Evaluation of the atherosclerotic change in the ascending aorta using helical CT

The purpose of this study is to investigate the clinical usefulness of helical computed tomography (CT) for the evaluation of atherosclerotic changes in the ascending aorta. Eighteen subjects are examined. Contrast-enhanced helical CT was performed before and after the operation of the coronary artery bypass graft (CABG). Forty six histological samples of the ascending aorta were obtained from the sites where the saphenous grafts were anastomosed and classified microscopically into 3 histological grade; grade 1: mainly intimal fibrosis (n=38), grade 2: mainly atheroma (n=6) and grade 3: mainly calcification (n=2). In comparison with CT images, all the portions of the aortic walls with grade 2 and 3 showed low density areas, while any of those with grade 1 did not reveal the low density areas along the inner margin of the aortic wall. However, the walls with grade 2 and those with grade 3 were not able to be differentiated on CT images. Three dimensional reconstructed images clearly demonstrated the spatial distribution of atheromatous changes and calcification in the ascending aorta. In conclusion, helical CT is clinically useful for the evaluation of the atherosclerotic changes in the ascending aorta. (author)