This is one of the most common of all urologic studies. It is a test that uses a dye that is injected into a vein to outline the kidneys, ureters and bladder on an X-ray. A urologist is likely to order this test if a patient complains of pain in his or her side, blood in the urine or any stone-related symptoms. It also is used sometimes as a screening test to prompt the urologist to order other tests for more information.

This test is performed in the hospital radiology department or sometimes in the doctor’s office with an X-ray technician.

Before the test, the patient will be on a restricted diet for 24 hours and asked to urinate right before the test to ensure that the bladder is empty. The patient then lies on his or her back and is asked to stay still. An X-ray will be taken of the abdomen and pelvis without dye. This helps to determine the proper technique and positioning. The doctor also first may order some X-rays of the kidneys.

The patient is then injected with a dye, usually through the arm veins. As the dye travels through the bloodstream to the kidneys, it’s normal for the patient to feel a warm rush. The dye will go through the kidneys, and the kidneys will filter the dye out of the blood and send it down through the ureters into the bladder.

While this is happening, X-rays are taken at specific time intervals, from 2 to 10 minutes. These X-rays will show any tumors, cysts, stones or other structural or functional abnormality.

At the end, the patient is asked to urinate for final images to see how well the bladder has emptied. The entire test can take up to an hour and is not uncomfortable.

When it’s over, the patient can immediately resume normal activities.

Risks
The main risk in IVP is a reaction to the dye. This happens 3 to 13 percent of the time. Minor reactions include hot flashes, nausea and vomiting. The doctor would then give antihistamines, and the patient typically feels better. Antihistamines are drugs that reduce the effects of an allergic reaction. In very rare circumstances, more severe complications – breathing difficulties, low blood pressure, swelling of the mouth or throat, and even cardiac arrest – can happen. Statistics estimate these major reactions occur in about 1 out of 200 to 2,000 patients.

Patients with certain health factors – a history of hay fever, asthma or hives – are at greater risk, as are those with congestive heart failure, diabetes or a prior reaction. Giving the patient antihistamines or steroids before the exam may prevent any reaction. Also, there are new non-ionic dyes that have lowered the incidence of these reactions.

There is relatively low radiation exposure during this test; however, a patient who is or may be pregnant should tell the physician before this test, because a fetus is susceptible to the risks associated with radiation.

Information Courtesy of American Urological Society

Washington University physicians are the medical staff of
Barnes-Jewish Hospital and St. Louis Children's Hospital