16-slice Multidetector-row Computed Tomography Research Articles

Quantitative Analysis of the Deltoid Ligament Degradation in Chronic Ankle Instability Patients using the CT Value

Category:Ankle; OtherIntroduction/Purpose:Chronic lateral ankle instability (CLAI) that is developed after multiple lateral ankle ligament injury lead to ankle osteoarthritis. Although isolated deltoid ligament injury is rare compared to lateral ankle ligament injury, deltoid ligament tear, especially deep posterior tibiotalar ligament (PTT) can be observed arthroscopically in CLAI patients. Unphysiological loading of the ankle joint with CLAI might cause degradation of the deltoid ligament. This study aimed to investigate image findings of the deltoid ligament using computed tomography (CT) value for quantitative analysis of degenerative ligament changes in CLAI patients.Methods:Among the enrolled patients who underwent ankle magnetic resonance imaging (MRI) and CT scans of the ankle, this retrospective analysis included 24 ankles without ankle osteoarthritis, osteochondral lesion of the talus (OLT), flatfoot and ankle fractures (14 males and 10 females; mean age, 42.8 years) as a control group, and 14 CLAI ankles without OLT (7 males and 7 females; mean age, 31.1 years) as CLAI group. The CT scans were performed using a 64-slice multidetector row CT. Deep PTT was detected on coronal T2-weighted MR images. Both the coronal MR and CT images were matched for analysis, then average CT values were measured using the region of interest that was applied to the detected area of deep PTT on the CT images.Spearman’s correlation coefficient was used to evaluate the correlation between age and CT value in the control group.Results:The strong negative correlation was identified between age and CT value in the control group (Spearman ρ= -0.88; p< 0.001). The CT value of the deep PTT are degraded with aging. Mean CT value of deep PTT in participants under 60 years old were 79.9 HU (95% CI, 75.1-84.8) in the control group (18 ankles), and 66.5 HU (95% CI, 58.6-74.5) in the CLAI group (14 ankles) (Welch’s t test; p = 0.005).Conclusion:MRI techniques and protocols recently have been developed, however, some limitations remain such as a quantitative evaluation of the ligament. Our findings suggest that the CLAI can lead to degradation of the deltoid ligament via an overloading of medial ankle structures. Additionally, CT values should be useful for quantitatively evaluating ligament status including degenerative changes.

How to assess a CTA of the abdomen to plan an autologous breast reconstruction.

The deep inferior epigastric perforator (DIEP) flap is recognised as the most popular option for autologous breast reconstruction. Planning of the DIEP flap involves pre-operative assessment of abdominal vascular anatomy with imaging, of which computed tomographic angiography (CTA) has become the mainstay. CTA enables detailed planning of a range of surgical steps, leading to reduced operative times and improved surgical outcomes. The value of CTA is only demonstrated when the relevant vascular anatomy is able to be demonstrated and appraised. For optimal analysis, a 64-slice multi-detector row CT scanner and imaging software including OsiriX™, Siemens InSpace™ or Horos™ are required. The seven major steps to consider include: (I) perforator size; (II) perforator angiosome; (III) intramuscular course; (IV) deep inferior epigastric artery (DIEA) pedicle; (V) venous anatomy; (VI) superficial inferior epigastric artery (SIEA) and superficial inferior epigastric vein (SIEV); and (VII) abdominal wall structure. These steps should also be reviewed when marking the patient and planning the flap intra-operatively. While CTA has superior sensitivity and specificity in mapping perforator anatomy it also faces challenges due to ionising radiation exposure, contrast-induced allergy and potential nephrotoxicity. Despite these challenges, the benefits of CTA to the individual patient has maintained its role in pre-operative planning of the DIEP flap.

Prevalence and characteristics of coronary artery anomalies in an adult population undergoing multidetector-row computed tomography for the evaluation of coronary artery disease.

