What is a Venous Doppler Ultrasound Exam?
A venous Doppler ultrasound is a diagnostic test used to check the circulation in the large veins in the legs (or sometimes the arms). This exam shows any blockage in the veins by a blood clot or “thrombus” formation.
The veins return blood to the heart. There are two sets of veins in the legs:
- Deep veins – which are underneath the leg muscles
- Superficial veins – which are right underneath the surface of the skin
The veins in the leg deflate easily; blood flows under low pressure and against gravity. Two things help the blood pump more efficiently:
- The calf “muscle pump.” As you walk, calf muscle movement pushes blood upward.
- Venous valves – the one-way valves in the veins that prevent blood from flowing back into your feet
Superficial thrombophlebitis is a clot that has formed in the veins near the surface of your skin. Clotting can occur after injury or in old varicose veins. Superficial thrombophlebitis usually responds very well to local treatment.
Venous thrombosis (sometimes called phlebitis) is a blood clot in a deep vein, resulting in partial or complete blockage of blood flow in that vein. The symptoms of this deep vein thrombosis (sometimes called DVT) can be vague. Pain, swelling and redness are usually found.
Unlike superficial thrombophlebitis, a DVT is a serious health concern, because it’s possible that the clot could break off and travel to your lungs. It is then referred to as a pulmonary embolus. The risk of pulmonary embolus is decreased if you recognize the symptoms of a DVT quickly and get it treated right away.
No one understands completely why some people are more likely than others to develop a DVT. Some situations increase the chance of clots forming in the deep veins:
- Surgery or injury
- Long-term bedrest or immobility
- A history of venous thrombosis
If your doctor thinks you might have a venous disorder, he or she may order a diagnostic exam to determine what type of a problem you have and how bad it might be.
Getting Ready for the Exam
You will come to the Vascular Lab for a venous Doppler/ultrasound duplex exam. This test involves no needles, catheters or dye. Ultrasound is used to listen to the flow of the blood through your veins. Please allow 30 to 45 minutes for the exam. Often, the examination can be completed in less time.