What is a venogram?

A venogram is a test that lets your healthcare provider see the veins in your body, especially in your legs. A special dye is injected that can be seen on an X-ray. The dye lets your healthcare provider see your veins and how healthy they are.

A venogram is used to diagnose deep vein thrombosis (DVT) or other abnormalities of your veins. This test can also help your healthcare provider diagnose other health problems.

A venogram can be done in several ways:

  • Ascending venography. This looks for a DVT and finds out where it is in your vein.
  • Descending venography. This looks at how well your deep vein valves are working.
  • Venography of the upper extremities. This looks for blockages, blood clots, or other vascular problems in your neck and armpits.
  • Venacavography. This looks at your inferior or superior vena cava. The vena cava is the vein that brings blood to your heart. The healthcare provider looks for blockages or other problems.

X-rays use a small amount of radiation to create images of your bones and internal organs. X-rays are often used to detect bone or joint problems, or to check the heart and lungs. A venogram is one type of X-ray.

Why might I need a venogram?

A venogram is used to confirm a diagnosis of DVT. It is also used to tell if a vein problem is a blood clot or another kind of blockage. It can be used to look at vein problems present at birth (congenital) or to find a vein for bypass graft surgery. It may be used to find out what is causing swelling or pain in a leg. It can also be used to find out where a blood clot started that has traveled to a lung (pulmonary embolism).

What are the risks of a venogram?

A venogram is done with X-rays. These use a small amount of radiation. Talk with your healthcare provider about the amount of radiation used and any risks that apply to you.

Consider writing down all X-rays you get, including past scans and X-rays for other health reasons. Show this list to your provider. The risks of radiation exposure may be tied to the number of X-rays you have and the X-ray treatments you have over time.

Tell your provider if you are pregnant or think you may be pregnant. Radiation exposure during pregnancy may lead to birth defects.

Because contrast dye is used, there is a risk for allergic reaction to the dye. Tell your healthcare provider if you are allergic to or sensitive to any medicines, contrast dye, or iodine.

Tell your provider if you have:

  • Kidney failure or other kidney problems. In some cases, the contrast dye can cause kidney failure, especially if you are taking certain diabetes medicines.
  • A bleeding disorder or are taking blood-thinning medicine (anticoagulant), aspirin, or other medicines that affect blood clotting.

You may not be able to have a venogram if you are allergic to the contrast dye, or have severe congestive heart failure or severe pulmonary hypertension.

You may have other risks depending on your specific health condition. Be sure to talk with your provider about any concerns you have before the procedure.

Some things may make your venogram less accurate. These include:

  • Moving your leg during the procedure
  • Extreme obesity
  • Severe swelling in your legs

How do I get ready for a venogram?

  • Your healthcare provider will explain the procedure to you. Ask him or her any questions you have about the procedure.
  • You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
  • Tell your healthcare provider if you have ever had a reaction to any contrast dye. Tell your provider if you are allergic to iodine.
  • Tell your provider if you are sensitive to or are allergic to any medicines, latex, tape, or anesthetic medicines (local and general).
  • You may be asked to stop eating and drinking for at least 4 hours before the test.
  • Tell your provider if you are pregnant or think you may be pregnant.
  • Tell your provider about all medicines you are taking. This includes prescriptions, over-the-counter medicines, and herbal supplements.
  • Tell your provider if you have a bleeding disorder. Also tell your provider if you are taking any blood-thinning medicines (anticoagulants), aspirin, or other medicines that affect blood clotting. You may need to stop taking these medicines before the test.
  • You will need to have someone drive you home after the test if the healthcare provider gives you medicine to relax (sedative) during the test.
  • Follow any other instructions your provider gives you to get ready.

What happens during a venogram?

You may have the venogram done as an outpatient or as part of your stay in a hospital. The way the test is done may vary depending on your condition and your healthcare provider's practices.

Generally, a lower leg venogram follows this process:

  1. You will be asked to remove your jewelry or other objects that might get in the way of the test.
  2. You will be asked to remove clothing. You will be given a gown to wear.
  3. The healthcare provider may use a pen to mark places on your leg where pulses are before the test. This will make it easier for the medical team to check the pulses after the test.
  4. You will lie on your back on the X-ray table.
  5. The healthcare provider will clean an area on your foot. Then he or she will put an intravenous (IV) line into a vein in your foot.
  6. The healthcare provider will inject the contrast dye. You may feel some effects when the dye is added to the IV line. These effects include a flushing sensation, a brief headache, nausea, or vomiting. These effects usually last for a few moments. Let the healthcare provider know if you are having problems breathing, itchy skin, or hives.
  7. The healthcare provider will take X-rays at timed intervals as the dye moves through your legs.
  8. The healthcare provider may use a tourniquet on your leg to control how fast the blood flows.
  9. When the test is done, the healthcare provider will flush the IV site, and remove the needle from the vein.
  10. The healthcare provider will put a pressure dressing over the puncture site.

What happens after a venogram?

After the procedure, the medical team will watch your heart rate, breathing rate, and blood pressure. They will also check the pulses in your feet, as well as the temperature, color, and sensation in your legs. They will watch the injection site for redness, warmth, swelling, and tenderness.

You can go back to your normal activities and diet as directed by your healthcare provider.

Drink plenty of fluids to keep from getting dehydrated. This will also help the contrast dye to leave your body.

Call your healthcare provider right away if you have any of these:

  • Fever of 100.4°F (38.0°C) or higher or chills
  • Pain, redness, or swelling at the injection site
  • Bleeding or other drainage from the injection site

Your healthcare provider may give you additional instructions, depending on your situation.

Next steps

Before you agree to the test or the procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person’s qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
  • Who to call after the test or procedure if you have questions or problems
  • How much will you have to pay for the test or procedure

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