Renal imaging: duplex ultrasound, computed tomography angiography, magnetic resonance angiography, and angiography.

Renal artery stenosis (RAS) is one of the most common causes of severe hypertension (approximately 1-5% of all patients with hypertension). Presently, there is no universally accepted screening test for RAS. However, most clinicians use renal duplex ultrasound (RDU) imaging; while others use magnetic resonance angiography (MRA) or contrast computed tomography angiography in selected patients. This review will highlight various imaging modalities and discuss the pros and cons of each.