What is a Venogram?
A venogram, also known as venography, is a test that lets your doctor see your veins on an X-ray. (Veins cannot be seen on a normal X-ray.) You’ll be injected with a liquid called “contrast dye” to make the veins visible on the X-ray. The dye is an iodine-based solution that permits your veins to be seen on an X-ray. You will be given the contrast dye intravenously, and you will release it through normal urination.
Venography is used to assess the size and condition of your veins. It can also be used to diagnose medical conditions like blood clots and tumors. The test can also show doctors any abnormalities of the veins. Additionally, venography can be used to determine why you experience pain or swelling in your limbs.
Types of Venography
A venogram is usually used to visualize the veins in the legs or stomach, but can be used on any area of the body. Your doctor will choose which type of venography is appropriate for you depending on the reason for your test. The types of venography are:
- ascending venogram: shows the location of deep vein thrombosis, which are blood clots in your legs
- descending venogram: measures the function of the deep vein valves
- upper extremity venogram: looks for blockages or other problems with the veins in your neck and arms
- venacavogram: assesses the function of the inferior vena cava which brings blood to your heart
Each type of venogram uses the same contrast dye and X-ray machine.
Preparing for a Venogram
You and your doctor should discuss all of your medications and allergies before undergoing a venogram. People who are allergic to shellfish or iodine may be especially sensitive to the contrast dye. Let your doctor know if you are pregnant. Radiation exposure to X-ray is minimal but carries a slight risk to the developing fetus—so tell your doctor if you are or suspect you are pregnant. Remove all jewelry before the venogram.
You might be advised to fast for four hours prior to the venogram test.
You will be given a hospital gown to wear during the venogram to make the testing areas easy to access. The technician will clean one of your feet with a sterile fluid and insert an intravenous line. Then, the technician will inject the vein with the contrast dye.
You might feel warm, develop a slight headache, or feel nauseated as the contrast dye travels through your body. Let the technician know if you have trouble breathing or feel itchy after the injection of the dye. This could indicate an allergic reaction.
People who have multiple food or drug allergies are more likely to display an allergic reaction to contrast dye. Those who have hay fever or asthma also have an increased risk of allergy. Patients who have kidney disease are also at risk.
You most likely will not be tested for allergies to contrast dye before you have a venogram. This is why it’s important to let your doctor know if you have previously reacted to the dye. The doctor might give you an antihistamine before using contrast dye to prevent itching or he may decide not to risk a reaction and will not use the dye.
X-rays will be taken at regular intervals as the contrast dye moves throughout your legs and lower body. After the X-rays are finished, the injection site will be bandaged.
You will rest for a short time after the venogram and your vital signs will be monitored. You can usually go home the same day as your venogram. Complications like redness or swelling at the injection site, fever, or chills may indicate infection or allergies to the contrast dye. In cases such as these, your condition may be watched for a longer period in the hospital.
Risks of Venogram
Venogram is safe for most people. Those who have congestive heart failure, pulmonary hypertension, or an allergy to contrast dye should not have a venogram.
People who have kidney disease, have diabetes, and take the drug metformin (Glucophage) to control glucose levels may be at a higher risk for going into kidney failure after a venogram. Studies have noted that between 0.1% and up to 13 percent of people who have contrast dye during medical procedures can experience kidney failure, states the American Academy of Family Physicians (AAFP).
Diabetics have an increased risk of developing kidney problems. The most common cause of kidney failure is diabetes, explains the National Kidney and Urologic Diseases Information Clearinghouse (NKUID).
Other factors may make venography more difficult to perform, especially if you:
- are obese
- cannot sit still during the X-ray process
- have severe swelling in your legs
Obesity and excessive swelling in your limbs make the veins harder to locate and see during a venogram. You must also be able to remain still for the length of the test so the technician can accurately perform the venogram.
Discuss your overall health with your doctor to determine if the benefits of venogram outweigh the risks.