Which statement best differentiates TIA from ischemic stroke?

• A. Stroke has persistent deficits with infarction on imaging
• B. TIA is transient deficits lasting less than 24 hours without infarction
• C. TIA lasts longer than 24 hours
• D. Ischemic stroke is always accompanied by hemorrhage on imaging

Answer: (B)

The key idea is that TIAs are brief disruptions in blood flow with no lasting brain injury. A true differentiator is a transient neurological deficit that resolves, and there is no acute infarction visible on imaging. That combination—symptoms that disappear within a day and no infarct on imaging—best separates a TIA from an ischemic stroke, where deficits are persistent and infarction is present.

Traditionally, TIAs were defined by symptom duration under 24 hours, and many patients with TIAs have no imaging evidence of infarction. Some modern definitions emphasize tissue status (no infarct on MRI), but the classic test statement uses the <24-hour duration with no infarction to distinguish TIAs.

The other statements don’t fit as well. A description about stroke with persistent deficits and infarction reflects the opposite scenario. Saying TIAs last longer than 24 hours contradicts the defining feature. And claiming ischemic stroke is always accompanied by hemorrhage is incorrect, since ischemic strokes can occur without bleeding and only some undergo hemorrhagic transformation later.