Pyelogram – Indications, Procedures, Results

Intravenous pyelography (IVP), or intravenous urography, is a diagnostic test that involves the administration of intravenous contrast and X-ray imaging of the urinary tract. The iodinated contrast flows through the renal vasculature and is filtered into the collecting system highlighting the anatomic structures on the X-ray image. It is often useful for the evaluation of hematuria, and renal stone disease, and as a follow-up after the intervention. The urographic imaging sequence is designed to depict specific parts of the urinary tract optimally. Portions of the urinary system appear opaque when filled with contrast material.[rx] Accurate conclusions from the IVP are feasible only when the technique, limitations, and basic rules of interpretation are known.

An intravenous pyelogram (IVP) is a special x-ray exam of the kidneys, bladder, and ureters (the tubes that carry urine from the kidneys to the bladder).

How the Test is Performed

An IVP is done in a hospital radiology department or a health care provider’s office.

You may be asked to take some medicine to clear your bowels before the procedure to provide a better view of the urinary tract. You will need to empty your bladder right before the procedure starts.

Your provider will inject an iodine-based contrast (dye) into a vein in your arm. A series of x-ray images are taken at different times. This is to see how the kidneys remove the dye and how it collects in your urine.

A compression device (a wide belt containing two balloons that can be inflated) may be used to keep the contrast material in the kidneys.

You will need to lie still during the procedure. The test may take up to an hour.

Before the final image is taken, you will be asked to urinate again. This is to see how well the bladder has emptied.

You can go back to your normal diet and medicines after the procedure. You should drink plenty of fluids to help remove all the contrast dye from your body.

or

Contrast material, radiologic table, X-ray tubes, monitor, fluoroscope, and detector are required to perform the test.

The patient must empty the bladder before the procedure. Images should systematically be obtained to improve the visualization of stones and increase the soft-tissue contrast.[rx] Imaging shall include the area from the suprarenal region to below the pubic symphysis. Before the injection of contrast, the fields of calcification must undergo evaluation. Otherwise, the contrast may conceal the calcification, potentially missing the findings.

Oblique radiographs help confirm the position and nature of calcifications. This view is vital in cases where the patient may have signs of urinary tract calculus, but none is otherwise observable on the AP view.

Although unenhanced computed tomography has replaced intravenous pyelography (IVP) in the evaluation of flank pain, IVP might play a role in the follow-ups of these patients. Adjustments after contrast administration can be made based on preliminary images. The initial images play a vital role as they indicate urinary causes for the patient’s discomfort and also indirectly help detect other abdominal pathologies.

The standard procedure for pyelography consists of the following steps[rx][rx]:

• A set of preliminary images (Kidney-ureter-bladder [KUB] radiograph) is necessary before contrast administration. This imaging is a crucial step and should not be missed. Additional oblique images can also be helpful.
• Next, a bolus of contrast should be administered.
• After 1 to 3 minutes of contrast administration, nephrographic images should be obtained. (Oblique images are also an option.)
• A KUB radiograph should follow five minutes after contrast administration.
• Apply abdominal compression immediately after getting a KUB radiograph.
• Five minutes after compression, obtain pyelographic images during early bladder filling.
• Immediately after the release of compression, obtain a KUB radiograph and fluoroscopic spot images of ureters.
• Obtain the radiographic image of the bladder.

How to Prepare for the Test

As with all x-ray procedures, tell your provider if you:

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

Your provider will tell you if you can eat or drink before this test. You may be given a laxative to take the afternoon before the procedure to clear the intestines. This will help your kidneys to be seen clearly.

You must sign a consent form. You will be asked to wear a hospital gown and to remove all jewelry.

How the Test will Feel

You may feel a burning or flushing sensation in your arm and body as the contrast dye is injected. You may also have a metallic taste in your mouth. This is normal and will go away quickly.

Some people develop a headache, nausea, or vomiting after the dye is injected.

The belt across the kidneys may feel tight over your belly area.

Why the Test is Performed

An IVP can be used to evaluate:

• It is useful in diagnosing congenital anomalies of the urinary tract, urinary calculi, enlarged prostate, neoplasms of the kidney, ureter, bladder, and scars and strictures of the urinary tract.
• An abdominal injury
• Bladder and kidney infections
• Blood in the urine
• Flank pain (possibly due to kidney stones )
• Tumors

What Abnormal Results Mean

The test may reveal kidney diseases, birth defects of the urinary system, tumors, kidney stones, or damage to the urinary system.

Risks

There is a chance of an allergic reaction to the dye, even if you have received contrast dye in the past without any problem. If you have a known allergy to iodine-based contrast, a different test can be done. Other tests include retrograde pyelography, MRI, or ultrasound.

There is low radiation exposure. Most experts feel that the risk is low compared with the benefits.

Children are more sensitive to the risks of radiation. This test is not likely to be done during pregnancy.

Considerations

Computed tomography (CT) scans have replaced IVP as the main tool for checking the urinary system. Magnetic resonance imaging (MRI) is also used to look at the kidneys, ureters, and bladder.