Jason M. Toliao

Background: Traumatic brain injury (TBI) is a leading cause of disability and death in children. More than 30% of children presenting to the emergency department (ED) with head trauma undergo brain computed tomography (CT), the standard neuroimaging modality in acute evaluation of intracranial pathology. Conventional magnetic resonance imaging (MRI) provides a non-ionizing alternative with greater sensitivity for certain intracranial injuries but is infrequently used in acute TBI because of limited scanner access and longer scan duration. Rapid brain MRI protocols reduce scan time and can be completed without sedation, with diagnostic accuracy for TBI comparable to CT, yet real-world availability remains limited. Point-of-care, low-field MRI (POC LF-MRI) systems are a recent radiologic advance that are portable, require less infrastructure, and allow bedside neuroimaging, including in critically injured children who cannot be safely transported. However, critical knowledge gaps exist regarding the diagnostic accuracy and feasibility of POC LF-MRI for pediatric head trauma in emergency and critical care settings. Objective: Our research aims to (1) determine the accuracy of POC LF-MRI for neuroradiographic TBI and clinically important TBI compared to current clinical standard of care initial neuroimaging, (2) determine the accuracy of POC LF-MRI for neuroradiographic injury progression on repeat neuroimaging, and (3) determine feasibility metrics and balancing measures of POC LF-MRI, including order-to-scan time, scan duration, proportion of incomplete scans, and ED length-of-stay. Methods: We will conduct a prospective, single-center, observational diagnostic accuracy cohort study of children 7–17 years old with blunt head trauma who undergo standard-of-care neuroimaging. Children with MR-unsafe implants or metallic shrapnel and wards of the state will be excluded. POC LF-MRI will be obtained within a reasonable time window of clinical neuroimaging, with a flexible window up to 72 hours, either in the ED, inpatient unit, or intensive care unit (ICU). The primary outcome is neuroradiographic TBI, defined as any traumatic intracranial finding on neuroimaging. Secondary outcomes include clinically important TBI (defined as TBI-related neurosurgical intervention, endotracheal intubation >24 hours, death, or ≥2-night hospitalization) and neuroradiographic injury progression on repeat neuroimaging (yes/no). Feasibility outcomes include order-to-scan time, scan duration, proportion of incomplete scans, and ED length of stay, along with other operational and balancing measures. Accuracy will be determined using imaging-level analyses comparing POC LF-MRI with clinical standard-of-care neuroimaging, reporting sensitivity, specificity, predictive values, and likelihood ratios with 95% confidence intervals for neuroradiographic TBI, clinically important TBI, and neuroradiographic injury progression, including predefined non-inferiority criteria for sensitivity, subgroup analyses, descriptive analyses of feasibility metrics, and exploratory analyses addressing incomplete imaging and missing data. Results: The project was funded in 2024, and enrollment will be completed in July 2026. Data analyses are expected to be completed by December 2026, and the primary study results will be submitted for publication in 2027. Conclusions: This study will evaluate accuracy and feasibility for POC LF-MRI in an important subset of pediatric trauma patients and will provide preliminary data to inform future multicenter studies evaluating POC LF-MRI for children with head trauma.

