Three-dimensional quantitative volumetry of chronic total occlusion plaque using coronary multidetector computed tomography

Background: The purpose of the present study was to investigate whether multidetector computed tomography (MDCT) can identify the nature of chronic total occlusion (CTO) plaque, which cannot be measured quantitatively using traditional coronary angiography, and predict the success of percutaneous coronary intervention (PCI). Methods and Results: MDCT and 3-dimensional volumetric radiologic density analysis was performed for 186 consecutive CTO lesions. Plaque characteristics were determined using Hounsfield units (HU) of the image voxels. The remodeling index decreased significantly as the duration of CTO lengthened. Volumetric plaque analysis using HU showed that volumetric fraction of calcification (>324 HU) did not, but low-density plaque (<49 HU) did decrease significantly as the duration of CTO lengthened. The overall PCI success rate was 77.4% (144/186). In addition to the unknown or >12-month occlusion duration (odds ratio [OR]=3.0, 95% confidence interval [CI]=1.4-6.5, P=0.005), 2 MDCT parameters, that is, lesion length >18 mm (OR=2.7, 95%CI=1.1-6.4, P=0.024) and segmental radiologic density >139 HU (OR=2.7, 95%CI=1.2-6.4, P=0.021), were independent predictors of PCI failure on multivariate analysis. Conclusions: MDCT might be helpful for the prediction of successful CTO PCI. In addition to the occlusion duration, lesion length and high segmental radiologic density measured on MDCT were significant predictors of PCI failure in the present study.