How would you approach the upfront management of a patient with acute unilateral vision loss with strong clinical risk factors for both cardioembolic stroke and GCA if an expedited MRI is not possible due to the presence of an AICD?

I'm definitely not an expert in this topic, but you have many clinical tools to increase/decrease your clinical suspicion for GCA vs. cardioembolic stroke.

Some things I would ask:

1. Is this patient currently in Afib? What's their CHADSVASC? Are they anticoagulated?
2. Can we get a TTE to check for vegetations? Have they had a shunt study before?
3. Do they have clinical symptoms of GCA (jaw claudication, etc.)? What's their ESR?

Regarding imaging, a CTA is not super sensitive for medium-sized crania...

I think the question here is addressing the urgency of diagnosis and the most time-efficient choices and management tools to be offered. Dr. @Dr. First Last makes an excellent point that we are lacking clinical information, which would help us. The fact that a temporal artery biopsy has already been obtained at least leads the reader to believe some time has passed (i.e., we are not in the ER with acute vision loss). The most critical piece of information I would need to make an imaging choice i...