Abstract 55: Gray Matter to White Matter Ratio in CT Radiography of the Brain is Not Associated With Outcome After Cardiac Arrest
Introduction: Brain injury is a leading cause of death after cardiac arrest. Grey matter to white matter (GM/WM) differentiation on early CT scan is a potential predictor of outcome.
Hypothesis: We hypothesized that the ratio of GM/WM attenuation predicts survival and good outcome (discharge home or to rehabilitation) after cardiac arrest.
Methods: GM/WM ratios were calculated from subjects selected from four categories of post-cardiac arrest illness severity which were defined by neurological examination and sequential organ failure assessment (SOFA) score on presentation: 1) awake, 2) coma (not following commands but intact brainstem responses) and mild cardiopulmonary dysfunction (SOFA cardiac + respiratory score <4), 3) coma with moderate-severe cardiopulmonary dysfunction (SOFA cardiac + respiratory score >=4), and 4) coma without brainstem reflexes. Average tissue attenuation (Hounsfield Units) in regions of interest in GM (caudate, putamen, thalamus) and WM (corpus callosum, posterior internal capsule) provided a midbrain GM/WM ratio. Attenuation in the centrum semiovale (medial cortex and medial WM) and high convexity area (medial cortex and medial WM) provided a cerebral GM/WM ratio. ANOVA compared GM/WM ratios between illness severity categories. Logistic regression tested associations between ratio, survival and good outcome.
Results: Among 40 subjects, 45% survived, and 35% had good outcome. GM/WM ratios for midbrain and cerebrum were not associated with survival (midbrain p=0.54; cerebrum p=0.57), good outcome (midbrain p=0.67; cerebrum p=0.21), or illness severity (midbrain F=0.685; cerebrum F=1.579). However, ratios tended to be higher in category 2 subjects.
Conclusions: In this cohort, the GM/WM ratio is not associated with survival, good outcome, or initial illness severity after cardiac arrest. These data do not support the use of GM/WM ratio as an adjunct for prognostication after cardiac arrest.
- © 2010 by American Heart Association, Inc.