Preoperative Brain MRI Does Not Reduce Neurologic Injury in Neonates Undergoing Cardiac Surgery

Abstract

The 64th Annual Medical Student Research Forum at UT Southwestern Medical Center (Tuesday, January 27, 2026, 3-6 p.m., D1.700)BACKGROUND: Neonates with congenital heart disease (CHD) are vulnerable to central nervous system (CNS) injury, and cardiac surgery with cardiopulmonary bypass (CPB) adds further risk. Since 2017, our institution has implemented a routine preoperative brain MRI screening protocol to identify unrecognized CNS injury that might alter the timing of surgical intervention. This study evaluates whether MRI findings altered surgical timing or impacted postoperative CNS outcomes. METHODS: We retrospectively reviewed 397 neonates with CHD who underwent surgery with CPB within 30 days of life (2017-2025). Patients were grouped by whether they received preoperative MRI (pre-MRI vs. no-MRI). Clinical, imaging, and surgical data were analyzed using chi-square, Fisher's exact, and two-sample t-tests, with the primary outcomes being changes in surgical timing and postoperative CNS injury. RESULTS: Of 397 patients, 339 (85%) had preoperative brain MRI. Patients who did not receive MRI were more likely to present with emergent or salvage-level acuity, including emergent (no-MRI: 21% vs. pre-MRI: 5%), salvage (9% vs. 0%), and ECMO-supported (3% vs. 0%) cases (all p ≤ 0.02). These patients were also more likely to have diagnoses associated with hemodynamic instability such as obstructed total anomalous pulmonary venous return (no-MRI: 34% vs. pre-MRI: 3%, p=0.0001), likely precluding the opportunity for imaging prior to surgery. Preoperative MRI detected abnormalities in 47% of cases; however, only two patients (0.6%) had surgical delays due to low-grade screening MRI findings (grade II IVH and large cephalohematoma). Surgery was delayed by two weeks and then proceeded uneventfully for both. Postoperative neurologic outcomes were similar between groups (seizure, stroke, hemorrhage; all p>0.05). CONCLUSION: Our preoperative brain MRI screening protocol revealed that nearly half of neonates with CHD harbor abnormal findings. However, surgical timing was rarely influenced as only two patients (0.6%) experienced a documented change in surgical management out of an abundance of caution due to low-grade MRI findings. Additionally, preoperative brain MRI did not reduce incidence of postoperative CNS injury, with similar rates of seizure, stroke, or hemorrhage observed between groups. Nonetheless, preoperative MRI may serve an important role in multidisciplinary care by guiding neurodevelopmental counseling, establishing a baseline for longitudinal follow-up, and assisting in the interpretation of postoperative events.Southwestern Medical Foundatio