(739) Ultralow-Field Brain MRI Feasibility in Pediatric ECMO Patients

Introduction: Extracorporeal membrane oxygenation (ECMO) is used to treat refractory cardiopulmonary failure. Survival has significantly improved, yet high rates of acute brain injury (ABI) in this population results in significant morbidity and mortality. Currently available imaging modalities [ultrasound (US), computed tomography (CT)] have low detection of early hypoxic-ischemic and cerebrovascular-type injuries, which delays the diagnosis of ABI while on ECMO. CT sensitivity increases only when it is too late to effectively intervene. High-field (>=1.5 Tesla) magnetic resonance imaging (MRI) is the gold standard to diagnose pediatric ischemic brain injury but is not compatible with ECMO. An ultralow-field (0.064 T) portable MRI system is FDA cleared and has been studied in critically ill adults with various types of ABI and with equipment that is typically not MRI compatible. Two small case series of ECMO patients (adult n=3, pediatric n=4) undergoing bedside MRIs have been reported, yet additional feasibility data is needed.

Methods: This single center, IRB approved study was conducted at a free-standing pediatric quaternary hospital with a large ECMO program (40-50 runs/year). All neonatal and pediatric patients cannulated onto ECMO were screened for eligibility. Subjects underwent bedside ultralow-field MRI with Swoop (Hyperfine, Guilford, CT). Data on ECMO variables, time for patient positioning and scan, sequences, concurrent critical care equipment, changes in ECMO flow/SpO2/mean arterial pressure, and cannula displacement was collected in REDCap.

Results: Over a 1-year period (Aug 2023-Aug 2024) 39 patients were screened. 14 out of 19 enrolled subjects had bedside MRI attempted and 11 (79%) received the full imaging protocol (T1, T2, FLAIR and DWI). The mean number of staff for positioning was 4.85 (0.90). Mean time for positioning and imaging was 75.09 min (19.15). One patient had a ≥ 20% decrease in mean arterial pressure, however this remained within the patient clinical goals. No patients experienced complications during or because of bedside imaging.

Conclusions: Pediatric ECMO patients can feasibly undergo bedside ultralow-field MRI with no clinically relevant complications. Time and staff required for bedside imaging is comparable to travel to a radiology suite for CT.