Abstract W P317: Early CSF Volume Changes Predict Malignant Edema in Large Hemispheric Infarction

Abstract

Background: Early clinical and radiographic measures (such as NIHSS or early CT hypodensity) incompletely predict which patients with hemispheric stroke will develop malignant cerebral edema. We evaluated whether quantitative changes in volume of CSF compartments on early follow-up (FU) CT predict peak radiographic edema and clinical worsening. Methods: We retrospectively identified patients with hemispheric infarcts, NIHSS≥8, baseline CT within 6 hours of stroke onset and FU CT within 48 hours (i.e. prior to development of maximal edema). Volumes of CSF in ipsilateral (IL) and contralateral (CL) sulci and lateral ventricles were manually outlined on both scans, as was infarct volume on FU CT. Midline shift (MLS) was measured on later CT at time of peak edema (if available). Reduction in CSF compartments from baseline and symmetry (IL:CL ratios) were correlated to peak MLS and edema-related clinical deterioration (need for hemicraniectomy, osmotic therapy, or GCS decline, with MLS>5mm). Results: Ten patients were analyzed (median NIHSS 13, FU CT at median of 30 hours, IQR 15-37). Sulcal asymmetry (ratio of IL:CL volume) on FU CT was greater in the 4 subjects who deteriorated from malignant edema (median 0.26 vs. 0.79, see Figure), as was % reduction in IL sulcal volume from baseline (76% vs. 35%, p=0.06), while volume of early infarct was not. Hemispheric CSF asymmetry and % reduction in IL ventricular volume at early FU CT were strongly correlated with peak MLS (r=-0.95 and -0.96, both p=0.01). Linear regression found that both early infarct volume and % reduction in IL ventricle volume were strongly associated with MLS, adjusting for baseline CSF volume (Betas 0.55 and -0.48, both p=0.001). Conclusions: In this preliminary study, early CSF asymmetry and reduction in IL CSF volumes appear to predict development of MLS and malignant edema. Further validation is needed to test whether CSF volumetrics have utility in selection of patients for early aggressive interventions.