Significant coronary artery stenosis: Comparison on per-patient and per-vessel or per-segment basis at 64-section CT angiography

Purpose: To prospectively evaluate the accuracy of 64-section computed tomographic (CT) coronary angiography for assessing significant stenosis on a global and segmental level, by using conventional coronary artery angiography as the reference standard. Materials and Methods: This study was HIPAA compliant and had local institutional review board approval. Patients gave informed consent. Patients suspected of having coronary artery disease (CAD) underwent both conventional coronary catheter angiography and contrast material - enhanced retrospectively electrocardiographically gated 64- section multi - detector row CT of the coronary arteries. Two experienced observers analyzed all CT scans for signs of CAD (stenosis of 0%, <= 49%, 50% - 69%, 70% - 99%, or 100%). Diagnostic accuracy of CT coronary angiography compared with that of conventional angiography was determined on a per- segment, per-vessel, and per-patient basis. No patients, vessels, or segments were excluded from analysis. Spearman correlation, cross tables, and a X-2 test were used for statistical analysis. Results: On a per-segment basis, 92.4% ( 762 of 825) of all segments could be clearly evaluated. In 7.6% of segments, image quality was compromised either by misregistration ( 16%), motion artifacts ( 30%), or small vessel size ( 54%). Correlation coefficients for detection and grading of stenosis were r = 0.65 on a per- segment, r = 0.83 on a per-vessel, and r = 0.88 on a per-patient basis. Stenoses of 50% or greater were detected with accuracy, sensitivity, and specificity, respectively, of 96.1% ( 793 of 825), 82% ( 50 of 61), and 97.1% ( 743 of 765) on a per- segment basis, 90.9% ( 150 of 165), 89% ( 32 of 36), and 91.5% ( 118 of 129) on a per- vessel basis, and 89% ( 49 of 55), 100% ( 19 of 19), and 83% ( 30 of 36) on a per- patient basis. Conclusion: On a per-patient basis, 64-section multi-detector row CT coronary angiography enables the diagnosis of significant ( >= 50%) stenosis in CAD with an accuracy of 89%. On a per-segment and per-vessel basis, diagnostic accuracy is still impaired, primarily by limited spatial resolution. (c) RSNA, 2007.