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.
Sildenafil citrate (Viagra) does not exacerbate myocardial ischemia in canine models of coronary artery stenosis
