Is there an indication for computed tomography and magnetic resonance imaging in the evaluation of coronary artery bypass grafts?

This meta-analysis evaluates the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) for bypass graft occlusion and stenosis detection compared with coronary angiography in post-coronary artery bypass graft patients. The indication for noninvasive imaging in post-coronary artery bypass graft patients with these techniques is discussed. Overall, MRI had significantly lower sensitivity (81%) and specificity (91%) for occlusion detection than MDCT (96% and 98%, respectively). Only 2 studies assessed the accuracy of stenosis detection with MRI. Stenosis detection with MDCT had a pooled sensitivity of 89% and specificity of 97%. Multidetector computed tomography is therefore superior to MRI for the noninvasive detection of coronary bypass graft occlusion and stenosis. For stenosis detection, the accuracy of MDCT is, however, not sufficient to warrant a wide clinical use. The remaining indication for MRI-guided bypass graft assessment is in combination with myocardial evaluation such as magnetic resonance perfusion, wall motion, and stress test as a "one-stop-shop" procedure.

Visualization of anomalous coronary arteries on dual-source computed tomography.

The purpose of this study is to assess the capability of dual-source computed tomography (DSCT) in evaluating coronary artery anomalies. Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death. In 16 patients (12 men, mean age 50 +/- 14 years), anomalous coronary arteries were detected on contrast-enhanced DSCT in a patient cohort of 230 individuals (incidence of 7%). Six different types of anomalies were diagnosed (three fistula, four anomalies of the circumflex artery, four anomalous right coronary arteries, three anomalies of the left coronary artery, one absent left main coronary artery, and one left coronary artery arising from the pulmonary trunk). Of the 16 patients, 10 also underwent conventional coronary angiography (CAG). Retrospective evaluation of the CAGs by an experienced interventional cardiologist resulted in a precise diagnosis in 50% of patients. With DSCT, sufficient image quality and exact visualization of the aberrant anatomy were achieved in all patients. Therefore, DSCT seems to be an accurate diagnostic tool for examining the precise origin, course, and shape of aberrant coronary arteries.

Echocardiographic and electron beam tomographic assessment of stenosis in patients with aortic valve disease: gradient versus valve area.

BACKGROUND: Transthoracic echocardiography (TTE) is routinely used to evaluate aortic valve stenosis. However, it does not give reliable results in every patient. There is growing interest in electron-beam tomography (EBT) as a noninvasive cardiac imaging technique. The usefulness of EBT to evaluate aortic stenosis has yet to be evaluated. AIM: To compare EBT with TTE in assessing severity of aortic stenosis. METHODS: In total 47 patients (18 females, 29 males) underwent a contrast-enhanced EBT scan and TTE within 6±20 days. The calcium score of the aortic valve was determined and the aortic valve area (AVA) was measured by planimetry. A complete TTE study, during which the peak pressure gradient across the aortic valve was measured, was performed in all patients by an experienced sonographer. RESULTS: There was a significant correlation between AVA assessed by EBT and peak pressure gradient (r=-0.38, p=0.009). The calcium score of the aortic valve assessed by EBT correlated with peak pressure gradient (r=0.48, p=0.001). CONCLUSION: EBT is a useful noninvasive method to evaluate the severity of aortic stenosis. It holds the possibility of assessing the AVA as well as quantification of the degree of calcification.

Risk factors associated with postnecrotizing enterocolitis strictures in infants.

INTRODUCTION: Survivors of necrotizing enterocolitis (NEC) often develop a post-NEC intestinal stricture, causing severe and prolonged morbidity. OBJECTIVES: We first aimed to determine the incidence of post-NEC strictures. Second, we aimed to determine risk factors associated with intestinal post-NEC strictures. MATERIALS AND METHODS: A total of 441 patients diagnosed with NEC Bell's stage ≥2 were retrospectively included in three academic pediatric surgical centers between January 2005 and January 2013. Clinical data were related to the occurrence of intestinal post-NEC strictures. Post-NEC strictures were defined as clinically relevant strictures with a radiological and/or surgical confirmation of this post-NEC stricture. RESULTS: The median gestational age of the 337 survivors of the acute phase of NEC was 29weeks (range 24-41) and median birth weight was 1130g (range 410-4130). Of the survivors, 37 (17%) medically treated NEC patients developed a post-NEC strictures versus 27 surgically treated NEC patients (24%; p=0.001). Highest C-reactive protein (CRP) level measured during the NEC episode was associated with the development of post-NEC strictures (OR 1.20, 95% confidence interval 1.11-1.32; p=0.03). No post-NEC strictures were detected in patients with CRP levels <46mg/L. CONCLUSION: This multicenter retrospective cohort study demonstrates an overall incidence of clinical relevant post-NEC strictures of 19%, with a higher rate (24%) in NEC cases treated surgically. Increased CRP levels during the NEC episode were associated with the development of post-NEC strictures.

Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: a phantom study.

