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Typical aortic arch branching pattern with patent origin of common carotid and vertebral arteries. No mural irregularity, aneurysm or stenosis of anterior or posterior circlulation from aortic arch to circle of Willis.

Abrupt loss of opacification of the right PICA approximately 10mm from its origin. Circle of Willis is complete without aneurysm, stenosis, or filling defect.

There is a possibility of the right cerebellar lesion being a mass rather than infarct. There is occlusion of the right PICA secondary to extrinsic compression by mass effect within the right cerebellum.