When do you recommend hyperacute MRI for patients with wake-up stroke?  

Wake-up stroke patients with arrival within 4.5 hours of symptom discovery may be eligible for tPA or tenecteplase if the acute MRI shows a DWI lesion but little or no FLAIR lesion.

I get a hyper-acute MRI to guide the thrombolysis decision if there are deficits that I would otherwise treat with TNK/TPA within the 4.5 window based on imaging and symptoms. Specifically, no large hypodensity on CT that would concern me for hemorrhagic transformation.