To identify early predictors of malignant cerebral edema in patients presenting with hemispheric infarcts and no mechanical thrombectomy.

Malignant cerebral edema (MCE) is a devastating complication of large hemispheric infarction, usually peaks 48-72 hours after stroke onset. Early prediction of MCE may help to improve patient outcome. CT-perfusion (CTP) RAPID parameters have not been extensively studied as predictors of MCE.

Institutional stroke database was reviewed for acute stroke between April 2018 and December 2020. Included patients had an admission National Institute of Health Stroke Scale ≥12, CTP, middle cerebral or internal carotid artery occlusion, no mechanical thrombectomy, and a follow up imaging at 48 hours.  MCE was defined as midline shift (MLS) >5 mm on follow-up imaging. Multivariable logistic regression analysis modeled MCE as the outcome variable and stepwise selection was used for variables that were captured on patient arrival. The CTP parameters of interest were hypoperfusion index ratio (HIR), cerebral blood volume index (CBVI), and volume of cerebral blood flow <30% of the contralateral cerebral region (CBF<30).

Analysis included 138 patients. In a model that included HIR and CBVI, the strong predictors (p<0.05) of MCE with odds ratios (95% CI) were age: 0.93 (0.88-0.97), HIR: 50.4 (0.90-7,931) per 0.1 unit increase in HIR, and CBVI: 0.01 (0.0-1.07) per 0.1 unit increase in CBVI. In a model that included CBF<30 the strong predictors of MCE were age: 0.92 (0.87-0.96), CBF<30: 1.02 (1.01-1.03), and last known normal to arrival time: 0.88 (0.79-0.97) per hour. HIR <0.5 had a negative predictive value for MCE of 98.1% (54/55).

HIR and CBVI may be useful early objective predictors of MCE in patients with hemispheric strokes not treated with mechanical thrombectomy. These findings should be confirmed by larger studies.