Leg venography, also called lower extremity venography or phlebography, offers a way for doctors to see the veins in your legs. Veins do not normally show up on X-rays. In a venogram, a doctor injects a special kind of dye into your veins. This dye, called contrast material, is visible on X-rays, and enables your doctor to take images of the veins in your leg.
Your doctor might choose to perform this procedure to find out if there are blood clots in your leg veins and if your veins are damaged or not functioning properly. Your doctor might also order a leg venogram to try to locate a particular vein or to find out why your leg is swollen or painful.
You must tell your doctor about various conditions before you undergo this procedure. Tell your doctor if:
- you are pregnant or breastfeeding
- you have a history of bleeding problems or kidney problems
- you have allergies to medications, dye, or iodine substances
- you have asthma
- you have diabetes
- you are taking metformin (Glucophage)
You should also make sure that your doctor knows about any prescription or over-the-counter medications you’re taking.
You will change into a hospital gown and then lie down on an X-ray table. Your doctor will typically numb an area on the foot of the leg to be examined. He or she will then insert a needle connected to an intravenous (IV) line into a vein in your foot.
Dye will flow through this line into your vein. You will then receive X-rays as the dye travels up your leg. Because the dye shows up on X-rays, your doctor will be able to gain a better understanding of what is happening in your veins.
After your doctor has taken all the required X-rays, he or she will typically inject saline solution into the IV line. This helps flush out the contrast material. The IV line and needle will then be removed and the puncture site will be dressed with a bandage.
You may experience a variety of uncomfortable or unpleasant sensations during your leg venogram. These are typically not serious and usually last for only a few minutes.
Possible reactions to the contrast dye include:
- a flushing sensation
- a headache (brief)
In rare cases, the contrast material may make you feel itchy, give you hives, or cause difficulty breathing. If you experience any of these three symptoms, tell your doctor immediately. You might be having an allergic reaction.
You may feel pain when the intravenous line is inserted into the vein on your foot, even though the area has been numbed.
In some cases, your doctor might tie a tourniquet around your leg to force the dye into deeper veins. Depending on how tightly the tourniquet is tied, it may cause some discomfort.
A normal leg venogram shows your blood flowing freely through the veins in your leg.
An abnormal result shows blockage in one or more of your veins. This blockage may be caused by a blood clot. Other possible causes include a tumor or inflammation.
Your doctor will be able to give you more specific information about any abnormal results on your leg venogram.
Tell your doctor if you think you could be pregnant. Any X-ray involves low-level radiation exposure. This isn’t generally dangerous, but could be an issue for young children or pregnant women.
You might develop an infection at the puncture site on your foot. You may also suffer damage to the veins from the insertion of the catheter.
Other risks include:
- an allergic reaction to the dye
- kidney failure
- creation or worsening of a blood clot
According to the National Institutes of Health (NIH), kidney failure is more likely in the elderly or in diabetic people on the medications metformin (Glucophage) (NIH, 2012).
In very rare cases, an existing blood clot may break loose during the procedure and travel to your lungs. This can cause a pulmonary embolism, a blockage of one or more lung arteries.