Doppler ultrasound exam of an arm or leg

Definition

This test uses ultrasound to examine the blood flow in the major arteries and veins in the arms and legs.

How the test is performed

The test is done in the ultrasound or radiology department or in a peripheral vascular lab.

To examine the veins:

A water-soluble gel is placed on the transducer (a handheld device that directs the high-frequency sound waves to the artery or vein being tested) and the skin over the veins of the extremity being tested.

There is a "swishing" sound on the Doppler if the venous (vein) system is normal. Both the superficial and deep venous systems are evaluated.

To examine the arteries:

Blood pressure cuffs will be put around the thigh, calf, and ankle to examine the legs. In the arms, the blood pressure cuffs are placed at different points along the arm. A conductive paste is applied to the skin over the arteries being examined. The cuff will be inflated above the normal systolic blood pressure for the extremity.

The transducer is placed near the cuff, and the pressure in the cuff is released slowly. When the "swishing" is detected, it is recorded as the blood pressure. This is repeated for each cuff.

How to prepare for the test

You will need to remove clothing from the extremity being examined.

How the test will feel

There is little or no discomfort associated with this test.

Why the test is performed

This test is done as an alternative to arteriography and venography. It may help diagnose a blood clot, venous insufficiency, arterial occlusion (closing), abnormalities in the carotid artery blood flow caused by a narrowing and to evaluate trauma to the arteries. The test may also be used to monitor arterial reconstruction and bypass grafts.

Normal Values

• The vessels show no evidence of narrowing or closure.
• The arteries have normal systolic and diastolic components.
• Blood pressure is normal.
• The ankle-to-brachial arterial blood pressure index (comparison of the pressure at the ankle to that of the brachial artery in the arm) is 0.85 or greater.

What abnormal results mean

• In the veins:
  • Venous occlusion (closing of vein)
  • Blood clots
• In the arteries:
  • Arterial occlusive disease
  • Spastic arterial disease (arterial contractions brought on by cold or emotion)
  • Embolic arterial occlusion (obstruction in the artery by a blood clot, a fat globule, or an air bubble)

Additional conditions under which Doppler ultrasound may be performed include the following:

• Aortic dissection
• Arteriosclerosis of the extremities
• Coarctation of the aorta
• Deep venous thrombosis
• Stroke secondary to carotid stenosis
• Superficial thrombophlebitis
• SVC obstruction
• Thromboangiitis obliterans
• Vascular tumors of the extremities

What the risks are

There are no risks specifically associated with this procedure.

Special considerations

Cigarette smoking may alter the results of this test, because nicotine can cause the arteries in the extremities to constrict.

Quitting smoking significantly lowers the risk of problems with the heart and circulatory system. Most smoking-related deaths are caused by cardiovascular problems, not lung cancer.

Illustrations

Doppler ultrasonography of an extremity