Stroke and Neurovascular Imaging: Pearls for Practice (2025)-M6-CNR05-2025

Video Transcription

Video Summary

The RSNA session reviews practical imaging “pearls” for acute stroke, focusing on medium vessel occlusions (MEVO), large-core infarcts, CTA pitfalls, and stroke mimics.<br /><br />MEVOs involve distal MCA (M2–M4), ACA (A1–A3), and PCA (P1–P3) branches and are common and disabling. IV thrombolysis is standard but only recanalizes ~50%. Three recent RCTs (DISTAL, DISCOUNT, ESCAPE-MEVO) were negative for endovascular thrombectomy benefit, possibly due to heterogeneous clinical endpoints and especially variable imaging selection. CTA can miss distal occlusions; adding perfusion markedly improves detection. MEVO-specific perfusion thresholds and collateral metrics differ from LVO (e.g., HIR <0.3 and CBV index ≥0.7 predict better outcomes).<br /><br />For large-core stroke, newer trials show thrombectomy benefits beyond prior limits (historically ASPECTS ≤5/core >70 mL). Evidence supports treatment down to ASPECTS ~3 and late-window cores up to ~125 mL, with hemorrhage rates <10%; uncertainty remains for very large cores and patients without perfusion mismatch.<br /><br />CTA pitfalls include missed M2/PCA occlusions, reliance on reconstructions, satisfaction-of-search, and pseudo-occlusion; noncontrast CT and perfusion help.<br /><br />Finally, stroke mimics occur in ~30% of “stroke” presentations. Perfusion patterns plus normal angiography and non-territorial abnormalities help identify seizures (ictal hyperperfusion; interictal hypoperfusion) and migraines (hypoperfusion during aura, hyperperfusion during headache), reducing unnecessary thrombolysis.

Keywords

acute stroke imaging

medium vessel occlusion (MEVO)

CT angiography (CTA) pitfalls

CT perfusion (CTP)

endovascular thrombectomy trials

large-core infarct

ASPECTS

collateral metrics (HIR, CBV index)

stroke mimics (seizure, migraine)