I am doing reserch that prospectively follow pt with atrial fibrillation on warfarin for incidence of stroke hemorrhagic due to SIde effect of warfarin or ischemic due to cardioembolism I WONDER if NONcontrast CT beside history and exam and coagulation profile is sufficient to diffrentiate ischemic from hemorrhagic
This is tricky mainly because individuals are going to have 1) asymptomatic (Issue 1) or non-stroke like 'chameleonic' manifestations of focal ICH or cardioembolism (Issue 2). Moreover, if all participants are seen hyperacutely after symptoms, CT is less sensitive for hyperacute infarcts (Issue 3). This becomes a little bit more complicated that CTs can potentially miss focal infarcts in the brainstem(Issue 4) both in hyperacute or acute setting( Issues 4a and 4b)
If patients are likely to be seen less acutely ( or imaged only at follow up) a CT loses its ability to discriminate ischemic vs hemorrhagic lesions as days pass since event or symptoms (Issue 5)
Of course there is also a problem of hemorrhagic infarcts which can pose problems ascertaining the exact underlying problem
Hemorrhage smaller than infarct - easy (grade 1 and 2 HTI )
Hemorrhage as big as the infarct or bigger than the infarct often masquerades as a hematoma rather than a hemorrhagic infarct, thus misleading as to the exact mechanism (Issue 6). These limitations should be borne in mind. An MRI will resolve
Issues 1 and 2 ( if routine follow up MRIs are done at intervals)
Issues 3 and 4 (if MRI study triggered by presentation)
Issue 5 if GRE/SW sequences are undertaken
Issue 6 (I don't think even an MR can help here)
The reason history and examination are not being mentioned with emphasis(though very useful) is because of the difficulties they pose due to interpersonal variability in ascertaining or interpreting, individuals with pre-existing neurological signs (making new vs old virtually impossible to ascertain unless the clinician continuity is there - though that cant fix the problem entirely). There is then an argument of whether asymptomatic infarcts and bleeds classify as a stroke (but may classify as an adverse event happening whilst on anticoagulation)
Having MRI will help giving more clarity to the study you do but a CT could help in
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