the original NLST dose (i.e. approximately 1.0 and 0.5 mGy CTDIvol). For each case at each dose level, the CAD detection algorithm was run and nodules greater than 4 mm in diameter were reported. These CAD results were compared to “truth”, defined as the approximate nodule centroids from the NLST reports. Subject-level mean sensitivities and false-positive rates were calculated for each dose level. Results: The mean sensitivities of the CAD algorithm were 35% at the original dose, 20% at 50% dose, and 42.5% at 25% dose. The false-positive rates, in decreasing-dose order, were 3.7, 2.9, and 10 per case. In certain cases, particularly in larger patients, there were severe photon-starvation artifacts, especially in the apical region due to the high-attenuating shoulders. Conclusion: The detection task was challenging for the CAD algorithm at all dose levels, including the original NLST dose. However, the false-positive rate at 25% dose approximately tripled, suggesting a loss of CAD robustness somewhere between 0.5 and 1.0 mGy. NCI grant U01 CA181156 (Quantitative Imaging Network); Tobacco Related Disease Research Project grant 22RT-0131.

  14. Preoperative quantification of aortic valve stenosis: comparison of 64-slice computed tomography with transesophageal and transthoracic echocardiography and size of implanted prosthesis.

    PubMed

    Mizia-Stec, Katarzyna; Pysz, Piotr; Jasiński, Marek; Adamczyk, Tomasz; Drzewiecka-Gerber, Agnieszka; Chmiel, Artur; Krejca, Michał; Bochenek, Andrzej; Woś, Stanisław; Sosnowski, Maciej; Gąsior, Zbigniew; Trusz-Gluza, Maria; Tendera, Michał

    2012-02-01

    Precise measurements of aortic complex diameters are essential for preoperative examinations of patients with aortic stenosis (AS) scheduled for aortic valve (AV) replacement. We aimed to prospectively compare the accuracy of transthoracic echocardiography (TTE), transoesophageal echocardiography (TEE) and multi-slice computed tomography (MSCT) measurements of the AV complex and to analyze the role of the multi-modality aortic annulus diameter (AAd) assessment in the selection of the optimal prosthesis to be implanted in patients surgically treated for degenerative AS. 20 patients (F/M: 3/17; age: 69 ± 6.5 years) with severe degenerative AS were enrolled into the study. TTE, TEE and MSCT including AV calcium score (AVCS) assessment were performed in all patients. The values of AAd obtained in the long AV complex axis (TTE, TEE, MSCT) and in multiplanar perpendicular imaging (MSCT) were compared to the size of implanted prosthesis. The mean AAd was 24 ± 3.6 mm using TTE, 26 ± 4.2 mm using TEE, and 26.9 ± 3.2 in MSCT (P = 0.04 vs. TTE). The mean diameter of the left ventricle out-flow tract in TTE (19.9 ± 2.7 mm) and TEE (19.5 ± 2.7 mm) were smaller than in MSCT (24.9 ± 3.3 mm, P < 0.001 for both). The mean size of implanted prosthesis (22.2 ± 2.3 mm) was significantly smaller than the mean AAd measured by TTE (P = 0.0039), TEE (P = 0.0004), and MSCT (P < 0.0001). The implanted prosthesis size correlated significantly to the AAd: r = 0.603, P = 0.005 for TTE, r = 0.592, P = 0.006 for TEE, and r = 0.791, P < 0.001 for MSCT. Obesity and extensive valve calcification (AV calcium score ≥ 3177Ag.U.) were identified as potent factors that caused a deterioration of both TTE and MSCT performance. The accuracy of AAd measurements in TEE was only limited by AV calcification. In multivariate regression analysis the mean value of the minimum and maximum AAd obtained in MSCT-multiplanar perpendicular imaging was an independent factor (r = 0.802, P < 0.0001) predicting the size of implanted prosthesis. In patients with AS echocardiography remains the main diagnostics tool in clinical practice. MSCT as a 3-dimentional modality allows for accurate measurement of entire AV complex and facilitates optimal matching of prosthesis size.

  15. Evaluation of the pelvic apophysis with multi-detector computed tomography for legal age estimation in living individuals

    PubMed Central

    Karami, Mehdi; Rabiei, Meisam; Riahinezhad, Maryam

    2015-01-01

    Background: Legal age estimations of living individuals are gaining increasing importance for radiologists involved in delivering expert opinions. The present study aimed to assess the correlation between chronological age and apophyseal centers distance from pelvic bone. Materials and Methods: This was a cross-sectional study carried out on 2013. Subjects were chosen from 15 to 25 years old people who had previous pelvic multi-detector computed tomography for any reason. The distance of iliac crest apophysis to iliac bone, and pubic apophysis to pubic bone were assessed. Results: There was a reverse linear correlation between chronological age and distance of iliac crest apophysis (P < 0.001, r = 0.899) and pubic apophysis to pelvic bone (P < 0.001, r = 0.898). Pubic apophysis was not appeared in subjects before 16 years old and it was appeared in all of the subjects with 18 years old and more. Subjects with age of 21 had near ossification of iliac or pubic apophysis and subjects with age of 24 had full ossification of iliac or pubic apophysis. Conclusion: skeletalage can be estimated by assessing the apophyseal centers distance from the pelvic bone in adolescents 15-25 years old. PMID:26109964

  16. Non-invasive coronary angiography with multi-detector computed tomography: comparison to conventional X-ray angiography.

    PubMed

    Schoenhagen, Paul; Stillman, Arthur E; Halliburton, Sandy S; Kuzmiak, Stacie A; Painter, Tracy; White, Richard D

    2005-02-01

    Selective coronary angiography introduced clinical coronary imaging in the late 1950s. The angiographic identification of high-grade coronary lesions in patients with acute and chronic symptomatic coronary artery disease (CAD) led to the development of surgical and percutaneous coronary revascularization. However, the fact that CAD remains the major cause of death in North America and Europe demonstrates the need for novel, complementary diagnostic strategies. These are driven by the need to characterize both increasingly advanced disease stages but also early, asymptomatic disease development. Complex revascularization techniques for patients with advanced disease stages will initiate a growing demand for 3-dimensional coronary imaging and integration of imaging modalities with new mechanical therapeutic devices. An emerging focus is atherosclerosis imaging with the goal to identify subclinical disease stages as the basis for pharmacological intervention aimed at disease stabilization or reversal. Non-invasive coronary imaging with coronary multidetector computed tomographic angiography (MDCTA) allows both assessment of luminal stenosis and subclinical disease of the arterial wall. Its complementary role in the assessment of early and advanced stages of CAD is increasingly recognized.

  17. Anatomical variations of the celiac trunk and hepatic arterial system: an analysis using multidetector computed tomography angiography*

    PubMed Central

    Araujo Neto, Severino Aires; Franca, Henrique Almeida; de Mello Júnior, Carlos Fernando; Silva Neto, Eulâmpio José; Negromonte, Gustavo Ramalho Pessoa; Duarte, Cláudia Martina Araújo; Cavalcanti Neto, Bartolomeu Fragoso; Farias, Rebeca Danielly da Fonseca

    2015-01-01

    Objective To analyze the prevalence of anatomical variations of celiac arterial trunk (CAT) branches and hepatic arterial system (HAS), as well as the CAT diameter, length and distance to the superior mesenteric artery. Materials and Methods Retrospective, cross-sectional and predominantly descriptive study based on the analysis of multidetector computed tomography images of 60 patients. Results The celiac trunk anatomy was normal in 90% of cases. Hepatosplenic trunk was found in 8.3% of patients, and hepatogastric trunk in 1.7%. Variation of the HAS was observed in 21.7% of cases, including anomalous location of the right hepatic artery in 8.3% of cases, and of the left hepatic artery, in 5%. Also, cases of joint relocation of right and left hepatic arteries, and trifurcation of the proper hepatic artery were observed, respectively, in 3 (5%) and 2 (3.3%) patients. Mean length and caliber of the CAT were 2.3 cm and 0.8 cm, respectively. Mean distance between CAT and superior mesenteric artery was 1.2 cm (standard deviation = 4.08). A significant correlation was observed between CAT diameter and length, and CAT diameter and distance to superior mesenteric artery. Conclusion The pattern of CAT variations and diameter corroborate the majority of the literature data. However, this does not happen in relation to the HAS. PMID:26811552

  18. Preoperative evaluation value of aortic arch lesions by multidetector computed tomography angiography in type A aortic dissection

    PubMed Central

    Huang, Fang; Chen, Qiang; Lai, Qing-quan; Huang, Wen-han; Wu, Hong; Li, Wei-cheng

    2016-01-01

    Abstract The purpose of this study was to preoperatively evaluate the value of aortic arch lesions by multidetector computed tomography (MDCT) angiography in type A aortic dissection (AD). From January 2013 to December 2015, we enrolled 42 patients with type A AD who underwent MDCT angiography in our hospital. The institutional database of patients was retrospectively reviewed to identify MDCT angiography examinations for type A AD. Surgical corrections were conducted in all patients to confirm diagnostic accuracy. In this study, the diagnostic accuracy of MDCT angiography was 100% in all 42 patients. The intimal tear site locations that were identified in patients included the ascending aorta (n = 25), aortic arch (n = 12), and all other sites (n = 5). Compared with the control group, there were significant differences in the aortic arch anatomy among the cases. Regarding the distance between the left common carotid and left subclavian arteries, compared with the control group, most cases with type A AD had a significant variation. MDCT angiography plays an important role in detecting aortic arch lesions of type A AD, especially in determining the location of the intimal entry site and change of branch blood vessels. Surgeons can formulate an appropriate operating plan, according to the preoperative MDCT diagnosis information. PMID:27684852

  19. Development of a Radiation Dose Reporting Software for X-ray Computed Tomography (CT)

    NASA Astrophysics Data System (ADS)

    Ding, Aiping

    X-ray computed tomography (CT) has experienced tremendous technological advances in recent years and has established itself as one of the most popular diagnostic imaging tools. While CT imaging clearly plays an invaluable role in modern medicine, its rapid adoption has resulted in a dramatic increase in the average medical radiation exposure to the worldwide and United States populations. Existing software tools for CT dose estimation and reporting are mostly based on patient phantoms that contain overly simplified anatomies insufficient in meeting the current and future needs. This dissertation describes the development of an easy-to-use software platform, “VirtualDose”, as a service to estimate and report the organ dose and effective dose values for patients undergoing the CT examinations. “VirtualDose” incorporates advanced models for the adult male and female, pregnant women, and children. To cover a large portion of the ignored obese patients that frequents the radiology clinics, a new set of obese male and female phantoms are also developed and applied to study the effects of the fat tissues on the CT radiation dose. Multi-detector CT scanners (MDCT) and clinical protocols, as well as the most recent effective dose algorithms from the International Commission on Radiological Protection (ICRP) Publication 103 are adopted in “VirtualDose” to keep pace with the MDCT development and regulatory requirements. A new MDCT scanner model with both body and head bowtie filter is developed to cover both the head and body scanning modes. This model was validated through the clinical measurements. A comprehensive slice-by-slice database is established by deriving the data from a larger number of single axial scans simulated on the patient phantoms using different CT bowtie filters, beam thicknesses, and different tube voltages in the Monte Carlo N-Particle Extended (MCNPX) code. When compared to the existing CT dose software packages, organ dose data in this

  20. Thoracic textilomas: CT findings*

    PubMed Central

    Machado, Dianne Melo; Zanetti, Gláucia; Araujo, Cesar Augusto; Nobre, Luiz Felipe; Meirelles, Gustavo de Souza Portes; Pereira e Silva, Jorge Luiz; Guimarães, Marcos Duarte; Escuissato, Dante Luiz; Souza, Arthur Soares; Hochhegger, Bruno; Marchiori, Edson

    2014-01-01

    OBJECTIVE: The aim of this study was to analyze chest CT scans of patients with thoracic textiloma. METHODS: This was a retrospective study of 16 patients (11 men and 5 women) with surgically confirmed thoracic textiloma. The chest CT scans of those patients were evaluated by two independent observers, and discordant results were resolved by consensus. RESULTS: The majority (62.5%) of the textilomas were caused by previous heart surgery. The most common symptoms were chest pain (in 68.75%) and cough (in 56.25%). In all cases, the main tomographic finding was a mass with regular contours and borders that were well-defined or partially defined. Half of the textilomas occurred in the right hemithorax and half occurred in the left. The majority (56.25%) were located in the lower third of the lung. The diameter of the mass was ≤ 10 cm in 10 cases (62.5%) and > 10 cm in the remaining 6 cases (37.5%). Most (81.25%) of the textilomas were heterogeneous in density, with signs of calcification, gas, radiopaque marker, or sponge-like material. Peripheral expansion of the mass was observed in 12 (92.3%) of the 13 patients in whom a contrast agent was used. Intraoperatively, pleural involvement was observed in 14 cases (87.5%) and pericardial involvement was observed in 2 (12.5%). CONCLUSIONS: It is important to recognize the main tomographic aspects of thoracic textilomas in order to include this possibility in the differential diagnosis of chest pain and cough in patients with a history of heart or thoracic surgery, thus promoting the early identification and treatment of this postoperative complication. PMID:25410842

  1. CT scanning of the breast using a conventional CT scanner.

    PubMed

    Doust, B D; Milbrath, J R; Doust, V L

    1981-09-01

    Using a conventional body CT scanner, computed tomography of the breast was performed on 32 patients known to have or suspected of having breast masses. Xeromammograms were available for comparison in all cases. All mass lesions were histologically proved. Seven patients were examined prone, 25 supine. The prone position yielded pictures that resembled craniocaudal mammograms. Breast asymmetry, skin thickening, stranding from a mass to the chest wall, calcification, and axillary lymphadenopathy could be demonstrated by means of CT. The portion of the breast adjacent to the chest wall was more readily examined by means of CT than by conventional mammography. Internal mammary nodes could not be demonstrated.

  2. Combining 2D wavelet edge highlighting and 3D thresholding for lung segmentation in thin-slice CT.

    PubMed

    Korfiatis, P; Skiadopoulos, S; Sakellaropoulos, P; Kalogeropoulou, C; Costaridou, L

    2007-12-01

    The first step in lung analysis by CT is the identification of the lung border. To deal with the increased number of sections per scan in thin-slice multidetector CT, it has been crucial to develop accurate and automated lung segmentation algorithms. In this study, an automated method for lung segmentation of thin-slice CT data is presented. The method exploits the advantages of a two-dimensional wavelet edge-highlighting step in lung border delineation. Lung volume segmentation is achieved with three-dimensional (3D) grey level thresholding, using a minimum error technique. 3D thresholding, combined with the wavelet pre-processing step, successfully deals with lung border segmentation challenges, such as anterior or posterior junction lines and juxtapleural nodules. Finally, to deal with mediastinum border under-segmentation, 3D morphological closing with a spherical structural element is applied. The performance of the proposed method is quantitatively assessed on a dataset originating from the Lung Imaging Database Consortium (LIDC) by comparing automatically derived borders with the manually traced ones. Segmentation performance, averaged over left and right lung volumes, for lung volume overlap is 0.983+/-0.008, whereas for shape differentiation in terms of mean distance it is 0.770+/-0.251 mm (root mean square distance is 0.520+/-0.008 mm; maximum distance is 3.327+/-1.637 mm). The effect of the wavelet pre-processing step was assessed by comparing the proposed method with the 3D thresholding technique (applied on original volume data). This yielded statistically significant differences for all segmentation metrics (p<0.01). Results demonstrate an accurate method that could be used as a first step in computer lung analysis by CT.

  3. Effect of low-xenon and krypton supplementation on signal/noise of regional CT-based ventilation measurements.

    PubMed

    Chon, Deokiee; Beck, Kenneth C; Simon, Brett A; Shikata, Hidenori; Saba, Osama I; Hoffman, Eric A

    2007-04-01

    Xenon computed tomography (Xe-CT) is used to estimate regional ventilation by measuring regional attenuation changes over multiple breaths while rebreathing a constant Xe concentration ([Xe]). Xe-CT has potential human applications, although anesthetic properties limit [Xe] to multidetector row CT. Lungs were imaged by respiratory gating during washin of a 30%, 40%, 55% Xe, and a 30% Xe/30% Kr mixture. Using Kr avoids unwanted effects of Xe. Mean TCs, coefficients of variation (CV), and half confidence intervals (CI)/mean served as indexes of sensitivity to noise. Mean supine and prone TCs of three [Xe] values were not significantly different. Average CVs of TCs increased from 57% (55% Xe), 58% (40% Xe), and 73% (30% Xe) (P < 0.05: paired t-tests; 30% Xe vs. higher [Xe]). Monte Carlo simulation indicated a CV based on inherent image noise was 8% for 55% Xe and 17% for 30% Xe (P < 0.05). Adding 30% Kr to 30% Xe gave a washin signal equivalent to 40% Xe. Half CI/mean using the 30% Xe/30% Kr mixture was not significantly different from 55 and 40% Xe. Although average TCs were not affected by changes in [Xe], the higher CV and half CI/mean suggested reduced signal-to-noise ratio at the 30% [Xe]. The 30% Xe/30% Kr mixture was comparable to that of 40% Xe, providing an important agent for CT-based assessment of regional ventilation in humans.

  4. SU-E-I-34: Evaluating Use of AEC to Lower Dose for Lung Cancer Screening CT Protocols

    SciTech Connect

    Arbique, G; Anderson, J; Guild, J; Duan, X; Malguria, N; Omar, H; Brewington, C; Zhang, D

    2015-06-15

    Purpose: The National Lung Screening Trial mandated manual low dose CT technique factors, where up to a doubling of radiation output could be used over a regular to large patient size range. Recent guidance from the AAPM and ACR for lung cancer CT screening recommends radiation output adjustment for patient size either through AEC or a manual technique chart. This study evaluated the use of AEC for output control and dose reduction. Methods: The study was performed on a multidetector helical CT scanner (Aquillion ONE, Toshiba Medical) equipped with iterative reconstruction (ADIR-3D), AEC was adjusted with a standard deviation (SD) image quality noise index. The protocol SD parameter was incrementally increased to reduce patient population dose while image quality was evaluated by radiologist readers scoring the clinical utility of images on a Likert scale. Results: Plots of effective dose vs. body size (water cylinder diameter reported by the scanner) demonstrate monotonic increase in patient dose with increasing patient size. At the initial SD setting of 19 the average CTDIvol for a standard size patient was ∼ 2.0 mGy (1.2 mSv effective dose). This was reduced to ∼1.0 mGy (0.5 mSv) at an SD of 25 with no noticeable reduction in clinical utility of images as demonstrated by Likert scoring. Plots of effective patient diameter and BMI vs body size indicate that these metrics could also be used for manual technique charts. Conclusion: AEC offered consistent and reliable control of radiation output in this study. Dose for a standard size patient was reduced to one-third of the 3 mGy CTDIvol limit required for ACR accreditation of lung cancer CT screening. Gary Arbique: Research Grant, Toshiba America Medical Systems; Cecelia Brewington: Research Grant, Toshiba America Medical Systems; Di Zhang: Employee, Toshiba America Medical Systems.

  5. Helical CT in emergency radiology.

    PubMed

    Novelline, R A; Rhea, J T; Rao, P M; Stuk, J L

    1999-11-01

    Today, a wide range of traumatic and nontraumatic emergency conditions are quickly and accurately diagnosed with helical computed tomography (CT). Many traditional emergency imaging procedures have been replaced with newer helical CT techniques that can be performed in less time and with greater accuracy, less patient discomfort, and decreased cost. The speed of helical technology permits CT examination of seriously ill patients in the emergency department, as well as patients who might not have been taken to CT previously because of the length of the examinations of the past. Also, helical technology permits multiple, sequential CT scans to be quickly obtained in the same patient, a great advance for the multiple-trauma patient. Higher quality CT examinations result from decreased respiratory misregistration, enhanced intravenous contrast material opacification of vascular structures and parenchymal organs, greater flexibility in image reconstruction, and improved multiplanar and three-dimensional reformations. This report summarizes the role and recommended protocols for the helical CT diagnosis of thoracic aortic trauma; aortic dissection; pulmonary embolism; acute conditions of the neck soft tissues; abdominal trauma; urinary tract stones; appendicitis; diverticulitis; abdominal aortic aneurysm; fractures of the face, spine, and extremities; and acute stroke.

  6. MULTIMODALITY IMAGING: BEYOND PET/CT AND SPECT/CT

    PubMed Central

    Cherry, Simon R.

    2009-01-01

    Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar potential to impact medical science and clinical medicine? The combination of PET or SPECT with MRI is an area of active research at the present time, while other, perhaps less obvious combinations, including CT/MR and PET/optical also are being studied. In addition to the integration of the instrumentation, there are parallel developments in synthesizing imaging agents that can be viewed by multiple imaging modalities. Is the fusion of PET and SPECT with CT the ultimate answer in multimodality imaging, or is it just the first example of a more general trend towards harnessing the complementary nature of the different modalities on integrated imaging platforms? PMID:19646559

  7. Development of a parallel detection and processing system using a multidetector array for wave field restoration in scanning transmission electron microscopy.

    PubMed

    Taya, Masaki; Matsutani, Takaomi; Ikuta, Takashi; Saito, Hidekazu; Ogai, Keiko; Harada, Yoshihito; Tanaka, Takeo; Takai, Yoshizo

    2007-08-01

    A parallel image detection and image processing system for scanning transmission electron microscopy was developed using a multidetector array consisting of a multianode photomultiplier tube arranged in an 8 x 8 square array. The system enables the taking of 64 images simultaneously from different scattered directions with a scanning time of 2.6 s. Using the 64 images, phase and amplitude contrast images of gold particles on an amorphous carbon thin film could be separately reconstructed by applying respective 8 shaped bandpass Fourier filters for each image and multiplying the phase and amplitude reconstructing factors.

  8. Errors in CT colonography.

    PubMed

    Trilisky, Igor; Ward, Emily; Dachman, Abraham H

    2015-10-01

    CT colonography (CTC) is a colorectal cancer screening modality which is becoming more widely implemented and has shown polyp detection rates comparable to those of optical colonoscopy. CTC has the potential to improve population screening rates due to its minimal invasiveness, no sedation requirement, potential for reduced cathartic examination, faster patient throughput, and cost-effectiveness. Proper implementation of a CTC screening program requires careful attention to numerous factors, including patient preparation prior to the examination, the technical aspects of image acquisition, and post-processing of the acquired data. A CTC workstation with dedicated software is required with integrated CTC-specific display features. Many workstations include computer-aided detection software which is designed to decrease errors of detection by detecting and displaying polyp-candidates to the reader for evaluation. There are several pitfalls which may result in false-negative and false-positive reader interpretation. We present an overview of the potential errors in CTC and a systematic approach to avoid them.

  9. Organ dose measurements from multiple-detector computed tomography using a commercial dosimetry system and tomographic, physical phantoms

    NASA Astrophysics Data System (ADS)

    Lavoie, Lindsey K.

