Abstract 15924: Early Non-contrast Head Computed Tomography for Prognostication of Neurologic Outcomes Following Cardiac Arrest

Abstract

Introduction: Prognostication of neurologic outcomes in patients achieving return of spontaneous circulation (ROSC) following cardiac arrest poses a difficult challenge. A low ratio of gray matter to white matter (GWR) attenuation on early non-contrast head computed tomography (NCHCT) may be a specific predictor of poor neurologic outcome following arrest. We sought to validate this finding and to determine if there is a GWR cutoff that is completely specific for predicting poor neurologic outcomes. Methods: We identified 145 patients from our institution with a cardiac arrest between February 2007 and March 2015 who underwent NCHCT within 24 hours following ROSC. GWRs were calculated by measuring the attenuation of 10-15 mm 2 regions of interest in Hounsfield units, identifying the head of the caudate nucleus for gray matter and the posterior limb of the internal capsule for white matter. Neurologic outcomes were recorded by cerebral performance category (CPC) upon hospital discharge. A CPC score of 1 or 2 defined a favorable neurologic outcome, whereas a score of 3, 4, or 5 marked a poor neurologic outcome. Results: Fifty patients had favorable neurologic outcomes, with a median GWR of 1.29 and an interquartile range (IQR) of 1.24-1.34. Ninety-five patients had poor neurologic outcomes, with a median GWR of 1.25 and an IQR of 1.18-1.30. Performance of the GWR as a predictor of neurologic outcome was examined by plotting a receiver operating characteristic curve; the area under the curve was 0.658. However, a GWR below 1.16 was found to have 100% specificity for predicting a poor neurologic outcome following arrest (20 cases, 21.1% sensitivity). Conclusion: In our study, a GWR below 1.16 was shown to be a completely specific predictor of poor neurologic outcome following cardiac arrest. In combination with other modalities, GWR on NCHCT could help guide management by lending prognostic information early in the post arrest course.