Gray matter to white matter ratio for predicting neurological outcomes in patients treated with target temperature management after cardiac arrest: A systematic review and meta-analysis.

Abstract

This study aimed to evaluate the prognostic accuracy of the gray matter to white matter ratio (GWR) in predicting neurological outcomes in post-cardiac arrest patients treated with target temperature management. We systematically searched MEDLINE and EMBASE (Search date: 09/13/2017). Included studies were those evaluating neurological outcomes using the cerebral performance categories scale. We performed a subgroup analysis based on the location of the measurement. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias. In total, 1150 patients from 10 observational studies were included. GWR of the basal ganglia (BG) average showed the highest value (area under the curve [AUC] 0.96, SE 0.02, Q 0.90) compared with the putamen/posterior limb of internal capsule (AUC 0.93, SE 0.05, Q 0.87), overall average (AUC 0.91, SE 0.02, Q 0.85), and cerebrum (AUC 0.89, SE 0.05, Q 0.82) for prognostic accuracy. Furthermore, the highest pooled diagnostic odd ratio of GWR for predicting poor neurological outcomes was shown for the BG average (21.00, 95% CI 6.85-64.40) followed by the overall average (20.71, 95% CI 9.53-44.98), putamen/posterior limb of internal capsule (16.08, 95% CI 4.36-59.23), and cerebrum (13.96, 95% CI 4.26-45.76). GWR in the early cranial computed tomography scan had high prognostic value in predicting poor neurological outcomes in post-cardiac arrest patients. The BG GWR had the highest prognostic accuracy when compared to other locations of the brain.