Noninvasive Coronary Angiography by 320-Row Computed Tomography With Lower Radiation Exposure and Maintained Diagnostic Accuracy

Abstract

Background— Noninvasive coronary angiography with the use of multislice computed tomography (CT) scanners is feasible with high sensitivity and negative predictive value; however, the radiation exposure associated with this technique is rather high. We evaluated coronary angiography using whole-heart 320-row CT, which avoids exposure-intensive overscanning and overranging. Methods and Results— A total of 30 consecutive patients with suspected coronary artery disease referred for clinically indicated conventional coronary angiography (CCA) were included in this prospective intention-to-diagnose study. CT was performed with the use of up to 320 simultaneous detector rows before same-day CCA, which, together with quantitative analysis, served as the reference standard. The per-patient sensitivity and specificity for CT compared with CCA were 100% (95% confidence interval [CI], 72 to 100) and 94% (95% CI, 73 to 100), respectively. Per-vessel versus per-segment sensitivity and specificity were 89% (95% CI, 62 to 98) and 96% (95% CI, 90 to 99) versus 78% (95% CI, 56 to 91) and 98% (95% CI, 96 to 99), respectively. Interobserver agreement between the 2 readers was significantly better for CCA (97% of 121 coronary arteries) than for CT (90%; P =0.04). Percent diameter stenosis determined with the use of CT showed good correlation with CCA ( P <0.001, R =0.81) without significant underestimation or overestimation (−3.1±24.4%; P =0.08). Intraindividual comparison of CT with CCA revealed a significantly smaller effective radiation dose (median, 4.2 versus 8.5 mSv; P <0.05) and amount of contrast agent required (median, 80 versus 111 mL; P <0.001) for 320-row CT. The majority of patients (87%) indicated that they would prefer CT over CCA for future diagnostic imaging ( P <0.001). Conclusions— CT with the use of emerging technology has the potential to significantly reduce the radiation dose and amount of contrast agent required compared with CCA while maintaining high diagnostic accuracy.