    The technology of computed tomography (CT) imaging has soared over the last decade with the use of multi-detector CT (MDCT) scanners that are capable of performing studies in a matter of seconds. While the diagnostic information obtained from MDCT imaging is extremely valuable, it is important to ensure that the radiation doses resulting from these studies are at acceptably safe levels. This research project focused on the measurement of organ doses resulting from modern MDCT scanners. A commercially-available dosimetry system was used to measure organ doses. Small dosimeters made of optically-stimulated luminescent (OSL) material were analyzed with a portable OSL reader. Detailed verification of this system was performed. Characteristics studied include energy, scatter, and angular responses; dose linearity, ability to erase the exposed dose and ability to reuse dosimeters multiple times. The results of this verification process were positive. While small correction factors needed to be applied to the dose reported by the OSL reader, these factors were small and expected. Physical, tomographic pediatric and adult phantoms were used to measure organ doses. These phantoms were developed from CT images and are composed of tissue-equivalent materials. Because the adult phantom is comprised of numerous segments, dosimeters were placed in the phantom at several organ locations, and doses to select organs were measured using three clinical protocols: pediatric craniosynostosis, adult brain perfusion and adult cardiac CT angiography (CTA). A wide-beam, 320-slice, volumetric CT scanner and a 64-slice, MDCT scanner were used for organ dose measurements. Doses ranged from 1 to 26 mGy for the pediatric protocol, 1 to 1241 mGy for the brain perfusion protocol, and 2-100 mGy for the cardiac protocol. In most cases, the doses measured on the 64-slice scanner were higher than those on the 320-slice scanner. A methodology to measure organ doses with OSL dosimeters received from CT

  10. Improvement in the quality of the cardiac vein images by optimizing the scan protocol of multidetector-row computed tomography.

    PubMed

    Hara, Tetsuya; Yamashiro, Kohei; Okajima, Katsunori; Hayashi, Takatoshi; Kajiya, Teishi

    2009-11-01

    The present study aimed at optimizing the scan protocol for multidetector-row computed tomography (MDCT) to adequately visualize coronary veins. Circulation time (Cir.T) was defined as the time period from the injection of contrast media into the coronary artery to the pervasion of the contrast media into the coronary sinus as observed by coronary angiography. We investigated the relation between the Cir.T and echocardiographic parameters in 64 patients. The left ventricular end-diastolic diameter (LVDd) and left ventricular end-systolic diameter (LVDs) were correlated with the Cir.T (r = 0.58, P < 0.0001, and r = 0.60, P < 0.0001 respectively). In addition, the left ventricular ejection fraction (LVEF) was negatively correlated with the Cir.T (r = 0.48, P < 0.0001). The average Cir. T was longer in patients with LVEF < 35% (8.0 s vs 6.7 s; P < 0.05) or LVDd > 55 mm (7.9 s vs 6.2 s; P < 0.05) than in the other patients. The quality of the MDCT images of the coronary veins obtained at different scan timings (coronary artery phase and 10 s or 15 s after the coronary artery phase) were graded and classified into four categories (0 = worst, 3 = best) in 25 patients with LVEF < 35%. The delays of 10 and 15 s after the coronary artery phase significantly improved the mean image quality (P < 0.05). The Cir.T was prolonged in patients with low LVEF and LV dilation. An appropriate delay improved the quality of the MDCT images of the coronary veins in patients with LV dysfunction.

  11. Anatomical variation of celiac axis, superior mesenteric artery, and hepatic artery: Evaluation with multidetector computed tomography angiography

    PubMed Central

    Farghadani, Maryam; Momeni, Mohammad; Hekmatnia, Ali; Momeni, Fateme; Baradaran Mahdavi, Mohammad Mehdi

    2016-01-01

    Background: The celiac axis, superior mesenteric artery (SMA), and hepatic artery are the most important branches of abdominal aorta due to their vascularization field. The aim of our study was to evaluate the prevalence of different anatomical variation of celiac axis, SMA, hepatic artery, and its branches with multidetector computed tomography (MDCT) angiography of upper abdomen arteries. Materials and Methods: MDCT of 607 kidney donor and traumatic patients that referred to MDCT unit at Al Zahra Hospital in Isfahan from 2012 to 2015 were retrospectively evaluated. We excluded patients with history of abdominal vascular surgery and hepatic or pancreatic surgery. Computed tomography images of the patient were obtained with 64-row MDCT scanner and anatomical variations were analyzed. Results: Three hundred and eighty-eight (63.9%) of the 607 patients had classic arterial anatomy and 219 (36.1%) patients had variant types. The most common type of variation was the origin of the right hepatic artery (RHA) from SMA (9.6%), and the next common variation was the origin of the left hepatic artery (LHA) from the left gastric artery (6.9%). Variations in the origin of the common hepatic artery (CHA) were seen in 16 (2.6%) patients. Buhler arc was identified in two patients. The RHA originated from the celiac axis in 11 (1.8%) patients and from the aorta in 8 (1.3%) patients. Trifurcation of CHA into gastroduodenal artery, RHA, and LHA was detected in 11 (1.8%) patients. Conclusion: The results of the present study showed that anatomical variation occurs in a high percentage of patients. Detection of these variations can guide surgical and radiological interventional planning.

  12. Multidetector-row computed tomography of thoracic aortic anomalies in dogs and cats: Patent ductus arteriosus and vascular rings

    PubMed Central

    2011-01-01

    Background Diagnosis of extracardiac intrathoracic vascular anomalies is of clinical importance, but remains challenging. Traditional imaging modalities, such as radiography, echocardiography, and angiography, are inherently limited by the difficulties of a 2-dimensional approach to a 3-dimensional object. We postulated that accurate characterization of malformations of the aorta would benefit from 3-dimensional assessment. Therefore, multidetector-row computed tomography (MDCT) was chosen as a 3-dimensional, new, and noninvasive imaging technique. The purpose of this study was to evaluate patients with 2 common diseases of the intrathoracic aorta, either patent ductus arteriosus or vascular ring anomaly, by contrast-enhanced 64-row computed tomography. Results Electrocardiography (ECG)-gated and thoracic nongated MDCT images were reviewed in identified cases of either a patent ductus arteriosus or vascular ring anomaly. Ductal size and morphology were determined in 6 dogs that underwent ECG-gated MDCT. Vascular ring anomalies were characterized in 7 dogs and 3 cats by ECG-gated MDCT or by a nongated thoracic standard protocol. Cardiac ECG-gated MDCT clearly displayed the morphology, length, and caliber of the patent ductus arteriosus in 6 affected dogs. Persistent right aortic arch was identified in 10 animals, 8 of which showed a coexisting aberrant left subclavian artery. A mild dilation of the proximal portion of the aberrant subclavian artery near its origin of the aorta was present in 4 dogs, and a diverticulum analogous to the human Kommerell's diverticulum was present in 2 cats. Conclusions Contrast-enhanced MDCT imaging of thoracic anomalies gives valuable information about the exact aortic arch configuration. Furthermore, MDCT was able to characterize the vascular branching patterns in dogs and cats with a persistent right aortic arch and the morphology and size of the patent ductus arteriosus in affected dogs. This additional information can be of help

  13. Detection of root perforations using conventional and digital intraoral radiography, multidetector computed tomography and cone beam computed tomography

    PubMed Central

    Eskandarloo, Amir; Noruzi-Gangachin, Maruf; Khajeh, Samira

    2015-01-01

    Objectives This study aimed to compare the accuracy of conventional intraoral (CI) radiography, photostimulable phosphor (PSP) radiography, cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) for detection of strip and root perforations in endodontically treated teeth. Materials and Methods Mesial and distal roots of 72 recently extracted molar were endodontically prepared. Perforations were created in 0.2, 0.3, or 0.4 mm diameter around the furcation of 48 roots (strip perforation) and at the external surface of 48 roots (root perforation); 48 roots were not perforated (control group). After root obturation, intraoral radiography, CBCT and MDCT were taken. Discontinuity in the root structure was interpreted as perforation. Two observers examined the images. Data were analyzed using Stata software and Chi-square test. Results The sensitivity and specificity of CI, PSP, CBCT and MDCT in detection of strip perforations were 81.25% and 93.75%, 85.42% and 91.67%, 97.92% and 85.42%, and 72.92% and 87.50%, respectively. For diagnosis of root perforation, the sensitivity and specificity were 87.50% and 93.75%, 89.58% and 91.67%, 97.92% and 85.42%, and 81.25% and 87.50%, respectively. For detection of strip perforation, the difference between CBCT and all other methods including CI, PSP and MDCT was significant (p < 0.05). For detection of root perforation, only the difference between CBCT and MDCT was significant, and for all the other methods no statistically significant difference was observed. Conclusions If it is not possible to diagnose the root perforations by periapical radiographs, CBCT is the best radiographic technique while MDCT is not recommended. PMID:25671214

  14. Assessment of modified Blalock-Taussig shunt in children with congenital heart disease using multidetector-row computed tomography.

    PubMed

    Nabo, Manal Mohamed Helmy; Hayabuchi, Yasunobu; Inoue, Miki; Watanabe, Noriko; Sakata, Miho; Kagami, Shoji

    2010-11-01

    The purpose of this study was to assess the feasibility of multidetector-row computed tomography (MDCT) for the evaluation of modified Blalock-Taussig (B-T) shunt in children with congenital heart disease associated with reduced pulmonary blood flow. A total of 25 consecutive patients (mean age, 2.6 ± 3.6 years; range, 2 months-16 years) underwent MDCT angiography of the thorax with a 16-detector row scanner prior to cardiac catheterization. A total of 39 shunts (right, 22; left, 17) were included in the study. Conventional angiographic findings were used as the gold standard for the detection of B-T shunts. Shunt diameter was measured quantitatively and independently at four sites (the subclavian artery site, the pulmonary artery site, the widest site, and the stenotic site) on MDCT and on conventional invasive angiography. All B-T shunts were depicted on multiplanar reconstruction (MPR), maximum intensity projection (MIP), curved planar reconstruction (CPR), and three-dimensional volume-rendered (VR) images, enabling evaluation in all patients except for one with occluded shunt. There were excellent correlations between MDCT- and conventional angiography-based measurements of shunt diameter at the subclavian artery site, pulmonary artery site, and the widest site (R² = 0.46, 0.74 and 0.64, respectively; p < 0.0001 for each), although systematic overestimation was observed for MDCT (mean percentage of overestimation, 23.1 ± 32.4%). Stenotic site diameter and degree of stenosis showed a mild correlation (R² = 010 and 0.25, respectively; p < 0.01 for each). This study demonstrates that MDCT is a promising tool for the detection of lesions in B-T shunts.

  15. Greening America's Capitals - Hartford, CT

    EPA Pesticide Factsheets

    This Greening America's Capitals report gives Hartford, CT, a new vision for Capitol Avenue that highlights existing assets and fills in gaps along the mile-long area of focus and into the surrounding neighborhoods.

  16. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V. Jr.

    1986-01-01

    This is an illustrated text on computed tomography (CT) of the lumbar spine with an emphasis on the role and value of multiplanar imaging for helping determine diagnoses. The book has adequate discussion of scanning techniques for the different regions, interpretations of various abnormalities, degenerative disk disease, and different diagnoses. There is a 50-page chapter on detailed sectional anatomy of the spine and useful chapters on the postoperative spine and the planning and performing of spinal surgery with CT multiplanar reconstruction. There are comprehensive chapters on spinal tumors and trauma. The final two chapters of the book are devoted to CT image processing using digital networks and CT applications of medical computer graphics.

  17. CT Perfusion of the Head

    MedlinePlus

    ... ray beam follows a spiral path. A special computer program processes this large volume of data to create ... process. Nearly all CT scanners now have special computer programs that help to increase image quality at lower ...

  18. CT Demonstration of Caput Medusae

    ERIC Educational Resources Information Center

    Weber, Edward C.; Vilensky, Joel A.

    2009-01-01

    Maximum intensity and volume rendered CT displays of caput medusae are provided to demonstrate both the anatomy and physiology of this portosystemic shunt associated with portal hypertension. (Contains 2 figures.)

  19. Adrenal cortex dysfunction: CT findings

    SciTech Connect

    Huebener, K.H.; Treugut, H.

    1984-01-01

    The computed tomographic appearance of the adrenal gland was studied in 302 patients with possible endocrinologic disease and 107 patients undergoing CT for nonendocrinologic reasons. Measurements of adrenal size were also made in 100 adults with no known adrenal pathology. CT proved to be a sensitive diagnostic tool in combination with clinical studies. When blood hormone levels are increased, CT can differentiate among homogeneous organic hyperplasia, nodular hyperplasia, benign adenoma, and malignant cortical adenoma. When blood hormone levels are decreased, CT can demonstrate hypoplasia or metastatic tumorous destruction. Calcifications can be demonstrated earlier than on plain radiographs. When hormone elimination is increased, the morphologic substrate can be identified; tumorous changes can be localized and infiltration of surrounding organs recognized.

  20. Children's (Pediatric) CT (Computed Tomography)

    MedlinePlus Videos and Cool Tools

    ... What are the limitations of Children's CT? A person who is very large may not fit into ... facility staff and/or your insurance provider to get a better understanding of the possible charges you ...

  1. CT angiography - head and neck

    MedlinePlus

    ... medlineplus.gov/ency/article/007677.htm CT angiography - head and neck To use the sharing features on this page, ... create pictures of the blood vessels in the head and neck. How the Test is Performed You will be ...

  2. Multiplanar CT of the spine

    SciTech Connect

    Rothman, S.L.G.; Glenn, W.V.

    1985-01-01

    This book contains 16 chapters. Some of the topics are: CT of the Sacrum, The Postoperative Spine, Film Organizations and Case Reporting, Degeneration and Disc Disease of the Intervertebral Joint, Lumbar Spinal Stenosis, and Cervical and Thoracic Spine.

  3. A tonsillolith seen on CT.

    PubMed

    Espe, B J; Newmark, H

    1992-01-01

    A case of a large tonsillolith visualized by computerized tomography is presented. Although otolaryngologists are well aware of this entity, few radiologists are. The importance of distinguishing tonsilloliths from other structures by CT scan is discussed.

  4. Liver echinococcus - CT scan (image)

    MedlinePlus

    This upper abdominal CT scan shows multiple cysts in the liver, caused by dog tapeworm (echinococcus). Note the large circular cyst (seen on the left side of the screen) and multiple smaller cysts throughout ...

  5. WE-B-207-01: CT Lung Cancer Screening and the Medical Physicist: Background, Findings and Participant Dosimetry Summary of the National Lung Screening Trial (NLST)

    SciTech Connect

    Kruger, R.

    2015-06-15

    The US National Lung Screening Trial (NLST) was a multi-center randomized, controlled trial comparing a low-dose CT (LDCT) to posterior-anterior (PA) chest x-ray (CXR) in screening older, current and former heavy smokers for early detection of lung cancer. Recruitment was launched in September 2002 and ended in April 2004 when 53,454 participants had been randomized at 33 screening sites in equal proportions. Funded by the National Cancer Institute this trial demonstrated that LDCT screening reduced lung cancer mortality. The US Preventive Services Task Force (USPSTF) cited NLST findings and conclusions in its deliberations and analysis of lung cancer screening. Under the 2010 Patient Protection and Affordable Care Act, the USPSTF favorable recommendation regarding lung cancer CT screening assisted in obtaining third-party payers coverage for screening. The objective of this session is to provide an introduction to the NLST and the trial findings, in addition to a comprehensive review of the dosimetry investigations and assessments completed using individual NLST participant CT and CXR examinations. Session presentations will review and discuss the findings of two independent assessments, a CXR assessment and the findings of a CT investigation calculating individual organ dosimetry values. The CXR assessment reviewed a total of 73,733 chest x-ray exams that were performed on 92 chest imaging systems of which 66,157 participant examinations were used. The CT organ dosimetry investigation collected scan parameters from 23,773 CT examinations; a subset of the 75,133 CT examinations performed using 97 multi-detector CT scanners. Organ dose conversion coefficients were calculated using a Monte Carlo code. An experimentally-validated CT scanner simulation was coupled with 193 adult hybrid computational phantoms representing the height and weight of the current U.S. population. The dose to selected organs was calculated using the organ dose library and the abstracted scan

  6. Gd-EOB-DTPA-enhanced 3.0-Tesla MRI findings for the preoperative detection of focal liver lesions: Comparison with iodine-enhanced multi-detector computed tomography

    NASA Astrophysics Data System (ADS)

    Park, Hyong-Hu; Goo, Eun-Hoe; Im, In-Chul; Lee, Jae-Seung; Kim, Moon-Jib; Kwak, Byung-Joon; Chung, Woon-Kwan; Dong, Kyung-Rae

    2012-12-01

    The safety of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic-acid (Gd-EOB-DTPA) has been confirmed, but more study is needed to assess the diagnostic accuracy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) in patients with a hepatocellular carcinoma (HCC) for whom surgical treatment is considered or with a metastatic hepatoma. Research is also needed to examine the rate of detection of hepatic lesions compared to multi-detector computed tomography (MDCT), which is used most frequently to localize and characterize a HCC. Gd-EOB-DTPA-enhanced MRI and iodine-enhanced MDCT imaging were compared for the preoperative detection of focal liver lesions. The clinical usefulness of each method was examined. The current study enrolled 79 patients with focal liver lesions who preoperatively underwent MRI and MDCT. In these patients, there was less than one month between the two diagnostic modalities. Imaging data were taken before and after contrast enhancement in both methods. To evaluate the images, we analyzed the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) in the lesions and the liver parenchyma. To compare the sensitivity of the two methods, we performed a quantitative analysis of the percentage signal intensity of the liver (PSIL) on a high resolution picture archiving and communication system (PACS) monitor (paired-samples t-test, p < 0.05). The enhancement was evaluated based on a consensus of four observers. The enhancement pattern and the morphological features during the arterial and the delayed phases were correlated between the Gd-EOB-DTPA-enhanced MRI findings and the iodine-enhanced MDCT by using an adjusted x2 test. The SNRs, CNRs, and PSIL all had a greater detection rate in Gd-EOB-DTPA enhanced MRI than in iodine-enhanced MDCT. Hepatocyte-selective uptake was observed 20 minutes after the injection in the focal nodular hyperplasia (FNH, 9/9), adenoma (9/10), and highly-differentiated HCC (grade G1, 27/30). Rim

  7. Primary lower extremity lymphedema: CT diagnosis

    SciTech Connect

    Gamba, J.L.; Silverman, P.M.; Ling, D.; Dunnick, N.R.; Korobkin, M.

    1983-10-01

    The CT findings of two cases of primary lymphedema of the lower extremities are presented. CT showed a coarse, nonenhancing, reticular pattern in an enlarged subcutaneous compartment. CT excluded the diagnosis of secondary lymphedema from an obstructing mass by demonstrating a normal retroperitoneum and pelvis. The CT findings are correlated with pedal lymphangiograms.

  8. Primary epiploic appendagitis: CT diagnosis.

    PubMed

    Sandrasegaran, Kumaresan; Maglinte, Dean D; Rajesh, Arumugam; Akisik, Fatih M

    2004-08-01

    The purpose of this study was to analyze the CT signs of primary epiploic appendagitis. A retrospective search of the CT database over 12 months for this diagnosis revealed 11 cases. The clinical findings were recorded. Softcopy CT images were reviewed by two experienced abdominal radiologists (KS, DM) for location of lesion, size, shape, presence of central hyperdense focus, degree of bowel wall thickening, mass effect, and ancillary signs. Abdominal pain was the primary symptom in all patients. Preliminary diagnoses were appendicitis (n=2), diverticulitis (n=5), pancreatitis (n=1), ovarian lesion (n=1), or unknown (n=2). Abdominal examination and white blood cell count were uninformative. CT examination revealed a solitary (n=11), ovoid (n=9) fatty lesion with some soft tissue stranding adjacent to the left colon (n=6), transverse colon (n=3), or right colon (n=2). Central hyperdensity (n=5), mild bowel wall thickening (n=2), and parietal peritoneal thickening (n=4) were also seen. In 4 patients the lesions were not visible on follow-up CT examination performed 23-184 days later. Primary epiploic appendagitis can clinically mimic other, more serious inflammatory conditions. Knowledge of its findings on CT would help the radiologist make the diagnosis and allow a more conservative approach to patient care.

  9. Pentalogy of Cantrell with Ectopia Cordis: CT Findings.

    PubMed

    Pirasteh, Ali; Carcano, Carolina; Kirsch, Jacobo; Mohammed, Tan-Lucien H

    2014-12-01

    A 14-month-old girl with pentalogy of Cantrell, a very rare congenital syndrome characterized by an epigastric omphalocele and malformations of the heart, sternum, pericardium, and diaphragm, underwent echocardiography and multidetector computed tomography before surgical repair of these deformities was attempted. These tests revealed multiple cardiovascular and noncardiovascular abnormalities. After surgery, the patient's cardiovascular status was stable. Although studies have shown that echocardiography, multidetector computed tomography, and magnetic resonance imaging may each play a role in the diagnosis and management of this condition, there are few data available to support the use of one imaging modality over another.

  10. Pentalogy of Cantrell with Ectopia Cordis: CT Findings

    PubMed Central

    Pirasteh, Ali; Carcano, Carolina; Kirsch, Jacobo; Mohammed, Tan-Lucien H.

    2014-01-01

    A 14-month-old girl with pentalogy of Cantrell, a very rare congenital syndrome characterized by an epigastric omphalocele and malformations of the heart, sternum, pericardium, and diaphragm, underwent echocardiography and multidetector computed tomography before surgical repair of these deformities was attempted. These tests revealed multiple cardiovascular and noncardiovascular abnormalities. After surgery, the patient’s cardiovascular status was stable. Although studies have shown that echocardiography, multidetector computed tomography, and magnetic resonance imaging may each play a role in the diagnosis and management of this condition, there are few data available to support the use of one imaging modality over another. PMID:25926914

  11. Gender Differences of Airway Dimensions in Anatomically Matched Sites on CT in Smokers

    PubMed Central

    Kim, Yu-Il; Schroeder, Joyce; Lynch, David; Newell, John; Make, Barry; Friedlander, Adam; Estépar, Raúl San José; Hanania, Nicola A.; Washko, George; Murphy, James R.; Wilson, Carla; Hokanson, John E.; Zach, Jordan; Butterfield, Kiel; Bowler, Russell P.

    2013-01-01

    Rationale and Objectives There are limited data on, and controversies regarding gender differences in the airway dimensions of smokers. Multi-detector CT (MDCT) images were analyzed to examine whether gender could explain differences in airway dimensions of anatomically matched airways in smokers. Materials and Methods We used VIDA imaging software to analyze MDCT scans from 2047 smokers (M:F, 1021:1026) from the COPDGene® cohort. The airway dimensions were analyzed from segmental to subsubsegmental bronchi. We compared the differences of luminal area, inner diameter, wall thickness, wall area percentage (WA%) for each airway between men and women, and multiple linear regression including covariates (age, gender, body sizes, and other relevant confounding factors) was used to determine the predictors of each airway dimensions. Results Lumen area, internal diameter and wall thickness were smaller for women than men in all measured airway (18.4 vs 22.5 mm2 for segmental bronchial lumen area, 10.4 vs 12.5 mm2 for subsegmental bronchi, 6.5 vs 7.7 mm2 for subsubsegmental bronchi, respectively p < 0.001). However, women had greater WA% in subsegmental and subsubsegmental bronchi. In multivariate regression, gender remained one of the most significant predictors of WA%, lumen area, inner diameter and wall thickness. Conclusion Women smokers have higher WA%, but lower luminal area, internal diameter and airway thickness in anatomically matched airways as measured by CT scan than do male smokers. This difference may explain, in part, gender differences in the prevalence of COPD and airflow limitation. PMID:21756032

  12. Regularization design for high-quality cone-beam CT of intracranial hemorrhage using statistical reconstruction

    NASA Astrophysics Data System (ADS)

    Dang, H.; Stayman, J. W.; Xu, J.; Sisniega, A.; Zbijewski, W.; Wang, X.; Foos, D. H.; Aygun, N.; Koliatsos, V. E.; Siewerdsen, J. H.

