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Abstract

Introduction: Loss of gray/white matter differentiation on head computed tomography (HCT) in adults after cardiac arrest (CA) is quantifiable, and a known threshold is associated with cerebral edema and correlates with outcome. A similar threshold for detecting loss of gray/white matter differentiation is not known in children, in whom white matter (WM) is still developing. Hypothesis: Children without prior brain injury requiring extra-corporeal membrane oxygenation (ECMO) following CA will demonstrate gray/white matter ratios (GWRs) consistent with brain edema compared to children requiring ECMO for other diseases. Methods: We reviewed HCTs of 42 children imaged while cannulated on ECMO or immediately after ECMO decannulation from 2007-2011. Patients were cervically cannulated on the right (n=34) or centrally via sternotomy (n=8). GWR was quantified with Hounsfield units (HU) in the basal ganglia (BG: caudate, putamen, corpus callosum, posterior limb of internal capsule) and parietal cortex (CTX: cortex, WM in 2 slices). GWR closer to 1.0 reflects greater cerebral edema. GWR was also averaged across both hemisperes. Data was compared between CA patients (+CA) vs. no CA (-CA), age, and between hemispheres using Mann-Whitney U test. Results: Patients?1y/o in the +CA group (n=10) demonstrated GWRBG closer to 1.0 vs. patients in the -CA group (n=9), (1.15 ± 0.06 vs. 1.31 ± 0.04 HU, p=0.05). GWRBG was most affected in the right hemisphere of +CA patients compared to –CA patients (1.11 ± 0.07 vs. 1.30 ± 0.06 HU, p=0.05), with no difference between groups in the left hemisphere (1.19 ± 0.07 vs. 1.32 ± 0.04 HU, p=0.14), or in GWRCTX. In patients <1y/o, GWR was not different between groups in any region analyzed. Conclusions: GWRBG was most consistent with increased cerebral edema in the right BG of patients?1y/o after CA on ECMO. As patients were cervically cannulated on the right or centrally, investigation into associations between cannula site and brain lesions is warranted. There were no GWR differences in patients <1y/o associated with CA possibly due to immature WM. Since cerebral edema portends worse outcome in CA patients, GWRBG may be useful to predict outcome in pediatric ECMO and CA patients?1y/o.Support: T32HD040686