Excretory urography; Intravenous pyelogram
An intravenous pyelogram 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 intravenously (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, distribution of contrast within a kidney, asymmetry in the amount of contrast in each kidney, or defects in the collecting systems can be identified and are suggestive of particular diseases and conditions.
How the test is performed
As with other studies, the test is performed in a hospital radiology department or in the health care provider’s office by an X-ray technician. The patient will need to urinate immediately prior the procedure to ensure the bladder is empty, and intravenous access will be placed in a vein of an arm. An initial “scout” image will be taken with the patient lying on his/her back.
Once the injection of contrast 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, the patient will again be asked to void for a final image to see how well the bladder has emptied. Usual diet and medications should be resumed after the exam, and adequate hydration is recommended to ensure complete removal of contrast from the blood.
How to prepare for the test
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. You need to eat a very light dinner or no food the night before the test and should 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 feces that could obscure the view of the kidneys. You will be given a gown to put on, and you must remove all jewelry.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:
- infant test or procedure preparation (birth to 1 year)
- toddler test or procedure preparation (1 to 3 years)
- preschooler test or procedure preparation (3 to 6 years)
- schoolage test or procedure preparation (6 to 12 years)
- adolescent test or procedure preparation (12 to 18 years)
How the test will feel
- You may be hungry and thirsty from not eating and drinking.
- 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 subside.
- Some people develop headaches, nausea, or vomiting after the dye is injected.
- The compression device may produce pressure across the abdomen.
Why the test 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), tumors, and evaluates 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 since it can be rapidly performed, uses less contrast solution, and provides additional imaging of the abdomen which may reveal other potential sources for the patient’s symptoms.
What abnormal results mean
The test may reveal kidney diseases, birth defects, 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)
- injury of the kidney and ureter
- medullary cystic disease
- polycystic kidney disease
- prostate cancer
- pyelonephritis; acute
- reflux nephropathy
- renal cell carcinoma
- renal papillary necrosis
- renovascular hypertension
- retroperitoneal fibrosis
- unilateral hydronephrosis
- Wilms’ tumor
What the risks are
There is a chance of an allergic reaction to the dye, even if the patient has received prior injections of contrast without incident. Physicians should seek alternative imaging of the urinary system for patients with documented allergies to iodinated contrast, including 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 the X-ray.
by Potos A. Aagen, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.