CHEST RADIOLOGY

48 year old man presented for angiography following subarachnoid hemorrhage.
Selected frame from the four vessel angiography is shown below.
.What is the diagnosis?

Diagnosis

Subclavian Steal phenomenon.

Findings:

Right Vertbral artery injection shows filling of left subclavian artery from reversed flow in the left vertebral artery.

Arch aortogram done in the same setting shows occluded left subclavian artery beyond a small patent stump. Delayed frame of the arch aortogram shows faint filling of the left subclavian by reversed flow in the left vertebral.