(Venography, Phlebography, Lower Limb Venography)
What is a venogram?
A venogram is a procedure that provides x-ray visualization of the veins, particularly in the lower extremities (legs). A special dye is injected that is visible upon x-ray. The contrast dye allows the physician to evaluate the size and condition of the veins. A venogram is one of the more accurate tests used for diagnosing deep vein thrombosis (DVT), but can also be used to diagnose other abnormalities.
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Depending on the reason for the procedure, several methods can be used to examine the veins with venography:
ascending venography - identifies the presence and location of DVT.
descending venography - assesses the function of the deep vein valves.
venography of the upper extremities - assesses blockage, lesions, or thrombosis in the veins of the neck and axillary (armpit) region.
venacavography - evaluates the inferior vena cava, the vein that brings bloods to the heart, for obstruction and malformation.
What is an x-ray?
X-rays use invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film. X-rays are made by using external radiation to produce images of the body, its organs, and other internal structures for diagnostic purposes. X-rays pass through body structures onto specially-treated plates (similar to camera film) and a "negative" type picture is made (the more solid a structure is, the whiter it appears on the film).
Other related procedures that may be used to diagnose problems of the veins include vascular studies and renal venogram. Please see these procedures for additional information.
Reasons for the Procedure
A venogram is used to confirm a diagnosis of DVT and to distinguish clot formation from other venous obstructions. It can also be used to evaluate congenital (present at birth) venous malformations or to locate a vein for arterial bypass graft surgery. It may be used to determine the cause of swelling or pain in the extremity and also to determine the source of pulmonary emboli (blood clots that have traveled to the lung).
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Risks of the Procedure
You may want to ask your physician about the amount of radiation used during the procedure and the risks related to your particular situation. It is a good idea to keep a record of your past history of radiation exposure, such as previous scans and other types of x-rays, so that you can inform your physician. Risks associated with radiation exposure may be related to the cumulative number of x-ray examinations and/or treatments over a long period of time.
If you are pregnant or suspect that you may be pregnant, you should notify your physician. Radiation exposure during pregnancy may lead to birth defects.
Because contrast dye is used, there is a risk for allergic reaction to the dye. Patients who are allergic to or sensitive to medications, contrast dye, or iodine should notify their physician.
Patients with kidney failure or other kidney problems should notify their physician. In some cases, the contrast dye can cause kidney failure, especially if the person is taking Glucophage (a diabetic medication).
Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting.
For certain individuals, a venogram may be contraindicated. These include persons with a known allergy to contrast dye, severe congestive heart failure, and severe pulmonary hypertension.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
Certain factors or conditions may interfere with the accuracy of a venogram. These factors include, but are not limited to, the following:
Before the Procedure
Your physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.
You will be asked to sign a consent form that gives your permission to do the test. Read the form carefully and ask questions if something is not clear.
Notify your physician if you have ever had a reaction to any contrast dye, or if you are allergic to iodine.
Notify your physician if you are sensitive to or are allergic to any medications, latex, tape, and anesthetic agents (local and general).
You may be asked to stop eating and/or drinking for at least four hours before the procedure.
Notify your physician if you are pregnant or suspect you may be pregnant.
Notify your physician of all medications (prescribed and over-the-counter) and herbal supplements that you are taking.
Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.
If a sedative is given before or during the procedure, you may need to have someone drive you home afterwards.
Based upon your medical condition, your physician may request other specific preparation.
During the Procedure
A venogram may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your physician's practices.
Generally, the venogram follows this process:
You will be asked to remove your jewelry or other objects that interfere with the procedure.
You will be asked to remove clothing and will be given a gown to wear.
A pen may be used to mark various sites of pulses on the leg before the procedure. This will allow easier monitoring of the pulses after the procedure.
You will lie on your back on the x-ray table.
After cleansing the area, an intravenous (IV) line will be inserted into a vein in your foot.
An injection of contrast dye will be given. You may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation, a brief headache, or nausea and/or vomiting. These effects usually last for a few moments. Also, let the physician know if you are having difficulty breathing, itching of the skin, or hives.
X-rays will be taken at timed intervals as the dye travels through the lower extremities.
A tourniquet may be placed on the extremity to control the speed of blood flow.
The intravenous site will be flushed with heparin/saline solution, and the needle will be removed from the vein.
A pressure dressing will be placed over the puncture site.
After the Procedure
Following the procedure, your vital signs (heart rate, breathing rate, and blood pressure) will be monitored frequently and then at intervals determined by your physician. The peripheral pulses in your feet, as well as the temperature, color, and sensation in your legs will be checked. The injection site will also be monitored for redness, warmth, swelling, and tenderness.
Normal activities and diet can be resumed after the procedure as directed by your physician.
Drink plenty of fluids to prevent dehydration and to help pass the contrast dye.
Notify your physician to report any of the following:
Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.
The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition.
This page contains links to other Web sites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these Web sites, nor do these sites endorse the information contained here.
American College of Radiology
National Heart, Lung, and Blood Institute (NHLBI)
National Institutes of Health (NIH)
National Library of Medicine
Radiological Society of North America
Society of Interventional Radiology