MAGNETIC-RESONANCE ANGIOGRAPHY

Literature of the past year contains several worthwhile papers describing the application of MR angiography techniques to imaging of the vascular system. MR angiography has been performed with two-dimensional time-of-flight, two-dimensional phase-contrast, and three-dimensional time-of-flight techniques. With current methodology it appears that a variety of MR angiography techniques are necessary to image the various vascular beds of the vascular system, with the appropriate MR angiography technique determined by the velocity and flow characteristics of the vascular bed of interest. Knowledge of the change in velocity patterns in disease states appears necessary for appropriate pulse sequence selection. Signal loss due to higher motion disorders remains problematic; however, the steady progress in MR angiography techniques suggests that these limitations will be overcome. Efforts are also underway to measure the velocity of blood flow. The potential combination of imaging and functional capabilities makes it likely that MR angiography will be an important technique for assessing the vascular system.