DEFUSE-3 criteria rely on which feature to extend the thrombectomy window?

• A. Perfusion mismatch within 6–16/24 hours with imaging criteria.
• B. Clinical-core mismatch within 6–24 hours.
• C. Only diffusion restriction on MRI.
• D. Only non-contrast CT perfusion.

Answer: (A)

Defuse-3 extends the thrombectomy window by using perfusion imaging to detect a mismatch between the infarct core and the surrounding hypoperfused tissue (penumbra) in patients evaluated 6 to 16 hours after onset. That mismatch indicates there is still salvageable brain tissue, making thrombectomy beneficial even outside the early window. The other ideas don’t fit as well: a clinical-core mismatch is the criterion used in the DAWN trial to extend to 24 hours, not the Defuse-3 approach; relying on diffusion restriction alone identifies core tissue but doesn’t demonstrate the at-risk penumbra; and perfusion assessment requires imaging beyond a non-contrast CT, as perfusion imaging (CTP or MR perfusion) is essential to quantify the mismatch.