MR angiography of the coronary arteries.

Magnetic resonance angiography (MRA) of the coronary arteries has recently become possible due to the development of a new group of ultrafast imaging sequences. Coronary arteries are small, tortuous vessels subjected to significant physiological motions (respiration and cardiac contractions). Most coronary MRA pulse sequences rely on a combination of segmental acquisition of data (in k-space) to minimize cardiac motion artifacts and patient breath-holding to minimize respiratory motion artifacts. MR is noninvasive, does not require any contrast agents or ionizing radiation, and thus offers the potential of becoming a very important cardiac screening tool. Coronary MRA can routinely depict the proximal and middle portion of most coronary arteries and some coronary artery branches. However, its clinical utility for detecting lesions has not yet been proven. As coronary MRA techniques improve they may become an integral part of the evaluation of patients with ischemic heart disease. Existing coronary MRA techniques can already play a significant clinical role in the evaluation of coronary artery anomalies, in the follow-up of proximal lesions after angioplasty, and in the noninvasive determination of patency of bypass grafts and coronary stents.