A complete guide to your renal artery duplex ultrasound — a scan that evaluates blood flow to your kidneys, often the missing piece in difficult-to-control hypertension.
Many patients have never had this type of scan before. Here is exactly what will happen — no surprises.
Completely painless and non-invasive. Ultrasound uses sound waves — no radiation, no needles, no discomfort. Most patients find the experience relaxing.
The exam begins with you lying on your back. The sonographer uses the liver and spleen as acoustic windows to visualize the renal arteries near their origin from the aorta.
The aorta is identified at the level of the renal arteries. Flow velocity in the aorta provides the denominator for the renal-to-aortic ratio calculation.
The right renal artery is traced from its origin on the aorta to the kidney. Velocity measurements are taken at the origin, mid-artery, and hilum.
You may be asked to roll slightly to your right side to improve visualization of the left renal artery, which lies deeper and is often more challenging to image.
Each kidney is measured in length and assessed for structural appearance. A kidney significantly smaller than the other often indicates chronic reduced blood flow on that side.
Your cardiologist report includes peak systolic velocities, renal-aortic ratios, kidney measurements, and clinical interpretation — often with specific implications for blood pressure management.
Your cardiologist report is written in plain language, but here are the specific measurements and terms you may encounter — and exactly what they mean.
The most direct measure of stenosis. A velocity above 180–200 cm/s at the renal artery origin is highly suspicious for significant stenosis.
Compares renal artery velocity to adjacent aortic velocity. A ratio above 3.5 is generally considered diagnostic of hemodynamically significant renal artery stenosis.
A measurement of intrarenal blood flow resistance. Elevated values suggest significant parenchymal (kidney tissue) disease that may limit the benefit of treating the artery.
The time for blood flow to reach peak velocity in the intrarenal arteries. A prolonged acceleration time (tardus-parvus pattern) is an indirect sign of proximal renal artery stenosis.
Normal kidney length: 9–12 cm. A kidney more than 1.5 cm smaller than the other is considered significantly asymmetric — a classic sign of chronic ischemic nephropathy.
Renal artery imaging can occasionally be limited by body habitus, bowel gas, or depth. If incomplete, additional fasting or a repeat study with positioning changes may be recommended.
Your report will clearly state whether follow-up is needed and how urgently. Here is what each outcome typically means.
No significant abnormalities. Share your report with your primary care physician. Consider repeat screening in 1–3 years based on your risk profile.
Minor findings that warrant monitoring. Your report will specify follow-up timing and any lifestyle recommendations.
Clinically significant findings requiring physician review. Your report will indicate appropriate urgency.
Findings requiring prompt evaluation. We will contact you directly in addition to delivering your report.
Proper preparation is important for renal artery imaging because the kidneys sit deep in the abdomen. Here is what to know before your appointment.
Explore our clinical service page, related articles, and booking options for your renal artery screening.
You should fast for 8–12 hours before your renal artery ultrasound to reduce bowel gas that can obstruct visualization of the deep abdominal vessels. Wear loose, comfortable clothing with easy access to your abdomen. Continue taking all prescribed medications with small sips of water.
A board-certified cardiologist reviews your renal artery images and delivers a written clinical report within 24–48 hours via secure email. The report includes peak systolic velocities, renal-aortic ratios, kidney measurements, and clinical interpretation.
BlackPoint Diagnostics is a direct-pay service at $397 per scan, all-inclusive. No insurance pre-authorization or referral is required. HSA and FSA payments are accepted.
Yes. A renal artery ultrasound is completely non-invasive — no sedation, no needles, no contrast dye. You can drive, return to work, and resume all normal activities immediately after the scan.
Your cardiologist report will grade the degree of stenosis based on velocity measurements and renal-aortic ratios, and assess kidney size asymmetry. Findings often have direct implications for blood pressure management. For significant stenosis, referral to a vascular specialist or nephrologist may be recommended. Our team contacts you directly for significant findings.
No referral needed. $397 all-inclusive. Results from a board-certified cardiologist within 24–48 hours.