Efficacy of diffusion-weighted magnetic resonance imaging performed before therapeutic hypothermia in predicting clinical outcome in comatose cardiopulmonary arrest survivors

Aim of the study: To develop a clinically relevant and qualitative brain magnetic resonance imaging (MRI) scoring system for acute stage comatose cardiac arrest patients.

Methods: Consecutive comatose post-cardiopulmonary arrest patients were prospectively enrolled. Routine brain MRI sequences were scored by two independent and blinded experts. Predefined brain regions were qualitatively scored on diffusion-weighted imaging (DWI) sequences according to the severity of the abnormality on a scale from 0 to 4. The mean score provided by the raters determined poor outcome defined under the Cerebral Performance Categories 3, 4, or 5. DWI scans were repeated after therapeutic hypothermia (TH). The same qualitative scoring system was applied and results were compared to the initial scores.

Results: Out of 24 recruited patients, 19 with brain MRI scans were included. Of the 19 included patients, seven showed a good outcome at hospital discharge and 12 patients showed poor neurologic outcome. Median time from the arrest to the initial DWI was 166min (IQR 114-240min). At 100% specificity, the overall, cortex, and cortex plus deep grey nuclei scores predicted poor patient outcome with a sensitivity of 91.7-100% (95% CI). Follow-up DWI scans after TH showed worse results than initial scans.

Conclusion: A qualitative MRI scoring system effectively assessed the severity of hypoxic-ischaemic brain injury following cardiopulmonary arrest. The scoring system may provide useful prognostic information in comatose cardiopulmonary arrest patients.