A renal artery Doppler test is a type of ultrasound that measures the speed of blood flow in the arteries leading to the kidney, explains WebMD. Doctors order this test if they suspect a patient has renal artery stenosis, or a narrowing of the arteries leading to the kidneys. In addition to the Doppler test, the doctor may also order blood or urine tests, imaging or an ultrasound of the kidney.
During a Doppler ultrasound, the doctor or technician applies a gel to the skin to promote better movement of the sound waves, states WebMD. He places a handheld transducer in the gel and moves it along the skin covering the area of the renal arteries. Depending on the type of Doppler, he may listen to the flow of blood or look at an image of the arteries on an ultrasound screen. The test is painless and takes approximately 30 to 60 minutes to complete.
Renal artery stenosis can progress over time and cause high blood pressure, kidney damage and kidney failure, reports WebMD. In most cases, it is the result of plaque build-up in the renal arteries. Treatment often begins with medications to control high blood pressure and lower cholesterol. In some cases, the doctor may recommend surgery to open the artery, perform a bypass of the blocked artery or remove the nonfunctioning kidney.