Current applications of magnetic resonance vascular imaging.

A wide variety of MRI techniques is available for vascular imaging, each exploiting a different property of flowing blood to achieve contrast. These include spin-echo, which has been used for the diagnosis of aortic dissection and of great vessel anomalies, as well as for the evaluation of pulmonary flow in patients with pulmonary hypertension and pulmonary embolism. Spin echo excels in detecting infection and hematoma in the tissues around grafts and vessels. Phase display imaging has proven useful in differentiating signal of slow flow from that of intravascular thrombus. Imaging of peripheral vessels can be achieved with gradient refocused sequences, which provide bright intravascular signal over a wide range of flow velocities. These sequences may be combined with subtraction strategies to eliminate the signal from stationary tissues in order to generate an angiographic image. The advent of three-dimensional MR angiographic imaging techniques provides an effective way to display peripheral vessels. Early experience implies that MR angiography will play an important role in vascular imaging in the future, provided that the signal loss from turbulent flow can be minimized.