Introduction: Early brain injury (EBI) after aneurysmal subarachnoid hemorrhage (aSAH) is the most important determinant of clinical outcome. Global cerebral edema (GCE) is a manifestation of EBI after SAH and is a known independent risk factor for poor outcome. The inability to quantify GCE has limited further investigations into pathomechanisms of GCE after SAH.

Methods: Patients with aSAH were enrolled into the Neuroscience Research Repository (NRR). Initial CT scans were graded for the presence or absence of GCE in a qualitative manner using established criteria. Volumetric analysis of sulcal space and cisternal blood volume was performed using MIPAV (Medical Image Processing, Analysis and Visualization Ver 7.0.1). Selective sulcal volume(SSV) was defined as total mL of sulcal volumes on axial CT slices from above the most cranial section of the lateral ventricles to the last visible section. Automated contour selection tool in MIPAV was used to measure areas of sulcal and cisternal blood. Clinical, demographic and outcome information was gathered from the chart. Cytokines levels were measured by Luminex (a multiplexed bead array assay platform) using kits obtained from Millipore.

Results: A total of 50 patients with volumetric and cytokine analysis were included in this study. Mean age was 51 years (±14 years), 37/50(74%) were female. 88% had Fisher 3 Grade SAH with a median HH score of 3. 15/50(30%) had GCE. Mean sulcal volume was 18ml. Mean sulcal volumes differed between patients with GCE and without GCE (6.67ml v 22.85ml; sig <0.005). Volume of cisternal blood positively correlated with serum IL-6 and MCP1 levels (p <0.001;p=0.004). Lower SSV was an independent predictor of poor outcome at discharge (p=0.031) while controlling for age, gender, initial Hunt-Hess Grade and aneurysm size.

Conclusions: GCE can be objectively quantified using volumetric analysis of selective sulcal volume measurements. Cerebral edema measured through SSV predicted worse outcomes after SAH.

Patient Care: Further knowledge into pathomechanisms of Global Cerebral Edema after aneurysmal subarachnoid hemorrhage.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify that volumetric analyses of sulcal spaces is a useful research tool to quantify GCE, 2) Objective measurement of cerebral edema can be used to study inflammatory markers in SAH, 3) Quantifying GCE can be used to predict outcome.

References: Claassen, J., Carhuapoma, J. R., Kreiter, K. T., Du, E. Y., Connolly, E. S., & Mayer, S. A. (2002). Global cerebral edema after subarachnoid hemorrhage frequency, predictors, and impact on outcome. Stroke, 33(5), 1225-1232. Helbok, R., Ko, S. B., Schmidt, J. M., Kurtz, P., Fernandez, L., Choi, H. A., ... & Claassen, J. (2011). Global cerebral edema and brain metabolism after subarachnoid hemorrhage. Stroke, 42(6), 1534-1539.