    2016-03-01

    Intracranial hemorrhage (ICH) is associated with pathologies such as hemorrhagic stroke and traumatic brain injury. Multi-detector CT is the current front-line imaging modality for detecting ICH (fresh blood contrast 40-80 HU, down to 1 mm). Flat-panel detector (FPD) cone-beam CT (CBCT) offers a potential alternative with a smaller scanner footprint, greater portability, and lower cost potentially well suited to deployment at the point of care outside standard diagnostic radiology and emergency room settings. Previous studies have suggested reliable detection of ICH down to 3 mm in CBCT using high-fidelity artifact correction and penalized weighted least-squared (PWLS) image reconstruction with a post-artifact-correction noise model. However, ICH reconstructed by traditional image regularization exhibits nonuniform spatial resolution and noise due to interaction between the statistical weights and regularization, which potentially degrades the detectability of ICH. In this work, we propose three regularization methods designed to overcome these challenges. The first two compute spatially varying certainty for uniform spatial resolution and noise, respectively. The third computes spatially varying regularization strength to achieve uniform "detectability," combining both spatial resolution and noise in a manner analogous to a delta-function detection task. Experiments were conducted on a CBCT test-bench, and image quality was evaluated for simulated ICH in different regions of an anthropomorphic head. The first two methods improved the uniformity in spatial resolution and noise compared to traditional regularization. The third exhibited the highest uniformity in detectability among all methods and best overall image quality. The proposed regularization provides a valuable means to achieve uniform image quality in CBCT of ICH and is being incorporated in a CBCT prototype for ICH imaging.

  13. SU-E-I-24: Method for CT Automatic Exposure Control Verification

    SciTech Connect

    Gracia, M; Olasolo, J; Martin, M; Bragado, L; Gallardo, N; Miquelez, S; Maneru, F; Lozares, S; Pellejero, S; Rubio, A

    2015-06-15

    Purpose: Design of a phantom and a simple method for the automatic exposure control (AEC) verification in CT. This verification is included in the computed tomography (CT) Spanish Quality Assurance Protocol. Methods: The phantom design is made from the head and the body phantom used for the CTDI measurement and PMMA plates (35×35 cm2) of 10 cm thickness. Thereby, three different thicknesses along the longitudinal axis are obtained which permit to evaluate the longitudinal AEC performance. Otherwise, the existent asymmetry in the PMMA layers helps to assess angular and 3D AEC operation.Recent acquisition in our hospital (August 2014) of Nomex electrometer (PTW), together with the 10 cm pencil ionization chamber, led to register dose rate as a function of time. Measurements with this chamber fixed at 0° and 90° on the gantry where made on five multidetector-CTs from principal manufacturers. Results: Individual analysis of measurements shows dose rate variation as a function of phantom thickness. The comparative analysis shows that dose rate is kept constant in the head and neck phantom while the PMMA phantom exhibits an abrupt variation between both results, being greater results at 90° as the thickness of the phantom is 3.5 times larger than in the perpendicular direction. Conclusion: Proposed method is simple, quick and reproducible. Results obtained let a qualitative evaluation of the AEC and they are consistent with the expected behavior. A line of future development is to quantitatively study the intensity modulation and parameters of image quality, and a possible comparative study between different manufacturers.

  14. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

  15. Assessment of regional ventilation and deformation using 4D-CT imaging for healthy human lungs during tidal breathing.

    PubMed

    Jahani, Nariman; Choi, Sanghun; Choi, Jiwoong; Iyer, Krishna; Hoffman, Eric A; Lin, Ching-Long

    2015-11-15

    This study aims to assess regional ventilation, nonlinearity, and hysteresis of human lungs during dynamic breathing via image registration of four-dimensional computed tomography (4D-CT) scans. Six healthy adult humans were studied by spiral multidetector-row CT during controlled tidal breathing as well as during total lung capacity and functional residual capacity breath holds. Static images were utilized to contrast static vs. dynamic (deep vs. tidal) breathing. A rolling-seal piston system was employed to maintain consistent tidal breathing during 4D-CT spiral image acquisition, providing required between-breath consistency for physiologically meaningful reconstructed respiratory motion. Registration-derived variables including local air volume and anisotropic deformation index (ADI, an indicator of preferential deformation in response to local force) were employed to assess regional ventilation and lung deformation. Lobar distributions of air volume change during tidal breathing were correlated with those of deep breathing (R(2) ≈ 0.84). Small discrepancies between tidal and deep breathing were shown to be likely due to different distributions of air volume change in the left and the right lungs. We also demonstrated an asymmetric characteristic of flow rate between inhalation and exhalation. With ADI, we were able to quantify nonlinearity and hysteresis of lung deformation that can only be captured in dynamic images. Nonlinearity quantified by ADI is greater during inhalation, and it is stronger in the lower lobes (P < 0.05). Lung hysteresis estimated by the difference of ADI between inhalation and exhalation is more significant in the right lungs than that in the left lungs.

  16. Assessment of regional ventilation and deformation using 4D-CT imaging for healthy human lungs during tidal breathing

    PubMed Central

    Jahani, Nariman; Choi, Jiwoong; Iyer, Krishna; Hoffman, Eric A.

    2015-01-01

    This study aims to assess regional ventilation, nonlinearity, and hysteresis of human lungs during dynamic breathing via image registration of four-dimensional computed tomography (4D-CT) scans. Six healthy adult humans were studied by spiral multidetector-row CT during controlled tidal breathing as well as during total lung capacity and functional residual capacity breath holds. Static images were utilized to contrast static vs. dynamic (deep vs. tidal) breathing. A rolling-seal piston system was employed to maintain consistent tidal breathing during 4D-CT spiral image acquisition, providing required between-breath consistency for physiologically meaningful reconstructed respiratory motion. Registration-derived variables including local air volume and anisotropic deformation index (ADI, an indicator of preferential deformation in response to local force) were employed to assess regional ventilation and lung deformation. Lobar distributions of air volume change during tidal breathing were correlated with those of deep breathing (R2 ≈ 0.84). Small discrepancies between tidal and deep breathing were shown to be likely due to different distributions of air volume change in the left and the right lungs. We also demonstrated an asymmetric characteristic of flow rate between inhalation and exhalation. With ADI, we were able to quantify nonlinearity and hysteresis of lung deformation that can only be captured in dynamic images. Nonlinearity quantified by ADI is greater during inhalation, and it is stronger in the lower lobes (P < 0.05). Lung hysteresis estimated by the difference of ADI between inhalation and exhalation is more significant in the right lungs than that in the left lungs. PMID:26316512

  17. Dose reduction assessment in dynamic CT myocardial perfusion imaging in a porcine balloon-induced-ischemia model

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    We investigated the use of an advanced hybrid iterative reconstruction (IR) technique (iDose4, Philips Health- care) for low dose dynamic myocardial CT perfusion (CTP) imaging. A porcine model was created to mimic coronary stenosis through partial occlusion of the left anterior descending (LAD) artery with a balloon catheter. The severity of LAD occlusion was adjusted with FFR measurements. Dynamic CT images were acquired at end-systole (45% R-R) using a multi-detector CT (MDCT) scanner. Various corrections were applied to the acquired scans to reduce motion and imaging artifacts. Absolute myocardial blood flow (MBF) was computed with a deconvolution-based approach using singular value decomposition (SVD). We compared a high and a low dose radiation protocol corresponding to two different tube-voltage/tube-current combinations (80kV p/100mAs and 120kV p/150mAs). The corresponding radiation doses for these protocols are 7.8mSv and 34.3mSV , respectively. The images were reconstructed using conventional FBP and three noise-reduction strengths of the IR method, iDose. Flow contrast-to-noise ratio, CNRf, as obtained from MBF maps, was used to quantitatively evaluate the effect of reconstruction on contrast between normal and ischemic myocardial tissue. Preliminary results showed that the use of iDose to reconstruct low dose images provide better or comparable CNRf to that of high dose images reconstructed with FBP, suggesting significant dose savings. CNRf was improved with the three used levels of iDose compared to FBP for both protocols. When using the entire 4D dynamic sequence for MBF computation, a 77% dose reduction was achieved, while considering only half the scans (i.e., every other heart cycle) allowed even further dose reduction while maintaining relatively higher CNRf.

  18. Topomorphologic Separation of Fused Isointensity Objects via Multiscale Opening: Separating Arteries and Veins in 3-D Pulmonary CT

    PubMed Central

    Gao, Zhiyun; Alford, Sara K.; Sonka, Milan; Hoffman, Eric A.

    2015-01-01

    A novel multiscale topomorphologic approach for opening of two isointensity objects fused at different locations and scales is presented and applied to separating arterial and venous trees in 3-D pulmonary multidetector X-ray computed tomography (CT) images. Initialized with seeds, the two isointensity objects (arteries and veins) grow iteratively while maintaining their spatial exclusiveness and eventually form two mutually disjoint objects at convergence. The method is intended to solve the following two fundamental challenges: how to find local size of morphological operators and how to trace continuity of locally separated regions. These challenges are met by combining fuzzy distance transform (FDT), a morphologic feature with a topologic fuzzy connectivity, and a new morphological reconstruction step to iteratively open finer and finer details starting at large scales and progressing toward smaller scales. The method employs efficient user intervention at locations where local morphological separability assumption does not hold due to imaging ambiguities or any other reason. The approach has been validated on mathematically generated tubular objects and applied to clinical pulmonary noncontrast CT data for separating arteries and veins. The tradeoff between accuracy and the required user intervention for the method has been quantitatively examined by comparing with manual outlining. The experimental study, based on a blind seed selection strategy, has demonstrated that above 95% accuracy may be achieved using 25–40 seeds for each of arteries and veins. Our method is very promising for semiautomated separation of arteries and veins in pulmonary CT images even when there is no object-specific intensity variation at conjoining locations. PMID:20199919

  19. Bone Mineral Density Estimations From Routine Multidetector Computed Tomography: A Comparative Study of Contrast and Calibration Effects

    PubMed Central

    Kaesmacher, Johannes; Liebl, Hans; Baum, Thomas; Kirschke, Jan Stefan

    2017-01-01

    Introduction Phantom-based (synchronous and asynchronous) and phantomless (internal tissue calibration based) assessment of bone mineral density (BMD) in routine MDCT (multidetector computed tomography) examinations potentially allows for diagnosis of osteoporosis. Although recent studies investigated the effects of contrast-medium application on phantom-calibrated BMD measurements, it remains uncertain to what extent internal tissue-calibrated BMD measurements are also susceptible to contrast-medium associated density variation. The present study is the first to systemically evaluate BMD variations related to contrast application comparing different calibration techniques. Purpose To compare predicative performance of different calibration techniques for BMD measurements obtained from triphasic contrast-enhanced MDCT. Materials and Methods Bone mineral density was measured on nonenhanced (NE), arterial (AR) and portal-venous (PV) contrast phase MDCT images of 46 patients using synchronous (SYNC) and asynchronous (ASYNC) phantom calibration as well as internal calibration (IC). Quantitative computed tomography (QCT) served as criterion standard. Density variations were analyzed for each contrast phase and calibration technique, and respective linear fitting was performed. Results Both asynchronous calibration-derived BMD values (NE-ASYNC) and values estimated using IC (NE-IC) on NE MDCT images did reasonably well in predicting QCT BMD (root-mean-square deviation, 8.0% and 7.8%, respectively). Average NE-IC BMD was 2.7% lower when compared with QCT (P = 0.017), whereas no difference could be found for NE-ASYNC (P = 0.957). All average BMD estimates derived from contrast-enhanced scans differed significantly from QCT BMD (all P < 0.005) and led to notable systemic BMD biases (mean difference at least > 6.0 mg/mL). All regression fits revealed a consistent linear dependency (R2 range, 0.861–0.963). Overall accuracy and goodness of fit tended to decrease from AR to

  20. Malignant external otitis: CT evaluation

    SciTech Connect

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

    1982-11-01

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

  1. Diagnostic accuracy of sub-mSv prospective ECG-triggering cardiac CT in young infant with complex congenital heart disease.

    PubMed

    Gao, Wei; Zhong, Yu Min; Sun, Ai Min; Wang, Qian; Ouyang, Rong Zhen; Hu, Li Wei; Qiu, Han Sheng; Wang, Shi Yu; Li, Jian Ying

    2016-06-01

    To explore the clinical value and evaluate the diagnostic accuracy of sub-mSv low-dose prospective ECG-triggering cardiac CT (CCT) in young infants with complex congenital heart disease (CHD). A total of 102 consecutive infant patients (53 boys and 49 girls with mean age of 2.9 ± 2.4 m and weight less than 5 kg) with complex CHD were prospectively enrolled. Scans were performed on a 64-slice high definition CT scanner with low dose prospective ECG-triggering mode and reconstructed with 80 % adaptive statistical iterative reconstruction algorithm. All studies were performed during free breathing with sedation. The subjective image quality was evaluated by 5-point grading scale and interobserver variability was calculated. The objective image noise (standard deviation, SD) and contrast to noise ratio (CNR) was calculated. The effective radiation dose from the prospective ECG-triggering mode was recorded and compared with the virtual conventional retrospective ECG-gating mode. The detection rate for the origin of coronary artery was calculated. All patients also underwent echocardiography before CCT examination. 81 patients had surgery and their preoperative CCT and echocardiography findings were compared with the surgical results and sensitivity, specificity, positive and negative predictive values and accuracy were calculated for separate cardiovascular anomalies. Heart rates were 70-161 beats per minute (bpm) with mean value of 129.19 ± 14.52 bpm. The effective dose of 0.53 ± 0.15 mSv in the prospective ECG-triggering cardiac CT was lower than the calculated value in a conventional retrospective ECG-gating mode (2.00 ± 0.35 mSv) (p < 0.001). The mean CNR and SD were 28.19 ± 13.00 and 15.75 ± 3.61HU, respectively. The image quality scores were 4.31 ± 0.36 and 4.29 ± 0.41 from reviewer 1 and 2 respectively with an excellent agreement between them (Kappa = 0.85). The detection rate for the origins of the left and right coronary

  2. [Gallstone ileus. Abdominal CT usefulness].

    PubMed

    Sukkarieh, F; Brasseur, P; Bissen, L

    2004-06-01

    The authors report the case of a 93-year old woman referred to the emergency department and presenting with an intestinal obstruction. Abdominal CT reveals a biliary ileus caused by the migration and the impaction of a 3 cm gallstone in the small bowel. Surgical treatment by enterolithotomy was successful. In over 90% of cases, gallstone ileus is a complication of cholelithiasis and accounts for 25% of intestinal obstruction in patients over 65 years. To reduce morbidity and mortality, early diagnosis and prompt treatment are essential. Abdominal CT-scan is the gold standard technique.

  3. Granulocytic sarcoma (chloroma): CT manifestations

    SciTech Connect

    Pomeranz, S.J.; Hawkins, H.H.; Towbin, R.; Lisberg, W.N.; Clark, R.A.

    1985-04-01

    Nests of granulocytic tumor cells in patients who have myelogeneous leukemia are termed chloromas. Eight cases of chloroma seen on CT were reviewed. Lymph nodes, subcutaneous tissues, peritoneum, pleural space, pelvis, and portal hepatis were involved. The extracranial appearance of chloroma on CT is that of small, nonenhancing, nodular densities that resemble lymphoma. Cranial involvement is characteristically in the orbit. The central nervous system appearance is variable, however, and high attenuation masses may occur that mimic lymphoma, hematoma, and metastatic neuroblastoma. The recognition of these lesions is important, since radiation, not chemotherapy, is often the preferred treatment for localized chloroma.

  4. Ontological analysis of SNOMED CT

    PubMed Central

    Héja, Gergely; Surján, György; Varga, Péter

    2008-01-01

    Background SNOMED CT is the most comprehensive medical terminology. However, its use for intelligent services based on formal reasoning is questionable. Methods The analysis of the structure of SNOMED CT is based on the formal top-level ontology DOLCE. Results The analysis revealed several ontological and knowledge-engineering errors, the most important are errors in the hierarchy (mostly from an ontological point of view, but also regarding medical aspects) and the mixing of subsumption relations with other types (mostly 'part of'). Conclusion The found errors impede formal reasoning. The paper presents a possible way to correct these problems. PMID:19007445

  5. PET/CT in radiation oncology

    SciTech Connect

    Pan, Tinsu; Mawlawi, Osama

    2008-11-15

    PET/CT is an effective tool for the diagnosis, staging and restaging of cancer patients. It combines the complementary information of functional PET images and anatomical CT images in one imaging session. Conventional stand-alone PET has been replaced by PET/CT for improved patient comfort, patient throughput, and most importantly the proven clinical outcome of PET/CT over that of PET and that of separate PET and CT. There are over two thousand PET/CT scanners installed worldwide since 2001. Oncology is the main application for PET/CT. Fluorine-18 deoxyglucose is the choice of radiopharmaceutical in PET for imaging the glucose uptake in tissues, correlated with an increased rate of glycolysis in many tumor cells. New molecular targeted agents are being developed to improve the accuracy of targeting different disease states and assessing therapeutic response. Over 50% of cancer patients receive radiation therapy (RT) in the course of their disease treatment. Clinical data have demonstrated that the information provided by PET/CT often changes patient management of the patient and/or modifies the RT plan from conventional CT simulation. The application of PET/CT in RT is growing and will become increasingly important. Continuing improvement of PET/CT instrumentation will also make it easier for radiation oncologists to integrate PET/CT in RT. The purpose of this article is to provide a review of the current PET/CT technology, to project the future development of PET and CT for PET/CT, and to discuss some issues in adopting PET/CT in RT and potential improvements in PET/CT simulation of the thorax in radiation therapy.

  6. Low-dose interpolated average CT for attenuation correction in cardiac PET/CT

    NASA Astrophysics Data System (ADS)

    Wu, Tung-Hsin; Zhang, Geoffrey; Wang, Shyh-Jen; Chen, Chih-Hao; Yang, Bang-Hung; Wu, Nien-Yun; Huang, Tzung-Chi

    2010-07-01

    Because of the advantages in the use of high photon flux and thus the short scan times of CT imaging, the traditional 68Ge scans for positron emission tomography (PET) image attenuation correction have been replaced by CT scans in the modern PET/CT technology. The combination of fast CT scan and slow PET scan often causes image misalignment between the PET and CT images due to respiration motion. Use of the average CT derived from cine CT images is reported to reduce such misalignment. However, the radiation dose to patients is higher with cine CT scans. This study introduces a method that uses breath-hold CT images and their interpolations to generate the average CT for PET image attenuation correction. Breath-hold CT sets are taken at end-inspiration and end-expiration. Deformable image registration is applied to generate a voxel-to-voxel motion matrix between the two CT sets. The motion is equally divided into 5 steps from inspiration to expiration and 5 steps from expiration to inspiration, generating a total of 8 phases of interpolated CT sets. An average CT image is generated from all the 10 phase CT images, including original inhale/exhale CT and 8 interpolated CT sets. Quantitative comparison shows that the reduction of image misalignment artifacts using the average CT from the interpolation technique for PET attenuation correction is at a similar level as that using cine average CT, while the dose to the patient from the CT scans is reduced significantly. The interpolated average CT method hence provides a low dose alternative to cine CT scans for PET attenuation correction.

  7. CT angiography - arms and legs

    MedlinePlus

    ... combines a CT scan with the injection of dye. This technique is able to create pictures of ... Some exams require a special dye, called contrast, to be injected into your body before the test. Contrast helps certain areas show up better on the x- ...

  8. Pocket atlas of normal CT anatomy

    SciTech Connect

    Weinstein, J.B.; Lee, J.K.T.; Sagel, S.S.

    1985-01-01

    This book is a quick reference for interpreting CT scans of the extracranial organs. This collection of 41 CT scans covers all the major organs of the body: neck and larynx; chest; abdomen; male pelvis; and female pelvis.

  9. Abdominal CT findings in small bowel perforation.

    PubMed

    Zissin, R; Osadchy, A; Gayer, G

    2009-02-01

    Small bowel perforation is an emergent medical condition for which the diagnosis is usually not made clinically but by CT, a common imaging modality used for the diagnosis of acute abdomen. Direct CT features that suggest perforation include extraluminal air and oral contrast, which are often associated with secondary CT signs of bowel pathology. This pictorial review illustrates the CT findings of small bowel perforation caused by various clinical entities.

  10. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... الأشعة المقطعية الحاسوبية - العربية Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) CT (Computerized Tomography) Scan CT ( ... 扫描 - 简体中文 (Chinese - Simplified) Bilingual PDF Health Information Translations Chinese - Traditional (繁體中文) CT (Computerized Tomography) Scan CT ( ...

  11. Three-dimensional multidetector computed tomography may aid preoperative planning of the transmanubrial osteomuscular-sparing approach to completely resect superior sulcus tumor.

    PubMed

    Saji, Hisashi; Kato, Yasufumi; Shimada, Yoshihisa; Kudo, Yujin; Hagiwara, Masaru; Matsubayashi, Jun; Nagao, Toshitaka; Ikeda, Norihiko

    2015-11-01

    The anterior transcervical-thoracic approach clearly exposes the subclavian vessels and brachial plexus. We believe that this approach is optimal when a superior sulcus tumor (SST) invades the anterior part of the thoracic inlet. However, this approach is not yet widely applied because anatomical relationships in this procedure are difficult to visualize. Three-dimensional tomography can considerably improve preoperative planning, enhance the surgeon's skill and simplify the approach to complex surgical procedures. We applied preoperative 3-dimensional multidetector computed tomography to a case where an SST had invaded the anterior part of the thoracic inlet including the clavicle, sternoclavicular joint, first rib, subclavian vessels and brachial plexus. After the patient underwent induction chemotherapy, we performed the transmanubrial osteomuscular-sparing approach and added a third anterolateral thoracotomy with a hemi-clamshell incision and completely resected the tumor.

  12. Dataset of calcified plaque condition in the stenotic coronary artery lesion obtained using multidetector computed tomography to indicate the addition of rotational atherectomy during percutaneous coronary intervention.

    PubMed

    Akutsu, Yasushi; Hamazaki, Yuji; Sekimoto, Teruo; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Suyama, Jumpei; Gokan, Takehiko; Sakai, Koshiro; Kosaki, Ryota; Yokota, Hiroyuki; Tsujita, Hiroaki; Tsukamoto, Shigeto; Sakurai, Masayuki; Sambe, Takehiko; Oguchi, Katsuji; Uchida, Naoki; Kobayashi, Shinichi; Aoki, Atsushi; Kobayashi, Youichi

    2016-06-01

    Our data shows the regional coronary artery calcium scores (lesion CAC) on multidetector computed tomography (MDCT) and the cross-section imaging on MDCT angiography (CTA) in the target lesion of the patients with stable angina pectoris who were scheduled for percutaneous coronary intervention (PCI). CAC and CTA data were measured using a 128-slice scanner (Somatom Definition AS+; Siemens Medical Solutions, Forchheim, Germany) before PCI. CAC was measured in a non-contrast-enhanced scan and was quantified using the Calcium Score module of SYNAPSE VINCENT software (Fujifilm Co. Tokyo, Japan) and expressed in Agatston units. CTA were then continued with a contrast-enhanced ECG gating to measure the severity of the calcified plaque condition. We present that both CAC and CTA data are used as a benchmark to consider the addition of rotational atherectomy during PCI to severely calcified plaque lesions.

