Background and purpose Our purpose was to compare clinical diffusion mismatch (CDM) and mean transit time (MTT)-diffusion mismatch as predictors of infarct growth in patients with proximal middle cerebral artery (MCA) occlusion and small infarct core on presentation.
Methods Retrospective analysis of consecutive stroke patients with: (1) MCA-M1 occlusion; (2) MRI performed ≤10 h from symptoms onset; and (3) baseline MRI-diffusion weighted imaging (DWI) volume ≤25 mL. Definitions included: CDM=baseline National Institutes of Health Stroke Scale (NIHSS) score ≥8 and DWI volume ≤25 mL; MTT-DWI mismatch=visually assessed unthresholded MTT lesion ((MTT-DWI))/DWI) ≥20% and ≥10 mL larger than the DWI lesion; and significant infarct growth (>20% (≥5 mL) increase in infarct volume on follow-up). Uni-/multivariate analyses were performed to define the predictors of infarct growth.
Results 63 stroke patients with MCA-M1 occlusions and MRI within 10 h of onset were evaluated. 20 patients were excluded on the basis of DWI volume >25 mL leaving 43 patients (mean age 75.8 years; median NIHSS=13) in the study cohort. On univariate analysis, larger admission DWI volume (p<0.0001), baseline NIHSS score ≥8 (p=0.001), lack of IV and/or endovascular treatment (p=0.021), glucose levels >125 mg/dL (p=0.024), poor CT angiography collaterals (p=0.046), and lower admission Alberta Stroke Program Early CT score (ASPECTS) (p=0.049) predicted infarct growth. Baseline NIHSS score ≥8 was the only independent predictor of stroke growth in the multivariate analysis (p=0.001). All patients had MTT-DWI mismatch >20%. There was no significant association between the amount of MTT-DWI mismatch and infarct growth (p=0.33).
Conclusions CDM is the most powerful predictor of infarct growth in patients with MCA-M1 occlusion and small infarct core. Most of these patients will have a significant oligemic MTT lesion regardless of admission NIHSS score.
- CT perfusion
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Contributors RGN: study conception and design, interpretation of the data, and drafting of the manuscript. AK, LMS, and SP: data acquisition and critical revision of the manuscript. JAH and AJY: critical revision of the manuscript. MHL: data acquisition and management, and critical revision of the manuscript. All authors gave final approval of the version to be published, and are in agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Competing interests RGN: principal investigator for the TREVO-2 and DAWN trials (Stryker Neurovascular); steering committee member of the SWIFT and SWIFT-Prime Trials, Core Lab of the STAR Trial (Covidien/ev3 Neurovascular), and executive committee member of the 3D Separator Trial (Penumbra). AJY: research grant from Penumbra Inc. MHL: research support from GE Healthcare, and consultant to CoAxia, GE Healthcare, and Millennium Pharmaceuticals.
Ethics approval The study was approved by the institutional review board of Massachusetts General Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The unpublished data from this dataset are held by MGH and Michael H Lev. Requests for data sharing would be required to be discussed with them directly.
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