What imaging should be performed immediately when acute stroke is suspected to differentiate ischemic from hemorrhagic stroke?

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When acute stroke is suspected, quickly distinguishing hemorrhage from ischemia is essential to guide treatment decisions, especially whether thrombolysis or endovascular therapy is appropriate and safe. A noncontrast head CT performed immediately is the best first step because it can rapidly rule out intracranial hemorrhage at the bedside in most centers. This quick exclusion of bleed is the decisive factor in enabling urgent reperfusion therapy for ischemic stroke, as giving thrombolytics in the presence of hemorrhage would be dangerous. Although CT may be less sensitive than MRI for very early ischemic changes, its speed and wide availability make it the standard initial imaging in the emergency setting.

MRI with perfusion offers detailed information about tissue at risk and infarct core, and CT angiography can identify a vessel occlusion, but both take more time and resources and are not typically the first imaging performed in an acute scenario where time is critical. A chest X-ray does not help differentiate intracranial pathology in this context. So the immediate step to differentiate ischemic from hemorrhagic stroke is a noncontrast head CT.