Myocardium: Dynamic versus Single-Shot CT Perfusion Imaging

Purpose To determine the diagnostic accuracy of dynamic computed tomographic (CT) perfusion imaging of the myocardium for the detection of hemodynamically relevant coronary artery stenosis compared with the accuracy of coronary angiography and fractional flow reserve (FFR) measurement. Materials and Methods This study was approved by the institutional review board and the Federal Radiation Safety Council (Bundesamt für Strahlenschutz). All patients provided written informed consent. Thirty-two consecutive patients in adenosine stress conditions underwent dynamic CT perfusion imaging (14 consecutive data sets) performed by using a 256-section scanner with an 8-cm detector and without table movement. Time to peak, area under the curve, upslope, and peak enhancement were determined after calculation of time-attenuation curves. In addition, myocardial blood flow (MBF) was determined quantitatively. Results were compared with those of coronary angiography and FFR measurement by using a receiver operating characteristic (ROC) analysis. In addition, threshold values based on the Youden index and sensitivity and specificity were calculated. Results Area under the ROC curve, sensitivity, and specificity, respectively, were 0.67, 41.4% (95% confidence interval CI: 23.5%, 61.1%), and 86.6% (95% CI: 76.0%, 93.7%) for time to peak; 0.74, 58.6% (95% CI: 38.9%, 76.5%), and 83.6% (95% CI: 72.5%, 91.5%) for area under the curve; 0.87, 82.8% (95% CI: 64.2%, 94.1%), and 88.1% (95% CI: 77.8%, 94.7%) for upslope; 0.83, 82.8% (95% CI: 64.2%, 94.1%), and 89.6% (95% CI: 79.6%, 95.7%) for peak enhancement; and 0.86, 75.9% (95% CI: 56.5%, 89.7%), and 100% (95% CI: 94.6%, 100%) for MBF. The thresholds determined by using the Youden index were 148.5 HU · sec for area under the curve, 12 seconds for time to peak, 2.5 HU/sec for upslope, 34 HU for peak enhancement, and 1.64 mL/g/min for MBF. Conclusion The semiquantitative parameters upslope and peak enhancement and the quantitative parameter MBF showed similar high diagnostic accuracy. © RSNA, 2013 Supplemental material: S1