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

Abstract

Background and purpose: Pediatric out-of-hospital cardiac arrest (OHCA) is associated with a high rate of morbidity and mortality from hypoxic-ischemic brain injury. The patterns and evolution of brain injury on MRI after pediatric OHCA have not been well described. The purpose of this study was to evaluate regional brain injury patterns on MRI after pediatric OHCA and its association with clinical factors.

Materials and methods: We analyzed a retrospective cohort of pediatric patients aged between 48 hours and 18 years who experienced OHCA between 2016-2023 and underwent brain MRI containing DWI and T2-weighted sequences within 8 days postarrest. Two neuroradiologists independently scored the presence or absence of signal abnormality in the cortex, WM, globus pallidus, putamen/caudate, thalamus, posterior limb of the internal capsule (PLIC), hippocampus, brainstem, and cerebellum.

Results: Of the 68 patients included, 46 (68%) exhibited brain injury on initial MRI, with the most common locations being the cortex (50%), putamen/caudate (43%), and WM (40%). First MRI was obtained at a median of 3 (interquartile range 1-4) days postarrest. Patients with WM injury were younger (median age 1.4 years) than those without WM injury (3.6 years; P = .01), and those with PLIC injury were younger (median age 0.4 years) than those without PLIC injury (3.5 years; P = .003). Longer time to return of spontaneous resuscitation was associated with injury across a greater number of brain regions (P < .001). Among 11 patients who underwent 2 MRIs within 8 days, WM injury occurred more frequently on later imaging (36% on first MRI versus 73% on second MRI; P < .05).

Conclusions: Patterns of injury after pediatric OHCA are influenced by patient age, timing of imaging, and cardiac arrest characteristics. The evolving distribution of injury, such as delayed appearance of WM injury, and greater vulnerability of WM and PLIC in younger patients, highlights the importance of considering clinical context when interpreting postarrest brain MRI. Recognizing these patterns may aid in identifying hypoxic-ischemic injury, especially when clinical history is limited.