Arteries can become narrowed due to two main processes:
The renal duplex scan uses an ultrasound beam to measure the velocity of blood passing through the renal arteries. Scanning is performed with the probe placed on the abdomen and lower back.
The renal arteries lie at the back of the abdomen and can be obscured by gas in the intestines. This is less of a problem if the patient has not eaten for several hours, so the best results are obtained in the patient has been fasting (starving) for about 6 hours. Drinking water up to two hours before the test does not cause any difficulty. All medications may be taken as normal.
A report on the study will be sent to the referring doctor, with any recommendations for further investigations as appropriate.