Utility of white matter to gray matter signal intensity ratio in comatose patients treated by targeted temperature management after cardiac arrest: a preliminary study

ABSTRACT

OBJECTIVE: This study examined the efficacy of the white matter (WM) to gray matter (GM) signal intensity ratio (SIR) in predicting the clinical prognosis of cardiac arrest patients. METHODS: Thirty-one patients who were resuscitated from cardiac arrest and underwent brain magnetic resonance imaging (MRI) were investigated retrospectively. Thirty one subjects with normal brain MRI findings served as the controls. The signal intensities (SI) were measured on T2-weighted image (T2WI). The circular regions of measurement (2–10 mm²) were placed over the regions of interest, and the average signals in GM and WM were recorded in the caudate nucleus (CN), putamen, anterior limb of the internal capsule, corpus callosum (CC), and in the cortex and WM of the frontal lobe. Cerebral performance category (CPC) 1–2 were classified as a good prognosis, and CPC 3–5 were classified as a poor prognosis. RESULTS: Most combinations of the SIR of WM to GM and most SIs of GM, except the frontal cortex, were significantly different between the two groups. On the other hand, the SI of WM was insignificant between both groups. In receiver operating characteristic (ROC) curve analysis, the SIR of the CC to CN had an area under the ROC curve (AUROC) of 1.00 for a cut-off value of 1.59 (sensitivity, 100%; specificity, 100%), the SIR of the CC to putamen had also an AUROC of 1.00 for a cut-off value of 1.43 (sensitivity, 100%; specificity, 100%). CONCLUSION: The SIR of WM to GM measured on a T2WI is related to the neurological outcome after a cardiac arrest.