Tissue Characterization of Coronary PlaquesComparison of Integrated Backscatter Intravascular Ultrasound With Virtual Histology Intravascular Ultrasound

Background Integrated backscatter (IB) intravascular ultrasound (IVUS) and IVUS Virtual Histology (VH) have been developed for tissue characterization, but have never been compared directly. The purpose of this study was to compare the overall agreement between IB-IVUS and IVUS-VH in the tissue characterization of plaques from the same coronary arterial cross- section. Methods and Results Images were acquired from 46 coronary arteries from 25 cadavers. Of a total of 392 histology/IVUS image pairs, 152 pairs were diagnosed as Stary's type III, IV, Va, Vb and Vc, and compared for IB- IVUS, IVUS-VH and histology. In the qualitative comparison, the overall agreement between histological and IB-IVUS diagnoses was higher ([kappa]=0.81, 95% confidence interval (CI): 0.74-0.89) than that of the IVUS-VH diagnoses ([kappa]=0.66, 95%CI: 0.56-0.75). The % fibrosis area determined by IB-IVUS was significantly correlated with the relative area of fibrosis based on histology (r=0.67, p-0.001). In the quantitative comparison, the overall agreement between the histological and IB-IVUS diagnoses was higher ([kappa]=0.83, 95% CI: 0.75-0.91) than that of the IVUS- VH diagnoses ([kappa]=0.73, 95% CI: 0.63-0.83). Conclusion Based on histology as the gold standard, IB-IVUS provided higher diagnostic accuracy than IVUS- VH for tissue characterization of coronary plaques. (Circ J 2008; 72: 1631 - 1639)