For renal artery stenosis, which test is considered definitive (gold standard) for diagnosis?

• A. Duplex ultrasound
• B. Renal arteriography
• C. CT angiography
• D. MR angiography

Answer: (B)

Conventional renal arteriography is the definitive test because it directly image the renal arteries with the highest spatial resolution, precisely showing the location and degree of stenosis. It provides accurate anatomical detail and can be combined with immediate endovascular treatment if needed, making it the reference standard for confirming renal artery stenosis.

Noninvasive options like duplex Doppler assesses flow velocities but is operator-dependent and can miss or mischaracterize lesions; CT or MR angiography give good anatomical pictures but carry risks such as iodinated contrast or gadolinium, and can be less accurate in certain settings.