Ultrasound

An ultrasound is typically the first test that is performed in a patient that is suspected of having a DVT. It is a painless test that usually takes less than 30 minutes to perform. During this test, the sonographer places the ultrasound transducer on the leg and images the veins of the leg from the groin to the calf. It is possible to directly visualize blood flow and clot within a leg vein using ultrasound.

Venogram

Historically, this test was used for diagnosing a DVT. Today, it is reserved for patients who have difficulty undergoing an ultrasound examination (usually due to large legs) or who have had an ultrasound examination that was unable to definitely conclude if a DVT is present. An interventional radiologist performs this test. It involves placing a small needle into a vein in the foot and then injecting an x-ray dye into the veins. This enables the veins to be directly observed with x-rays, which typically allows for a definitive diagnosis of DVT to be made.