Renal artery sonography applies color and spectral Doppler interrogation to the renal arteries and intrarenal vasculature to detect renovascular hypertension, assess renal perfusion after transplantation, and evaluate for renal artery stenosis (RAS) caused by atherosclerosis or fibromuscular dysplasia.
The examination requires measurement of peak systolic velocity in the main renal arteries at the aortic origin and hilum, calculation of the renal-to-aortic ratio (RAR), and assessment of intrarenal waveforms for the tardus-parvus pattern that indicates significant proximal stenosis. Renal transplant duplex includes resistive index measurement and assessment of arterial and venous anastomoses.
Renal artery duplex falls under the ARDMS Vascular Technology (VT) specialty. It is performed in hospital vascular labs, nephrology practices, and transplant centers. Technical success rates depend heavily on patient preparation (fasting to reduce bowel gas) and sonographer experience with challenging anatomy.