First of all, make sure you identify what you are trying to treat. If your provider is trying to dilate a carotid artery stricture, maybe to deliver a coil embolization to another vessel intracranially, and can't advance his catheter without dilating this more proximal stricture,you should not bill for a PTA. PTA can only be billed when treating athersclerotic disease. You may want to consider billing 37799 for dilating a stricture of a vessel (the Dotter technique) although I don't think Ive ever read a report where this was done to a carotid artery, they usually do this in the legs.
35475/75962 should be used for PTAs of the brachiocephalic artery and its branches outside of the head. If you are treating an intracranial area (like the intracranial carotid artery) use 61630 for PTA of athersclerotic disease. RS&I, cath placement, and diagnostic imaging is all included in that code. If you are treating intracranial vasospasm, check out 61640 - 61642.
PTA of a carotid or vertebral artery without stent placement is considered a noncovered service by CMS at this time. It is covered only when furnished in accordance with the FDA-approved protocols governing Category B IDE clinical trials (NCD 20.7). So you might have a tricky time getting this paid if the only service rendered to the diseased area was a PTA.
Jayna