Can you provide a citation for the France assertion? I think it’s wildly unlikely a protocol for acute stroke would favor mri over ct but could be wrong. It would take 20 minutes to transfer a pt to mri in a lot of stroke centers in the USA, as opposed to CT’s that are generally across the hall, where imaging should be read within 30 minutes of door time I believe.

Also I’m not sure what you increased “sensitivity” would get you. Acute stroke is a clinical diagnosis, the imaging determines the type of stroke and treatment.

> Can you provide a citation for the France assertion? I think it’s wildly unlikely a protocol for acute stroke would favor mri over ct but could be wrong.

https://www.sciencedirect.com/science/article/abs/pii/S00353... (there's free pdf available when you search for it): "The first-line brain imaging at WH was MRI in 69 SU (56.1%), CT in 6 (4.9%), and either MRI or CT depending on delay and severity in 48 (39.0%). The first-line brain imaging at NWH was MRI in 54 SU (43.9%), CT in 16 (13.0%) and either MRI or CT in 53 (43.1%). In practice, the proportion of patients who really underwent first-line MRI was higher than 90% in 46 SU (37.4%) at WH and in 36 SU (29.3%) at NWH"

> Also I’m not sure what you increased “sensitivity” would get you. Acute stroke is a clinical diagnosis, the imaging determines the type of stroke and treatment.

In clean and easy cases sure, not all cases are like that though and MRI is very useful then; by sensitivity I mean sensitivity - https://pmc.ncbi.nlm.nih.gov/articles/PMC1859855/

Reading that couldn't be more clear, CT is the primary modality for stroke, worldwide.

  > by sensitivity I mean sensitivity

You're a little confused. You're using "sensitivity" to mean sensitivity of detecting ischemic stroke. MRI is the obvious follow-up. When available, worldwide. But it doesn't guide emergency treatment.

> Reading that couldn't be more clear, CT is the primary modality for stroke, worldwide.

Well yes, it's primary modality for stroke worldwide and it's leading modality in France, just like I've said before.

> You're a little confused. You're using "sensitivity" to mean sensitivity of detecting ischemic stroke. MRI is the obvious follow-up. When available, worldwide. But it doesn't guide emergency treatment.

I would appreciate if you stopped using condescending tone. It does not guide emergency treatment decisions because in most cases it is not performed in emergency settings. When it is performed in this setting it is guiding treatment and MRI is included in stroke guidelines for cases where clinical diagnosis is not clear (and these cases are not that rare). Why is it not widely adopted? Mostly logistic reasons (which can be overcome - like they were in France) and because TOF-MRA is generally worse than CTA. It has others positives apart from higher sensitivity though, e.g. you can use FLAIR/DWI mismatch in wake-up strokes which are VERY common (obviously perfusion serves generally same purpose).