Abstract 4181: Dual-Energy CT of the Heart for Diagnosing Coronary Artery Stenosis and Myocardial Ischemia - Comparison with SPECT
A single dual-energy CT (DECT) scan can assess coronary anatomy and detect myocardial perfusion defects (PD) seen on SPECT. 28 patients underwent SPECT myocardial perfusion imaging, invasive coronary angiography (ICA), and a single contrast medium-enhanced, retrospectively ECG-gated DECT scan using a dual-source CT system with simultaneous acquisition of high and low x-ray spectra. Scan data was used to reconstruct anatomic coronary CT angiographic (cCTA) images and to map the myocardial iodine distribution on virtually non-contrast enhanced long- and short-axis views of the left ventricle. Two independent observers analyzed all DECT studies for coronary artery stenosis and myocardial blood-pool deficits. Segmental comparison was performed between DECT, ICA, and SPECT. Data were analyzed using the Bayesian model. 484 myocardial segments were evaluated. 135 segments in 21 patients showed blood-pool deficits on DECT. In all territories where DECT showed blood-pool deficits, SPECT or catheter angiography confirmed PD or critical stenosis. Overall, DECT had 94.4% sensitivity and 95.2% specificity with 95% accuracy for detecting PD seen on SPECT. In patients without significant stenosis and negative SPECT (n=7), DECT showed no sign of blood-pool deficits. Interobserver agreement was very good (weighted kappa = 0.87). Compared with ICA, cCTA reconstructions had 98% sensitivity, 88% specificity and 92% accuracy for detection of >50% stenosis. Initial experience suggests that DECT may be promising for the comprehensive analysis of coronary artery morphology and the myocardial blood pool in good agreement with ICA and SPECT.