Streitberger KJ, Endisch C, Ploner CJ, et al. - Given the value of gray–white-matter ratio (GWR) calculated from head CT as a radiologic index of tissue changes that are associated with hypoxic-ischemic encephalopathy after cardiac arrest (CA), researchers examined if the accuracy of neurologic prognostication by GWR is correlated with timing of CT. They calculated GWR from CT radiologic densities in 16 regions of interest among 195 patients admitted to the ICU following CA. Using the cerebral performance category (CPC), they assessed outcome upon intensive care unit discharge. A comparison of the accuracy of outcome prediction of GWR for 3 epochs was done (< 6, 6–24, and > 24 h after CA). Observations suggest that independent of time of acquisition of CT, a GWR below 1.10 is predictive of poor outcome (CPC4–5) in patients after CA with high specificity. As patients with severe HIE show a decrease in GWR over time, a higher sensitivity for prediction of poor outcome was evident for late CTs (> 24 h after CA) as compared with early CTs (< 6 h after CA).