PURPOSE: To assess the influence of temporal resolution on image quality of computed tomographic (CT) coronary angiography by comparing 64-row Dual Source CT (DSCT) and Single Source CT (SSCT) at different heart rates. METHODS: An anthropomorphic moving heart phantom was scanned at rest, and at 50 beats per minute (bpm) up to 110 bpm, with intervals of 10 bpm. 3D volume rendered images and curved multi-planar reconstructions (MPRs) were acquired and image quality of the coronary arteries was rated on a 5-points scale (1=poor image quality with many artefacts, 5=excellent image quality) for each heart rate and each scanner by 3 observers. Paired sample t-test and Wilcoxon Signed Ranks test were used to assess clinically relevant differences between both modalities. RESULTS: The mean image quality scores at 70, 100 and 110 bpm were significantly higher for DSCT compared to SSCT. The overall mean image quality scores for DSCT (4.2+/-0.6) and SSCT (3.0+/-1.1) also differed significantly (p<0.001). CONCLUSION: These initial results show a clinically relevant overall higher image quality for DSCT compared to SSCT, especially at heart rates of 70, 100 and 110 bpm. With its comparatively high image quality and low radiation dose, DSCT appears to be the method of choice in CT coronary angiography at heart rates above 70 bpm.

Coronary revascularization treatment based on dual-source computed tomography.

Therapy advice based on dual-source computed tomography (DSCT) in comparison with coronary angiography (CAG) was investigated and the results evaluated after 1-year follow-up. Thirty-three consecutive patients (mean age 61.9 years) underwent DSCT and CAG and were evaluated independently. In an expert reading (the "gold standard"), CAG and DSCT examinations were evaluated simultaneously by an experienced radiologist and cardiologist. Based on the presence of significant stenosis and current guidelines, therapy advice was given by all readers blinded from the results of other readings and clinical information. Patients were treated based on a multidisciplinary team evaluation including all clinical information. In comparison with the gold standard, CAG had a higher specificity (91%) and positive predictive value (PPV) (95%) compared with DSCT (82% and 91%, respectively). DSCT had a higher sensitivity (96%) and negative predictive value (NPV) (89%) compared with CAG (91% and 83%, respectively). The DSCT-based therapy advice did not lead to any patient being denied the revascularization they needed according to the multidisciplinary team evaluation. During follow-up, two patients needed additional revascularization. The high NPV for DSCT for revascularization assessment indicates that DSCT could be safely used to select patients benefiting from medical therapy only.

The benefit of 64-MDCT prior to invasive coronary angiography in symptomatic post-CABG patients.

PURPOSE: The purpose of this study is to assess the diagnostic accuracy of 64-MDCT in symptomatic patients after CABG and to explore the advantages of the 64-MDCT results on the CAG procedure. MATERIAL AND METHODS: From December 2004 until August 2005, 34 post-CABG patients (29 men, mean age 63.5 +/- 8.5 years) with 69 coronary artery bypass grafts were scanned on a 64-MDCT (Somatom Sensation 64, Siemens AG, Forchheim, Germany) prior to CAG. Angiograms and 64-MDCT images were evaluated for the existence of occlusions or significant stenosis (>or=50% lumen reduction) in bypass grafts and native coronary arteries. RESULTS: 64-MDCT had a sensitivity, a specificity, and a diagnostic accuracy of 100% for occlusion detection. For stenosis detection, sensitivity was 100%, specificity 98.7% and diagnostic accuracy 98.7%. For detecting significant stenosis in native coronary arteries, 64-MDCT had a sensitivity of 80.0%, specificity of 90.8%, and a diagnostic accuracy of 87.1%. Seventeen patients (50.0%) did not need invasive treatment, 14 patients (41.2%) underwent a percutaneous coronary intervention (PCI), and 3 patients (8.8%) underwent surgery. Treatment advice based on 64-MDCT was correct in 88.2% of patients and when 64-MDCT results would have been known 58.8% of diagnostic CAG procedures could have been prevented. CONCLUSION: In conclusion, 64-MDCT has a high diagnostic accuracy in detecting bypass graft stenosis and occlusions, and 64-MDCT based treatment advice was correct in 88.2% of patients.

The clinical value of a negative multi-detector computed tomographic angiography in patients suspected of coronary artery disease: A meta-analysis.

The aim of this meta-analysis was to calculate the sensitivity of contrast-enhanced multi-detector computed tomography (MDCT) compared with coronary angiography (CAG) in incident patients suspected of coronary artery disease (CAD). We searched PubMed, Embase, bibliographies of original papers and reviews to identify original papers including > or =20 patients. Two independent reviewers selected papers and judged eligible papers on quality. Heterogeneity was assessed and homogeneous subgroups were pooled. Of the 15 included studies, ten provided moderately homogeneous patient-based analyses with absolute diagnostic numbers (n = 630 patients). Pooled sensitivity was 89% (95% confidence interval: 85-92%). Scanners with 16 detectors (n = 4) had higher sensitivities (pooled sensitivity: 91%) than four-detector scanners (n = 6; pooling not possible due to heterogeneity). Seven studies reported sensitivity for a proximal stenosis, but different definitions were used making pooling impossible; sensitivities ranged from 75 to 100%. The sensitivity of four- and 16-detector MDCT is not sufficient to rule out any stenosis in patients suspected of CAD. No conclusions can be drawn with respect to the sensitivity for clinically relevant or proximal stenoses.