What exactly is renal stenosis ultrasound?

Ultrasound of vessel: Renal artery stenosis is a disease that is caused by tightness of the renal arteries feeding the kidneys which causes elevated blood pressure and if severe shrinking of the kidney sizes. This is diagnosed by a few tests amongst which is the ultrasound of the blood vessel to evaluate the speed of blood flow which if spurting fast means stenosis. This is different than routine kidney ultrasound.

Kidney Artery eval: Ultrasound can evaluate the renal (kidney) arteries and attempt to identify stenoses, narrowings, which may contribute to kidney failure or high blood pressure.

Renal artery Doppler: Renal artery stenosis can be evaluated with doppler ultrasound. The renal arteries are imaged with color doppler for localization and then pulse doppler measurements for blood velocity are made. Artery stenosis can manifest as increased or decreased velocity depending on severity of stenosis. Graphic display of blood velocity are useful for demonstrating flow patterns.

Renal ultrasound: Renal artery ultrasound is called "renal duplex" which originally combined B-mode ultrasound to image the renal arteries with a pulsed Doppler to sample the velocity of blood flow in the artery. Now color Doppler and other extras are available. If renal velocity>200cm/sec artery likely abnormal. If RAR (ratio of renal velocity over aortic velocity) >3.5 likely 60% stenosis present. Accuracy good.