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OBJECTIVE: Our aim in this study was to determine the relationship between chest circumference and the radiation doses received by breast tissues during Dual-Source Computed Tomography (DSCT) cardiac scans. MATERIALS AND METHODS: Routine cardiac DSCT examinations with similar exposure lengths were applied to 30 female patients. The scanogram image, multi-slice helical scan x-ray tube voltage and anode-cathode current were adjusted automatically according to attenuation for each patient during the scanogram acquisition. The standard protocol was otherwise applied to all patients. The 30 patients had an average weight of 67.8±15.3 kg, and the average length of the scanned region was 278.0±11.6 mm. Radiation doses were calculated from the dose-length product (DLP) and the computed tomography dose index (CTDI) scanner data values. The correlations between radiation dose and chest circumference were investigated. The level of significance was set at p<0.05. RESULTS: For routine cardiac DSCT scans, the average values were as follows: total DLP: 715.54±317.01 mGycm, CTDIvol: 40.79±19.41 mGy, and effective dose (ED): 17.89±7.93 mSv. The chest circumference of patients correlates well with their radiation exposure (p<0.01). CONCLUSION: The distribution of different tissues throughout the human body may vary among races and genders. Because of this, many researchers use body mass index (BMI) to set image quality and predict the radiation dose distribution from general computed tomography (CT) examinations. Additional anthropomorphic phantom studies should be conducted to determine more accurate conversion factors and, hence, better ED predictions.

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The purpose of this article is to provide an up to date review on the spectrum of applications of perfusion computed tomography (CT) in the abdomen. New imaging techniques have been developed with the objective of obtaining a structural and functional analysis of different organs. Recently, perfusion CT has aroused the interest of many researchers who are studying the applicability of imaging modalities in the evaluation of abdominal organs and diseases. Per-fusion CT enables fast, non-invasive imaging of the tumor vascular physiology. Moreover, it can act as an in vivo biomarker of tumor-related angiogenesis.

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The SYNTAX score is an angiographic scoring system that is currently used for evaluating the complexity of coronary lesions. Its efficiency in both long-term prognosis and the selection of treatment modalities has been shown in many studies. However, there is little evidence for the use of this scoring system in CT angiography, which has become a part of coronary artery disease practice. Here, we showed that the SYNTAX score could be used in a feasible way in CT angiography.

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Interrupted aortic arch is a rare congenital malformation of the aortic arch defined as a loss of luminal continuity between the ascending and descending portions of the aorta. In a simple interrupted aortic arch, only a ventricular septal defect and patent ductus arteriosus are observed. We present a rare complex form of type A interrupted aorta with an aortopulmonary window, an atrial septal defect, a ventricular septal defect, and a patent ductus arteriosus on multidetector computed tomography (MDCT) imaging.

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BACKGROUND AND PURPOSE: The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. METHODS: The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. RESULTS: The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9±20.5°) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8±11°). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2±20.4°) than the other cases (mean: 78.9±10.7°). CONCLUSION: A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

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OBJECTIVE: X-ray attenuation coefficients are used in common radiological, pathological and spectroscopic examinations and in the determination of the radiation dose distribution in biological tissues. In radiology, these coefficients enable diagnosis by differentiating the abnormal tissues from the normal ones using their morphological structure and contrast differences. In this study, our aim is to precisely determine the linear x-ray attenuation coefficients of pathological brain tissues and to use x-ray beam filters to enhance the tissue contrast in computed tomography. MATERIALS AND METHODS: To directly measure the relative linear attenuation coefficients, an energy dispersive x-ray spectroscopy system (EDXRS-Canberra, Si(Li) with DSA-1000 spectrum analyzer 1998; CT, USA) was used with collimators and a medical-purpose x-ray tube (Siemens, Siremobil, 1985; Erlangen, Germany) in a linear geometry. RESULTS: Using a Mo filter with Computed Tomography CT and photon energies from 15 to 25 keV, EDXRS acquisitions were found to significantly distinguish grades of brain tumors (p<0.05). For the data acquired from CT systems with the decreasing filtered photon mean energy, the x-ray attenuation coefficients (i.e., the Hounsfield units) show that the ratio of EDXRS to CT for water's attenuation coefficient are increased. With our suggested x-ray filters, the tissue contrast has been found to be increased in ex vivo brain tumor slices compared with slices scanned in conventional CT scanners. CONCLUSION: X-ray attenuations measured with the EDXRS are found to be statistically more reliable because of the length of acquisition times in this study.

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PURPOSE: The authors present the findings of contrast-enhanced electrocardiogram (ECG)-gated cardiac computed tomography (CT) in 18 patients with probably spontaneous closure of muscular ventricular septal defect (VSD). MATERIALS AND METHODS: The study included 2,725 consecutive patients referred to our hospitals for multidetector computed tomography (MDCT) coronary angiography. The patients were between the ages of 5 and 78 [mean+/-standard deviation (SD) 59+/-13.86] years, and 1,816 (66.6%) were male. Evaluating the images for coronary artery pathologies revealed pouches or sacs in the central muscular location of the septa of some patients. RESULTS: All patient records were retrospectively reviewed, and 18 patients were found to have pouches or sacs in the interventricular septum location likely to be spontaneous closure of muscular VSD (0.66% prevalence). MDCT findings of these 18 patients correlated with their echocardiographic findings. Of the patients with muscular VSD, 13 were male and five were female. These 18 patients were initially referred due to indications such as chest pain (n=11), risk-factor assessment (n=3), coronary artery anomaly (n=1), suspected aberrant right subclavian artery due to dysphagia (n=1) and coronary artery bypass graft (n=2). CONCLUSIONS: Our study shows that the incidence of spontaneous closure of muscular VSD with central septum location is probably higher than expected. Thus, some patients initially diagnosed with ventricular diverticula with an apical and marginal septum location may actually have spontaneously closed muscular VSD. This finding may affect previously reported rates of both ventricular diverticula and spontaneous closure of muscular VSD.

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PURPOSE: Depending on the perfusing interventricular septum of the arteries, there are 3 types of circulation dominance: right, left, and balanced. In this study, coronary artery branches supplying the ventricular septum were investigated in vivo in a large group of patients by multidetector computed tomography (MDCT) coronary angiography. In addition, the association of coronary artery variations with coronary arterial disease was investigated. MATERIALS AND METHODS: The study included 325 consecutive patients (214 men and 108 women, with a mean age of 59 +/- 14 years) who underwent MDCT coronary angiography. Multidetector computed tomography was performed with a 16-detector-row computed tomographic scanner. The type of dominance, coronary arterial diseases, and coronary artery variations were recorded. RESULTS: In our study, the types of coronary circulation were right, left, and balanced in 227 (70%), 40 (12.5%), and 58 (17.5%) patients, respectively. Dominance of right circulation was detected in 150 of 217 (69%) of men and in 77 of 108 (71%) of women; dominance of left circulation was found in 26 of 217(12%) of men and in 14 of 108 (13%) of women; balanced/codominance circulation was found in 41 of 217 (19%) of men and in 17 of 108 (16%) of women. However, no significant differences were detected between the sexes for the type of coronary circulation. Coronary artery disease was determined in 68 patients (20.9%) by MDCT, and coronary artery variations were also determined in 34 patients (10.4%). Both the number and the rate of coronary artery variations were significantly higher among the patients with left artery dominance. CONCLUSIONS: Knowledge of coronary artery variations and pathologies is important in planning the treatment and in interpretation of findings of cardiovascular diseases. Our study indicated that, although right dominance circulation is more common in general population, both the coronary diseases and coronary artery variations are more common in individuals with left dominance circulation.

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