The upper or lower extremity arterial ultrasound detects blockages in the arm and leg arteries. The blood flow to the muscles in the legs or arms is decreased by a plaque buildup on the artery walls. The arterial duplex ultrasound detects this plaque and prevents serious consequences, such as gangrene and, in some cases, even death. Peripheral arterial disease is caused by the hardening of arteries, also known as atherosclerosis. An average of 10 million Americans suffer from this disease, and this exam can be used to detect or prevent this disease. This ultrasound takes 30 minutes.