Background: Recent trials of endovascular thrombectomy (EVT) for acute distal medium vessel occlusions (DMVOs) were negative but also used inconsistent imaging-based inclusion criteria, whereas many successful large vessel occlusion (LVO) EVT trials used empirically validated CT perfusion-based target mismatch (TMM) criteria: an ischemic penumbra (time-to-maximum Tmax >6s) to core (relative cerebral blood flow rCBF 4s, >6s, >8s, and >10s volumes correlated with FIVs in unrecanalized patients. Then, we evaluated whether these improved parameters for core and penumbra better quantified LVO TMM and identified an optimal DMVO TMM definition. Results: In 122 core patients, rCBF 8s most strongly correlated with FIVs (CCC 0.49 0.25-0.77), outperforming Tmax >6s (CCC 0.39 0.17-0.68) (p 6s to rCBF 8s and rCBF 8s to rCBF 8s best correspond to ischemic core and penumbra, respectively; more favorably quantify LVO TMM, and reveal optimal TMM criteria. These results should be prospectively investigated as inclusion criteria for EVT in this population and suggest recent negative DMVO EVT trials may have been confounded by suboptimal patient selection.
Lakhani et al. (2026) studied this question.