Diagnostic accuracy of dual-source computed tomography in the characterization of coronary atherosclerotic plaques: comparison with intravascular optical coherence tomography

Background: Dual-source computed tomography (DSCT) has enabled us to non-invasively visualize coronary artery stenosis, but its ability to characterize coronary atherosclerotic plaques (ASPs) has not been evaluated. Intravascular optical coherence tomography (OCT) provides tissue images of coronary artery wall that are validated by pathohistological studies. We studied the diagnostic accuracy of DSCT in the characterization of coronary ASPs, especially lipid-rich ASP with thin fibrous cap (TCFA), in comparison with OCT.

Methods: DSCT and OCT were used to image non-stenotic ASPs in non-culprit coronary arteries of 17 acute coronary syndrome (ACS) patients, and 162 coronary regions were enrolled.

Results: The mean CT values of fibrous ASP, ASP with lipid core, and ASP with calcium deposit were 77.5, 28.9, and 515.9 HU, respectively (P<0.0001). ASP with calcium deposit was detected with a sensitivity of 88.9% and a specificity of 98.6%, while ASP with lipid core was detected by DSCT with a relatively low sensitivity of 73.1% and a high specificity of 94.0%. In TCFA, cross-sectional areas of both ASP and lipid core were significantly larger, mean CT value of ASP was significantly lower, and concomitant calcification was more frequently observed compared with lipid-rich ASP with thick fibrous cap (ThCFA). The combination of these CT parameters seems to be a useful index for the differentiation of TCFA from ThCFA.

Conclusion: DSCT is useful for non-invasive evaluation of calcified and fibro-fatty tissue characters in coronary artery plaque, but it is still not able to differentiate TCFA, one of the features of vulnerable plaque.