Approaches to ultra-low radiation dose coronary artery calcium scoring based on 3rd generation dual-source CT: A phantom study

Objectives: To investigate to what extent 3rd generation dual-source computed tomography (DSCT) can reduce radiation dose in coronary artery calcium scoring. Methods: Image acquisition was performed using a stationary calcification phantom. Prospectively electrocardiogram (ECG)-triggered 120 kV sequential, and 120 and Sn100 kV ultra-high pitch (UHP) acquisitions were performed with different tube currents (80, 60, 40, 20 mA). Images were reconstructed using filtered back projection (FBP) and 3rd generation iterative reconstruction (IR). Contrast-to-noise ratio (CNR), Agatston score, calcium volume, and radiation dose were assessed. For statistical analysis Friedman tests and Wilcoxon rank sum tests were used. Results: Even at reduced tube currents, the three acquisition techniques did not show significant differences in Agatston score (p = 0.4) or calcium volume (p = 0.08) with FBP reconstruction. Calcium volumes were significantly lower for 3rd generation IR compared to FBP reconstructions (p <0.01). CTDIvol for the 120 kV sequential, 120 and Sn100 kV UHP acquisitions at 80 and 20 mA were 1.2-0.37, 0.48-0.17, and 0.07-0.02 mGy, respectively. Conclusion: 3rd generation DSCT enabled a reduction of tube current in both the sequential and UHP acquisitions without significantly affecting coronary calcium scoring. Tin filtered 100 kV scanning may allow accurate quantification of calcium score without correction of the HU threshold. (C) 2015 Elsevier Ireland Ltd. All rights reserved

Absolute Versus Relative Myocardial Blood Flow by Dynamic CT Myocardial Perfusion Imaging in Patients With Anatomic Coronary Artery Disease

OBJECTIVE. The purpose of this study was to evaluate differences in the diagnostic accuracy of absolute and relative territorial myocardial blood flow (MBF) derived from stress dynamic CT myocardial perfusion imaging (MPI) for the detection of significant coronary artery stenosis. MATERIALS AND METHODS. Dynamic CT MPI and coronary CT angiography (CTA) datasets from a multicenter registry of 137 patients (mean age, 60.9 +/- 8.4 years; 88 men) with suspected or known coronary artery disease were retrospectively analyzed. For each coronary territory, absolute MBF and the MBF relative to remote myocardium (MBF ratio) were calculated. Coronary CTA datasets were visually assessed for significant stenosis (>= 50% luminal narrowing) in consensus by two observers. RESULTS. Significant stenosis was detected in 137 of 411 (33.3%) vessels. Mean absolute MBF and MBF ratio were statistically significantly lower in territories supplied by arteries with stenosis (80.7 +/- 33.7 vs 140.0 +/- 38.4 mL/100 mL/min and 0.52 vs 0.89, respectively; both p <0.0001). ROC analysis showed better discrimination by MBF ratio than by absolute MBF (AUC, 0.925 vs 0.882; p = 0.0022) and increased sensitivity (90.7% vs 82.4%; p <0.04) and specificity (93.1% vs 80.5%; p <0.03) for MBF ratio and absolute MBF cutoff values of 0.71 or less and 103 mL/100 mL/min or less, respectively. CONCLUSION. In stress dynamic CT MPI, relative MBF provides superior diagnostic accuracy compared with absolute territorial MBF values for coronary CTA-detected significant coronary artery stenosis

Myocardial Late Gadolinium Enhancement:Accuracy of T1 Mapping-based Synthetic Inversion-Recovery Imaging

Cardiovascular Aspects of Radiolog