A way to visualize the renal (kidney) veins using contrast material and X-rays.

The veins are not normally seen in an X-ray, so a contrast material is injected into the vein so it may be seen. For renal venography the contrast material is injected into the renal vein.

X-rays are a form of electromagnetic radiation (like radio waves or light). The wavelength is very short and is capable of penetrating the body and producing a shadow picture of the structures inside the body. Some of the X-rays are absorbed by the body tissues, while other X-rays will pass through. The denser tissues, such as bone, appear on the film as white. Less dense tissues, such as muscles, appear as gray; and air on the X-ray appear as black.

See also renal arteriography.

This test is done in the hospital. You will be asked to lie on the X-ray table. The area over the vein to be used is cleansed, and a local anesthetic is given. The renal veins are usually accessed through a vein in the groin area. A needle is used to puncture the vein, and a catheter (a long, narrow, flexible tube) is inserted through the needle and into the vein.

The catheter is then threaded through the main veins until it is placed in the renal (kidney) vein. This procedure is monitored by a fluoroscope (a special X-ray that projects the images on a TV monitor). The contrast medium is then injected into the vein, and the X-rays are taken. The catheter is then withdrawn and the puncture site is bandaged.

Inform the health care provider if you are pregnant, and if you have ever had any bleeding problems. Some medications, such as aspirin and other blood thinners, may need to be stopped before the examination. Report any allergic reactions to X-ray contrast material or any iodine substance and any other allergic reactions. You must sign a consent form. Food and fluid may be restricted for 8 hours before the test. You will be given a gown to wear. Remove all jewelry. You may be given a sedative or pain pill before the procedure.

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 experience, 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)

The test will detect a thrombosis (a blood clot that partially or completely blocks the vessel), tumor, and venous abnormalities. The test may also be used to measure hormone levels produced by the kidney.

However, this test is now performed only on rare occasions and has largely been replaced by CT scan and MRI.