MRI-based quantitative profiling of hypoxic-ischemic brain injury in postanoxic status epilepticus and other EEG patterns

Aim: The pathophysiology and prognostic significance of postanoxic status epilepticus (SE) remain poorly defined. We compared the extent of hypoxic–ischemic brain injury (HIBI) in postanoxic SE with other EEG patterns, particularly generalized periodic discharges (GPDs), using quantitative MRI analysis. Methods: Retrospective two-center observational study of consecutive comatose patients after cardiac arrest, having EEG and brain MRI data. Patients were classified into four EEG pattern groups (SE, GPDs, malignant, or benign). Quantitative ADC maps were compared across groups using region-of-interest and voxel-wise analyses. Secondary multivariable logistic models assessed predictors of neurological recovery (coma recovery at discharge and Cerebral Performance Category at 3 months). Results: Among 192 postanoxic patients (76 benign, 46 GPDs, 44 malignant, 26 SE), coma recovery occurred in 30.7% and 21.2% achieved a CPC 1–2 at 3 months. Whole-brain ADC values differed significantly across EEG patterns (p < 0.001), with the lowest values in malignant patterns (median 750 × 10−6 mm2/s) and GPDs (838 × 10−6 mm2/s), and higher values in SE (893 × 10−6 mm2/s) and benign patterns (907 × 10−6 mm2/s; p < 0.001). SE showed significantly higher ADC than malignant (p < 0.001) and GPD groups (p = 0.021), but did not differ from the benign group (p = 0.26). Regional and voxel-wise analyses confirmed these findings. In multivariable models, higher occipital cortical ADC was an independent predictor of good outcome, alongside EEG pattern, clinical variables, and neuron-specific enolase. Conclusions: Postanoxic SE exhibited a more favorable HIBI profile than GPDs or malignant EEG patterns.