Stress myocardial perfusion computed tomography at 320 detector-row to detect hemodynamically significant coronary stenoses in the presence of a high coronary calcium score

Abstract

Objectives: We sought to assess the diagnostic performance of visual and quantitative analysis of stress perfusion CT (CTP) imaging with 320-slice CT, when added to coronary computed tomographic angiography (CCTA), against invasively determined fractional flow reserve (FFR) in the presence of a high coronary calcium score. Background: Cardiac CT examination integrating CCTA and stress CTP allows for comprehensive assessment of coronary arterial stenosis and myocardial ischemia. However, further clinical validation is required in high-risk populations. Methods: Thirty-three patients with high calcium score stratified by higher than 400 Agatston units underwent comprehensive CT examination starting stress CTP followed by rest CCTA and angiography. FFR was measured in all main coronary arteries with a luminal narrowing greater than 50%. FFR<0.80 was considered hemodynamically significant. Two observers visually assessed presence or absence of perfusion defect in each major coronary arterial territory. The transmural perfusion ratio (TPR) was calculated using 16-segment model. Results: A total of 48 coronary vessels had flow limiting stenoses. The sensitivity and specificity of CCTA and visual CTP analysis alone to detect flow limiting CAD was 91% and 62%, respectively, and 77%, 73%, respectively. With use of quantitative analysis of CTP employing TPR, 5 lesions were correctly reclassified as hemodynamically significant, resulting in sensitivity of 87% and specificity of 75%. Combined assessment was better predictor of flow limiting CAD, with a sensitivity of 81% and specificity of 92%, with an AUC of 0.87, compared with 0.77 for CCTA alone and 0.81 for CTP alone. ![Figure][1] Figure 1 Conclusions: Stress myocardial CTP over CCTA had moderate sensitivity and high specificity for predicting flow limiting CAD. [1]: pending:yes