Emergent Magnetic Resonance Angiography for Evaluation of the Thoracoabdominal and Peripheral Vasculature.

Thoracoabdominal and peripheral vasculature pathologies include a variety of severe and life threatening conditions that may be encountered in the emergent setting. Computed tomography angiography (CTA) is the first-line modality for imaging of the vasculature in this context, but magnetic resonance angiography (MRA) also plays an important and emerging role in the evaluation of carefully selected patients. Intravenous (IV) iodinated contrast is necessary for CTA, although MRA is most useful in patients who cannot receive IV iodinated contrast for reasons including prior severe allergic-like reaction to iodinated contrast, poor IV access, or severe renal insufficiency. Gadolinium-based contrast agents are administered for MRA when possible, as they generally improve the diagnostic quality and shorten the duration of the exam. In most clinical situations, however, noncontrast MRA is sufficient to obtain a diagnostic evaluation. In this review, we discuss the key strengths and limitations of MRA performed in the emergent setting, highlighting the role of MRA in the diagnosis of acute aortic syndromes, aortitis, aortic aneurysm, pulmonary embolism, and peripheral vascular disease.