Your Donations in Action: Jonathan J. Shih, BS

Hypoxic-ischemic brain injury is the leading cause of death and lasting neurological problems in children after cardiac arrest. MRI findings after cardiac arrest are well understood in adults and neonates, while age-related injury patterns and outcomes in older children remain unclear.

For his 2024 RSNA Research Medical Student Grant project, “MRI Brain after Pediatric Cardiac Arrest: Descriptive and Quantitative Patterns of Injury in Association with Neurologic Outcome,” Jonathan J. Shih, BS, a fourth-year medical student at the University of California, San Francisco (UCSF), and colleagues retrospectively analyzed brain MRIs to identify injury patterns and predictors of neurological outcomes in children following cardiac arrest.

Researchers analyzed MRIs from 68 children (ages 48 hours to 18 years) within eight days of out-of-hospital cardiac arrest. Two pediatric neuroradiologists independently reviewed nine brain regions for acute injury.

Of the 68 patients, 46 exhibited acute injury, most commonly in the cortex, putamen/caudate and white matter (WM). Younger children were more likely to have injuries to the WM and posterior limb of the internal capsule (PLIC). WM injury appeared more frequently on later imaging in patients who underwent two MRIs.

Prolonged return of spontaneous circulation was associated with a two- to five-fold increase in injury odds across most brain regions, whereas witnessed arrest and bystander CPR significantly reduced injury risk.

A complementary quantitative analysis of 55 children, including those who experienced in-hospital cardiac arrest, showed that lower average apparent diffusion coefficient (ADC) values were linked to unfavorable neurological outcomes. Region-specific ADC cutoffs helped predict which children were at risk for unfavorable neurological outcomes with excellent specificity.

“The evolving distribution of injury, such as delayed appearance of WM injury and greater vulnerability of WM and PLIC in younger patients, reinforces the importance of considering clinical context when interpreting post-cardiac arrest brain MRI,” Shih said. “Quantitative diffusion MRI, particularly regional analysis used alongside whole-brain ADC metrics, may enhance prognostication after pediatric cardiac arrest when integrated into a multimodal clinical framework.”

Funding from the R&E Foundation meaningfully impacted Shih’s academic pursuits and career trajectory. “The opportunity to lead an independent, hypothesis-driven research project in pediatric neuroradiology has solidified my decision to pursue a career in diagnostic radiology.”

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