MR coronary angiography is a non-invasive method of imaging the coronary arteries. Coronary artery aneurysms may demonstrate anatomic and functional information. Flow characteristics within aneurysmally dilated vessels may be observed. Coronary thrombus can be identified and distinguished from slow blood flow by having low signal on T1-weighted cardiac gated studies and having high signal on GRE imaging. The major problem currently prohibiting widespread clinical use are related to the complex 3D heart motion caused by cardiac contraction and respiration. Artifacts can be lessened by using ECG-triggering and breath-hold techniques. However, breath-holding is not required with the navigator technique, which allows real-time motion detection and monitoring of diaphragm position. Currently, the origin, proximal and middle parts of the coronary arteries can be evaluated with 3D MR coronary angiography.