A venogram is an X-ray test that takes pictures of blood flow through the veins in a certain area of the body.
During a venogram, a special dye (contrast material) is put into your veins so they can be seen clearly on an X-ray picture. A venogram looks at the condition of your veins and the valves in your veins.
A venogram can show the veins in your legs, pelvis, or arm; the veins leading to the heart; or the veins leaving your kidneys. Venography also may be done to find a blood clot (deep vein thrombosis, or DVT). Blood clots in the deep veins can be serious because the clot or part of it can break off and move through the blood vessels. A clot that blocks an artery in your lung (pulmonary embolus) can be life-threatening.
Why It Is Done
Venography is done to:
- Find blood clots in the deep veins of your leg, arm, or pelvis (deep vein thrombosis, or DVT).
- Find healthy veins to be used in coronary artery bypass graft (CABG) surgery.
- Find the right placement in blood vessels for medical devices such as filters or stents.
- Put a thin flexible tube (catheter) in your kidney (renal) vein to collect a blood sample.
- Check the condition of the valves in the veins of your leg when surgery for varicose veins is being considered.
- Guide the placement of a special intravenous (IV) line that is used for long-term medicine or fluid treatment.
How To Prepare
Do not eat for 4 hours before a venogram. You may drink only clear fluids for 4 hours before the test.
Before a venogram, tell your doctor if you:
- Are or might be pregnant.
- Are allergic to any medicines, contrast material, or iodine dye.
- Have bleeding problems or take blood-thinning medicines, such as aspirin, heparin, or warfarin (Coumadin).
- Have asthma.
- Have had a severe allergic reaction (anaphylaxis).
- Have had kidney problems.
- Have diabetes, especially if you take metformin (Glucophage).
You will be asked to sign a consent form for this test. Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .
How It Is Done
A venogram usually is done in a hospital X-ray department by a radiologist and an X-ray technologist. A nurse may also be present.
Take off all jewelry and metal objects before the test. You will need to take off all or most of your clothes. You will be given a gown to use during the test. You may be asked to urinate just before the test begins.
Arm, pelvis, or leg venogram
You will lie on an X-ray table. A tilting X-ray table is usually used when studying the legs. Safety straps will help you lie still if the table is tilted.
For a leg venogram, you will be asked to relax the leg and keep it still during the X-rays. An elastic band will be put around your leg or ankle to make the veins of the foot fill with blood. The dye will be put in a vein (IV) on the top of your foot.
If the veins in your pelvis are studied, the dye may be placed in a vein in your groin. For an arm venogram, the dye will be put into a vein on the top of your hand or in your arm.
After the dye is put in, a series of X-rays is taken of each section of the arm or leg or pelvis. Your arm or leg may be placed in several different positions so that X-rays from different views can be taken. If your doctor is placing an intravenous (IV) line, X-rays will be taken as the line is put in to help guide it to the correct position.
After the X-rays are taken, your arm or leg will be raised. A sterile salt solution (saline) may be put into the vein to help flush out the dye. Heparin, a blood thinner, may be put into the vein to prevent a blood clot. A small bandage will be placed on the IV site. Drink extra fluids after the test to help flush the dye out of your body.
This test usually takes 30 to 45 minutes.
You will lie on the X-ray table and a numbing medicine (local anesthetic) will be put in the skin in your groin area. A small, thin tube (catheter) is put into the femoral vein in your groin. The catheter is guided through the blood vessels into the vein of one kidney and then the other. Blood samples may be taken from each kidney for more tests. The dye is put through the catheter into each vein and X-rays are taken. The dye may also be put into the large blood vessel (inferior vena cava) in your belly to check the blood flow in it. After the X-rays are taken, the catheter is removed and a bandage is put on the IV site.
The test takes about 1 hour. When it is done, you will need to rest in bed for 2 to 3 hours. You will get IV fluids to flush the dye out of your body. You will usually be asked to drink lots of fluids for the next 24 hours.
How It Feels
You will feel a quick sting or pinch when the numbing medicine is given. When the dye is put into the vein, you may feel a warm flush or have a metallic taste in your mouth.
You may feel like your arm or leg is going to sleep during the test. This goes away after the test.
There is some risk of problems with a venogram.
- There is a small risk of developing an allergic reaction to the dye.
- There is a small risk of infection or damage to the veins being studied. In rare cases, a venogram can cause a deep vein thrombosis.
- There is a risk of kidney problems if you take metformin (Glucophage) to control your diabetes.
- There is always a slight chance of damage to cells or tissue from radiation, including the low levels of radiation used for this test. But the chance of damage from the X-rays is usually very low compared with the benefits of the test.
After the test
In rare cases, a venogram can cause an infection or a blood clot in the area studied. Call your doctor immediately if you have:
- A fever.
- Increasing pain, redness, or swelling in the arm or leg studied.
A venogram is an X-ray test that takes pictures of the blood flow through the veins in a certain area of the body.
The dye moves quickly and evenly through all the deep veins of the arm, leg, or pelvis. There are no enlarged veins or blood clots present. The valves in the veins look normal and work properly.
The venogram shows blocked blood flow to one or more of the deep veins of the arm, leg, or pelvis. A blood clot may be blocking blood flow. The appearance of the clot may help tell if it is old or new.
Veins in the arm, leg, or pelvis are enlarged (varicose veins). This can be caused by blocked blood flow or damage to the valves.
The dye moves quickly and evenly through all of the veins of the kidneys (renal veins). There are no enlarged veins or blood clots present.
A blocked vein from the kidney, a tumor, or a damaged kidney vein is present.
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
- Pregnancy. A venogram is not usually done during pregnancy because the radiation from the X-rays could harm the unborn baby (fetus).
- The inability to stay still during the test.
Arm or leg venogram
- Putting any weight on the leg being tested may stop the dye from moving through the leg veins properly.
- Moving your arm or leg may affect how the dye moves.
- In rare cases, foot veins are too small to put the dye into for the test.
- Stool (feces) or gas in the intestines (bowel) may make it hard to see the kidney veins clearly.
What To Think About
- Doppler ultrasound is often the first test done to look for blood clots in the veins of the arms or legs. Venography may be done when another test, such as ultrasound, cannot give a clear picture of the veins.
- Some X-ray departments use computed tomography venography (CTV) or magnetic resonance venography (MRV) instead of the more standard X-ray venography.
Other Works Consulted
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2006). Mosby’s Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis: Mosby.
|Editor||Susan Van Houten, RN, BSN, MBA|
|Associate Editor||Tracy Landauer|
|Primary Medical Reviewer||Kathleen Romito, MD - Family Medicine|
|Specialist Medical Reviewer||Howard Schaff, MD - Diagnostic Radiology|
|Last Updated||August 18, 2009|