LAUSR

Quantitative myocardial perfusion imaging with CT is increasingly used for the diagnosis of coronary artery disease. Relative flow reserve (RFRCT) derived from dynamic stress CT perfusion (CTP) is defined as the ratio between myocardial blood flow (MBF) in the stenosis-related territory and MBF in the non-stenosis-related territory. We sought to evaluate whether RFRCTcan be used as a non-invasive method for detection of functionally significant coronary artery stenosis compared with stress MBF. This study was retrospectively included 31 consecutive patients (40 vessels) with coronary artery disease and examined with CT angiography, CTP, coronary angiography, and FFR. RFRCT and stress MBF results were compared with invasive FFR using a threshold of 0.80. The RFRCT values were significantly correlated to FFR values (R2=0.788, P<0.0001, Fig 1). The area under the receiver operator curve was larger for RFRCT (0.961) compared with stress MBF (0.837, Fig 2). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of RFRCT were 92.5%, 84.2%, 100%, 100%, and 87.5%, respectively. Figures 1 & 2 RFRCT was superior to stress MBF for detecting abnormal FFR in patients with stable coronary artery disease.