  13. Dataset of calcified plaque condition in the stenotic coronary artery lesion obtained using multidetector computed tomography to indicate the addition of rotational atherectomy during percutaneous coronary intervention

    PubMed Central

    Akutsu, Yasushi; Hamazaki, Yuji; Sekimoto, Teruo; Kaneko, Kyouichi; Kodama, Yusuke; Li, Hui-Ling; Suyama, Jumpei; Gokan, Takehiko; Sakai, Koshiro; Kosaki, Ryota; Yokota, Hiroyuki; Tsujita, Hiroaki; Tsukamoto, Shigeto; Sakurai, Masayuki; Sambe, Takehiko; Oguchi, Katsuji; Uchida, Naoki; Kobayashi, Shinichi; Aoki, Atsushi; Kobayashi, Youichi

    2016-01-01

    Our data shows the regional coronary artery calcium scores (lesion CAC) on multidetector computed tomography (MDCT) and the cross-section imaging on MDCT angiography (CTA) in the target lesion of the patients with stable angina pectoris who were scheduled for percutaneous coronary intervention (PCI). CAC and CTA data were measured using a 128-slice scanner (Somatom Definition AS+; Siemens Medical Solutions, Forchheim, Germany) before PCI. CAC was measured in a non-contrast-enhanced scan and was quantified using the Calcium Score module of SYNAPSE VINCENT software (Fujifilm Co. Tokyo, Japan) and expressed in Agatston units. CTA were then continued with a contrast-enhanced ECG gating to measure the severity of the calcified plaque condition. We present that both CAC and CTA data are used as a benchmark to consider the addition of rotational atherectomy during PCI to severely calcified plaque lesions. PMID:26977441

  14. Surgically Cured, Relapsed Pneumococcal Meningitis Due to Bone Defects, Non-invasively Identified by Three-dimensional Multi-detector Computed Tomography

    PubMed Central

    Akimoto, Takayoshi; Morita, Akihiko; Shiobara, Keiji; Hara, Makoto; Minami, Masayuki; Shijo, Katsunori; Nomura, Yasuyuki; Shigihara, Shuntaro; Haradome, Hiroki; Abe, Osamu; Kamei, Satoshi

    2016-01-01

    A 43-year-old Japanese man presented with a history of bacterial meningitis (BM). He was admitted to our department with a one-day history of headache and was diagnosed with relapse of BM based on the cerebrospinal fluid findings. The conventional imaging studies showed serial findings suggesting left otitis media, a temporal cephalocele, and meningitis. Three-dimensional multi-detector computed tomography (3D-MDCT) showed left petrous bone defects caused by the otitis media, and curative surgical treatment was performed. Skull bone structural abnormalities should be considered a cause of relapsed BM. 3D-MDCT was useful for revealing the causal minimal bone abnormality and performing pre-surgical mapping. PMID:27980270

  15. SU-F-207-03: Dosimetric Effect of the Position of Arms in Torso CT Scan with Tube Current Modulation

    SciTech Connect

    Liu, H; Gao, Y; Xu, X; Zhuo, W; Wu, J

    2015-06-15

    Purpose: To evaluate the patient organ dose differences between the arms-raised and arms-lowered postures in Torso multidetector computed tomography (MDCT) scan protocols with tube current modulation (TCM). Methods: Patient CT organ doses were simulated using the Monte Carlo method with human phantoms and a validated CT scanner model. A set of adult human phantoms with arms raised and arms lowered postures were developed using advanced BREP-based mesh surface geometries. Organ doses from routine Torso scan protocols such as chest, abdomen-pelvis, and CAP scans were simulated. The organ doses differences caused by two different posutres were investigated when tube current modulation (TCM) were applied during the CT scan. Results: With TCM applied, organ doses of all the listed organs of arms-lowered posture phantom are larger than those of arms raised phantom. The dose difference for most of the organs or tissues are larger than 50%, and the skin doses difference for abdomen-pelvis scan even reaches 112.03%. This is due to the fact that the tube current for patient with arms-lowered is much higher than for the arms raised posture. Conclusion: Considering CT scan with TCM, which is commonly applied clinically, patients who could not raise their arms will receive higher radiation dose than the arms raised patient, with dose differences for some tissues such as the skin being larger than 100%. This is due to the additional tube current necessary to penetrate the arms while maintaining consistent image quality. National Nature Science Foundation of China(No.11475047)

  16. Dose coefficients in pediatric and adult abdominopelvic CT based on 100 patient models

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Recent studies have shown the feasibility of estimating patient dose from a CT exam using CTDIvol-normalized-organ dose (denoted as h), DLP-normalized-effective dose (denoted as k), and DLP-normalized-risk index (denoted as q). However, previous studies were limited to a small number of phantom models. The purpose of this work was to provide dose coefficients (h, k, and q) across a large number of computational models covering a broad range of patient anatomy, age, size percentile, and gender. The study consisted of 100 patient computer models (age range, 0 to 78 y.o.; weight range, 2-180 kg) including 42 pediatric models (age range, 0 to 16 y.o.; weight range, 2-80 kg) and 58 adult models (age range, 18 to 78 y.o.; weight range, 57-180 kg). Multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare) were included. A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which h, k, and q were derived. The relationships between h, k, and q and patient characteristics (size, age, and gender) were ascertained. The differences in conversion coefficients across the scanners were further characterized. CTDIvol-normalized-organ dose (h) showed an exponential decrease with increasing patient size. For organs within the image coverage, the average differences of h across scanners were less than 15%. That value increased to 29% for organs on the periphery or outside the image coverage, and to 8% for distributed organs, respectively. The DLP-normalized-effective dose (k) decreased exponentially with increasing patient size. For a given gender, the DLP-normalized-risk index (q) showed an exponential decrease with both increasing patient size and patient age. The average differences in k and q across scanners were 8% and 10%, respectively. This study demonstrated that the knowledge of patient information and CTDIvol/DLP values may

  17. Reduction of image noise in low tube current dynamic CT myocardial perfusion imaging using HYPR processing: A time-attenuation curve analysis

    PubMed Central

    Speidel, Michael A.; Bateman, Courtney L.; Tao, Yinghua; Raval, Amish N.; Hacker, Timothy A.; Reeder, Scott B.; Van Lysel, Michael S.

    2013-01-01

    Purpose: This study describes a HighlY constrained backPRojection (HYPR) image processing method for the reduction of image noise in low tube current time-resolved CT myocardial perfusion scans. The effect of this method on myocardial time-attenuation curve noise and fidelity is evaluated in an animal model, using varying levels of tube current. Methods: CT perfusion scans of four healthy pigs (42–59 kg) were acquired at 500, 250, 100, 50, 25, and 10 mA on a 64-slice scanner (4 cm axial coverage, 120 kV, 0.4 s/rotation, 50 s scan duration). For each scan a sequence of ECG-gated images centered on 75% R-R was reconstructed using short-scan filtered back projection (FBP). HYPR processing was applied to the scans acquired at less than 500 mA using parameters designed to maintain the voxel noise level in the 500-mA FBP images. The processing method generates a series of composite images by averaging over a sliding time window and then multiplies the composite images by weighting images to restore temporal fidelity to the image sequence. HYPR voxel noise relative to FBP noise was measured in AHA myocardial segment numbers 1, 5, 6, and 7 at each mA. To quantify the agreement between HYPR and FBP time-attenuation curves (TACs), Bland-Altman analysis was performed on TACs measured in full myocardial segments. The relative degree of TAC fluctuation in smaller subvolumes was quantified by calculating the root mean square deviation of a TAC about the gamma variate curve fit to the TAC data. Results: HYPR image sequences were produced using 2, 7, and 20 beat composite windows for the 250, 100, and 50 mA scans, respectively. At 25 and 10 mA, all available beats were used in the composite (41–60; average 50). A 7-voxel-wide 3D cubic filter kernel was used to form weighting images. The average ratio of HYPR voxel noise to 500-mA FBP voxel noise was 1.06, 1.10, 0.97, 1.11, and 2.15 for HYPR scans at 250, 100, 50, 25, and 10 mA. The average limits-of-agreement between HYPR and

  18. Cervical tuberculous adenitis: CT manifestations

    SciTech Connect

    Reede, D.L.; Bergeron, R.T.

    1985-03-01

    Cervical tuberculous adenitis is being seen with increasing frequency in the United States; in the appropriate clinical setting it should be included in the differential diagnosis of an asymptomatic neck mass. Patients are typically young adults who are recent arrivals from Southeast Asia. A history of tuberculosis is not always elicited nor is the chest radiograph always abnormal. All of these patients have positive purified protein derivative tests unless they are anergic. The CT findings may lead to the diagnosis. Several CT patterns of nodal disease can be seen in tuberculous adenitis; some may mimic benign and neoplastic disease. The presence of a multiloculated or multichambered (conglomerate nodal) mass with central lucency and thick rims of enhancement and minimally effaced fascial planes is highly suggestive of tuberculous adenitis, especially if the patient has a strongly positive tuberculosis skin test.

  19. Dual energy CT for attenuation correction with PET/CT

    SciTech Connect

    Xia, Ting; Alessio, Adam M.; Kinahan, Paul E.

    2014-01-15

    Purpose: The authors evaluate the energy dependent noise and bias properties of monoenergetic images synthesized from dual-energy CT (DECT) acquisitions. These monoenergetic images can be used to estimate attenuation coefficients at energies suitable for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging. This is becoming more relevant with the increased use of quantitative imaging by PET/CT and SPECT/CT scanners. There are, however, potential variations in the noise and bias of synthesized monoenergetic images as a function of energy. Methods: The authors used analytic approximations and simulations to estimate the noise and bias of synthesized monoenergetic images of water-filled cylinders with different shapes and the NURBS-based cardiac-torso (NCAT) phantom from 40 to 520 keV, the range of SPECT and PET energies. The dual-kVp spectra were based on the GE Lightspeed VCT scanner at 80 and 140 kVp with added filtration of 0.5 mm Cu. The authors evaluated strategies of noise suppression with sinogram smoothing and dose minimization with reduction of tube currents at the two kVp settings. The authors compared the impact of DECT-based attenuation correction with single-kVp CT-based attenuation correction on PET quantitation for the NCAT phantom for soft tissue and high-Z materials of bone and iodine contrast enhancement. Results: Both analytic calculations and simulations displayed the expected minimum noise value for a synthesized monoenergetic image at an energy between the mean energies of the two spectra. In addition the authors found that the normalized coefficient of variation in the synthesized attenuation map increased with energy but reached a plateau near 160 keV, and then remained constant with increasing energy up to 511 keV and beyond. The bias was minimal, as the linear attenuation coefficients of the synthesized monoenergetic images were within 2.4% of the known true values across the entire energy range

  20. Ultra-low dose CT attenuation correction for PET/CT

    NASA Astrophysics Data System (ADS)

    Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

    2012-01-01

    A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging.

  1. Postmortem pulmonary CT in hypothermia.

    PubMed

    Schweitzer, Wolf; Thali, Michael; Giugni, Giannina; Winklhofer, Sebastian

    2014-12-01

    Fatal hypothermia has been associated with pulmonary edema. With postmortem full body computed tomography scanning (PMCT), the lungs can also be examined for CT attenuation. In fatal hypothermia cases low CT attenuation appeared to prevail in the lungs. We compared 14 cases of fatal hypothermia with an age-sex matched control group. Additionally, 4 cases of carbon monoxide (CO) poisoning were examined. Furthermore, 10 test cases were examined to test predictability based on PMCT. Two readers measured CT attenuation on four different axial slices across the lungs (blinded to case group and other reader's results). Hypothermia was associated with statistically significantly lower lung PMCT attenuation and lower lung weights than controls, and there was a dose-effect relationship at an environmental temperature cutoff of 2 °C. CO poisoning yielded low pulmonary attenuation but higher lung weights. General model based prediction yielded a 94% probability for fatal hypothermia deaths and a 21% probability for non-hypothermia deaths in the test group. Increased breathing rate is known to accompany both CO poisoning and hypothermia, so this could partly explain the low PMCT lung attenuation due to an oxygen dissociation curve left shift. A more marked distension in fatal hypothermia, compared to CO poisoning, indicates that further, possibly different mechanisms, are involved in these cases. Increased dead space and increased stiffness to deflation (but not inflation) appear to be effects of inhaling cold air (but not CO) that may explain the difference in low PMCT attenuation seen in hypothermia cases.

  2. CT-assisted agile manufacturing

    NASA Astrophysics Data System (ADS)

    Stanley, James H.; Yancey, Robert N.

    1996-11-01

    The next century will witness at least two great revolutions in the way goods are produced. First, workers will use the medium of virtual reality in all aspects of marketing, research, development, prototyping, manufacturing, sales and service. Second, market forces will drive manufacturing towards small-lot production and just-in-time delivery. Already, we can discern the merging of these megatrends into what some are calling agile manufacturing. Under this new paradigm, parts and processes will be designed and engineered within the mind of a computer, tooled and manufactured by the offspring of today's rapid prototyping equipment, and evaluated for performance and reliability by advanced nondestructive evaluation (NDE) techniques and sophisticated computational models. Computed tomography (CT) is the premier example of an NDE method suitable for future agile manufacturing activities. It is the only modality that provides convenient access to the full suite of engineering data that users will need to avail themselves of computer- aided design, computer-aided manufacturing, and computer- aided engineering capabilities, as well as newly emerging reverse engineering, rapid prototyping and solid freeform fabrication technologies. As such, CT is assured a central, utilitarian role in future industrial operations. An overview of this exciting future for industrial CT is presented.

  3. Computer-aided measurement of liver volumes in CT by means of geodesic active contour segmentation coupled with level-set algorithms

    SciTech Connect

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

    2010-05-15

    Purpose: Computerized liver extraction from hepatic CT images is challenging because the liver often abuts other organs of a similar density. The purpose of this study was to develop a computer-aided measurement of liver volumes in hepatic CT. Methods: The authors developed a computerized liver extraction scheme based on geodesic active contour segmentation coupled with level-set contour evolution. First, an anisotropic diffusion filter was applied to portal-venous-phase CT images for noise reduction while preserving the liver structure, followed by a scale-specific gradient magnitude filter to enhance the liver boundaries. Then, a nonlinear grayscale converter enhanced the contrast of the liver parenchyma. By using the liver-parenchyma-enhanced image as a speed function, a fast-marching level-set algorithm generated an initial contour that roughly estimated the liver shape. A geodesic active contour segmentation algorithm coupled with level-set contour evolution refined the initial contour to define the liver boundaries more precisely. The liver volume was then calculated using these refined boundaries. Hepatic CT scans of 15 prospective liver donors were obtained under a liver transplant protocol with a multidetector CT system. The liver volumes extracted by the computerized scheme were compared to those traced manually by a radiologist, used as ''gold standard.''Results: The mean liver volume obtained with our scheme was 1504 cc, whereas the mean gold standard manual volume was 1457 cc, resulting in a mean absolute difference of 105 cc (7.2%). The computer-estimated liver volumetrics agreed excellently with the gold-standard manual volumetrics (intraclass correlation coefficient was 0.95) with no statistically significant difference (F=0.77; p(F{<=}f)=0.32). The average accuracy, sensitivity, specificity, and percent volume error were 98.4%, 91.1%, 99.1%, and 7.2%, respectively. Computerized CT liver volumetry would require substantially less completion time

  4. Changes in entrance surface dose in relation to the location of shielding material in chest computed tomography

    NASA Astrophysics Data System (ADS)

    Kang, Y. M.; Cho, J. H.; Kim, S. C.

    2015-07-01

    This study examined the effects of entrance surface dose (ESD) on the abdomen and pelvis of the patient when undergoing chest computed tomography (CT) procedure, and evaluated the effects of ESD reduction depending on the location of radiation shield. For CT scanner, the 64-slice multi-detector computed tomography was used. The alderson radiation therapy phantom and optically stimulated luminescence dosimeter (OSLD), which enabled measurement from low to high dose, were also used. For measurement of radiation dose, the slice number from 9 to 21 of the phantom was set as the test range, which included apex up to both costophrenic angles. A total of 10 OSLD nanoDots were attached for measurement of the front and rear ESD. Cyclic tests were performed using the low-dose chest CT and high-resolution CT (HRCT) protocol on the following set-ups: without shielding; shielding only on the front side; shielding only on the rear side; and shielding for both front and rear sides. According to the test results, ESD for both front and rear sides was higher in HRCT than low-dose CT when radiation shielding was not used. It was also determined that, compared to the set-up that did not use the radiation shield, locating the radiation shield on the front side was effective in reducing front ESD, while locating the radiation shield on the rear side reduced rear ESD level. Shielding both the front and rear sides resulted in ESD reduction. In conclusion, it was confirmed that shielding the front and rear sides was the most effective method to reduce the ESD effect caused by scatter ray during radiography.

  5. CT of 338 active professional boxers.

    PubMed

    Jordan, B D; Jahre, C; Hauser, W A; Zimmerman, R D; Zarrelli, M; Lipsitz, E C; Johnson, V; Warren, R F; Tsairis, P; Folk, F S

    1992-11-01

    Computed tomography (CT) was performed in 338 active professional boxers. CT scans were abnormal in 25 boxers (7%). The most common CT abnormality was brain atrophy (22 cases). Focal lesions of low attenuation consistent with posttraumatic encephalomalacia were noted in only three boxers. Boxers with abnormal CT scans did not differ from those with borderline or normal CT scans in regard to age, win-loss record, number of bouts, or history of an abnormal electroencephalogram. Thirty-seven boxers with borderline CT scans (49%) and 17 with abnormal CT scans (68%) reported a previous technical knockout (TKO) or knockout (KO), compared with only 89 (37%) of the 238 boxers with normal CT scans (P < .01). Brain atrophy was noted more frequently in boxers with a large cavum septum pellucidum (CSP) than in those with a small or no CSP (P < .05). Boxers with abnormal or borderline CT scans who experienced a TKO or KO were slightly older than those with normal CT scans and a history of a TKO or KO (P < .05).

  6. Modern CT applications in veterinary medicine.

    PubMed

    Garland, Melissa R; Lawler, Leo P; Whitaker, Brent R; Walker, Ian D F; Corl, Frank M; Fishman, Elliot K

    2002-01-01

    Although computed tomography (CT) is used primarily for diagnosis in humans, it can also be used to diagnose disease in veterinary patients. CT and associated three-dimensional reconstruction have a role in diagnosis of a range of illnesses in a variety of animals. In a sea turtle with failure to thrive, CT showed a nodal mass in the chest, granulomas in the lungs, and a ball in the stomach. CT of a sea dragon with balance and movement problems showed absence of the swim bladder. In a sloth with failure to thrive, CT allowed diagnosis of a coin in the intestine. CT of a puffin with failure to thrive showed a mass in the chest, which was found to be a hematoma. In a smooth-sided toad whose head was tilted to one side and who was circling in that direction, CT showed partial destruction of the temporal bone. CT of a domestic cat with listlessness showed a mass with focal calcification, which proved to be a leiomyosarcoma. CT of a sea otter showed pectus excavatum, which is caused by the animal smashing oysters against its chest. In a Japanese koi with abdominal swelling, CT allowed diagnosis of a hepatoma.

  7. Calculations of two new dose metrics proposed by AAPM Task Group 111 using the measurements with standard CT dosimetry phantoms

    SciTech Connect

    Li, Xinhua; Zhang, Da; Liu, Bob

    2013-08-15

    papers. R{sub 100} is presented for a majority of multidetector CT scanners currently on the market, and can be easily assessed for other CT scanners or operating conditions not covered in this study. The central to peripheral D{sub eq} ratio is about 1.50 and 1.12 times of R{sub 100} for the 32- and 16-cm diameter PMMA phantom, respectively.

  8. Functional Imaging: CT and MRI

    PubMed Central

    van Beek, Edwin JR; Hoffman, Eric A

    2008-01-01

    Synopsis Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advances in magnetic resonance imaging (MRI) of the lung include gadolinium-enhanced perfusion imaging and hyperpolarized helium imaging, which can allow imaging of pulmonary ventilation and .measurement of the size of emphysematous spaces. PMID:18267192

  9. Cortical Tremor (CT) with coincident orthostatic movements.

    PubMed

    Termsarasab, Pichet; Frucht, Steven J

    2015-01-01

    Cortical tremor (CT) is a form of cortical reflex myoclonus that can mimic essential tremor (ET). Clinical features that are helpful in distinguishing CT from ET are the irregular and jerky appearance of the movements. We report two patients with CT with coexisting orthostatic movements, either orthostatic tremor (OT) or myoclonus, who experienced functional improvement in both cortical myoclonus and orthostatic movements when treated with levetiracetam.

  10. Pediatric CT and radiation: our responsibility

    NASA Astrophysics Data System (ADS)

    Frush, Donald P.

    2009-02-01

    In order to discuss the cost-benefit ratio of CT examinations in children, one must be familiar with the reasons why CT can provide a high collective or individual dose. The reasons include increasing CT use as well as lack of attention to dose reduction strategies. While those have been substantial efforts for dose reduction, additional work is necessary to prevent unnecessary radiation exposure. This responsibility is shared between science and medicine, industry, regulatory agencies, and patients as well.

  11. Multimodal CT in stroke imaging: new concepts.

    PubMed

    Ledezma, Carlos J; Wintermark, Max

    2009-01-01

    A multimodal CT protocol provides a comprehensive noninvasive survey of acute stroke patients with accurate demonstration of the site of arterial occlusion and its hemodynamic tissue status. It combines widespread availability with the ability to provide functional characterization of cerebral ischemia, and could potentially allow more accurate selection of candidates for acute stroke reperfusion therapy. This article discusses the individual components of multimodal CT and addresses the potential role of a combined multimodal CT stroke protocol in acute stroke therapy.

  12. Radiation dose measurements in coronary CT angiography

    PubMed Central

    Sabarudin, Akmal; Sun, Zhonghua

    2013-01-01

    Coronary computed tomography (CT) angiography is associated with high radiation dose and this has raised serious concerns in the literature. Awareness of various parameters for dose estimates and measurements of coronary CT angiography plays an important role in increasing our understanding of the radiation exposure to patients, thus, contributing to the implementation of dose-saving strategies. This article provides an overview of the radiation dose quantity and its measurement during coronary CT angiography procedures. PMID:24392190

  13. Normal conus medullaris: CT criteria for recognition

    SciTech Connect

    Grogan, J.P.; Daniels, D.L.; Williams, I.L.; Rauschning, W.; Haughton, V.M.

    1984-06-01

    The normal CT configuration and dimension of the conus medullaris and adjacent spinal cord were determined in 30 patients who had no clinical evidence of conus compression. CT studies were also correlated with anatomic sections in cadavers. The normal conus on CT has a distinctive oval configuration, an arterior sulcus, and a posterior promontory. The anteroposterior diameter ranged from 5 to 8 mm; the transverse diameter from 8 to 11 mm. Intramedullary processes altered both the dimensions and configuration of the conus.

