Coronary CT angiography -: IVUS image fusion for quantitative plaque and stenosis analyses

Rationale and Objective: Due to the limited temporal and spatial resolution, coronary CT angiographic image quality is not optimal for robust and accurate stenosis quantification, and plaque differentiation and quantification. By combining the high-resolution IVUS images with CT images, a detailed representation of the coronary arteries can be provided in the CT images. Methods: The two vessel data sets are matched using three steps. First, vessel segments are matched using anatomical landmarks. Second, the landmarks are aligned in cross-sectional vessel images. Third, the semiautomatically detected IVUS lumen contours are matched to the CTA data, using manual interaction and automatic registration methods. Results: The IVUS-CTA fusion tool facilitates the unique combined view of the high-resolution IVUS segmentation of the outer vessel wall and lumen-intima transitions on the CT images. The cylindrical projection of the CMPR image decreases the analysis time with 50 percent. The automatic registration of the cross-vessel views decreases the analyses time with 85 percent. Conclusions: The fusion of IVUS images and their segmentation results with coronary CT angiographic images provide a detailed view of the lumen and vessel wall of coronary arteries. The automatic fusion tool makes such a registration feasible for the development and validation of analysis tools.