A duplex study images a blood vessel and measures the flow inside it at the same time. It shows narrowing, blockage and reversed flow without needles or radiation.
What is examined
- Neck arteries — narrowing of the carotid arteries, often after a stroke or transient symptoms
- Leg veins — deep vein thrombosis, and valve failure causing varicose veins
- Leg arteries — narrowing causing calf pain on walking, or poor wound healing
- Arm vessels — assessment before or after dialysis access surgery
- Abdominal vessels — flow to the kidneys and liver
The examination
Expect 20 to 45 minutes depending on how much is being examined. Gel and a probe are used over the skin, and the sonographer may press firmly along a vein — that is part of the test for clot. Wear clothing that gives easy access to the area being scanned.
