What would be the clinical benefit of multiphase CTA over CTP?

Fundamentally, no one has ever formally tested and proven that one imaging modality (or imaging approach) is better than another in any time window, for any kind of stroke, when the test is treatment decision-making. Therefore the brief answer to your question is: we do not know. The imaging approaches we use in our centres now are based upon currently installed technology and broadly follow the paradigms used in randomized trials of acute stroke therapies (IV thrombolysis and EVT).

However, we ...

A multiphase CTA is a CT angiogram where the contrast is injected and the patient is scanned in three phases: arterial, peak venous, and late venous. It is a good tool to assess collateral circulation as well as it gives an idea of how slow the perfusion is across an occlusion. The advantage over perfusion is it takes less time. Given the recent evidence supporting thrombectomy even in large core patients, we should generally not rely on multiphase CTA or CTP to select patients for thrombectomy.

Excellent response @Dr. First Last. I suspect that centers experienced with CTP will continue to do it for the reasons you stated and those experienced with mCTA will continue that as well. As we move towards treating larger core LVOs, the utility of either study is going to be in more niche situations where our (and institution's) expertise in either CTP or mCTA is the deciding factor. I don't think there will be much transition between the modalities in the years to come, basically because of ...

What well informed and thought out answers to the question above. CTA has always been faster and easier to interpret than CTP!