Neurologic System

Non-contrast head CT — it is fast and reliably distinguishes ischemic stroke from intracranial hemorrhage, which must be excluded before giving thrombolytics.

Within 4.5 hours of symptom onset (or last-known-well), provided there are no contraindications such as recent hemorrhage, surgery, or uncontrolled hypertension >185/110.

For large-vessel occlusion (e.g., proximal MCA/ICA), generally up to 24 hours from onset in selected patients with favorable perfusion imaging.

A TIA is a transient focal neurologic deficit from ischemia that resolves (classically <1 hour) without infarction on imaging; a stroke leaves permanent tissue infarction.

Antiplatelet therapy (aspirin or clopidogrel), a high-intensity statin, blood pressure control, and risk-factor management; carotid endarterectomy for significant symptomatic stenosis.