In acute stroke evaluation, non-contrast head CT primarily serves to

• A. Detecting early ischemic changes within minutes
• B. Assessing perfusion deficits directly
• C. Detecting hemorrhage as a hyperdense area and ruling out hemorrhage before thrombolysis
• D. Measuring intracranial pressure

Answer: (C)

In acute stroke evaluation, the emphasis is on quickly ruling out intracranial hemorrhage so that thrombolytic therapy can be considered safely. A non-contrast head CT does this by showing fresh blood as a hyperdense (bright) area. If hemorrhage is present, thrombolysis is contraindicated, so identifying bleeding promptly determines the next step in treatment. The scan’s speed, wide availability, and lack of contrast make it ideal for emergent decisions in the hyperacute window.

While it can sometimes hint at early ischemic changes, non-contrast CT is not highly sensitive for early ischemia, and perfusion deficits are better assessed with CT perfusion or MR diffusion/perfusion imaging. It also doesn’t measure intracranial pressure.