Which imaging modality is best for distinguishing between acute hemorrhagic and ischemic stroke?

Non-contrast CT is considered the best imaging modality for distinguishing between acute hemorrhagic and ischemic stroke. In cases of hemorrhagic stroke, the presence of blood within the brain tissue or ventricular system is more readily visible on non-contrast CT, allowing for rapid identification of bleeding. This is crucial since the management of hemorrhagic stroke differs significantly from that of ischemic stroke, where time is of the essence in initiating treatment.

In acute ischemic stroke, non-contrast CT may initially appear normal or show subtle signs (such as early hypodensity) that can help in diagnosis but is typically used primarily to rule out hemorrhage before any thrombolytic therapy is considered. The speed and availability of non-contrast CT in emergency settings, alongside its effectiveness in visualizing acute bleeding, reinforce its role as the preferred method for immediate assessment in suspected stroke patients.

While other modalities like MR imaging and contrast CT can provide more detailed information about the brain's vascular structures or ischemic changes, they are not as readily available or practical for acute evaluation in emergency situations. Ultrasound, while useful in certain assessments of the carotid arteries, is not effective for evaluating intracranial hemorrhage or ischemic strokes.