BackgroundCongenital coronary anomalies are uncommon with an incidence ranging from 0.17 % in autopsy cases to 1.2 % in angiographically evaluated cases. The recent development of ECG–gated multi–detector row computed tomography (MDCT) coronary angiography allows accurate and noninvasive depiction of coronary artery anomalies.MethodsThis retrospective study included 2572 patients who underwent coronary 64-slice MDCT coronary angiography from January 2008 to March 2012. Coronary angiographic scans were obtained with injection of 80 ml nonionic contrast medium. Retrospective gating technique was used to synchronize data reconstruction with the ECG signal. Maximum intensity projection, multi-planar reformatted, and volume rendering images were derived from axial scans.ResultsOf the 2572 patients, sixty (2.33 %) were diagnosed with coronary artery anomalies (CAAs), with a mean age of 53.6 ± 11.8 years (range 29–80 years). High take-off of the RCA was seen in 16 patients (0.62 %), of the left main coronary artery (LMCA) in 2 patients (0.08 %) and both of them in 2 patients (0.08 %). Separate origin of the left anterior descending artery (LAD) and left circumflex artery (LCx) from left sinus of Valsalva (LSV) was found in 15 patients (an incidence of 0.58 %). In 9 patients (0.35 %) the right coronary artery (RCA) arose from the opposite sinus of Valsalva with a separate ostium. In 6 patients (0.23 %) an abnormal origin of LCX from the right sinus of Valsalva (RSV) was found with a further posterior course within the atrioventricular groove. A single coronary artery was seen in 3 patients (0.12 %). It originated from the right sinus of Valsalva in one patient and from LSV in two patients. In two other patients (0.08 %) the left coronary trunk originated from the RSV with separate ostium from the RCA. LCA originating from the pulmonary artery was found in one patient (0.04 %). A coronary artery fistula, which is a termination anomaly, was detected in 4 patients (0.15 %).DiscussionAlthough these anomalies, which are remarkably different from the normal structure, exist as early as birth, they are incidentally encountered during selective angiography or at autopsy. The incidence in reported angiographic series ranges from 0.6 % to 1.3 %. Variations in the frequency of primary congenital coronary anomalies may possibly have a genetic background. The largest angiographic series of 126595 patients, by Yamanaka and Hobbs, reported a 1.3 % incidence of anomalous coronary artery.ConclusionThe results of this study support the use MDCT coronary angiography as a safe and effective noninvasive imaging modality for defining CAAs in an appropriate clinical setting, providing detailed three-dimensional anatomic information that may be difficult to obtain with invasive angiography.

Attenuation-based automatic kilovoltage selection and sinogram-affirmed iterative reconstruction: effects on radiation exposure and image quality of portal-phase liver CT.

ObjectiveTo compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver.Materials and MethodsWe retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images.ResultsQualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001).ConclusionCombined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.

Evaluation of Radiation Exposure of Medical Staff During CT-Guided Interventions

PurposeThe purpose of this prospective study was to investigate absolute radiation exposure values and factors that influence radiation exposure of interventionists during CT-guided interventions (CTGIs). To our knowledge, no data exist regarding the radiation dose to which the interventionist is exposed during these procedures. MethodsAbsolute radiation dose values from a total of 131 CTGIs were analyzed. Radiation dose values were collected by thermoluminescent dosimeters that were positioned above the lead protection being worn, on the forehead, thyroid, chest, gonads, and right and left hand and foot.The radiation doses were analyzed with respect to the experience level of the person performing the procedure, the degree of difficulty measured on a 4-point Likert scale, the lesion size measured on a 3-point Likert scale, and the CT system used. ResultsMedian whole-body dose was 12 μSv. With the exception of the forehead, all whole-body radiation doses were statistically significantly lower in CTGIs performed using the modern dual-source CT system compared with the 16-slice multi-detector CT. For CTGIs rated as more complex, the radiation exposure of the radiologist performing the procedure was statistically significantly higher, with the exception of the left hand. A statistically significantly lower median whole-body dose was measured for inexperienced compared with experienced radiologists. However, a few dose measurements of more than 1 mSv were found at the right hand. ConclusionsRadiation exposure measured during CTGIs is low (<50 μSv). Because the radiation dose was higher in more-complex interventions and for 16-slice multi-detector row CT, inexperienced radiologists should focus on less-complex procedures.

Accessible or inaccessible? Diagnostic efficacy of CT-guided core biopsies of head and neck masses.