  14. Application of an asymmetric flow field flow fractionation multi-detector approach for metallic engineered nanoparticle characterization--prospects and limitations demonstrated on Au nanoparticles.

    PubMed

    Hagendorfer, Harald; Kaegi, Ralf; Traber, Jacqueline; Mertens, Stijn F L; Scherrers, Roger; Ludwig, Christian; Ulrich, Andrea

    2011-11-14

    In this work we discuss about the method development, applicability and limitations of an asymmetric flow field flow fractionation (A4F) system in combination with a multi-detector setup consisting of UV/vis, light scattering, and inductively coupled plasma mass spectrometry (ICPMS). The overall aim was to obtain a size dependent-, element specific-, and quantitative method appropriate for the characterization of metallic engineered nanoparticle (ENP) dispersions. Thus, systematic investigations of crucial method parameters were performed by employing well characterized Au nanoparticles (Au-NPs) as a defined model system. For good separation performance, the A4F flow-, membrane-, and carrier conditions were optimized. To obtain reliable size information, the use of laser light scattering based detectors was evaluated, where an online dynamic light scattering (DLS) detector showed good results for the investigated Au-NP up to a size of 80 nm in hydrodynamic diameter. To adapt large sensitivity differences of the various detectors, as well as to guarantee long term stability and minimum contamination of the mass spectrometer a split-flow concept for coupling ICPMS was evaluated. To test for reliable quantification, the ICPMS signal response of ionic Au standards was compared to that of Au-NP. Using proper stabilization with surfactants, no difference for concentrations of 1-50 μg Au L(-1) in the size range from 5 to 80 nm for citrate stabilized dispersions was observed. However, studies using different A4F channel membranes showed unspecific particle-membrane interaction resulting in retention time shifts and unspecific loss of nanoparticles, depending on the Au-NP system as well as membrane batch and type. Thus, reliable quantification and discrimination of ionic and particular species was performed using ICPMS in combination with ultracentrifugation instead of direct quantification with the A4F multi-detector setup. Figures of merit were obtained, by comparing the

  15. Volumetric quantification of lung nodules in CT with iterative reconstruction (ASiR and MBIR)

    SciTech Connect

    Chen, Baiyu; Barnhart, Huiman; Richard, Samuel; Robins, Marthony; Colsher, James; Samei, Ehsan

    2013-11-15

    Purpose: Volume quantifications of lung nodules with multidetector computed tomography (CT) images provide useful information for monitoring nodule developments. The accuracy and precision of the volume quantification, however, can be impacted by imaging and reconstruction parameters. This study aimed to investigate the impact of iterative reconstruction algorithms on the accuracy and precision of volume quantification with dose and slice thickness as additional variables.Methods: Repeated CT images were acquired from an anthropomorphic chest phantom with synthetic nodules (9.5 and 4.8 mm) at six dose levels, and reconstructed with three reconstruction algorithms [filtered backprojection (FBP), adaptive statistical iterative reconstruction (ASiR), and model based iterative reconstruction (MBIR)] into three slice thicknesses. The nodule volumes were measured with two clinical software (A: Lung VCAR, B: iNtuition), and analyzed for accuracy and precision.Results: Precision was found to be generally comparable between FBP and iterative reconstruction with no statistically significant difference noted for different dose levels, slice thickness, and segmentation software. Accuracy was found to be more variable. For large nodules, the accuracy was significantly different between ASiR and FBP for all slice thicknesses with both software, and significantly different between MBIR and FBP for 0.625 mm slice thickness with Software A and for all slice thicknesses with Software B. For small nodules, the accuracy was more similar between FBP and iterative reconstruction, with the exception of ASIR vs FBP at 1.25 mm with Software A and MBIR vs FBP at 0.625 mm with Software A.Conclusions: The systematic difference between the accuracy of FBP and iterative reconstructions highlights the importance of extending current segmentation software to accommodate the image characteristics of iterative reconstructions. In addition, a calibration process may help reduce the dependency of

  16. Intracranial CT angiography obtained from a cerebral CT perfusion examination

    SciTech Connect

    Gratama van Andel, H. A. F.; Venema, H. W.; Majoie, C. B.; Den Heeten, G. J.; Grimbergen, C. A.; Streekstra, G. J.

    2009-04-15

    CT perfusion (CTP) examinations of the brain are performed increasingly for the evaluation of cerebral blood flow in patients with stroke and vasospasm after subarachnoid hemorrhage. Of the same patient often also a CT angiography (CTA) examination is performed. This study investigates the possibility to obtain CTA images from the CTP examination, thereby possibly obviating the CTA examination. This would save the patient exposure to radiation, contrast, and time. Each CTP frame is a CTA image with a varying amount of contrast enhancement and with high noise. To improve the contrast-to-noise ratio (CNR) we combined all 3D images into one 3D image after registration to correct for patient motion between time frames. Image combination consists of weighted averaging in which the weighting factor of each frame is proportional to the arterial contrast. It can be shown that the arterial CNR is maximized in this procedure. An additional advantage of the use of the time series of CTP images is that automatic differentiation between arteries and veins is possible. This feature was used to mask veins in the resulting 3D images to enhance visibility of arteries in maximum intensity projection (MIP) images. With a Philips Brilliance 64 CT scanner (64x0.625 mm) CTP examinations of eight patients were performed on 80 mm of brain using the toggling table technique. The CTP examination consisted of a time series of 15 3D images (2x64x0.625 mm; 80 kV; 150 mAs each) with an interval of 4 s. The authors measured the CNR in images obtained with weighted averaging, images obtained with plain averaging, and images with maximal arterial enhancement. The authors also compared CNR and quality of the images with that of regular CTA examinations and examined the effectiveness of automatic vein masking in MIP images. The CNR of the weighted averaged images is, on the average, 1.73 times the CNR of an image at maximal arterial enhancement in the CTP series, where the use of plain averaging

  17. CT demonstration of bilateral adrenal hemorrhage

    SciTech Connect

    Ling, D.; Korobkin, M.; Silverman, P.M.; Dunnick, N.R.

    1983-08-01

    Bilateral adrenal hemorrhage with subsequent adrenal insufficiency is a recognized complication of anticoagulant therapy. Because the clinical manifestations are often nonspecific, the antemortem diagnosis of adrenal hemorrhage has been a difficult clinical problem. Computed tomography (CT) provides detailed images of the adrenal glands that are not possible with conventional imaging methods. The CT findings of bilateral adrenal hemorrhage in an anticoagulated patient are reported.

  18. Reconstructing misaligned x-ray CT data

    SciTech Connect

    Divin, C. J.

    2016-10-24

    Misalignment errors for x-ray computed tomography (CT) systems can manifest as artifacts and a loss of spatial and contrast resolution. To mitigate artifacts, significant effort is taken to determine the system geometry and minimizing any residual error in the system alignment. This project improved our ability to post-correct data which was acquired on a misaligned CT system.

  19. CT of schistosomal calcification of the intestine

    SciTech Connect

    Fataar, S.; Bassiony, H.; Satyanath, S.; Rudwan, M.; Hebbar, G.; Khalifa, A.; Cherian, M.J.

    1985-01-01

    The spectrum of schistosomal colonic calcification on abdominal radiographs has been described. The appearance on computed tomography (CT) is equally distinctive and occurs with varying degrees of genitourinary calcification. The authors have experience in three cases with the appearance on CT of intestinal calcification due to schistosomiasis.

  20. Support vector machine model for diagnosis of lymph node metastasis in gastric cancer with multidetector computed tomography: a preliminary study

    PubMed Central

    2011-01-01

    Background Lymph node metastasis (LNM) of gastric cancer is an important prognostic factor regarding long-term survival. But several imaging techniques which are commonly used in stomach cannot satisfactorily assess the gastric cancer lymph node status. They can not achieve both high sensitivity and specificity. As a kind of machine-learning methods, Support Vector Machine has the potential to solve this complex issue. Methods The institutional review board approved this retrospective study. 175 consecutive patients with gastric cancer who underwent MDCT before surgery were included. We evaluated the tumor and lymph node indicators on CT images including serosal invasion, tumor classification, tumor maximum diameter, number of lymph nodes, maximum lymph node size and lymph nodes station, which reflected the biological behavior of gastric cancer. Univariate analysis was used to analyze the relationship between the six image indicators with LNM. A SVM model was built with these indicators above as input index. The output index was that lymph node metastasis of the patient was positive or negative. It was confirmed by the surgery and histopathology. A standard machine-learning technique called k-fold cross-validation (5-fold in our study) was used to train and test SVM models. We evaluated the diagnostic capability of the SVM models in lymph node metastasis with the receiver operating characteristic (ROC) curves. And the radiologist classified the lymph node metastasis of patients by using maximum lymph node size on CT images as criterion. We compared the areas under ROC curves (AUC) of the radiologist and SVM models. Results In 175 cases, the cases of lymph node metastasis were 134 and 41 cases were not. The six image indicators all had statistically significant differences between the LNM negative and positive groups. The means of the sensitivity, specificity and AUC of SVM models with 5-fold cross-validation were 88.5%, 78.5% and 0.876, respectively. While the

  1. Artifact-Free and Detection-Profile-Independent Higher-Order Fluorescence Correlation Spectroscopy for Microsecond-Resolved Kinetics. 1. Multidetector and Sub-Binning Approach.

    PubMed

    Abdollah-Nia, Farshad; Gelfand, Martin P; Van Orden, Alan

    2017-03-10

    Fluorescence correlation spectroscopy (FCS) is a powerful tool in the time-resolved analysis of nonreacting or reacting molecules in solution, based on fluorescence intensity fluctuations. However, conventional (second-order) FCS alone is insufficient to measure all parameters needed to describe a reaction or mixture, including concentrations, fluorescence brightnesses, and forward and reverse rate constants. For this purpose, correlations of higher powers of fluorescence intensity fluctuations can be calculated to yield additional information from the single-photon data stream collected in an FCS experiment. To describe systems of diffusing and reacting molecules, considering cumulants of fluorescence intensity results in simple expressions in which the reaction and diffusion parts factorize. The computation of higher-order correlations in experiments is hindered by shot-noise and common detector artifacts, the effects of which become worse with increasing order. In this article, we introduce a technique to calculate artifact-free higher-order correlation functions with improved time resolution, and without any need for modeling and calibration of detector artifacts. The technique is formulated for general multidetector experiments and verified in both two-detector and single-detector configurations. Good signal-to-noise ratio is achieved down to 1 μs in correlation curves up to order (2, 2). This capability makes possible a variety of new measurements including multicomponent analysis and fast reaction kinetics, as demonstrated in a companion article (10.1021/acs.jpcb.7b00408).

  2. Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists

    PubMed Central

    Neubauer, Jakob; Benndorf, Matthias; Reidelbach, Carolin; Krauß, Tobias; Lampert, Florian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Fiebich, Martin; Goerke, Sebastian M.

    2016-01-01

    Purpose To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures. Methods As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care), RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging. Three raters independently evaluated the resulting images for fractures and the level of confidence for each finding. Gold standard was evaluated by consensus reading of a high-dose MDCT. Results Pooled sensitivity was higher in RED-MDCT with 0.89 and RED-MDCT with 0.81 compared to radiography with 0.54 (P = < .004). No significant differences were detected concerning the modalities’ specificities (with values between P = .98). Raters' confidence was higher in RED-MDCT and RED-CBCT compared to radiography (P < .001). Conclusion The diagnostic accuracy of RED-MDCT and RED-CBCT for wrist fractures proved to be similar and in some parts even higher compared to radiography. Readers are more confident in their reporting with the cross sectional modalities. Dose equivalent cross sectional computed tomography of the wrist could replace plain radiography for fracture diagnosis in the long run. PMID:27788215

  3. Multidetector thermal field-flow fractionation as a unique tool for the tacticity-based separation of poly(methyl methacrylate)-polystyrene block copolymer micelles.

    PubMed

    Greyling, Guilaume; Pasch, Harald

    2015-10-02

    Poly(methyl methacrylate)-polystyrene (PMMA-PS) micelles with isotactic and syndiotactic coronas are prepared in acetonitrile and subjected to thermal field-flow fractionation (ThFFF) analysis at various conditions of increasing temperature gradients. It is shown for the first time that multidetector ThFFF provides comprehensive information on important micelle characteristics such as size (Dh), shape (Rg/Rh), aggregation number (Z), thermal diffusion (DT) and Soret coefficients (ST) as a function of temperature from a single injection. Moreover, it is found that micelles exhibit a unique decreasing trend in DT as a function of temperature which is independent of the tacticity of the corona and the micelle preparation method used. It is also demonstrated that ThFFF can monitor micelle to vesicle transitions as a function of temperature. In addition to ThFFF, it is found from DLS analysis that the tacticity of the corona influences the critical micelle concentration and the magnitude to which micelles expand/contract with temperature. The tacticity does not, however, influence the critical micelle temperature. Furthermore, the separation of micelles based on the tacticity of the corona highlight the unique capabilities of ThFFF.

  4. Incidence of Venous Thromboembolism Using 64 Channel Multidetector Row Computed Tomography-Indirect Venography and Anti-Coagulation Therapy after Total Knee Arthroplasty in Korea

    PubMed Central

    Park, Kyung-Hyun; Cheon, Sang-Ho; Lee, Ji-Ho

    2012-01-01

    Purpose This study evaluated the incidence of a venous thromboembolism (VTE) after total knee arthroplasty (TKA) using multidetector row computed tomography-indirect venography (MDCT-indirect venography) and assessed the efficacy of anti-coagulation therapy. Materials and Methods We enrolled 118 patients with 126 cases of TKA. The average age of the patients was 68.4 years. We used 64 channel MDCT-indirect venography for the detection of VTE. We treated selectively proximal deep vein thrombosis (DVT) or pulmonary thromboembolism (PTE) cases according to the results of MDCT-indirect venography. We re-evaluated the change in VTE using follow-up MDCT-indirect venography after 3 months. Results We identified VTE in 35.7%. DVT only was identified in 22.2% including 8 cases of proximal DVT and 20 cases of distal DVT. PTE without DVT was identified in 4.8%, and combined DVT and PTE in 8.7%. All patients with PTE were asymptomatic, but 4 DVT patients had signs of leg swelling. After anti-coagulation therapy, 20 patients showed complete resolution in 16 cases, improvement in 3 cases and one case showed a new distal DVT. Conclusions The incidence of VTE after primary TKA was 35.7% in Korea. Furthermore, anti-coagulation therapy for proximal DVT and PTE patients may be a useful method for preventing the occurrence of a fatal PTE. PMID:22570848

  5. Opportunities for new CT contrast agents to maximize the diagnostic potential of emerging spectral CT technologies.

    PubMed

    Yeh, Benjamin M; FitzGerald, Paul F; Edic, Peter M; Lambert, Jack W; Colborn, Robert E; Marino, Michael E; Evans, Paul M; Roberts, Jeannette C; Wang, Zhen J; Wong, Margaret J; Bonitatibus, Peter J

    2016-09-09

    The introduction of spectral CT imaging in the form of fast clinical dual-energy CT enabled contrast material to be differentiated from other radiodense materials, improved lesion detection in contrast-enhanced scans, and changed the way that existing iodine and barium contrast materials are used in clinical practice. More profoundly, spectral CT can differentiate between individual contrast materials that have different reporter elements such that high-resolution CT imaging of multiple contrast agents can be obtained in a single pass of the CT scanner. These spectral CT capabilities would be even more impactful with the development of contrast materials designed to complement the existing clinical iodine- and barium-based agents. New biocompatible high-atomic number contrast materials with different biodistribution and X-ray attenuation properties than existing agents will expand the diagnostic power of spectral CT imaging without penalties in radiation dose or scan time.

  6. Dual source CT (DSCT) imaging of obese patients: evaluation of CT number accuracy, uniformity, and noise

    NASA Astrophysics Data System (ADS)

    Walz-Flannigan, A.; Schmidt, B.,; Apel, A.; Eusemann, C.; Yu, L.; McCollough, C. H.

    2009-02-01

    Obese patients present challenges in obtaining sufficient x-ray exposure over reasonable time periods for acceptable CT image quality. To overcome this limitation, the exposure can be divided between two x-ray sources using a dualsource (DS) CT system. However, cross-scatter issues in DS CT may also compromise image quality. We evaluated a DS CT system optimized for imaging obese patients, comparing the CT number accuracy and uniformity to the same images obtained with a single-source (SS) acquisition. The imaging modes were compared using both solid cylindrical PMMA phantoms and a semi-anthropomorphic thorax phantom fitted with extension rings to simulate different size patients. Clinical protocols were used and CTDIvol and kVp were held constant between SS and DS modes. Results demonstrated good agreement in CT number between SS and DS modes in CT number, with the DS mode showing better axial uniformity for the largest phantoms.

  7. Comparison of Two Accelerators for Monte Carlo Radiation Transport Calculations, NVIDIA Tesla M2090 GPU and Intel Xeon Phi 5110p Coprocessor: A Case Study for X-ray CT Imaging Dose Calculation

    NASA Astrophysics Data System (ADS)

    Liu, Tianyu; Xu, X. George; Carothers, Christopher D.

    2014-06-01

    Hardware accelerators are currently becoming increasingly important in boosting high performance computing sys- tems. In this study, we tested the performance of two accelerator models, NVIDIA Tesla M2090 GPU and Intel Xeon Phi 5110p coprocessor, using a new Monte Carlo photon transport package called ARCHER-CT we have developed for fast CT imaging dose calculation. The package contains three code variants, ARCHER - CTCPU, ARCHER - CTGPU and ARCHER - CTCOP to run in parallel on the multi-core CPU, GPU and coprocessor architectures respectively. A detailed GE LightSpeed Multi-Detector Computed Tomography (MDCT) scanner model and a family of voxel patient phantoms were included in the code to calculate absorbed dose to radiosensitive organs under specified scan protocols. The results from ARCHER agreed well with those from the production code Monte Carlo N-Particle eXtended (MCNPX). It was found that all the code variants were significantly faster than the parallel MCNPX running on 12 MPI processes, and that the GPU and coprocessor performed equally well, being 2.89~4.49 and 3.01~3.23 times faster than the parallel ARCHER - CTCPU running with 12 hyperthreads.

  8. Iterative image reconstruction in spectral CT

    NASA Astrophysics Data System (ADS)

    Hernandez, Daniel; Michel, Eric; Kim, Hye S.; Kim, Jae G.; Han, Byung H.; Cho, Min H.; Lee, Soo Y.

    2012-03-01

    Scan time of spectral-CTs is much longer than conventional CTs due to limited number of x-ray photons detectable by photon-counting detectors. However, the spectral pixel information in spectral-CT has much richer information on physiological and pathological status of the tissues than the CT-number in conventional CT, which makes the spectral- CT one of the promising future imaging modalities. One simple way to reduce the scan time in spectral-CT imaging is to reduce the number of views in the acquisition of projection data. But, this may result in poorer SNR and strong streak artifacts which can severely compromise the image quality. In this work, spectral-CT projection data were obtained from a lab-built spectral-CT consisting of a single CdTe photon counting detector, a micro-focus x-ray tube and scan mechanics. For the image reconstruction, we used two iterative image reconstruction methods, the simultaneous iterative reconstruction technique (SIRT) and the total variation minimization based on conjugate gradient method (CG-TV), along with the filtered back-projection (FBP) to compare the image quality. From the imaging of the iodine containing phantoms, we have observed that SIRT and CG-TV are superior to the FBP method in terms of SNR and streak artifacts.

  9. Cytomegalovirus pneumonia in transplant patients: CT findings

    SciTech Connect

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

    1996-03-01

    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 included 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.

  10. Ion Stopping Powers and CT Numbers

    SciTech Connect

    Moyers, Michael F.; Sardesai, Milind; Sun, Sean; Miller, Daniel W.

    2010-10-01

    One of the advantages of ion beam therapy is the steep dose gradient produced near the ion's range. Use of this advantage makes knowledge of the stopping powers for all materials through which the beam passes critical. Most treatment planning systems calculate dose distributions using depth dose data measured in water and an algorithm that converts the kilovoltage X-ray computed tomography (CT) number of a given material to its linear stopping power relative to water. Some materials present in kilovoltage scans of patients and simulation phantoms do not lie on the standard tissue conversion curve. The relative linear stopping powers (RLSPs) of 21 different tissue substitutes and positioning, registration, immobilization, and beamline materials were measured in beams of protons accelerated to energies of 155, 200, and 250 MeV; carbon ions accelerated to 290 MeV/n; and iron ions accelerated to 970 MeV/n. These same materials were scanned with both kilovoltage and megavoltage CT scanners to obtain their CT numbers. Measured RLSPs and CT numbers were compared with calculated and/or literature values. Relationships of RLSPs to physical densities, electronic densities, kilovoltage CT numbers, megavoltage CT numbers, and water equivalence values converted by a treatment planning system are given. Usage of CT numbers and substitution of measured values into treatment plans to provide accurate patient and phantom simulations are discussed.

  11. Porcine Ex Vivo Liver Phantom for Dynamic Contrast-Enhanced Computed Tomography: Development and Initial Results

    PubMed Central

    Thompson, Scott M.; Giraldo, Juan C. Ramirez; Knudsen, Bruce; Grande, Joseph P.; Christner, Jodie A.; Xu, Man; Woodrum, David A.; McCollough, Cynthia H.; Callstrom, Matthew R.

