Table 3.

Imaging selection criteria for recent positive acute stroke clinical trials

Imaging selection criteria	MR CLEAN	EXTEND -IA	ESCAPE	SWIFT PRIME	REVASCAT	THERAPY
Vessel occlusion	ICA, M1, M2, A1, A2 occlusion	ICA, M1, M2	ICA, M1 or functional M1 occlusion (both/all M2 occlusion)	ICA, M1	ICA or M1 occlusion	ICA, M1 or M2 occlusion -Hyperdense clot length ≥8 mm -Absence of tandem extracranial steno-occlusive disease requiring treatment prior to thrombectomy
Small core	Not required	RAPID perfusion infarct <70mL (relCBF<30% threshold)	ASPECTS score 6–10	ASPECTS score 6–10 on NCT or DWI, RAPID perfusion infarct <50mL (relCBF<30% threshold)	ASPECTS score >6 on NCCT, ASPECTS score >5 on DWI (NCCT ASPECTS >8 for age 80–85)	Acute ischemic changes on NCCT less than one-third of MCA territory
Penumbra	Not required	Target mismatch: RAPID perfusion ischemic core mismatch ratio>1.2, absolute mismatch >10mL (Tmax>6 sec threshold)	Not required	Target Mismatch: RAPID perfusion penumbra/infarct ratio>1.8, penumbra absolute volume >15mL (Tmax>6 sec threshold) - Tmax>10s lesion ≤100mL	Not required (Clinical/core mismatch [NIHSS >5])	Not required
Collaterals	Not required	Not required	Adequate collateral circulation defined as some filling of 50% or greater of the ischemic territory pial circulation beyond occlusion on CT angiography (preferably multiphase CTA)	Not required	Not required	Not required