Tissue 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. All 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. Sixteen 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. The 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.

Imaging in gastroenterology.

Imaging in gastroenterology.

MDCT of Small Bowel Obstruction: How Reliable Are Oblique Reformatted Images in Localizing Point of Transition?

The goal of this study is to prospectively assess the additional value of oblique reformatted images for localizing POT, having surgery as a reference standard. Materials and Methods. 102 consecutive patients with suspected small bowel obstruction (SBO) underwent 64-slice multidetector row CT (MDCT) using surgical findings as reference standard. Two independent GI radiologists reviewed the CT scans to localize the exact POT by evaluating axial images (data set A) followed by axial, coronal, and oblique MPR images. CT findings were compared to surgical findings in terms of diagnostic performance. McNemar's test was used to detect any statistical difference in POT evaluation between datasets A and B. Kappa statistics were applied for measuring agreement between two readers. Results. There was a diagnostic improvement of 9.9% in the case of the less experienced radiologist in localizing POT by using oblique reformatted images. The more experienced radiologist showed diagnostic improvement by 12.9%.

Meta-Analysis of Global Left Ventricular Function Comparing Multidetector Computed Tomography With Cardiac Magnetic Resonance Imaging

We compare the diagnostic accuracy of multidetector row computed tomography (MDCT) to cardiac magnetic resonance imaging (CMR) for evaluating global left ventricular function. We systematically searched PubMed, CINAHL, Cochrane CENTRAL, Scopus, and the Web of Science databases for studies published between 1966 to January 2013 that compared left ventricle (LV) volumes, ejection fraction (EF) and LV mass measured by MDCT and CMR. We performed meta-analyses and used random-effects model with inverse variance weighting test to determine the overall bias and limits of agreement of LV end-diastolic volume, end-systolic volume, stroke volume, and EF measured by MDCT and CMR. Furthermore, subgroup analyses were performed to compare 16-slice and 64-slice MDCT with CMR. Two study authors independently reviewed the 90 articles originally identified and selected 27 studies (n = 831) for analysis. Excellent correlation and a linear relation were seen between MDCT and CMR for LV end-diastolic volume (r = 0.93; p <0.001), LV end-systolic volume (r = 0.95; p <0.001), LV stroke volume (r = 0.85; p <0.001), LV ejection fraction (r = 0.93; p <0.001), and LV mass (r = 0.86; p <0.001). Subgroup analyses showed strong positive correlations for both 16- and 64-slice MDCT. In conclusion, although not the first-line test for LV function assessment in most patients, when appropriate, retrospectively gated MDCT provides an accurate and valid assessment of LV function compared with CMR.

Effect of brightness in the evaluation of lumbar pedicular screws position: clinical study

Artifact may lead to confusion when evaluating postoperative CT scans of lumbar pedicle screws. The aim of our study was to develop a specific metal artifact reduction image protocol, in order to reduce metal artifact caused by titanium pedicular screw in patients undergoing lumbar pathology by lumbar fusion. Therefore, the reduction in metal artifacts in lumbar pedicle screws allows surgeons to do an accurate diagnosis of the exact placement of inserted pedicle screws, minimizes false reexploration, and maximizes proper and prompt treatment of misplaced screw. In a first step, we performed a retrospective study of 103 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. CT scan was performed postoperatively evaluating the possible overdimension caused by artifact. In a second step, a prospective study was performed using a 64-slice multidetector-row computed tomography (MDCT) in 104 titanium alloy pedicle screws in patients undergoing a lumbar instrumented fusion for treatment for degenerative disease. Our results show that on the group of sequential CT scan, mean overdimension (on each side) due to brightness was 1.045 mm (SD 0.45). On the group of 64-slice multichannel CT, mean overdimension (on each side) due to brightness was 0.005 mm at the proximal part of the screw and 0.025 mm at the distal part of the screw. The results observed suggest that beam-hardening artifacts caused by the screw on CT after lumbar fusion are dramatically reduced by using specific metal artifact reduction image protocol in a 64-slice MDCT.

