Vascular Doppler ultrasound

What it is

Doppler ultrasound of blood vessels combines:

• the ultrasound image of the vessel (wall, plaques, clots)
• color Doppler, which shows the direction and speed of blood
• spectral analysis, which measures velocities quantitatively

When all three are used together, the exam is often called Triplex; the term Duplex is used for similar exams. It uses no radiation and usually no contrast.

What it assesses

• arteries — narrowing or blockages from atherosclerosis (the carotids in the neck, the leg arteries, the abdominal aorta)
• deep veins — deep vein thrombosis
• superficial veins — insufficiency of the venous valves and varicose veins (with a dedicated protocol)
• follow-up after some vascular procedures (stents, bypasses)

The exam request should clearly state which area and which clinical question — there is no such thing as a "Doppler of all vessels".

When there is a reason to have it

• one-sided, painful swelling of the leg (suspected thrombosis)
• calf pain when walking that goes away with rest (claudication)
• symptomatic varicose veins, before treatment
• transient neurological signs related to the carotids
• follow-up of a known narrowing

Diabetes, pregnancy or hypertension are not in themselves a reason for a Doppler of all vessels. International guidelines do not recommend routine screening of the carotids in adults without symptoms.

Preparation

• Vessels of the neck and limbs — usually no preparation.
• Abdominal vessels (aorta, renal arteries) — fasting for 6–8 hours may be required to reduce gas.

Follow the instructions for the specific exam.

How it is performed

The doctor applies gel to the skin and moves the probe along the vessel. You may be asked to change position, hold your breath or tense your abdomen. The exam is painless and takes 20–45 minutes depending on the area.

Limitations

The result is affected by calcifications, anatomy, body weight and gas in the bowel. The exam does not rule out every vascular disease and is sometimes supplemented with CT or MR angiography. The decision on treatment is not made from a single figure in the report.