Patterns of MRI Brain Injury in Children after Out-of-Hospital Cardiac Arrest

Area of Science:

• Neurology
• Pediatric critical care
• Radiology

Background:

• Pediatric out-of-hospital cardiac arrest (OHCA) poses significant risks of hypoxic-ischemic brain injury.
• Understanding brain injury patterns on MRI after pediatric OHCA is crucial for prognosis and management.
• Current knowledge on the evolution and specific regional patterns of MRI-detected brain injury following pediatric OHCA is limited.

Purpose of the Study:

• To investigate the regional patterns and evolution of brain injury visualized on MRI in pediatric patients following OHCA.
• To explore the association between these MRI-identified brain injury patterns and clinical factors such as patient age and cardiac arrest characteristics.

Main Methods:

• Retrospective analysis of pediatric patients (48 hours to 18 years) who experienced OHCA and underwent brain MRI (DWI and T2-weighted sequences) within 8 days post-arrest.
• Two independent neuroradiologists assessed signal abnormalities in specific brain regions: cortex, white matter (WM), globus pallidus, putamen/caudate, thalamus, posterior limb of the internal capsule (PLIC), hippocampus, brainstem, and cerebellum.
• Clinical data including age, time to return of spontaneous circulation (ROSC), and imaging timing were correlated with MRI findings.

Main Results:

• Out of 68 patients, 46 (68%) showed brain injury on MRI, most commonly in the cortex (50%), putamen/caudate (43%), and WM (40%).
• Younger patients exhibited a higher incidence of WM (median age 1.4 years) and PLIC (median age 0.4 years) injuries compared to older patients.
• Longer time to ROSC correlated with injury in more brain regions (P<0.001), and WM injury was observed more frequently on later MRIs (73% on second MRI vs. 36% on first).

Conclusions:

• Brain injury patterns following pediatric OHCA are significantly influenced by patient age, timing of MRI, and cardiac arrest severity.
• The delayed appearance of WM injury and the increased vulnerability of WM and PLIC in younger children are key findings.
• Recognizing these evolving injury patterns on post-arrest MRI, considering clinical context, is vital for accurate diagnosis of hypoxic-ischemic brain injury, especially with limited clinical history.