Mapping the coronary arteries on a sphere in CT angiography

Abstract

Current approaches for coronary artery inspection using cardiac CT angiography scans include curved planar reformation (CPR), slab maximum-intensity projection (MIP) and volume rendering (VR) techniques. While the first two allow a detailed examination of only one vessel or a few segments of the coronary artery tree at a time, the VR techniques are not considered suitable for a thorough clinical assessment. An innovative concept of visualization aimed at revealing the entire coronary tree in a CPR-type environment is presented. The new approach uses a sphere or an ellipsoid as a base surface to map the coronary tree. Using the spherical (or ellipsoidal) coordinate system a “true” surface running through the centerlines of all the vessels is defined. Resampling the volume data with this (preferably thick) surface and using a maximum-intensity projection will produce three possible modes of visualization. In one mode the “true form” surface is texture-mapped with the resampled volume data, while in another the data is projected onto the sphere that served as a base surface, forming the “Globe” mode of visualization. Peeling the data to form a 2D “map” of the entire coronary tree in its context in the heart constitutes the third mode.