A cerebrovascular ultrasound, also known as a carotid duplex scan, examines the major extracranial arteries supplying the brain to gain information about cerebrovascular blood flow. Carotid scans are used in the evaluation of ischemia, headache, dizziness, hemiparesis, paresthesias, and speech and visual disturbances. Testing is commonly performed before major cardiovascular surgery and as a follow-up to many surgeries. Carotid intima media thickness is used to predict heart disease risk in patients with no symptoms but who have a family history of heart disease.

1. Ask the patient to lie supine on the examining table with the neck slightly extended. The head typically is turned away from the side being examined.

2. Apply a couplant (ultrasound gel) to the neck area to enhance the transmission of sound. During Doppler evaluation, an audible signal, representing blood flow, can be heard.

3. Move a handheld transducer gently up and down the neck while images of appropriate blood vessels are made. Examine both sides of the neck.

4. Tell the patient that the examination time is 30–60 minutes.

5. See Chapter 1 guidelines for intratest care.

Abnormal images and Doppler signals may provide evidence of the following:

1. Plaque

2. Stenosis

3. Occlusion

4. Dissection

5. Aneurysm

6. Carotid body tumor

7. Arteritis

Excess thickness or narrowing of carotid wall indicates the following:

1. Increased risk for heart disease

2. Sign of plaque buildup

Pretest Patient Care

1. Explain the test purpose, benefits, and procedure. The patient should refrain from smoking or consuming caffeine for at least 2 hours before the study. Assure the patient that no radiation is employed, typically no contrast medium is injected, and no pain is involved; however, some slight discomfort may be experienced from lying with head extended.

2. Advise the patient that a liberal coating of coupling gel must be applied to the skin to promote sound transmission. A sensation of warmth or wetness may be felt during application.

3. Explain that necklaces and earrings must be removed before the study.

4. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

1. Severe obesity and patient movement compromise examination quality.

2. Cardiac arrhythmias and disease may cause changes in hemodynamic patterns.

Normal

• Normal vascular anatomy and course of common carotid artery, internal and external carotids, and vertebral arteries

• No evidence of stenosis or occlusion; normal flow patterns

• Normal thickness of inner layers of arterial wall