COMPARISON BETWEEN BOLUS TRACKING AND TIMING‐BOLUS TECHNIQUES FOR RENAL COMPUTED TOMOGRAPHIC ANGIOGRAPHY IN NORMAL CATS

Renal dual-phase computed tomograpic angiography (CTA) is used to assess suitability of feline donors prior to transplantation. A prerequisite for successful CTA is optimal synchronization between the arterial passage of contrast material and CT data acquisition. This retrospective study was conducted to compare quality of renal vascular enhancement at dual-phase CTA in normal cats between two techniques of timing of data acquisition: the timing-bolus and the bolus tracking method. Nine cats were scanned using the timing-bolus technique and 14 with the bolus tracking technique using otherwise similar scanning parameters in a 16-slice multidetector row CT scanner. The quality of enhancement of the renal vessels at the scanned arterial phase and venous phase was assessed both subjectively and objectively by three board-certified radiologists. Arterial enhancement was not observed at the scanned arterial phase in three of the nine cats with the timing-bolus technique but only 1 of the 14 cats with the bolus tracking technique. Early venous enhancement at the scanned arterial phase was common with the bolus tracking technique. Data acquisition was significantly faster with the bolus tracking technique. We conclude that the bolus tracking technique is a valid technique that could be integrated into the routine protocol for 16-detector row CT renal angiography in cats.

64列MDCTを用いた上腹部撮影におけるオーバレンジングに関する検討

64-slice multidetector-row computed tomography (MDCT) have become widely used in recent years, but there is a possibility that a large volume of dose is radiated at the outside of the scope of scanning due to the effect of over ranging (OR). In this research, the dose volume change at the outside of the scope of scanning in the case of X-ray beam width (BW) and pitch factor (PF) is measured, and the effect of BW and PF on OR is considered. We scanned the upper abdomen of an acrylic human phantom using 64-slice multidetector-row CT in 4 conditions while changing BW and PF. We then measured the dose volume absorbed in the breasts, ovary, uterus, and the dose profile on the surface of phantom. As a result, when BW and PF are increased, the dose volume radiated at the outside of the scope of scanning increased, and the effect of OR appeared. Therefore, when BW and PF are set, X-ray radiated at the outside of the scope of scanning should also be considered.

Reduction of Thoracic Aorta Motion Artifact With High-Pitch 128-Slice Dual-Source Computed Tomographic Angiography

Electrocardiogram-gated imaging combined with multi-detector row computed tomography (MDCT) has reduced cardiac motion artifacts, but it was not practical in the emergency setting. The purpose of this study was to evaluate the ability of a high-pitch, 128-slice dual-source CT (DSCT) scanner to reduce motion artifacts in patients admitted to the emergency room. This study comprised 100 patients suspected of having thoracic aorta lesions. We examined 47 patients with the 128-slice DSCT scanner (DSCT group), and 53 patients were examined with a 64-slice MDCT scanner (MDCT group). Six anatomic areas in the thoracic aorta were evaluated. Computed tomography images in the DSCT group were distinct, and significant differences were observed in images of all areas between the 2 groups except for the descending aorta. The high-pitch DSCT scanner can reduce motion artifacts of the thoracic aorta and enable radiological diagnosis even in patients with tachycardia and without breath hold.

In Vivo Evaluation of Carotid Artery Stents Using Multi–Detector-Row Computed Tomography Angiography

The objective of this study was to assess the lumen visibility of carotid artery stents using multi-detector-row computed tomography (MDCT) angiography; compare medium-smooth, medium-sharp, and sharp kernels; and correlate these results to those of digital subtraction angiography (DSA). We retrospectively evaluated 52 stents from 51 patients who underwent 16- and 64-slice MDCT angiography. Lumen diameters were measured 3 times by 2 neuroradiologists, and artificial luminal narrowing was calculated. To assess detection of in-stent restenosis (>50%), 2 neuroradiologists evaluated all MDCT and DSA images. Excellent intraobserver and interobserver agreements were obtained for the lumen diameter measurements (P < 0.001). Lumen diameter visibility improved, and artificial luminal narrowing decreased from the medium-smooth kernel to the sharp kernel. Visual estimation of all CT angiography using the 3 kernels showed high accuracy for detection of in-stent restenosis (>50%), compared with DSA. Computed tomography angiography using a sharp kernel allows for more accurate assessment of lumen visibility after carotid artery stenting.

