IAC Vascular Laboratory

Examination: Carotid Duplex

Purpose: Evaluation of the cervical carotid and vertebral arteries utilizing Doppler and imaging techniques to assess for the presence and severity of any abnormalities

Equipment Utilized:

• Duplex Ultrasound machine with Spectral Doppler, Color Doppler and B-mode capabilities
• 7-10 MHz linear transducer
• Printer and video recorder
• Ultrasound gel
• Standard blood pressure cuff
• Stethoscope
• Towels or wipes

Patient Preparation and Positioning:

• Introduction to patient and a brief explanation of what the examination entails
• Obtain pertinent patient history
• Perform bilateral upper extremity blood pressures
• Patient is to lay supine at forty-five degrees or less; small pillow or towel can be used to support head and neck of patient
• Expose patient's neck and protect clothing using towel

Examination Techniques:

• Bilateral examination is required for a complete examination
• Equipment gain and display settings should be optimized to provide the best possible b-mode images; color flow Doppler is utilized to assist in identifying vessels and flow disturbances
• Spectral waveforms are obtained using a Doppler angle of sixty degrees or less, keeping the cursor aligned parallel to the vessel wall
• The entire right side is assessed first in bilateral examination
• The entire carotid system should be assessed using both imaging and Doppler interrogation, obtaining hardcopy documentation as required by the Documentation Acquisition portion of this protocol

Documentation Acquisition:
The following documentation must be obtained with additional documentation of questionable and abnormal or incidental findings.

• B-Mode Images (longitudinal):
  1. Common Carotid Artery
  2. ICA/ECA Bifurcation
  3. Proximal Internal Carotid Artery

• Spectral Doppler Waveforms:
  1. Proximal Common Carotid Artery
  2. Distal Common Carotid Artery
  3. Vertebral Artery
  4. Proximal External Carotid Artery
  5. Proximal Internal Carotid Artery
  6. Distal Internal Carotid Artery
  7. Whenever stenosis is suspected a Doppler waveform distal to the stenosis must be documented
  8. If there is a difference of >20 mmHg between the blood pressures of the upper extremities, document Doppler waveform(s) from the Subclavian arteries

Special Considerations:

• For patients with thick or short necks, it may be necessary to place the probe at various planes (anterior, posterior) in order to obtain the most optimal assessment of the vessels
• Patients that are post-operative from CEA may have dressings, staples or swelling that can impede accurate assessment of the vessels
• Calcific plaque may limit the Doppler and/or imaging assessment