    2011-01-01

    Objectives To demonstrate the feasibility of developing a fixed, dual-input, biological liver phantom for dynamic contrast-enhanced computed tomography (CT) imaging and to report initial results of use of the phantom for quantitative CT perfusion imaging. Materials and Methods Porcine livers were obtained from completed surgical studies and perfused with saline and fixative. The phantom was placed in a body-shaped, CT-compatible acrylic container and connected to a perfusion circuit fitted with a contrast injection port. Flow-controlled contrast-enhanced imaging experiments were performed using a 128-slice and 64 slice, dual-source multidetector CT scanners. CT angiography protocols were employed to obtain portal venous and hepatic arterial vascular enhancement, reproduced over a period of four to six months. CT perfusion protocols were employed at different input flow rates to correlate input flow with calculated tissue perfusion, to test reproducibility and demonstrate the feasibility of simultaneous dual input liver perfusion. Histologic analysis of the liver phantom was also performed. Results CT angiogram 3D reconstructions demonstrated homogenous tertiary and quaternary branching of the portal venous system out to the periphery of all lobes of the liver as well as enhancement of the hepatic arterial system to all lobes of the liver and gallbladder throughout the study period. For perfusion CT, the correlation between the calculated mean tissue perfusion in a volume of interest and input pump flow rate was excellent (R2 = 0.996) and color blood flow maps demonstrated variations in regional perfusion in a narrow range. Repeat perfusion CT experiments demonstrated reproducible time-attenuation curves and dual-input perfusion CT experiments demonstrated that simultaneous dual input liver perfusion is feasible. Histologic analysis demonstrated that the hepatic microvasculature and architecture appeared intact and well preserved at the completion of four to six

  12. Accuracy in contouring of small and low contrast lesions: Comparison between diagnostic quality computed tomography scanner and computed tomography simulation scanner-A phantom study

    SciTech Connect

    Ho, Yick Wing; Wong, Wing Kei Rebecca; Yu, Siu Ki; Lam, Wai Wang; Geng Hui

    2012-01-01

    To evaluate the accuracy in detection of small and low-contrast regions using a high-definition diagnostic computed tomography (CT) scanner compared with a radiotherapy CT simulation scanner. A custom-made phantom with cylindrical holes of diameters ranging from 2-9 mm was filled with 9 different concentrations of contrast solution. The phantom was scanned using a 16-slice multidetector CT simulation scanner (LightSpeed RT16, General Electric Healthcare, Milwaukee, WI) and a 64-slice high-definition diagnostic CT scanner (Discovery CT750 HD, General Electric Healthcare). The low-contrast regions of interest (ROIs) were delineated automatically upon their full width at half maximum of the CT number profile in Hounsfield units on a treatment planning workstation. Two conformal indexes, CI{sub in}, and CI{sub out}, were calculated to represent the percentage errors of underestimation and overestimation in the automated contours compared with their actual sizes. Summarizing the conformal indexes of different sizes and contrast concentration, the means of CI{sub in} and CI{sub out} for the CT simulation scanner were 33.7% and 60.9%, respectively, and 10.5% and 41.5% were found for the diagnostic CT scanner. The mean differences between the 2 scanners' CI{sub in} and CI{sub out} were shown to be significant with p < 0.001. A descending trend of the index values was observed as the ROI size increases for both scanners, which indicates an improved accuracy when the ROI size increases, whereas no observable trend was found in the contouring accuracy with respect to the contrast levels in this study. Images acquired by the diagnostic CT scanner allow higher accuracy on size estimation compared with the CT simulation scanner in this study. We recommend using a diagnostic CT scanner to scan patients with small lesions (<1 cm in diameter) for radiotherapy treatment planning, especially for those pending for stereotactic radiosurgery in which accurate delineation of small

  13. Askin tumor: CT and FDG-PET/CT imaging findings and follow-up.

    PubMed

    Xia, Tingting; Guan, Yubao; Chen, Yongxin; Li, Jingxu

    2014-07-01

    The aim of the study was to describe the imaging findings of Askin tumors on computed tomography (CT) and fluorine 18 fluorodeoxyglucose-positron emission tomography (FDG-PET/CT).Seventeen cases of Askin tumors confirmed by histopathology were retrospectively analyzed in terms of CT (17 cases) and FDG-PET/CT data (6 cases).Fifteen of the tumors were located in the chest wall and the other 2 were in the anterior middle mediastinum. Of the 15 chest wall cases, 13 demonstrated irregular, heterogeneous soft tissue masses with cystic degeneration and necrosis, and 2 demonstrated homogeneous soft tissue masses on unenhanced CT scans. Two mediastinal tumors demonstrated the irregular, heterogeneous soft tissue masses. Calcifications were found in 2 tumors. The tumors demonstrated heterogeneously enhancement in 16 cases and homogeneous enhancement in 1 case on contrast-enhanced scans. FDG-PET/CT images revealed increased metabolic activity in all 6 cases undergone FDG-PET/CT scan, and the lesion SUVmax ranged from 4.0 to 18.6. At initial diagnosis, CT and FDG-PET/CT scans revealed rib destruction in 9 cases, pleural effusion in 9 cases, and lung metastasis in 1 case. At follow-up, 12 cases showed recurrence and/or metastases, 4 cases showed improvement or remained stable, and 1 was lost to follow-up.In summary, CT and FDG-PET/CT images of Askin tumors showed heterogeneous soft tissue masses in the chest wall and the mediastinum, accompanied by rib destruction, pleural effusion, and increased FDG uptake. CT and FDG-PET/CT imaging play important roles in the diagnosis and follow-up of patients with Askin tumors.

  14. CT & CBCT imaging: assessment of the orbits.

    PubMed

    Hatcher, David C

    2012-11-01

    The orbits can be visualized easily on routine or customized protocols for computed tomography (CT) or cone beam CT (CBCT) scans. Detailed orbital investigations are best performed with 3-dimensional imaging methods. CT scans are preferred for visualizing the osseous orbital anatomy and fissures while magnetic resonance imaging is preferred for evaluating tumors and inflammation. CBCT provides high-resolution anatomic data of the sinonasal spaces, airway, soft tissue surfaces, and bones but does not provide much detail within the soft tissues. This article discusses CBCT imaging of the orbits, osseous anatomy of the orbits, and CBCT investigation of selected orbital pathosis.

  15. Doses metrics and patient age in CT.

    PubMed

    Huda, Walter; Tipnis, Sameer V

    2016-03-01

    The aim of this study was to investigate how effective dose and size-specific dose estimate (SSDE) change with patient age (size) for routine head and abdominal/pelvic CT examinations. Heads and abdomens of patients were modelled as a mass-equivalent cylinder of water corresponding to the patient 'effective diameter'. Head CT scans were performed at CTDIvol(S) of 40 mGy, and abdominal CT scans were performed at CTDIvol(L) of 10 mGy. Values of SSDE were obtained using conversion factors in AAPM Task Group Report 204. Age-specific scan lengths for head and abdominal CT scans obtained from the authors' clinical practice were used to estimate the dose-length product for each CT examination. Effective doses were calculated from previously published age- and sex-specific E/DLP conversion factors, based on ICRP 103 organ-weighting factors. For head CT examinations, the scan length increased from 15 cm in a newborn to 20 cm in adults, and for an abdominal/pelvic CT, the scan length increased from 20 cm in a newborn to 45 cm in adults. For head CT scans, SSDE ranged from 37.2 mGy in adults to 48.8 mGy in a newborn, an increase of 31 %. The corresponding head CT effective doses range from 1.4 mSv in adults to 5.2 mSv in a newborn, an increase of 270 %. For abdomen CT scans, SSDE ranged from 13.7 mGy in adults to 23.0 mGy in a newborn, an increase of 68 %. The corresponding abdominal CT effective doses ranged from 6.3 mSv in adults to 15.4 mSv in a newborn, an increase of 140 %. SSDE increases much less than effective dose in paediatric patients compared with adults because it does not account for scan length or scattered radiation. Size- and age-specific effective doses better quantify the total radiation received by patients in CT by explicitly accounting for all organ doses, as well as their relative radio sensitivity.

  16. [The use of CT in meniscopathy].

    PubMed

    Tellkamp, H; Klein, W; Rosenkranz, G; Köhler, K

    1988-12-01

    The results of CT examination of meniscopathies in 54 patients, most of them competitive athletes, are presented. CT has an overall accuracy of about 90 per cent and can hence be used for diagnosing a lesion of the meniscus with a reasonable amount of safety, while being rapid and avoiding unnecessary exposure to stress. This method, therefore, should be a focal point of the imaging methods and thus be placed between the specialist doctor's findings and possible surgery. The pros and cons of CT compared with other imaging methods are discussed.

  17. Cine CT technique for dynamic airway studies

    SciTech Connect

    Ell, S.R.; Jolles, H.; Keyes, W.D.; Galvin, J.R.

    1985-07-01

    The advent of cine CT scanning with its 50-msec data acquisition time promises a much wider range of dynamic CT studies. The authors describe a method for dynamic evaluation of the extrathoracic airway, which they believe has considerable potential application in nonfixed upper-airway disease, such as sleep apnea and stridor of unknown cause. Conventional CT is limited in such studies by long data acquisition time and can be used to study only prolonged maneuvers such as phonation. Fluoroscopy and digital subtraction studies are limited by relatively high radiation dose and inability to image all wall motions simultaneously.

  18. WE-DE-207A-02: Advances in Cone Beam CT Anatomical and Functional Imaging in Angio-Suite to Enable One-Stop-Shop Stroke Imaging Workflow.

    PubMed

    Chen, G

    2016-06-01

    1. Parallels in the evolution of x-ray angiographic systems and devices used for minimally invasive endovascular therapy Charles Strother - DSA, invented by Dr. Charles Mistretta at UW-Madison, was the technology which enabled the development of minimally invasive endovascular procedures. As DSA became widely available and the potential benefits for accessing the cerebral vasculature from an endovascular approach began to be apparent, industry began efforts to develop tools for use in these procedures. Along with development of catheters, embolic materials, pushable coils and the GDC coils there was simultaneous development and improvement of 2D DSA image quality and the introduction of 3D DSA. Together, these advances resulted in an enormous expansion in the scope and numbers of minimally invasive endovascular procedures. The introduction of flat detectors for c-arm angiographic systems in 2002 provided the possibility of the angiographic suite becoming not just a location for vascular imaging where physiological assessments might also be performed. Over the last decade algorithmic and hardware advances have been sufficient to now realize this potential in clinical practice. The selection of patients for endovascular treatments is enhanced by this dual capability. Along with these advances has been a steady reduction in the radiation exposure required so that today, vascular and soft tissue images may be obtained with equal or in many cases less radiation exposure than is the case for comparable images obtained with multi-detector CT.

  19. Combined SPECT/CT and PET/CT for breast imaging

    NASA Astrophysics Data System (ADS)

    Russo, Paolo; Larobina, Michele; Di Lillo, Francesca; Del Vecchio, Silvana; Mettivier, Giovanni

    2016-02-01

    In the field of nuclear medicine imaging, breast imaging for cancer diagnosis is still mainly based on 2D imaging techniques. Three-dimensional tomographic imaging with whole-body PET or SPECT scanners, when used for imaging the breast, has performance limits in terms of spatial resolution and sensitivity, which can be overcome only with a dedicated instrumentation. However, only few hybrid imaging systems for PET/CT or SPECT/CT dedicated to the breast have been developed in the last decade, providing complementary functional and anatomical information on normal breast tissue and lesions. These systems are still under development and clinical trials on just few patients have been reported; no commercial dedicated breast PET/CT or SPECT/CT is available. This paper reviews combined dedicated breast PET/CT and SPECT/CT scanners described in the recent literature, with focus on their technological aspects.

  20. CT thermometry for cone-beam CT guided ablation

    NASA Astrophysics Data System (ADS)

    DeStefano, Zachary; Abi-Jaoudeh, Nadine; Li, Ming; Wood, Bradford J.; Summers, Ronald M.; Yao, Jianhua

    2016-03-01

    Monitoring temperature during a cone-beam CT (CBCT) guided ablation procedure is important for prevention of over-treatment and under-treatment. In order to accomplish ideal temperature monitoring, a thermometry map must be generated. Previously, this was attempted using CBCT scans of a pig shoulder undergoing ablation.1 We are extending this work by using CBCT scans of real patients and incorporating more processing steps. We register the scans before comparing them due to the movement and deformation of organs. We then automatically locate the needle tip and the ablation zone. We employ a robust change metric due to image noise and artifacts. This change metric takes windows around each pixel and uses an equation inspired by Time Delay Analysis to calculate the error between windows with the assumption that there is an ideal spatial offset. Once the change map is generated, we correlate change data with measured temperature data at the key points in the region. This allows us to transform our change map into a thermal map. This thermal map is then able to provide an estimate as to the size and temperature of the ablation zone. We evaluated our procedure on a data set of 12 patients who had a total of 24 ablation procedures performed. We were able to generate reasonable thermal maps with varying degrees of accuracy. The average error ranged from 2.7 to 16.2 degrees Celsius. In addition to providing estimates of the size of the ablation zone for surgical guidance, 3D visualizations of the ablation zone and needle are also produced.

  1. Radiation exposure in whole body CT screening.

    PubMed

    Suresh, Pamidighantam; Ratnam, S V; Rao, K V J

    2011-04-01

    Using a technology that "takes a look" at people's insides and promises early warnings of cancer, cardiac disease, and other abnormalities, clinics and medical imaging facilities nationwide are touting a new service for health conscious people: "Whole body CT screening" this typically involves scanning the body from the chin to below the hips with a form of x-ray imaging that produces cross-sectional images. In USA direct-to-consumer marketing of whole body CT is occurring today in many metropolitan areas. Free standing CT screening centres are being sited in shopping malls and other high density public areas, and these centres are being advertised in the electronic and print media. In this context the present article discussed the pros and cons of having such centres in India with the advent of multislice CT leading to fast scan times.

  2. CT appearance of thickened nerves in neurofibromatosis

    SciTech Connect

    Daneman, A.; Mancer, K.; Sonley, M.

    1983-11-01

    In neutrofibromatosis (von Recklinghausen disease), peripheral nerves may develop enlarged diameters or focal fusiform enlargement due to neurofibromatous involvement. Their appearance on computed tomography (CT) forms the basis of this report.

  3. Use of CT in stapedial otosclerosis

    SciTech Connect

    Mafee, M.F.; Henrikson, G.C.; Deitch, R.L.; Norouzi, P.; Kumar, A.; Kriz, R.; Valvassori, G.E.

    1985-09-01

    Otosclerosis (otospongiosis) is a primary focal disease of the labyrinthine capsule. The stapes footplate is fixed when the spongiotic focus expands and invades the oval window. Persons with stapedial otosclerosis experience a progressive conductive hearing loss. In many cases, cochlear degeneration is observed, in which a mixed hearing loss occurs. Using computed tomography (CT), the authors studied the ears of 45 selected patients with conductive or mixed hearing loss. CT proved valuable in determining otosclerotic changes of the oval window and otic capsule. Spongiotic changes of the otic capsule are better appreciated by CT than complex motion tomography. The usefulness of CT in diagnosing other causes of conductive or mixed hearing loss is also described.

  4. CT of soft-tissue neoplasms

    SciTech Connect

    Weekes, R.G.; McLeod, R.A.; Reiman, H.M.; Pritchard, D.J.

    1985-02-01

    The computed tomographic scans (CT) of 84 patients with untreated soft-tissue neoplasms were studied, 75 with primary and nine with secondary lesions. Each scan was evaluated using several criteria: homogeneity and density, presence and type of calcification, presence of bony destruction, involvement of multiple muscle groups, definition of adjacent fat, border definition, and vessel or nerve involvement. CT demonstrated the lesion in all 84 patients and showed excellent anatomic detail in 64 of the 75 patients with primary neoplasms. The CT findings were characteristic enough to suggest the histology of the neoplasm in only 13 lesions (nine lipomas, three hemangiomas, one neurofibroma). No malignant neoplasm had CT characteristics specific enough to differentiate it from any other malignant tumor. However, malignant neoplasms could be differentiated from benign neoplasms in 88% of the cases.

  5. CT in the diagnosis of enterovesical fistulae

    SciTech Connect

    Goldman, S.M.; Fishman, E.K.; Gatewood, O.M.B.; Jones, B.; Siegelman, S.S.

    1985-06-01

    Enterovesical fistulae are difficult to demonstrate by conventional radiographic methods. Computed tomography (CT), a sensitive, noninvasive method of documenting the presence of such fistulae, is unique in its ability to outline the extravesical component of the primary disease process. Twenty enterovesical fistulae identified by CT were caused by diverticulitis (nine), carcinoma of the rectosigmoid (two), Crohn disease (three), gynecologic tumors (two), bladder cancer (one), cecal carcinoma (one), prostatic neoplasia (one), and appendiceal abscess (one). The CT findings included intravesical air (90%), passage of orally or rectally administered contrast medium into the bladder (20%), focal bladder-wall thickening (90%), thickening of adjacent bowel wall (85%), and an extraluminal mass that often contained air (75%). CT proved to be an important new method in the diagnosis of enterovesical fistulae.

  6. CT Image Presentations For Oral Surgery

    NASA Astrophysics Data System (ADS)

    Rhodes, Michael L.; Rothman, Stephen L. G.; Schwarz, Melvyn S.; Tivattanasuk, Eva S.

    1988-06-01

    Reformatted CT images of the mandible and maxilla are described as a planning aid to the surgical implantation of dental fixtures. Precisely scaled and cross referenced axial, oblique, CT generated panorex, and 3-D images are generated to help indicate where and how critical anatomic structures are positioned. This information guides the oral surgeon to those sites where dental implants have optimal osteotic support and least risk to sensitive neural tissue. Oblique images are generated at 1-2 mm increments along the arch of the mandible (or maxilla). Each oblique is oriented perpendicular to the local arch curvature. The adjoining five CT generated panorex views match the patient's mandibular (or maxilla) arch, with each of the views separated by twice the distance between axial CT slices. All views are mutually cross-referenced to show fine detail of the underlying mandibular (or maxilla) structure. Several exams are illustrated and benefit to subsequent surgery is assessed.

  7. MR and CT appearance of cardiac hemangioma

    SciTech Connect

    Kemp, J.L.; Kessler, R.M.; Raizada, V.; Williamson, M.R.

    1996-05-01

    We present a case of cardiac hemangioma in a symptomatic patient. MR and CT each have specific characteristics that should make one consider including or excluding this in the differential diagnosis of a cardiac tumor. 7 refs., 3 figs.

  8. Measuring CT scanner variability of radiomics features

    PubMed Central

    Mackin, Dennis; Fave, Xenia; Zhang, Lifei; Fried, David; Yang, Jinzhong; Taylor, Brian; Rodriguez-Rivera, Edgardo; Dodge, Cristina; Jones, A. Kyle; Court, Laurence

    2015-01-01

    Objectives The purpose of this study was to determine the significance of inter-scanner variability in CT image radiomics studies. Materials and Methods We compared the radiomics features calculated for non-small cell lung cancer (NSCLC) tumors from 20 patients with those calculated for 17 scans of a specially designed radiomics phantom. The phantom comprised 10 cartridges, each filled with different materials to produce a wide range of radiomics feature values. The scans were acquired using General Electric, Philips, Siemens, and Toshiba scanners from four medical centers using their routine thoracic imaging protocol. The radiomics feature studied included the mean and standard deviations of the CT numbers as well as textures derived from the neighborhood gray-tone difference matrix. To quantify the significance of the inter-scanner variability, we introduced the metric feature noise. To look for patterns in the scans, we performed hierarchical clustering for each cartridge. Results The mean CT numbers for the 17 CT scans of the phantom cartridges spanned from -864 to 652 Hounsfield units compared with a span of -186 to 35 Hounsfield units for the CT scans of the NSCLC tumors, showing that the phantom’s dynamic range includes that of the tumors. The inter-scanner variability of the feature values depended on both the cartridge material and the feature, and the variability was large relative to the inter-patient variability in the NSCLC tumors for some features. The feature inter-scanner noise was greatest for busyness and least for texture strength. Hierarchical clustering produced different clusters of the phantom scans for each cartridge, although there was some consistent clustering by scanner manufacturer. Conclusions The variability in the values of radiomics features calculated on CT images from different CT scanners can be comparable to the variability in these features found in CT images of NSCLC tumors. These inter-scanner differences should be

  9. CT of trauma to the abnormal kidney

    SciTech Connect

    Rhyner, P.; Federle, M.P.; Jeffrey, R.B.

    1984-04-01

    Traumatic injuries to already abnormal kidneys are difficult to assess by excretory urography and clinical evaluation. Bleeding and urinary extravasation may accompany minor trauma; conversely, underlying tumors, perirenal hemorrhage, and extravasation may be missed on urography. Computed tomography (CT) was performed in eight cases including three neoplasms, one adult polycystic disease, one simple renal cyst, two hydronephrotic kidneys, and one horseshoe kidney. CT provided specific and clinically useful information in each case that was not apparent on excretory urography.

  10. Bronchogenic cysts with high CT numbers

    SciTech Connect

    Mendelson, D.S.; Rose, J.S.; Efremidis, S.C.; Kirschner, P.A.; Cohen, B.A.

    1983-03-01

    Four patients with mediastinal masses are described. CT examinations demonstrated masses of high attenuation, and solid masses were suspected. At thoracotomy each patient had a cystic mass containing a brownish, turbid, mucoid material. The pathologic diagnosis in each case was a bronchogenic cyst. The possibility of such a cyst should not be excluded because of a high CT number, which reflects the turbid contents of the cyst.

  11. Progress in Fully Automated Abdominal CT Interpretation

    PubMed Central

    Summers, Ronald M.

    2016-01-01

    OBJECTIVE Automated analysis of abdominal CT has advanced markedly over just the last few years. Fully automated assessment of organs, lymph nodes, adipose tissue, muscle, bowel, spine, and tumors are some examples where tremendous progress has been made. Computer-aided detection of lesions has also improved dramatically. CONCLUSION This article reviews the progress and provides insights into what is in store in the near future for automated analysis for abdominal CT, ultimately leading to fully automated interpretation. PMID:27101207

  12. Pulmonary talcosis: CT findings in three cases.

    PubMed

    Padley, S P; Adler, B D; Staples, C A; Miller, R R; Müller, N L

    1993-01-01

    The authors describe the computed tomographic (CT) appearances in three patients with pulmonary talcosis resulting from chronic intravenous drug abuse. There was widespread ground-glass attenuation in one case and an appearance similar to that of progressive massive fibrosis in two cases. In the latter cases, there were confluent perihilar masses with areas of high attenuation. While the CT appearances may be suggestive of pulmonary talcosis, tissue sampling is required for definitive diagnosis.

  13. ADAPTIVE SMALL-ANIMAL SPECT/CT

    PubMed Central

    Furenlid, L.R.; Moore, J.W.; Freed, M.; Kupinski, M.A.; Clarkson, E.; Liu, Z.; Wilson, D.W.; Woolfenden, J.M.; Barrett, H.H.

    2015-01-01

    We are exploring the concept of adaptive multimodality imaging, a form of non-linear optimization where the imaging configuration is automatically adjusted in response to the object. Preliminary studies suggest that substantial improvement in objective, task-based measures of image quality can result. We describe here our work to add motorized adjustment capabilities and a matching CT to our existing FastSPECT II system to form an adaptive small-animal SPECT/CT. PMID:26617457

  14. Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

    SciTech Connect

    Fanelli, Fabrizio Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

    2011-02-15

    We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound-color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

  15. Asbestos Surveillance Program Aachen (ASPA): initial results from baseline screening for lung cancer in asbestos-exposed high-risk individuals using low-dose multidetector-row CT.

    PubMed

    Das, Marco; Mühlenbruch, Georg; Mahnken, Andreas H; Hering, K G; Sirbu, H; Zschiesche, W; Knoll, Lars; Felten, Michael K; Kraus, Thomas; Günther, Rolf W; Wildberger, Joachim E

    2007-05-01

    The purpose of this study was to assess the prevalence of lung cancer in a high-risk asbestos-exposed cohort using low-dose MDCT. Of a population of 5,389 former power-plant workers, 316 were characterized as individuals at highest risk for lung cancer according to a lung-cancer risk model including age, asbestos exposure and smoking habits. Of these 316, 187 (mean age: 66.6 years) individuals were included in a prospective trial. Mean asbestos exposure time was 29.65 years and 89% were smokers. Screening was performed on a 16-slice MDCT (Siemens) with low-dose technique (10/20 mAs(eff.); 1 mm/0.5 mm increment). In addition to soft copy PACS reading analysis on a workstation with a dedicated lung analysis software (LungCARE; Siemens) was performed. One strongly suspicious mass and eight cases of histologically proven lung cancer were found plus 491 additional pulmonary nodules (average volume: 40.72 ml, average diameter 4.62 mm). Asbestos-related changes (pleural plaques, fibrosis) were visible in 80 individuals. Lung cancer screening in this high-risk cohort showed a prevalence of lung cancer of 4.28% (8/187) at baseline screening with an additional large number of indeterminate pulmonary nodules. Low-dose MDCT proved to be feasible in this highly selected population.

