Bow Hunter's syndrome: an unusual case of bilateral dynamic occlusion of vertebral arteries.

A 54-year-old man came to our attention complaining of occasional tinnitus and blurred vision for 2 years, particularly when driving, the symptoms were linked to rightward head rotation. Neurological examination highlighted the occurrence of the reported symptoms at the neck right torsion beyond 45° after about 10 s. After a preliminary Echo-colour Doppler, the patient underwent a dynamic contrast-enhanced MR angiography (CE-MRA) of the supra-aortic trunks. In a neutral position, vertebral artery (VA) blood flow and calibre were regular with no evidence of dominance; scans performed a in rightward head rotation beyond 60° showed a bilateral dynamic stenosis of VAs, in particular at the C5–C6 level on the right, and at the C2 level on the left (figure 1). Figure 1 Dynamic CE-MRA scans performed during right head rotation showing bilateral stenosis of the vertebral arteries at the C5–C6 level on the right (A, white arrow) and at the C2 level on the left (B, black arrow). CE-MRA, contrast-enhanced MR angiography. For diagnostic confirmation, a dynamic digital subtraction angiography (dDSA) was performed, adding selective injections of VAs at different degrees of right neck rotation. dDSA …