If you are suspected to have problems with your veins, a Duplex ultrasound may be done to determine the extent of venous disease. Ultrasound imaging, also called Ultrasound scanning, involves exposing the lower extremities to high-frequency sound waves to produce 2 or 3 dimensional pictures. Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels. A Doppler ultrasound study is routinely used as part of a venous ultrasound examination to evaluate blood flow in the superficial and deep veins of the lower extremities. Ultrasound and Doppler combned is called a Duplex scan.