That has a lot to do with the difficultly and cost of siting an MRI close enough and keeping it open for for emergency protocols.

It also relates to the patient though. Stroke patients are often not very compliant and a morality that is slow and requires a still patient is ill suited to a lot of the work an ED sees.

True enough, but MRI is not inherently too slow for this use. If the economics otherwise made sense, an acceptably fast throughput stroke protocol MR is quite doable.

It is. The requirements of the MR environment make it a lot more difficult than CT though. For example a tubed patient is harder to manage in MR than CT, and while this is done regularly it isn't as easily done as CT.

True, but the improved contrast would probably make it a no-brainer if the other issues were taken care of .

Pun intended?

The contrast is so good.

You are probably aware, but there are 5 minute protocols (Siemens call their one a “go brain”) that are pretty reasonable, and probably not far off a gold standard routine protocol 10 years ago.

That just excludes haemorrhagic stroke rather than confirms most ischaemic strokes. It allows for antiplatlets to be safely given. MRI is still needed to diagnose all but severe or very late strokes as far as I’m aware (although this is not my field. Happy to be proven wrong)

CT is often done both as a non-contrast study (to exclude hemorrhage or large established stroke) and also as a CTA and sometimes with perfusion. This data at most stroke centers is all that is needed acutely to decide whether and how to treat, and MRI is often not done until days later to evaluate final extent of the stroke.