Presentation
Intermittent dizziness. Investigated with normal CT head.
Patient Data
The right common carotid and internal carotid arteries demonstrate a widened waveform and low peak systolic velocity (parvus et tardus pattern).
There is bidirectional ('to-and-fro') flow within the right vertebral artery (second image sequence).
Elevated peak systolic velocites within the left internal carotid artery (192 cm/s maximally) indicating 50-69% stenosis.
CTA confirms high-grade, short-segment stenosis involving the brachiocephalic trunk due to circumferential calcified atheromatous disease.
Moderate calcified disease of the carotid bulbs.
Case Discussion
Parvus et tardus (slow-rising, late-arriving) Doppler waveform indicates the presence of proximal stenosis. Bidirectional flow within the right vertebral artery indicates that the site of stenosis is proximal to the vertebral artery origin.
In this case, ultrasound can accurately localize the site of obstructing lesion to the brachiocephalic trunk; confirmed with CT.