Power Doppler imaging in the evaluation of extracranial vertebral artery compression in patients with vertebrobasilar insufficiency

Objective: The recent introduction of Power Doppler Imaging (PDI) made a promise for better visualization of blood vessels lying in regions anatomically difficult for ultrasound imaging, i.e. vertebral arteries. The purpose of our study was to assess usefulness of PDI technique in visualization of vertebral artery course and to assess its utility in the detecting spondylotic vertebral artery compression in patients with vertebrobasilar insufficiency (VBI).

Methods: A total of 428 patients with VBI symptoms was evaluated. A total of 282 (66%) patients related their symptoms to a specific head position. Thus, all Doppler examinations were performed in four head positions: hyperextension, flexion and right/left rotation and also in a position reported by a patient to produce symptoms. PDI technique was employed as vertebral artery mapping for precise PW-Doppler range gate placing.

Results: Vertebral artery compression was found in 73 (17%) patients: 65 unilateral and eight bilateral. The diagnosis was based on flow decrease or its absence shown on PW-Doppler scans, after a specific head turning.

Conclusion: Vertebral artery compression, related to a specific head position is relatively frequent in patients with VBI symptoms, especially in an older population commonly suffering from cervical spondylosis. PDI facilitates noninvasive Doppler US diagnosis by showing the real course of vertebral artery, particularly its intertransverse portion.