  16. Relationships between the pulmonary densitometry values obtained by CT and the forced oscillation technique parameters in patients with silicosis

    PubMed Central

    Mogami, R; Camilo, G B; Machado, D C; Melo, P L; Carvalho, A R S

    2015-01-01

    Objective: To evaluate the correlations between pulmonary densitometry values and forced oscillation technique (FOT) parameters in patients with silicosis. Methods: This cross-sectional study comprised 36 non-smoker patients with silicosis and 20 matched control subjects who were submitted to FOT and multidetector CT (MDCT). Results: Compared with the control subjects, the MDCT evaluation demonstrated that patients with silicosis exhibited greater total lung mass. These patients also had larger non-aerated and poorly aerated compartments, which included nodules and scarring. Compared with the control subjects, FOT evaluation demonstrated that patients with silicosis exhibited changes in both reactive and resistive properties of the respiratory system. In these patients, there was a greater heterogeneity of the respiratory system and increased work of breathing. Significant correlations between non-aerated compartment size and FOT parameters that reflect the non-homogeneity of the respiratory system were observed. The dynamic compliance of the respiratory system was negatively correlated with non-aerated compartment size, while the impedance at 4 Hz was positively correlated with non-aerated compartment size. Conclusion: Patients with silicosis have heavier lungs. In these patients, a larger non-aerated compartment is associated with a worsening of lung function. A more significant pulmonary involvement is associated with a loss of homogeneity and increased mechanical load of the respiratory system. Advances in knowledge The findings provided by both pulmonary densitometry and FOT may add valuable information to the subjective analysis of silicosis; however, more studies are necessary to evaluate the potential use of these methods for assessing disease progression. PMID:25747897

  17. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a good'' surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  18. CT imaging of enhanced oil recovery experiments

    SciTech Connect

    Gall, B.L.

    1992-12-01

    X-ray computerized tomography (Cr) has been used to study fluid distributions during chemical enhanced oil recovery experiments. Four CT-monitored corefloods were conducted, and oil saturation distributions were calculated at various stages of the experiments. Results suggested that this technique could add significant information toward interpretation and evaluation of surfactant/polymer EOR recovery methods. CT-monitored tracer tests provided information about flow properties in the core samples. Nonuniform fluid advance could be observed, even in core that appeared uniform by visual inspection. Porosity distribution maps based on CT density calculations also showed the presence of different porosity layers that affected fluid movement through the cores. Several types of CT-monitored corefloods were conducted. Comparisons were made for CT-monitored corefloods using chemical systems that were highly successful in reducing residual oil saturations in laboratory experiments and less successful systems. Changes were made in surfactant formulation and in concentration of the mobility control polymer. Use of a poor mobility control agent failed to move oil that was not initially displaced by the injected surfactant solution; even when a ``good`` surfactant system was used. Use of a less favorable surfactant system with adequate mobility control could produce as much oil as the use of a good surfactant system with inadequate mobility control. The role of mobility control, therefore, becomes a critical parameter for successful application of chemical EOR. Continuation of efforts to use CT imaging in connection with chemical EOR evaluations is recommended.

  19. CT evaluation of the colon: inflammatory disease.

    PubMed

    Horton, K M; Corl, F M; Fishman, E K

    2000-01-01

    Computed tomography (CT) is valuable for detection and characterization of many inflammatory conditions of the colon. At CT, a dilated, thickened appendix is suggestive of appendicitis. A 1-4-cm, oval, fatty pericolic lesion with surrounding mesenteric inflammation is diagnostic of epiploic appendagitis. The key to distinguishing diverticulitis from other inflammatory conditions of the colon is the presence of diverticula in the involved segment. In typhlitis, CT demonstrates cecal distention and circumferential thickening of the cecal wall, which may have low attenuation secondary to edema. In radiation colitis, the clinical history is the key to suggesting the diagnosis because the CT findings can be nonspecific. The location of the involved segment and the extent and appearance of wall thickening may help distinguish Crohn disease and ulcerative colitis. In ischemic colitis, CT typically demonstrates circumferential, symmetric wall thickening with fold enlargement. CT findings of graft-versus-host disease include small bowel and colonic wall thickening, which may result in luminal narrowing and separation of bowel loops. In infectious colitis, the site and thickness of colon affected may suggest a specific organism. The amount of wall thickening in pseudomembranous colitis is typically greater than in any other inflammatory disease of the colon except Crohn disease.

  20. Negative appendectomy rate: influence of CT scans.

    PubMed

    McGory, Marcia L; Zingmond, David S; Nanayakkara, Darshani; Maggard, Melinda A; Ko, Clifford Y

    2005-10-01

    Negative appendectomy rate varies significantly depending on patient age and sex. However, the impact of computed tomography (CT) scans on the diagnosis of appendicitis is unknown. The goal of this study was to examine the negative appendectomy rate using a statewide database and analyze the association of receipt of CT scan. Using the California Inpatient File, all patients undergoing appendectomy in 1999-2000 were identified (n = 75,452). Demographic and clinical data were analyzed, including procedure approach (open vs laparoscopic) and appendicitis type (negative, simple, abscess, peritonitis). Patients with CT scans performed were identified to compare the negative appendectomy rate. For the entire cohort, appendicitis type was 59 per cent simple, 10 per cent with abscess, 18.7 per cent with peritonitis, and 9.3 per cent negative. Males had a lower rate of negative appendicitis than females (6.0% vs 13.4%, P < 0.0001). The use of CT scans was associated with an overall lower negative appendectomy rate for females, especially in the < 5 years and > 45 years age categories. Use of CT scans in males does not appear to be efficacious, as the negative appendectomy rates were similar across all age categories. In conclusion, use of CT was associated with lower rate of negative appendectomy, depending on patient age and sex.

  1. INCIDENTAL AND NONINCIDENTAL CANINE THYROID TUMORS ASSESSED BY MULTIDETECTOR ROW COMPUTED TOMOGRAPHY: A SINGLE-CENTRE CROSS SECTIONAL STUDY IN 4520 DOGS.

    PubMed

    Bertolini, Giovanna; Drigo, Michele; Angeloni, Luca; Caldin, Marco

    2017-02-09

    Thyroid nodules are common in dogs and are increasingly likely to be detected with the increased use of advanced imaging modalities. An unsuspected, nonpalpable, asymptomatic lesion, defined as a thyroid incidentaloma, may be discovered on an imaging study unrelated to the thyroid gland. The objective of this single-center cross-sectional study was to assess the prevalence and computed tomography (CT) characteristics of incidental and nonincidental thyroid tumors in a large population of dogs, using prospective recruitment of patients undergoing CT examination for various reasons during the period of 2005-2015. Unilateral or bilateral thyroid masses were detected in 96/4520 dogs (prevalence, 2.12%; 95% confidence interval [CI], 1.70-2.54%). Seventy-nine (82.3%) lesions were malignant and 17 (17.7%) were benign. Masses were discovered incidentally in 34/96 dogs (overall prevalence of incidentaloma, 0.76%; 95% CI, 0.51-1.02), and 24 (70.6%) of these 34 masses were thyroid carcinomas. Among the CT variables assessed, mineralization, vascular invasion, and tissue invasion were detected only in malignant tumors. Intratumoral vascularization was significantly associated with the presence of thyroid malignancy (P < 0.001). Although incidental thyroid nodules in dogs are relatively rare, they are often malignant. Findings indicated that the neck should be thoroughly assessed in middle-aged and old patients undergoing body CT for various reasons. Thyroid nodules detected incidentally on CT should be sampled to avoid missing thyroid cancer.

  2. Longitudinal changes in structural abnormalities using MDCT in COPD: do the CT measurements of airway wall thickness and small pulmonary vessels change in parallel with emphysematous progression?

    PubMed Central

    Takayanagi, Shin; Kawata, Naoko; Tada, Yuji; Ikari, Jun; Matsuura, Yukiko; Matsuoka, Shin; Matsushita, Shoichiro; Yanagawa, Noriyuki; Kasahara, Yasunori; Tatsumi, Koichiro

    2017-01-01

    Background Recent advances in multidetector computed tomography (MDCT) facilitate acquiring important clinical information for managing patients with COPD. MDCT can detect the loss of lung tissue associated with emphysema as a low-attenuation area (LAA) and the thickness of airways as the wall area percentage (WA%). The percentage of small pulmonary vessels <5 mm2 (% cross-sectional area [CSA] <5) has been recently recognized as a parameter for expressing pulmonary perfusion. We aimed to analyze the longitudinal changes in structural abnormalities using these CT parameters and analyze the effect of exacerbation and smoking cessation on structural changes in COPD patients. Methods We performed pulmonary function tests (PFTs), an MDCT, and a COPD assessment test (CAT) in 58 patients with COPD at the time of their enrollment at the hospital and 2 years later. We analyzed the change in clinical parameters including CT indices and examined the effect of exacerbations and smoking cessation on the structural changes. Results The CAT score and forced expiratory volume in 1 second (FEV1) did not significantly change during the follow-up period. The parameters of emphysematous changes significantly increased. On the other hand, the WA% at the distal airways significantly decreased or tended to decrease, and the %CSA <5 slightly but significantly increased over the same period, especially in ex-smokers. The parameters of emphysematous change were greater in patients with exacerbations and continued to progress even after smoking cessation. In contrast, the WA% and %CSA <5 did not change in proportion to emphysema progression. Conclusion The WA% at the distal bronchi and the %CSA <5 did not change in parallel with parameters of LAA over the same period. We propose that airway disease and vascular remodeling may be reversible to some extent by smoking cessation and appropriate treatment. Optimal management may have a greater effect on pulmonary vascularity and airway disease

  3. Prevalence and Distribution of Ossified Lesions in the Whole Spine of Patients with Cervical Ossification of the Posterior Longitudinal Ligament A Multicenter Study (JOSL CT study)

    PubMed Central

    Hirai, Takashi; Yoshii, Toshitaka; Iwanami, Akio; Takeuchi, Kazuhiro; Mori, Kanji; Yamada, Tsuyoshi; Wada, Kanichiro; Koda, Masao; Matsuyama, Yukihiro; Takeshita, Katsushi; Abematsu, Masahiko; Haro, Hirotaka; Watanabe, Masahiko; Watanabe, Kei; Ozawa, Hiroshi; Kanno, Haruo; Imagama, Shiro; Fujibayashi, Shunsuke; Yamazaki, Masashi; Matsumoto, Morio; Nakamura, Masaya; Okawa, Atsushi; Kawaguchi, Yoshiharu

    2016-01-01

    Ossification of the posterior longitudinal ligament (OPLL) can cause severe and irreversible paralysis in not only the cervical spine but also the thoracolumbar spine. To date, however, the prevalence and distribution of OPLL in the whole spine has not been precisely evaluated in patients with cervical OPLL. Therefore, we conducted a multi-center study to comprehensively evaluate the prevalence and distribution of OPLL using multi-detector computed tomography (CT) images in the whole spine and to analyze what factors predict the presence of ossified lesions in the thoracolumbar spine in patients who were diagnosed with cervical OPLL by plain X-ray. Three hundred and twenty-two patients with a diagnosis of cervical OPLL underwent CT imaging of the whole spine. The sum of the levels in which OPLL was present in the whole spine was defined as the OP-index and used to evaluate the extent of ossification. The distribution of OPLL in the whole spine was compared between male and female subjects. In addition, a multiple regression model was used to ascertain related factors that affected the OP-index. Among patients with cervical OPLL, women tended to have more ossified lesions in the thoracolumbar spine than did men. A multiple regression model revealed that the OP-index was significantly correlated with the cervical OP-index, sex (female), and body mass index. Furthermore, the prevalence of thoracolumbar OPLL in patients with a cervical OP-index ≥ 10 was 7.8 times greater than that in patients with a cervical OP-index ≤ 5. The results of this study reveal that the extent of OPLL in the whole spine is significantly associated with the extent of cervical OPLL, female sex, and obesity. PMID:27548354

  4. Computing effective dose in cardiac CT

    NASA Astrophysics Data System (ADS)

    Huda, Walter; Tipnis, Sameer; Sterzik, Alexander; Schoepf, U. Joseph

    2010-07-01

    We present a method of estimating effective doses in cardiac CT that accounts for selected techniques (kV mAs-1), anatomical location of the scan and patient size. A CT dosimetry spreadsheet (ImPACT CT Patient Dosimetry Calculator) was used to estimate effective doses (E) using ICRP 103 weighting factors for a 70 kg patient undergoing cardiac CT examinations. Using dose length product (DLP) for the same scans, we obtained values of E/DLP for three CT scanners used in cardiac imaging from two vendors. E/DLP ratios were obtained as a function of the anatomical location in the chest and for x-ray tube voltages ranging from 80 to 140 kV. We also computed the ratio of the average absorbed dose in a water cylinder modeling a patient weighing W kg to the corresponding average absorbed dose in a water cylinder equivalent to a 70 kg patient. The average E/DLP for a 16 cm cardiac heart CT scan was 26 µSv (mGy cm)-1, which is about 70% higher than the current E/DLP values used for chest CT scans (i.e. 14-17 µSv (mGy cm)-1). Our cardiac E/DLP ratios are higher because the cardiac region is ~30% more radiosensitive than the chest, and use of the ICRP 103 tissue weighting factors increases cardiac CT effective doses by ~30%. Increasing the x-ray tube voltage from 80 to 140 kV increases the E/DLP conversion factor for cardiac CT by 17%. For the same incident radiation at 120 kV, doses in 45 kg adults were ~22% higher than those in 70 kg adults, whereas doses in 120 kg adults were ~28% lower. Accurate estimates of the patient effective dose in cardiac CT should use ICRP 103 tissue weighting factors, and account for a choice of scan techniques (kV mAs-1), exposed scan region, as well as patient size.

  5. Characterizing anatomical variability in breast CT images

    PubMed Central

    Metheany, Kathrine G.; Abbey, Craig K.; Packard, Nathan; Boone, John M.

    2008-01-01

    Previous work [Burgess , Med. Phys. 28, 419–437 (2001)] has shown that anatomical noise in projection mammography results in a power spectrum well modeled over a range of frequencies by a power law, and the exponent (β) of this power law plays a critical role in determining the size at which a growing lesion reaches the threshold for detection. In this study, the authors evaluated the power-law model for breast computed tomography (bCT) images, which can be thought of as thin sections through a three-dimensional (3D) volume. Under the assumption of a 3D power law describing the distribution of attenuation coefficients in the breast parenchyma, the authors derived the relationship between the power-law exponents of bCT and projection images and found it to be βsection=βproj−1. They evaluated this relationship on clinical images by comparing bCT images from a set of 43 patients to Burgess’ findings in mammography. They were able to make a direct comparison for 6 of these patients who had both a bCT exam and a digitized film-screen mammogram. They also evaluated segmented bCT images to investigate the extent to which the bCT power-law exponent can be explained by a binary model of attenuation coefficients based on the different attenuation of glandular and adipose tissue. The power-law model was found to be a good fit for bCT data over frequencies from 0.07to0.45cyc∕mm, where anatomical variability dominates the spectrum. The average exponent for bCT images was 1.86. This value is close to the theoretical prediction using Burgess’ published data for projection mammography and for the limited set of mammography data available from the authors’ patient sample. Exponents from the segmented bCT images (average value: 2.06) were systematically slightly higher than bCT images, with substantial correlation between the two (r=0.84). PMID:18975714

  6. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    SciTech Connect

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Liu, Bob; Liu, Tianyu; Xu, X. George

    2014-09-15

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  7. In vitro dose measurements in a human cadaver with abdomen/pelvis CT scans

    PubMed Central

    Zhang, Da; Padole, Atul; Li, Xinhua; Singh, Sarabjeet; Khawaja, Ranish Deedar Ali; Lira, Diego; Liu, Tianyu; Shi, Jim Q.; Otrakji, Alexi; Kalra, Mannudeep K.; Xu, X. George; Liu, Bob

    2014-01-01

    Purpose: To present a study of radiation dose measurements with a human cadaver scanned on a clinical CT scanner. Methods: Multiple point dose measurements were obtained with high-accuracy Thimble ionization chambers placed inside the stomach, liver, paravertebral gutter, ascending colon, left kidney, and urinary bladder of a human cadaver (183 cm in height and 67.5 kg in weight) whose abdomen/pelvis region was scanned repeatedly with a multidetector row CT. The flat energy response and precision of the dosimeters were verified, and the slight differences in each dosimeter's response were evaluated and corrected to attain high accuracy. In addition, skin doses were measured for radiosensitive organs outside the scanned region with OSL dosimeters: the right eye, thyroid, both nipples, and the right testicle. Three scan protocols were used, which shared most scan parameters but had different kVp and mA settings: 120-kVp automA, 120-kVp 300 mA, and 100-kVp 300 mA. For each protocol three repeated scans were performed. Results: The tube starting angle (TSA) was found to randomly vary around two major conditions, which caused large fluctuations in the repeated point dose measurements: for the 120-kVp 300 mA protocol this angle changed from approximately 110° to 290°, and caused 8% − 25% difference in the point dose measured at the stomach, liver, colon, and urinary bladder. When the fluctuations of the TSA were small (within 5°), the maximum coefficient of variance was approximately 3.3%. The soft tissue absorbed doses averaged from four locations near the center of the scanned region were 27.2 ± 3.3 and 16.5 ± 2.7 mGy for the 120 and 100-kVp fixed-mA scans, respectively. These values were consistent with the corresponding size specific dose estimates within 4%. The comparison of the per-100-mAs tissue doses from the three protocols revealed that: (1) dose levels at nonsuperficial locations in the TCM scans could not be accurately deduced by simply scaling the

  8. Renal Cell Carcinoma with Paraneoplastic Manifestations: Imaging with CT and F-18 FDG PET/CT.

    PubMed

    Nguyen, Ba D; Roarke, Michael C

    2007-01-01

    We present a case of renal cell carcinoma with prominent inflammatory and paraneoplastic manifestations. The initial CT detection of renal malignancy and subsequent post-therapeutic F-18 FDG PET/CT diagnosis of occult osseous metastasis were based on the patient's anemia, thrombocytosis and abnormally increased levels of serum C-reactive protein.

  9. AAPM/RSNA Physics Tutorial for Residents: Topics in CT. Radiation dose in CT.

    PubMed

    McNitt-Gray, Michael F

    2002-01-01

    This article describes basic radiation dose concepts as well as those specifically developed to describe the radiation dose from computed tomography (CT). Basic concepts of radiation dose are reviewed, including exposure, absorbed dose, and effective dose. Radiation dose from CT demonstrates variations within the scan plane and along the z axis because of its unique geometry and usage. Several CT-specific dose descriptors have been developed: the Multiple Scan Average Dose descriptor, the Computed Tomography Dose Index (CTDI) and its variations (CTDI(100), CTDI(w), CTDI(vol)), and the dose-length product. Factors that affect radiation dose from CT include the beam energy, tube current-time product, pitch, collimation, patient size, and dose reduction options. Methods of reducing the radiation dose to a patient from CT include reducing the milliampere-seconds value, increasing the pitch, varying the milliampere-seconds value according to patient size, and reducing the beam energy. The effective dose from CT can be estimated by using Monte Carlo methods to simulate CT of a mathematical patient model, by estimating the energy imparted to the body region being scanned, or by using conversion factors for general anatomic regions. Issues related to radiation dose from CT are being addressed by the Society for Pediatric Radiology, the American Association of Physicists in Medicine, the American College of Radiology, and the Center for Devices and Radiological Health of the Food and Drug Administration.

  10. Current role of hybrid CT/angiography system compared with C-arm cone beam CT for interventional oncology

    PubMed Central

    Arai, Y; Inaba, Y; Inoue, M; Nishiofuku, H; Anai, H; Hori, S; Sakaguchi, H; Kichikawa, K

    2014-01-01

    Hybrid CT/angiography (angiography) system and C-arm cone beam CT provide cross-sectional imaging as an adjunct to angiography. Current interventional oncological procedures can be conducted precisely using these two technologies. In this article, several cases using a hybrid CT/angiography system are shown first, and then the advantages and disadvantages of the hybrid CT/angiography and C-arm cone beam CT are discussed with literature reviews. PMID:24968749

  11. Current role of hybrid CT/angiography system compared with C-arm cone beam CT for interventional oncology.

    PubMed

    Tanaka, T; Arai, Y; Inaba, Y; Inoue, M; Nishiofuku, H; Anai, H; Hori, S; Sakaguchi, H; Kichikawa, K

    2014-09-01

    Hybrid CT/angiography (angiography) system and C-arm cone beam CT provide cross-sectional imaging as an adjunct to angiography. Current interventional oncological procedures can be conducted precisely using these two technologies. In this article, several cases using a hybrid CT/angiography system are shown first, and then the advantages and disadvantages of the hybrid CT/angiography and C-arm cone beam CT are discussed with literature reviews.

  12. Evaluation of superior vena cava syndrome by axial CT and CT phlebography

    SciTech Connect

    Moncada, R.; Cardella, R.; Demos, T.C.; Churchill, R.J.; Cardoso, M.; Love, L.; Reynes, C.J.

    1984-10-01

    Transverse axial computed tomography (CT) has been combined with CT digital phlebography to study nine patients with superior vena cava syndrome. Six were due to malignancy, two were secondary to benign disease, and one was a paraneoplastic manifestation. This combined CT approach successfully identified the abnormal morphology of the superior vena cava, demonstrating external compression, encasement, or intraluminal thrombus in all patients and the collateral venous channels in eight. This technique is a rapid, informative, and cost-effective method for the workup of superior vena cava syndrome. The CT digital phlebogram, however, is not successful in regularly and optimally opacifying the normal superior vena cava because of the limited amount of contrast material, dilution effect of the nonopacified incoming flow from the jugular and azygos veins, and the lack of image enhancement from the CT digital scanograms.

  13. Friction Reduction for Microhole CT Drilling

    SciTech Connect

    Ken Newman; Patrick Kelleher; Edward Smalley

    2007-03-31

    The objective of this 24 month project focused on improving microhole coiled tubing drilling bottom hole assembly (BHA) reliability and performance, while reducing the drilling cost and complexity associated with inclined/horizontal well sections. This was to be accomplished by eliminating the need for a downhole drilling tractor or other downhole coiled tubing (CT) friction mitigation techniques when drilling long (>2,000 ft.) of inclined/horizontal wellbore. The technical solution to be developed and evaluated in this project was based on vibrating the coiled tubing at surface to reduce the friction along the length of the downhole CT drillstring. The Phase 1 objective of this project centered on determining the optimum surface-applied vibration system design for downhole CT friction mitigation. Design of the system would be based on numerical modeling and laboratory testing of the CT friction mitigation achieved with various types of surface-applied vibration. A numerical model was developed to predict how far downhole the surface-applied vibration would travel. A vibration test fixture, simulating microhole CT drilling in a horizontal wellbore, was constructed and used to refine and validate the numerical model. Numerous tests, with varying surface-applied vibration parameters were evaluated in the vibration test fixture. The data indicated that as long as the axial force on the CT was less than the helical buckling load, axial vibration of the CT was effective at mitigating friction. However, surface-applied vibration only provided a small amount of friction mitigation as the helical buckling load on the CT was reached or exceeded. Since it would be impractical to assume that routine field operations be conducted at less than the helical buckling load of the CT, it was determined that this technical approach did not warrant the additional cost and maintenance issues that would be associated with the surface vibration equipment. As such, the project was

  14. Fast CT-CT fluoroscopy registration with respiratory motion compensation for image-guided lung intervention

    NASA Astrophysics Data System (ADS)

    Su, Po; Xue, Zhong; Lu, Kongkuo; Yang, Jianhua; Wong, Stephen T.

