In venography, a contrast dye is injected through a thin, flexible tube (catheter) into a particular vein or group of veins and a series of x-rays is obtained. Filled with the dye, the veins are differentiated from other bodily structures on the x-ray images. Venography is most commonly used to evaluate veins in the kidneys, lower extremities, and adrenal glands, as well as the portal vein in the liver.

Purpose of the Venography

Lower extremity venography:

  • To identify and locate blood clots in the deep veins of the legs (deep vein thrombosis)
  • To distinguish between a blood clot and an obstruction caused by a large pelvic tumor encroaching on the venous system
  • To assess congenital venous malformations
  • To evaluate the competence of valves in the leg veins (which can aid in identifying the causes of leg swelling)

Renal venography:

  • To detect and evaluate blood clots, tumors, or abnormalities in the renal veins of the kidney
  • To collect blood samples from the renal vein to evaluate renovascular hypertension (increased blood pressure due to narrowing of the artery that leads to the kidney)

Adrenal venography:

  • To obtain blood samples from the adrenal gland veins to aid in the detection of diseases such as Cushing’s syndrome (marked by increased secretion of the hormone cortisol) and pheochromocytoma (a tumor marked by increased secretion of the hormones epinephrine or norepinephrine)

Portal venography:

  • To diagnose and assess portal hypertension (high pressure in the portal vein, which empties into the liver)
  • To detect and locate a suspected blood clot in the portal or splenic vein
  • To assess the progression of cirrhosis of the liver
  • To assess the patency of shunts that were constructed to treat portal hypertension (portal-systemic shunts)

Who Performs Venography

  • A radiologist or another physician

Special Concerns about Venography

  • Pregnant women should not undergo this test because exposure to ionizing radiation may harm the fetus.
  • People with allergies to iodine or shellfish may experience an allergic reaction to iodine-based contrast dyes.
  • In people with kidney disorders or chronic dehydration, the contrast dye can worsen kidney function and may cause renal failure. To determine whether the dye can be administered safely, your doctor may perform a blood test to assess your kidney function before the test.
  • This procedure may not be safe for people who have bleeding disorders. Coagulation studies may be performed prior to the test to ensure that your blood will clot normally.
  • The presence of feces, gas, or residual barium in the abdomen from recent contrast x-rays may make it difficult to obtain clear pictures of abdominal veins.

Before the Venography

  • You may be asked to observe certain dietary restrictions for variable periods before the test, depending on the specific procedure.
  • Report to your doctor any medications, herbs, or supplements you are taking. You may be advised to discontinue certain of these agents before the test.
  • Inform your doctor if you have a known shellfish or iodine allergy or have ever had an adverse reaction to x-ray contrast dyes. You may be given preventive medication to reduce the risk of an allergic reaction, or a noniodinated dye may be used.
  • Tell your doctor if you are pregnant or may be pregnant.
  • An intravenous (IV) line is inserted into a vein in your arm so that any necessary medications can be administered during the procedure.
  • Empty your bladder before the procedure.
  • You will be given a sedative to help you relax during the examination.

What You Experience during Venography

Lower extremity venography (ascending):

  • You are positioned lying down on a tilting x-ray table. The table is inclined so that your feet are elevated.
  • The skin on the top of your foot is cleansed with an antiseptic, and a local anesthetic is injected. A tourniquet may be tied around the ankle to make the foot veins fill with blood.
  • A catheter is inserted into a selected foot vein, and contrast dye is infused into the vein.
  • The movement of the dye up the leg is followed using continuous x-ray imaging, or fluoroscopy. Spot x-ray films are also obtained as the dye circulates through different regions of the leg.
  • The catheter is withdrawn, and a bandage is applied to the insertion site.
  • The procedure may take 30 to 45 minutes.

Lower extremity venography (descending):

  • You are positioned lying down on a tilting x-ray table.
  • The skin over a vein in your arm or neck is cleansed with an antiseptic solution, and a local anesthetic is injected.
  • A catheter is inserted into the selected vein. Under the guidance of fluoroscopic imaging, it is carefully guided to a selected pelvic or leg vein.
  • Contrast dye is injected through the catheter and the table is inclined so that your feet are lowered.
  • The movement of the dye down the leg is followed using continuous x-ray imaging, or fluoroscopy. Spot x-ray films are also obtained to document any “leaking” valves in the veins of the legs.
  • The catheter is withdrawn, and a bandage is applied to the insertion site.
  • The procedure may take 30 to 45 minutes.

Renal and adrenal venography:

  • You will lie on your back on an x-ray table.
  • The skin over the catheter insertion site—usually the femoral vein in the groin—is cleansed with an antiseptic solution and (if necessary) shaved. A local anesthetic is injected to numb the area.
  • A catheter is inserted into the femoral vein. Under the guidance of fluoroscopic imaging, it is carefully guided to either the renal or adrenal veins in the abdomen.
  • A contrast dye is injected through the catheter. This may cause a transient burning or flushing sensation.
  • As the contrast agent flows through the selected veins, a series of x-ray films is obtained.
  • If applicable, blood samples are then obtained and sent to a laboratory for analysis.
  • The catheter is withdrawn, and a bandage is applied to the insertion site.
  • The procedure takes about 1 hour.

Portal venography:

  • You will lie on your back on an x-ray table.
  • The skin over the catheter insertion site—usually the femoral artery in the groin—is cleansed with an antiseptic solution and (if necessary) shaved. A local anesthetic is injected to numb the area.
  • A catheter is inserted into the femoral artery. Under the guidance of fluoroscopic imaging, it is carefully guided to a selected abdominal artery.
  • A contrast dye is injected through the catheter. This may cause a transient burning or flushing sensation.
  • Fluoroscopy is used to follow the flow of the dye from the selected artery into draining veins and then into the portal vein near the liver.
  • The catheter is withdrawn, and a bandage is applied to the insertion site.
  • The procedure takes about 1 hour.

Risks and Complications of Venography

  • Possible risks include blood clot formation, bleeding, blood vessel damage, or infection at the site of catheter insertion.
  • Some people may experience an allergic reaction to the iodine-based contrast dye, which can cause symptoms such as nausea, sneezing, vomiting, hives, and occasionally a life-threatening response called anaphylactic shock. Emergency medications and equipment are kept readily available.
  • Venogram causes deep vein thrombosis in rare cases.
  • Renal failure may occur as a result of exposure to the contrast dye, especially in elderly patients with chronic dehydration or mild renal impairment.
  • Cellulitis, inflammation of connective tissue, and pain may occur if the contrast dye infiltrates into the tissues under the skin.

After the Venography

  • Your vital signs will be monitored until they are stable. Depending on the procedure, you may be advised to rest in bed for a certain period of time.
  • Cold compresses can help to relieve any swelling or discomfort at the puncture site.
  • You are encouraged to drink clear fluids to avoid dehydration and to help flush the contrast dye out of your system.
  • You may resume your normal diet and any medications discontinued before the test, according to your doctor‘s instructions.
  • If bleeding or any other complications develop, call your doctor or emergency medical service immediately.

Results of Venography

  • A physician will examine the recorded images and other test data for evidence of venous abnormalities.
  • This test usually establishes a definitive diagnosis. Based on the findings, your doctor will recommend an appropriate course of medical or surgical treatment.

Source:

The Johns Hopkins Consumer Guide to Medical Tests

Simeon Margolis, M.D., Ph.D., Medical Editor

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 25 Jan 2012

Last Modified: 13 Jan 2015