Interaction between time, ASPECTS, and clinical mismatch

Background: Imaging-based patient selection for neurothrombectomy relies on identifying irreversibly damaged brain tissue (core) and salvageable tissue (penumbra). The DAWN trial used the clinical-core mismatch (CCM) paradigm, where clinical deficit is disproportionate to infarct volume. This study aims to determine the prevalence of CCM in large vessel occlusion (LVO) strokes and examine the impact of time and ASPECTS on mismatch likelihood.

Methods: A retrospective observational analysis of ICA/MCA M1 occlusions with advanced imaging (rCBF/MRI). Automated software analyzed infarct volume and determined ASPECTS, and the prevalence of CCM and the influence of time and ASPECTS were analyzed.

Results: 185 LVO strokes were included (mean age 71, median NIHSS 17, mean core volume 50 mL). Within 0–24 hours, CCM was present in 53%, ranging from 63% (0–3 hours) to 25% (21–24 hours; p = 0.03), decreasing 1.6% per hour. CCM by ASPECTS: 9–10: 77%, 6–8: 65%, 0–5: 13% (p < 0.01). Higher ASPECTS was an independent predictor of CCM (OR 1.4; p < 0.001).

Conclusions: CCM is present in 57% of LVO strokes within 0–6 hours and 50% within 6–24 hours. Prevalence declines with time and decreasing ASPECTS but does not decline over time within ASPECTS groups, supporting an ASPECTS-based paradigm for late-window patient selection.