Magnetic resonance of coronary arteries: assessment of luminal narrowing and blood flow in the coronary arteries.

The assessment of luminal narrowing and altered blood flow in the coronary artery is challenging because of the small size of the vessel and the complex motion caused by cardiac contraction and respiration. Free-breathing, whole-heart coronary magnetic resonance angiography (MRA) has been introduced as a method that can provide visualization of all 3 major coronary arteries within a single 3-dimensional acquisition, either by using 1.5 T steady-state free precession or 3 T gradient-echo sequences. Recent studies have indicated that coronary MRA has sufficient diagnostic accuracy for excluding coronary artery disease (CAD) in patients with suspected CAD. Furthermore, coronary MRA can provide risk stratification for future cardiac events. In addition to the morphologic assessment of the coronary artery, phase-contrast cine MR imaging has unique advantages because it allows for measurement of blood flow and flow reserve in the coronary arteries. Comprehensive assessment of the morphology and blood flow in the coronary artery has a great potential in noninvasive detection of physiologically significant CAD that requires revascularization. The aim of this review is to provide an update on current technical improvements in coronary MRA and MR flow measurement of coronary arteries.