Linear Measurement Accuracy of Dental CT Images Obtained by 64-Slice Multidetector Row CT

To evaluate whether the measurement accuracy of dental CT images is affected by the mandibular positioning and the pitch factor at CT scanning. Three dry mandibles were scanned by 64-slice multidetector row CT (MDCT) and micro-CT. For MDCT scanning, 7 different mandibular positioning and 3 different pitch factors were applied. After reformatting dental CT images, the bone height was measured on these images. It was also measured on the corresponding micro-CT image, which was defined as the actual value. The difference of the measurement values between these 2 was defined as the measurement error. There was no significant difference in the measurement errors due to either the mandibular positioning or the pitch factor. The measurement accuracy of dental CT images obtained was not affected by either mandibular positioning or pitch factor at CT scanning.

Radiation dose reduction from low-kilovoltage liver computed tomography using multidetector rowcomputed tomography

The primary goal of this study was to ascertain the reduction in radiation dose when conducting low-kilovoltage liver computed tomography (CT) examinations using multidetector row CT (MDCT). Fifty patients under follow-up who were diagnosed with liver cancer were examined using a 16-slice MDCT scanner and volume CT dose index (CTDI(vol)) measured according to the methods of examination, which were based on a three-phase CT scan conducted in the previous year and a four-phase CT scan was done a year later. Scanning parameters were 120 kVp-140 mA s, 120 kVp-120 mA s and 80 kVp-280 mA s. The CTDI(vol) was decreased to ∼47% at 80 kVp -280 mA s. The results indicate that low-kilovoltage liver CT is a useful means of reducing radiation doses.

Comparison between integrated backscatter intravascular ultrasound and 64-slice multi-detector row computed tomography for tissue characterization and volumetric assessment of coronary plaques

BackgroundThe purpose of this study was to determine the cut-off values of Hounsfield units (HU) for the discrimination of plaque components and to evaluate the feasibility of measurement of the volume of plaque components using multi-detector row computed tomography (MDCT).MethodsCoronary lesions (125 lesions in 125 patients) were visualized by both integrated backscatter intravascular ultrasound (IB-IVUS) and 64-slice MDCT at the same site. The IB values were used as a gold standard to determine the cut off values of HU for the discrimination of plaque components.ResultsPlaques were classified as lipid pool (n =50), fibrosis (n =65) or calcification (n =35) by IB-IVUS. The HU of lipid pool, fibrosis and calcification were 18 ± 18 HU (−19 to 58 HU), 95 ± 24 HU (46 to 154 HU) and 378 ± 99 HU (188 to 605 HU), respectively. Using receiver operating characteristic curve analysis, a threshold of 50 HU was the optimal cutoff values to discriminate lipid pool from fibrosis. Lipid volume measured by MDCT was correlated with that measured by IB-IVUS (r =0.66, p <0.001), whereas fibrous volume was not (r =0.21, p =0.059).ConclusionLipid volume measured by MDCT was moderately correlated with that measured by IB-IVUS. MDCT may be useful for volumetric assessment of the lipid volume of coronary plaques, whereas the assessment of fibrosis volume was unstable.

Comparison of Hybrid and Pure Iterative Reconstruction Techniques With Conventional Filtered Back Projection

