Positional cervical Doppler ultrasonography suggesting proximal vertebral artery obstruction in Bow Hunter syndrome: a case report

Abstract Background Bow Hunter syndrome results from dynamic vertebral artery stenosis or occlusion during neck rotation. Case presentation: A man in his 70s presented with dizziness, nausea, and vomiting and was diagnosed with left occipital and right cerebellar infarctions. On hospital day 7, rightward neck rotation reproduced the dizziness. Positional cervical Doppler ultrasonography showed normal antegrade flow in the left vertebral artery in the neutral position, a to-and-fro waveform immediately after rotation, and partial recovery after approximately 30 s with a delayed systolic peak. These findings suggested an intermittent obstruction proximal to the sampling site. Computed tomography angiography in the neutral and rightward-rotated positions demonstrated kinking and slit-like narrowing of the proximal left vertebral artery at T1. Rotational digital subtraction angiography confirmed marked flow reduction. Computed tomography angiography revealed no fixed extravascular compressive lesions. The patient was treated with aspirin and restriction of neck rotation. Conclusions Positional Doppler waveform analysis may help guide the selection of anatomical imaging, although angiographic confirmation remains necessary.