Abstract 13082: Region-Specific Diffusion-Weighted Imaging Predicts Neurological Outcome in Comatose Post-Cardiac Arrest Patients

Abstract

Introduction & Hypothesis: Diffusion-weighted imaging (DWI), a technique sensitive to acute brain ischemia, may hold utility in predicting neurological outcome in comatose post-cardiac arrest patients. Outcome studies are biased by early withdrawal of life sustaining therapy (WLST), leading to a self-fulfilling prophecy. This creates a need to reassess the use of DWI as a neuroprognostic tool in patients who have not undergone WLST. We hypothesize that DWI abnormalities is a robust predictor of poor neurological outcome in our WLST - controlled cohort. Methods: We leveraged the MOCHA database, a registry of over 300 comatose post-cardiac arrest patients, to retrospectively examine neurological outcomes in a cohort of patients who did not undergo WLST. A good outcome was defined by a cerebral performance category (CPC) score at discharge of 1 - 3, while a poor outcome CPC 4 - 5 (n=43). We first examined the relationship between the number of brain regions with DWI abnormalities and CPC score using a linear regression. We then examined how DWI abnormalities in specific brain regions correlated with CPC score outcome groups using a fisher exact test. DWI abnormalities were qualitatively determined by two vascular neurologists. Results: We found a positive correlation between the number of brain regions with DWI abnormalities and CPC score ( linear regression , R 2 =0.572, p=2.670x10 -9 ). Interestingly, the association between DWI abnormalities and CPC score exhibited brain region-specific variability. DWI abnormalities exhibited the strongest association with poor neurological outcome in the occipital lobe ( fisher exact test , p=7.413x10 -10 ), parietal lobe (p=9.125x10 -9 ), frontal lobe (p=5.385x10 -9 ), temporal lobe (p=3.904x10 -8 ) and basal ganglia (p=2.342x10 -7 ); and the weakest association in the white matter (p=1.000) and brain stem (p=6.612x10 -2 ). Conclusion: Our preliminary results suggest that the region of ischemia is an important factor to consider in predicting neurological outcome. This warrants a larger scale WLST-controlled study examining region-specific DWI abnormalities and neurological outcome - the findings of which would improve our neuroprognostication capabilities in comatose post-cardiac arrest patients.