Excretory urography

Definition

An intravenous pyelogram (IVP) is a type of x-ray examination specifically designed to study the kidneys, bladder, and ureters (the tubes which carry urine from the kidneys to the bladder).

After iodine-based contrast dye is injected into a vein, a series of images are taken at timed intervals. The kidneys are responsible for removing contrast dye from the blood and collecting it in urine.

Abnormalities in the appearance of the kidneys or ureters, abnormalities in the distribution of contrast within a kidney, unequal amounts of dye in each kidney, or abnormalities in the collecting systems can be identified. These all suggest particular diseases and conditions.

Alternative Names

Why the Excretory urography is Performed

The procedure helps evaluate infections in the bladder and the kidneys, blood in the urine, flank pain (which may be from kidney stones), and tumors. It is also useful for evaluating the urinary tract for damage after an abdominal injury.

Recently, computed tomography (CT) has replaced IVP as the primary tool for evaluation of the urinary system. CT scans can be rapidly performed, use less contrast solution, and provide additional imaging of the abdomen which may reveal other potential sources for the patient's symptoms. Magnetic resonance imaging (MRI) is also being used to look at the kidneys, ureters and bladder. This test has the advantage of using no radiation. The choice of test is based on discussions between you and your doctor.

How the Excretory urography is Performed

As with other imaging tests, this one is performed in a hospital radiology department, or in the health care provider's office by an x-ray technician. You will need to urinate immediately prior the procedure to ensure the bladder is empty, and access to a vein will be placed in an arm. An initial "scout" image will be taken while you are lying face-up.

Once the injection of contrast dye is complete, it is necessary to remain still during the procedure, which may take up to one hour. A compression device (a wide belt containing two balloons that can be inflated) may be used to keep the contrast material in the kidneys.

At the end of the procedure, you will again be asked to urinate for a final image, to see how well the bladder has emptied. Usual diet and medications should be started again after the exam, and drinking plenty of fluids is recommended, to ensure complete removal of the dye from the blood.

How to Prepare for the Excretory urography

As with all x-ray procedures, inform the health care provider if you:

• Are pregnant
• Are allergic to contrast material
• Have any drug allergies

You must sign a consent form. Eat a very light dinner or no food the night before the test, and do not eat or drink ANYTHING until the test is over (including morning coffee!) You may be given a laxative to take the afternoon before the procedure to remove intestinal gas and stool that could obscure the view of the kidneys. You will put on a gown and remove all jewelry.

How the Excretory urography Will Feel

• You may be hungry and thirsty from not eating and drinking before the test.
• As the dye is injected, there may be a burning or flushing sensation in the arm and the body, and a metallic taste in the mouth. This is a normal occurrence and will quickly disappear.
• Some people develop headaches, nausea, or vomiting after the dye is injected.
• The compression device may cause pressure across the abdomen.

Risks

There is a chance of an allergic reaction to the dye, even if you have received prior injections of contrast with no problems. Doctors should look for alternative imaging of the urinary system for patients with known allergies to iodinated contrast. These alternatives include retrograde pyelography (performed by urologists), MRI, or ultrasound.

There is low radiation exposure. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits.

Pregnant women and children are more sensitive to the risks of radiation.

What Abnormal Results Mean

The test may reveal kidney diseases, birth abnormalities, tumors, kidney stones, and inflammation caused by infections.

Additional conditions under which the test may be performed:

• Acute arterial occlusion of the kidney
• Acute bilateral obstructive uropathy
• Acute unilateral obstructive uropathy
• Analgesic nephropathy
• Atheroembolic renal disease
• Benign prostatic hyperplasia
• Bilateral hydronephrosis
• Carcinoma of the renal pelvis or ureter
• Chronic bilateral obstructive uropathy
• Chronic glomerulonephritis
• Chronic unilateral obstructive uropathy
• Complicated UTI (pyelonephritis)
• Cystinuria
• Injury of the kidney and ureter
• Medullary cystic disease
• Polycystic kidney disease
• Prostate cancer
• Acute kidney infection
• Reflux nephropathy
• Renal cell carcinoma
• Renal papillary necrosis
• Renovascular hypertension
• Retroperitoneal fibrosis
• Unilateral hydronephrosis
• Ureterocele
• Wilms' tumor

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