MRI
In the neck, marked decreased flow is noted involving the proximal and mid cervical segments of the right vertebral artery consistent with a high-grade stenosis, dissection, or thrombus. The distal cervical segment of the right vertebral artery and the intracranial segment of the right vertebral artery are patent which could reflect collateral flow, slow anterograde flow, or retrograde flow across the vertebral basilar junction. Follow-up axial T1 fat saturation series of the neck and contrast enhanced neck MRA are recommended for further evaluation.