Prognostic value of phase information of 2D T2*-weighted gradient echo brain imaging in cardiac arrest survivors: A preliminary study

Background: Predicting neurological outcomes after cardiac arrest is important to guide therapeutic decisions. We assessed the prognostic value of phase information of 2D T2*-weighted gradient echo imaging (T2*WI) of the brain in CA survivors. Methods: This study included cardiac arrest survivors who had undergone MRI for prognostication. After application of homodyne filtering to T2*WI phase images, the contrast of three venous structures was assessed as normal (score 0) or abnormal (score 1): the superior sagittal sinus, the cortical veins, and the thalamostriate veins. The scores were summarized into a gradient-recalled echo (GRE) summary score. The prognostic performances of T2*WI, diffusion-weighted imaging (DWI), electroencephalography and serum biomarkers were evaluated using receiver operating characteristic (ROC) curves. Results: Of the 39 enrolled patients, 12 (31%) had good outcomes and 27 (69%) had poor outcomes. ROC curve analysis showed that T2*WI had good prognostic performance; the area under the curve (AUC) of the GRE summary score (0.980, 95% confidence interval CI 0.950–1.000) was comparable to those of conventional outcome predictors, including DWI patterns (0.949, 95% CI 0.889–1.000). The AUC increased when the summary GRE score was added to DWI patterns (0.991, 95% CI 0.973–1.000), although the difference was not statistically significant (P = 0.117). Most subjects with isoelectric electroencephalography (5/6) showed abnormally high phase contrast in the cerebral veins. Conclusions: Filtered phase images of T2*WI showed good prognostic value and can reveal various features of the cerebral metabolic consequences of cardiac arrest, such as decreased neuronal activity and brain death-like patterns.