Vascular Extracranial Carotid Artery ScanCoach™
View-by-View Acquisition Guidance
View-by-view acquisition guidance for extracranial carotid and vertebral artery ultrasound, aligned with current AIUM and SVU guidelines. Covers B-mode, color Doppler, and spectral Doppler technique with image optimization tips and stenosis grading criteria.
Common Carotid Artery (CCA)
High-frequency linear (7–15 MHz) · Longitudinal & transverse from clavicle to bifurcation
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Supine with a pillow or roll under the shoulders to extend the neck. Turn the head 30–45° away from the side being examined. Ensure the patient is comfortable — muscle tension elevates the CCA and makes insonation difficult.
Begin in the longitudinal plane at the base of the neck just above the clavicle. Slide superiorly to the bifurcation, then rotate 90° for transverse sweeps. Keep the transducer footprint parallel to the vessel long axis to minimize refraction artifact.
Vessel diameter, intima-media thickness (IMT) at the far wall 1 cm below the bifurcation, plaque presence (location, echogenicity, surface texture, calcification), flow direction, spectral waveform (normal triphasic or biphasic pattern), and PSV. Document bilateral CCA PSV for comparison.
Angle of insonation must be ≤60°. Sample volume 1.5–2 mm, placed mid-lumen. Normal CCA PSV: 50–100 cm/s. EDV typically 15–30 cm/s. A CCA PSV >100 cm/s warrants careful evaluation of the proximal ICA. Document waveform pulsatility — dampened waveform distal to a stenosis is a key indirect sign.
Use colour Doppler to identify the vessel before switching to spectral. Heel-toe the transducer to achieve the correct angle rather than steering the beam alone — this reduces aliasing and improves waveform quality. Compound imaging reduces speckle but may reduce plaque echogenicity; toggle off when characterising plaque.
IMT measurement is most reproducible at the far wall of the distal CCA in the longitudinal plane. Use the leading-edge method (intima–lumen interface to media–adventitia interface). Normal IMT <0.9 mm; ≥1.5 mm = plaque by consensus definition.
A very proximal CCA origin stenosis (aortic arch or innominate) can produce a dampened, tardus-parvus waveform throughout the CCA — do not mistake this for normal low-flow. Always compare bilateral CCA waveforms; asymmetry >30% PSV difference is a red flag.