Upon reviewing this educational exhibit, the reader will understand the basic principles and concepts of contrast enhanced time-resolved 3D MR angiography (TR-MRA). The reader will also become familiar with different applications of this technique used to evaluate a variety of pathologies in different anatomical regions.

In contrast-enhanced 3D MR angiography (MRA), spatial resolution and temporal resolution are competing objectives. High spatial resolution is desirable to visualize small vessels, but high temporal resolution is needed to visualize dynamic processes, especially in regions of high flow. Traditional single or multiphase bolus-chase contrast-enhanced 3D MRA has limited temporal resolution due to long acquisition times. Bolus-chase 3D MRA requires synchronization between bolus arrival time, image acquisition, and (if needed) suspended respiration. This task can be difficult in patients with altered hemodynamics or those unable...

Why TR-MRA? Contrast-enhanced TR-MRA offers quasi-real time vascular imaging with sufficiently high temporal resolution to assess contrast flow dynamics in arteries and veins using only a small contrast dose. Advantages of TR-MRA include short acquisition time, high-temporal resolution, reduced motion artifacts, and the ability to selectively visualize arteries and veins without the hassle and complexity of estimating contrast bolus arrival times. High temporal resolution is especially valuable for imaging arteries in anatomical areas with rapid venous return, including the neck, pulmonary circulation, kidneys, and high...

TR-MRA is a multifaceted vascular imaging technique that can be used to answer a variety of clinical questions. TR-MRA can acquire useful diagnostic information about complicated vascular lesions; and overcome many limitations of the bolus chase contrast enhanced MRA. The technique is particularly useful in answering clinical questions throughout the body, particularly in conditions where bolus-chase MRA is too slow to provide relevant temporal information, when the arterial arrival time is uncertain, the patient is freely breathing, or contrast dynamics are critical to a diagnosis....

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