    2012-02-01

    CT-fluoroscopy (CTF) is an efficient imaging method for guiding percutaneous lung interventions such as biopsy. During CTF-guided biopsy procedure, four to ten axial sectional images are captured in a very short time period to provide nearly real-time feedback to physicians, so that they can adjust the needle as it is advanced toward the target lesion. Although popularly used in clinics, this traditional CTF-guided intervention procedure may require frequent scans and cause unnecessary radiation exposure to clinicians and patients. In addition, CTF only generates limited slices of images and provides limited anatomical information. It also has limited response to respiratory movements and has narrow local anatomical dynamics. To better utilize CTF guidance, we propose a fast CT-CTF registration algorithm with respiratory motion estimation for image-guided lung intervention using electromagnetic (EM) guidance. With the pre-procedural exhale and inhale CT scans, it would be possible to estimate a series of CT images of the same patient at different respiratory phases. Then, once a CTF image is captured during the intervention, our algorithm can pick the best respiratory phase-matched 3D CT image and performs a fast deformable registration to warp the 3D CT toward the CTF. The new 3D CT image can be used to guide the intervention by superimposing the EM-guided needle location on it. Compared to the traditional repetitive CTF guidance, the registered CT integrates both 3D volumetric patient data and nearly real-time local anatomy for more effective and efficient guidance. In this new system, CTF is used as a nearly real-time sensor to overcome the discrepancies between static pre-procedural CT and the patient's anatomy, so as to provide global guidance that may be supplemented with electromagnetic (EM) tracking and to reduce the number of CTF scans needed. In the experiments, the comparative results showed that our fast CT-CTF algorithm can achieve better registration

  15. Patient doses from CT examinations in Turkey

    PubMed Central

    Ataç, Gökçe Kaan; Parmaksız, Aydın; İnal, Tolga; Bulur, Emine; Bulgurlu, Figen; Öncü, Tolga; Gündoğdu, Sadi

    2015-01-01

    PURPOSE We aimed to establish the first diagnostic reference levels (DRLs) for computed tomography (CT) examinations in adult and pediatric patients in Turkey and compare these with international DRLs. METHODS CT performance information and examination parameters (for head, chest, high-resolution CT of the chest [HRCT-chest], abdominal, and pelvic protocols) from 1607 hospitals were collected via a survey. Dose length products and effective doses for standard patient sizes were calculated from the reported volume CT dose index (CTDIvol). RESULTS The median number of protocols reported from the 167 responding hospitals (10% response rate) was 102 across five different age groups. Third quartile CTDIvol values for adult pelvic and all pediatric body protocols were higher than the European Commission standards but were comparable to studies conducted in other countries. CONCLUSION The radiation dose indicators for adult patients were similar to those reported in the literature, except for those associated with head protocols. CT protocol optimization is necessary for adult head and pediatric chest, HRCT-chest, abdominal, and pelvic protocols. The findings from this study are recommended for use as national DRLs in Turkey. PMID:26133189

  16. Study of tuberculous meningitis by CT.

    PubMed

    Rovira, M; Romero, F; Torrent, O; Ibarra, B

    1980-04-01

    Computed tomography is a very valuable method by which the pathogenic evolution of tuberculous meningitis may be followed, thereby facilitating its differential diagnosis and controlling the efficiency of therapy. The initial miliary tuberculosis in the brain, very often unaccompanied by neurological symptoms, may offer very evident CT images. CT may also demonstrate the fibrogelatinous exudate which fills the basal cisterns and surrounds the arterial vessels which cross this region. Because of this, secondary arteritis is frequent and may be indirectly detected by CT in the form of foci of ischemic infarcts. Tuberculomas may be multiple, and are found equally in the cerebral and the cerebellar parenchyma. These tuberculomas present different images on CT, depending on the evolution of the disease at that moment. Hydrocephalus is a common complication of TM and is caused by a lack of reabsorption of the cerebrospinal fluid, or by an obstructive lesion in the ventricular drainage pathways due to a tuberculoma. This complication is usually easily identified by CT, which, moreover, permits the control of its evolution.

  17. CRYPTOSPORIDIUM LOG-INACTIVATION WITH OZONE USING EFFLUENT CT 10, GEOMETRIC MEAN CT 10 EXTENDED INTEGRATED CT 10 AND EXTENDED-CSTR CALCULATIONS

    EPA Science Inventory

    The draft Long Term 2 Enhanced Surface Water Treatment Rule ("LT2ESWTR") contains Cryptosporidium log-inactivation CT tables. Depending on the water temperature, the Cryptosporidium CT values that are listed are 15 to 25 times greater than CT values fo...

  18. CT10: a new cancer-testis (CT) antigen homologous to CT7 and the MAGE family, identified by representational-difference analysis.

    PubMed

    Güre, A O; Stockert, E; Arden, K C; Boyer, A D; Viars, C S; Scanlan, M J; Old, L J; Chen, Y T

    2000-03-01

    Assays relying on humoral or T-cell-based recognition of tumor antigens to identify potential targets for immunotherapy have led to the discovery of a significant number of immunogenic gene products, including cancer-testis (CT) antigens predominantly expressed in cancer cells and male germ cells. The search for cancer-specific antigens has been extended via the technique of representational-difference analysis and SK-MEL-37, a melanoma cell line expressing a broad range of CT antigens. Using this approach, we have isolated CT antigen genes, genes over-expressed in cancer, e. g., PRAME and KOC, and genes encoding neuro-ectodermal markers. The identified CT antigen genes include the previously defined MAGE-A6, MAGE-A4a, MAGE-A10, CT7/MAGE-C1, as well as a novel gene designated CT10, which shows strong homology to CT7/MAGE-C1 both at cDNA and at genomic levels. Chromosome mapping localized CT10 to Xq27, in close proximity to CT7/MAGE-C1 and MAGE-A genes. CT10 mRNA is expressed in testis and in 20 to 30% of various human cancers. A serological survey identified 2 melanoma patients with anti-CT10 antibody, demonstrating the immunogenicity of CT10 in humans.

  19. [Analysis of Factors on Clinical Application of Vehicle CT Shelter].

    PubMed

    Shuai, Wanjun; Chao, Yong; Liu, Shuai; Dong, Can; Gao, Huayong; Tan, Shulin; Niu, Fu

    2015-09-01

    To assure the clinical quality and requirement of CT shelter used in field environment, the factors related with the practical application were studied. The evaluation indicators of CT equipment were investigated. Based on the technical modification of vehicle shelter CT, the scanning conditions of shelter CT were analyzed. Moreover, the comparative study was done between shelter CT and common CT in hospitals. In result, in order to meet maneuverability application in the field, vehicle shelter CT was restrictive by the field conditions, traffic impacts and running requirement. The application of vehicle shelter CT was affected by the factors, such as mechanical stabilization, moving precision, power fluctuations and variations of temperature and humidity, etc. The results were helpful to improve the clinical quality of vehicle shelter CT and made a base for the quality control study in the future.

  20. Noise, sampling, and the number of projections in cone-beam CT with a flat-panel detector

    SciTech Connect

    Zhao, Z.; Gang, G. J.; Siewerdsen, J. H.

    2014-06-15

    Purpose: To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. Methods: This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically motivated “clutter”) and theoretically (using a cascaded systems model describing CBCT noise) to elucidate the contributing factors of quantum noise (σ{sub Q}), electronic noise (σ{sub E}), and view aliasing (σ{sub view}). Analysis included investigation of the noise, noise-power spectrum, and modulation transfer function as a function of the number of projections (N{sub proj}), dose (D{sub tot}), and voxel size (b{sub vox}). Results: The results reveal a nonmonotonic relationship between image noise andN{sub proj} at fixed total dose: for the CBCT system considered, noise decreased with increasing N{sub proj} due to reduction of view sampling effects in the regime N{sub proj} <∼200, above which noise increased with N{sub proj} due to increased electronic noise. View sampling effects were shown to depend on the heterogeneity of the object in a direct analytical relationship to power-law anatomical clutter of the form κ/f {sup β}—and a general model of individual noise components (σ{sub Q}, σ{sub E}, and σ{sub view}) demonstrated agreement with measurements over a broad range in N{sub proj}, D{sub tot}, and b{sub vox}. Conclusions: The work elucidates fairly basic elements of CBCT noise in a manner that demonstrates the role of distinct noise components (viz., quantum, electronic, and view sampling noise). For configurations fairly typical of CBCT with a flat-panel detector (FPD), the analysis reveals a “sweet spot” (i.e., minimum noise) in the rangeN{sub proj} ∼ 250–350, nearly an order of magnitude lower in N{sub proj} than typical of multidetector CT, owing to the relatively high electronic noise in FPDs. The analysis

  1. 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

  2. CT measurments of cranial growth: normal subjects

    SciTech Connect

    Hahn, F.J.; Chu, W.K.; Cheung, J.Y.

    1984-06-01

    Growth patterns of the cranium measured directly as head circumference have been well documented. With the availability of computed tomography (CT) , cranial dimensions can be obtained easily. The objective of this project was to establish the mean values and their normal variance of CT cranial area of subjects at different ages. Cranial area and its long and short axes were measured on CT scans for 215 neurologic patients of a wide age range who presented no evidence of abnormal growth of head size. Growth patterns of the cranial area as well as the numeric product of it linear dimensions were determined via a curve fitting process. The patterns resemble that of the head circumference growth chart, with the most rapid growth observed in the first 12 months of age and reaching full size during adolescence.

  3. CT densitometry of the lungs: Scanner performance

    SciTech Connect

    Kemerink, G.J.; Lamers, R.J.S.; Thelissen, G.R.P.; Engelshoven, J.M.A. van

    1996-01-01

    Our goal was to establish the reproducibility and accuracy of the CT scanner in densitometry of the lungs. Scanner stability was assessed by analysis of daily quality checks. Studies using a humanoid phantom and polyethylene foams for lung were performed to measure reproducibility and accuracy. The dependence of the CT-estimated density on reconstruction filter, zoom factor, slice thickness, table height, data truncation, and objects outside the scan field was determined. Stability of the system at air density was within {approx}1 HU and at water density within {approx}2 HU. Reproducibility and accuracy for densities found for lung were within 2-3%. Dependence on the acquisition and reconstruction parameters was neglible, with the exceptions of the ultra high resolution reconstruction algorithm in the case of emphysema, and objects outside the scan field. The performance of the CT scanner tested is quite adequate for densitometry of the lungs. 26 refs., 5 figs., 4 tabs.

  4. Neck after total laryngectomy: CT study

    SciTech Connect

    DiSantis, D.J.; Balfe, D.M.; Hayden, R.E.; Sagel, S.S.; Sessions, D.; Lee, J.K.T.

    1984-12-01

    Computed tomographic scans in 23 patients who had undergone total laryngectomy were analyzed retrospectively to determine normal postoperative appearance and to evaluate the role of CT in assessing recurrent neoplasm. Nine patients without clinical evidence of recurrence illustrated the normal postoperative changes: a round or ovoid neopharynx connecting the base of the tongue with the cervical esophagus and intact fat planes surrounding the neopharynx, neurovascular bundles, and sternocleidomastoid muscles. In the 12 patients with recurrent neoplasm, the CT manifestations included masses involving the internal jugular lymph node chain, tracheostomy site, or paratracheal region. CT supplemented physical examination and indirect mirror examination, providing data regarding presence and extent of recurrent tumor and aiding in planning the mode and scope of therapy.

  5. Stercoral colitis: diagnostic value of CT findings

    PubMed Central

    Ünal, Emre; Onur, Mehmet Ruhi; Balcı, Sinan; Görmez, Ayşegül; Akpınar, Erhan; Böge, Medine

    2017-01-01

    PURPOSE We aimed to evaluate the CT findings of stercoral colitis (SC). METHODS Forty-one patients diagnosed with SC between February 2006 and April 2015 were retrospectively reviewed. RESULTS Rectosigmoid colon was the most frequently involved segment (100%, n=41). CT findings can be summarized as follows: dilatation >6 cm and wall thickening >3 mm of the affected colon segment (100%, n=41), pericolonic fat stranding (100%, n=41), mucosal discontinuity (14.6 %, n=6), presence of free air (14.6%, n=6), free fluid (9.7%, n=4), and pericolonic abscess (2.4%, n=1). The sign most related with mortality was the length of the affected colon segment >40 cm. CONCLUSION CT has an important role in SC, since life-threatening complications can be easily revealed by this imaging modality. Increased length of involved colon segment (>40 cm) is more likely to be associated with mortality. PMID:27910814

  6. Magnetic resonance imaging and multi-detector computed tomography assessment of extracellular compartment in ischemic and non-ischemic myocardial pathologies

    PubMed Central

    Saeed, Maythem; Hetts, Steven W; Jablonowski, Robert; Wilson, Mark W

    2014-01-01

    Myocardial pathologies are major causes of morbidity and mortality worldwide. Early detection of loss of cellular integrity and expansion in extracellular volume (ECV) in myocardium is critical to initiate effective treatment. The three compartments in healthy myocardium are: intravascular (approximately 10% of tissue volume), interstitium (approximately 15%) and intracellular (approximately 75%). Myocardial cells, fibroblasts and vascular endothelial/smooth muscle cells represent intracellular compartment and the main proteins in the interstitium are types I/III collagens. Microscopic studies have shown that expansion of ECV is an important feature of diffuse physiologic fibrosis (e.g., aging and obesity) and pathologic fibrosis [heart failure, aortic valve disease, hypertrophic cardiomyopathy, myocarditis, dilated cardiomyopathy, amyloidosis, congenital heart disease, aortic stenosis, restrictive cardiomyopathy (hypereosinophilic and idiopathic types), arrythmogenic right ventricular dysplasia and hypertension]. This review addresses recent advances in measuring of ECV in ischemic and non-ischemic myocardial pathologies. Magnetic resonance imaging (MRI) has the ability to characterize tissue proton relaxation times (T1, T2, and T2*). Proton relaxation times reflect the physical and chemical environments of water protons in myocardium. Delayed contrast enhanced-MRI (DE-MRI) and multi-detector computed tomography (DE-MDCT) demonstrated hyper-enhanced infarct, hypo-enhanced microvascular obstruction zone and moderately enhanced peri-infarct zone, but are limited for visualizing diffuse fibrosis and patchy microinfarct despite the increase in ECV. ECV can be measured on equilibrium contrast enhanced MRI/MDCT and MRI longitudinal relaxation time mapping. Equilibrium contrast enhanced MRI/MDCT and MRI T1 mapping is currently used, but at a lower scale, as an alternative to invasive sub-endomyocardial biopsies to eliminate the need for anesthesia, coronary

  7. Relationship between routine multi-detector cardiac computed tomographic angiography prior to reoperative cardiac surgery, length of stay, and hospital charges.

    PubMed

    Goldstein, Matthew A; Roy, Sion K; Hebsur, Shinivas; Maluenda, Gabriel; Weissman, Gaby; Weigold, Guy; Landsman, Marc J; Hill, Peter C; Pita, Francisco; Corso, Paul J; Boyce, Steven W; Pichard, Augusto D; Waksman, Ron; Taylor, Allen J

    2013-03-01

    While multi-detector cardiac computed tomography angiography (MDCCTA) prior to reoperative cardiac surgery (RCS) has been associated with improved clinical outcomes, its impact on hospital charges and length of stay remains unclear. We studied 364 patients undergoing RCS at Washington Hospital Center between 2004 and 2008, including 137 clinically referred for MDCCTA. Baseline demographics, procedural data, and perioperative outcomes were recorded at the time of the procedure. The primary clinical endpoint was the composite of perioperative death, myocardial infarction (MI), stroke, and hemorrhage-related reoperation. Secondary clinical endpoints included surgical procedural variables and the perioperative volume of bleeding and transfusion. Length of stay was determined using the hospital's electronic medical record. Cost data were extracted from the hospital's billing summary. Analysis was performed on individual categories of care, as well as on total hospital charges. Data were compared between subjects with and without MDCCTA, after adjustment for the Society of Thoracic Surgeons score. Baseline characteristics were similar between the two groups. MDCCTA was associated with shorter procedural times, shorter intensive care unit stays, fewer blood transfusions, and less frequent perioperative MI. There was additionally a trend towards a lower incidence of the primary endpoint (17.5 vs. 24.2 %, p = 0.13) primarily due to a lower incidence of perioperative MI (0 vs. 5.7 %, p = 0.002). MDCCTA was also associated with lower median recovery room [$1,325 (1,250-3,302) vs. $3,217 (1,325-5,353) p < 0.001] and nursing charges [$6,335 (3,623-10,478) vs. $6,916 (3,915-14,499) p = 0.03], although operating room charges were higher [$24,100 (22,300-29,700) vs. $23,500 (19,900-27,700) p < 0.05]. Median total charges [$127,000 (95,000-188,000) vs. $123,000 (86,800-226,000) p = 0.77] and length of stay [9 days (6-19) vs. 11 days (7-19), p = 0.21] were similar. Means analysis

  8. Patient position verification using CT images.

    PubMed

    Kress, J; Minohara, S; Endo, M; Debus, J; Kanai, T

    1999-06-01

    The use of ions in the radiotherapy of cancer patients requires an accurate patient positioning in order to exploit its potential benefits. Using CT images as the basis for the setup verification offers the advantage of a high in-plane resolution in combination with a geometrically accurate, volumetric information. Before each fraction a single CT slice is acquired at the isocenter level after the positioning procedure. This single slice is registered to the planning CT cube using automated image registration algorithms. Thus any erreonous translation or rotation can be detected and quantified. The registration process involves the interpolation of the volumetric data, the calculation of an energy function, and the minimization of this energy function. Several data interpolation functions as well as minimization algorithms were compared. CT studies with a head phantom were performed in which defined translations and rotations were simulated by moving a motor-driven treatment chair. Different slice thicknesses and anatomical sites were studied to investigate their potential influence on the registration accuracy. The accuracy of the registration was found to be a fraction of a voxel size for suitable combinations of algorithms (typically better than 0.16 mm/deg). A significant dependancy of the registration accuracy on the CT slice thickness and the anatomical site was found (the accuracy ranges from 0.05 mm/deg to 0.16 mm/deg depending on the site). The calculation time is dependant on the used algorithms and the magnitude of the setup error. For the standard combination of algorithms as proposed by the authors (Downhill Simplex minimization with Trilinear interpolation) the typical calculation time is about 20 s for a Sun UltraSPARC processor. Taking into account the mechanical accuracy of the setup device (motor-driven chair) the registration of CT images is thus a useful tool for detecting and quantifying any significant error in the patient position.

  9. CT angiography of renal arteriovenous fistulae: a report of two cases.

    PubMed

    Abdel-Gawad, Ehab A; Housseini, Ahmed M; Cherry, Kenneth J; Bonatti, Hugo; Maged, Ismaeel M; Norton, Patrick T; Hagspiel, Klaus D

    2009-01-01

    Renal arteriovenous fistulas (AVFs) are rare abnormal communications between the arterial and venous circulations that can be congenital or acquired. We describe the multidetector computed tomography angiography (MDCTA) appearance of 2 cases of renal AVF, one with the cirsoid and one with the aneurysmal subtype, and the impact of these findings on therapeutic decision making and treatment follow-up.

  10. Incidental pulmonary embolism in cancer patients: clinical characteristics and outcome – a comprehensive cancer center experience

    PubMed Central

    Abdel-Razeq, Hikmat N; Mansour, Asem H; Ismael, Yousef M

    2011-01-01

    Background and objectives: Cancer patients undergo routine imaging studies much more than others. The widespread use of the recently introduced multi-detector CT scanners has resulted in an increasing number of incidentally diagnosed pulmonary embolism (PE) in asymptomatic cancer patients. The significance and clinical outcome of such incidental PE is described. Methods: Both radiology department and hospital databases were searched for all cancer patients with a diagnosis of incidental PE. CT scans were performed using a 64-slice scanner with a 5.0 mm slice thickness. Results: During the study period, 34 patients with incidental PE were identified. The mean age (±SD) was 57.7 (±12.4) years. All patients had active cancer, gastric, lung, colorectal, and lymphomas being the most frequent. Most patients had advanced-stage disease at the time of PE diagnosis; 26 (77%) patients had stage IV, whereas only 3 patients had stages I or II disease. Twenty-seven (79%) patients had their PE while undergoing active treatment with chemotherapy (68%) or radiotherapy (12%); none, however, were on hormonal therapy. Most (74%) patients had their PE diagnosed without history of recent hospital admission. Except for 5 (15%), all other patients were anticoagulated. With follow-up, 2 patients developed recurrent PE, 2 others had clinical and echocardiographic evidence of pulmonary hypertension, and 9 (26%) died suddenly within 30 days of the diagnosis of incidental PE; 2 of these where among the 5 patients who were not anticoagulated. Conclusion: Incidental PE in cancer patients is increasingly encountered. Similar to symptomatic PE, many were diagnosed in patients with advanced stage disease and while undergoing active anti-cancer therapy. A significant percentage of patients had recurrent emboli, pulmonary hypertension, and sudden death. PMID:21468175

  11. Comparison of SPECT/CT, MRI and CT in diagnosis of skull base bone invasion in nasopharyngeal carcinoma.

    PubMed

    Zhang, Shu-xu; Han, Peng-hui; Zhang, Guo-qian; Wang, Rui-hao; Ge, Yong-bin; Ren, Zhi-gang; Li, Jian-sheng; Fu, Wen-hai

    2014-01-01

    Early detection of skull base invasion in nasopharyngeal carcinoma (NPC) is crucial for correct staging, assessing treatment response and contouring the tumor target in radiotherapy planning, as well as improving the patient's prognosis. To compare the diagnostic efficacy of single photon emission computed tomography/computed tomography (SPECT/CT) imaging, magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of skull base invasion in NPC. Sixty untreated patients with histologically proven NPC underwent SPECT/CT imaging, contrast-enhanced MRI and CT. Of the 60 patients, 30 had skull base invasion confirmed by the final results of contrast-enhanced MRI, CT and six-month follow-up imaging (MRI and CT). The diagnostic efficacy of the three imaging modalities in detecting skull base invasion was evaluated. The rates of positive findings of skull base invasion for SPECT/CT, MRI and CT were 53.3%, 48.3% and 33.3%, respectively. The sensitivity, specificity and accuracy were 93.3%, 86.7% and 90.0% for SPECT/CT fusion imaging, 96.7%, 100.0% and 98.3% for contrast-enhanced MRI, and 66.7%, 100.0% and 83.3% for contrast-enhanced CT. MRI showed the best performance for the diagnosis of skull base invasion in nasopharyngeal carcinoma, followed closely by SPECT/CT. SPECT/CT had poorer specificity than that of both MRI and CT, while CT had the lowest sensitivity.

  12. CT image visualization: a conceptual introduction.

    PubMed

    Furlow, Bryant

    2014-01-01

    Computed tomography (CT) postprocessing produces information-rich diagnostic images, transforming enormous amounts of x-ray attenuation data into clinical information that can assist in diagnosis and treatment. This article briefly reviews the history of the technological evolution of CT imaging equipment and provides a conceptual overview of scan data visualization processes. Trends in and examples of image postprocessing, segmentation, registration and fusion techniques, and comp