The volume information extracted from computed tomography angiogram is very useful for cardiologists to diagnose various diseases. An approach is presented to segment human coronary artery trees from the volumetric datasets. The coronary arteries’ surfaces are recovered by triangle mesh with the boundary points extracted from the coronary artery voxels segmented. The positions where the calcified plaques occur are identified by mapping the intensities of boundary points of the coronary artery trees on the triangle meshed surfaces. If different values of the computed maximum principle curvatures of boundary points surrounding the lumen cross section are mapped on the triangle meshed surfaces of the segmented coronary artery trees, the cross section structure of the coronary artery lumen segment is noncircular cross section structure.