Assess the effect of filtered back projection (FBP) and hybrid (adaptive statistical iterative reconstruction [ASIR]) and pure (model-based iterative reconstruction [MBIR]) iterative reconstructions on abdominal computed tomography (CT) acquired with 75% radiation dose reduction. In an institutional review board-approved prospective study, 10 patients (mean [standard deviation] age, 60 (8) years; 4 men and 6 women) gave informed consent for acquisition of additional abdominal images on 64-slice multidetector-row CT (GE 750HD, GE Healthcare). Scanning was repeated over a 10-cm scan length at 200 and 50 milliampere second (mA s), with remaining parameters held constant at 120 kilovolt (peak), 0.984:1 pitch, and standard reconstruction kernel. Projection data were deidentified, exported, and reconstructed to obtain 4 data sets (200-mA s FBP, 50-mA s FBP, 50-mA s ASIR, 50-mA s MBIR), which were evaluated by 2 abdominal radiologists for lesions and subjective image quality. Objective noise and noise spectral density were measured for each image series. Among the 10 patients, the maximum weight recorded was 123 kg, with maximum transverse diameter measured as 43.7 cm. Lesion conspicuity at 50-mA s MBIR was better than on 50-mA s FBP and ASIR images (P < 0.01). Image noise was rated as suboptimal on low-dose FBP and ASIR but deemed acceptable in MBIR images. Objective noise with 50-mA s MBIR was 2 to 3 folds lower compared to 50-mA s ASIR, 50-mA s FBP, and 200-mA s FBP (P < 0.0001). Noise spectral density analyses demonstrated that ASIR retains the noise spectrum signature of FBP, whereas MBIR has much lower noise with a more regularized noise spectrum pattern. Model-based iterative reconstruction renders acceptable image quality and diagnostic confidence in 50- mA s abdominal CT images, whereas FBP and ASIR images are associated with suboptimal image quality at this radiation dose level.

Comparison of image quality and radiation dose between combined automatic tube current modulation and fixed tube current technique in CT of abdomen and pelvis

Tube current is an important determinant of radiation dose and image quality in X-ray-based examination. The combined automatic tube current modulation technique (ATCM) enables automatic adjustment of the tube current in various planes (x-y and z) based on the size and attenuation of the body area scanned. To compare image quality and radiation dose of the ATCM with those of a fixed tube current technique (FTC) in CT of the abdomen and pelvis performed with a 16-slice multidetector row CT. We reviewed 100 patients in whom initial and follow-up CT of the abdomen and pelvis were performed with FTC and ATCM. All acquisition parameters were identical in both techniques except for tube current. We recorded objective image noise in liver parenchyma, subjective image noise and diagnostic acceptability by using a five-point scale, radiation dose, and body mass index (BMI, kg/m(2)). Data were analyzed with parametric and non-parametric statistical tests. There was no significant difference in image noise and diagnostic acceptability between two techniques. All subjects had acceptable subjective image noise in both techniques. The significant reduction in radiation dose (45.25% reduction) was noted with combined ATCM (P < 0.001). There was a significant linear statistical correlation between BMI and dose reduction (r = -0.78, P < 0.05). The ATCM for CT of the abdomen and pelvis substantially reduced radiation dose while maintaining diagnostic image quality. Patients with lower BMI showed more reduction in radiation dose.

Evaluation of coronary allograft vasculopathy using multi-detector row computed tomography: a systematic review

Coronary allograft vasculopathy (CAV) is a significant cause of morbidity and mortality after cardiac transplantation and requires frequent surveillance with catheter-based coronary angiography (CCA). Multi-detector row computed tomography (MDCT) has been shown to be effective in assessing atherosclerosis in native coronary arteries. This article systematically reviews the literature to determine the accuracy of MDCT in CAV assessment. An English-language literature search was performed using EMBASE, OVID, PubMed, and Cochrane Library databases. Studies that directly compared MDCT with CCA and/or IVUS for the detection of coronary artery stenosis or significant intimal thickening in cardiac transplant patients were analyzed. Data were pooled to obtain weighted sensitivities, specificities, and diagnostic accuracies. Negative and positive predictive values (NPV/PPV) were calculated. A total of seven studies with a sum of 272 patients were included in this review. There were three studies examining 16-slice MDCT and four studies looking at 64-slice MDCT in CAV. Using per-segment analysis, MDCT assessed between 91% and 96% of all coronary segments when evaluating for stenosis. Pooled estimates for sensitivity and specificity for MDCT ranged from 82% to 89% and 89% to 99%, respectively, while NPV was 99%. Per-patient analysis revealed a sensitivity of 87-100% and NPV of 96-100%. PPV was less than 50% for 64-slice MDCT in both per-segment and per-patient analysis. When compared with IVUS, MDCT had a sensitivity of 74-96% and specificity of 88-92% in assessment of intimal thickening. NPV and PPV were 80-81% and 84-98%, respectively. The high sensitivity and NPV of MDCT suggest that it may be a useful, noninvasive screening tool to rule out CAV.