In vivo characterisation of coronary plaques with conventional grey-scale intravascular ultrasound: Correlation with optical coherence tomography

Aims: Although intravascular ultrasound (IVUS) is widely used, there is limited published data on its accuracy in defining plaque characteristics in vivo. Optical coherence tomography (OCT) is a highresolution imaging technique that takes advantage of the pronounced optical contrast between the components of normal and diseased vessels. The aim of this study was to evaluate the ability of conventional grey-scale IVUS in identifying in vivo coronary plaque characteristics, in particular lipid content as a marker of the vulnerable plaque, when compared to OCT. Methods and results: In patients undergoing cardiac catheterisation, IVUS and OCT imaging was performed. Detailed qualitative analysis of lipid-rich plaque, calcific plaque, and plaque disruption were performed at corresponding sites using both modalities. A total of 146 matched sites were available for analysis. When compared to OCT, sensitivity of IVUS for identification of lipid pools was low (24.1%) but specificity was high (93.9%). The sensitivity and specificity of IVUS for detection of calcific plaque and plaque disruption were respectively 92.9%; 66.4%, and 66.7%; 96.1%. Conclusions: Conventional grey-scale IVUS may not be a reliable imaging modality for detection of lipid-rich and hence vulnerable plaques. This has important implications in using conventional grey-scale IVUS to identify the vulnerable plaque.