Background: Ventricular shunts divert cerebrospinal fluid (CSF) in patients with hydrocephalus, which can be lifesaving. Untreated shunt failure may lead to increased intracranial pressure and neurological injury. The process of diagnosing shunt malfunction can be complex, and historically, there has not been a simple method for noninvasive and quantitative measurement of CSF flow through shunts. The demonstration of successful clinical application of phase-contrast magnetic resonance imaging (PC-MRI) to noninvasively quantify shunt flow is relatively new and will benefit from standardization across varying types of magnetic resonance (MR) hardware to facilitate implementation at multiple medical sites. PC-MRI CSF flow measurement through ventricular shunts has not yet been compared across different types of MR hardware (ie, differing field strengths, radiofrequency coils, slew rates, gradient strengths, models, and manufacturers). Objective: This study describes a protocol aimed to standardize and optimize PC-MRI shunt flow measurements for widespread use on any MR scanner. Methods: To study shunt flow in a manner that would translate effectively to the patient care setting, a phantom model incorporating a human shunt catheter can be constructed to obtain data over a typical physiological range of CSF flow rates. Calibration curves are used to model data comparing known flow rates to flow measured via PC-MRI. The accuracy of each MR scanner is assessed using linear regression. This protocol will be repeated on 8 MR scanners before multisite data collection. Results: The shunt flow phantom was constructed in November 2024. Single-site phantom calibration began in April 2025 and concluded in December 2025. Registration of clinical data collection sites will take place between November 2025 and July 2026. Approval from the Children’s Hospital of Los Angeles Institutional Review Board was obtained in January 2023 (before scanner calibration), and single-site data collection is ongoing. Multi-institutional clinical data collection will begin in July 2026 and continue until January 2027. Results and statistical analyses are expected by April 2027. Conclusions: This study protocol provides a methodology to test and implement PC-MRI on any MR scanner using a phantom model that (1) represents real flow and catheter conditions, (2) provides a repeatable means for data collection, (3) is easy to assemble, (4) minimizes artifacts, and (5) is transportable. We also describe analytic methods for interscanner calibration across a range of hardware parameters and provide a framework for multisite data collection.

BACKGROUND: Phase-contrast MRI (PC-MRI) offers a rapid, noninvasive technique to directly quantify flow through ventricular shunts, and it serves as an adjunct MRI sequence to inform decision-making in complex postoperative settings. OBSERVATIONS: A 19-year-old man with Dandy-Walker–associated hydrocephalus underwent proximal catheter exchange of a right-sided parietal ventriculoperitoneal shunt. Postoperatively, he developed intraventricular hemorrhage and symptomatic shunt occlusion and required emergency left frontal external ventricular drain (EVD) placement. After 5 days of drainage, the EVD was clamped and limited brain MRI with PC-MRI was performed. Shunt flow measured 21.2 ± 2.8 mL/hr, exceeding the patient’s prior mean EVD output of 12 ± 6.8 mL/hr. The lateral ventricles had returned to their presymptomatic size, and the patient’s symptoms resolved. These concordant findings supported shunt patency, enabling safe EVD removal, and no additional shunt surgery was required. LESSONS: When ventricular size, pressure, and clinical status alone cannot conclusively establish ventricular shunt function, PC-MRI can supply a direct, quantitative measure of CSF flow. Incorporating this brief (60-second) sequence into surveillance imaging for patients with ventricular shunts may refine management decisions, avert unnecessary revisions, and improve patient safety. https://thejns.org/doi/10.3171/CASE25679

Objectives: Rapid brain MRI (rMRI) provides a radiation-free neuroimaging tool to screen children without sedation. Our objective was to retrospectively analyze clinical rMRI utilization by describing demographics, operational metrics, clinical indications, and temporal trends associated with rMRI utilization in the emergency department (ED). Methods: We conducted a single-center, retrospective, cross-sectional study of children who underwent rMRI in the ED at an urban children’s hospital between May 2014 and March 2024. We used descriptive statistics to examine operational metrics and trends in rMRI utilization over the study period. We performed a subgroup analysis of operational metrics by age and clinical indication. Results: We included 2401 patients who underwent rMRI during their ED encounter. rMRI was frequently performed in infants and toddlers younger than 3 years old (n = 604, 25.1%), with a median patient age of 8.0 [interquartile range (IQR): 3.0 to 14.5] years. The median (IQR) time to scan was 3.5 (2.4 to 5.1) hours, and the median (IQR) ED length of stay was 7.5 (5.8 to 9.6) hours. Of the total, 1917 (79.8%) patients were initially triaged as “emergent,” and 990 (41.2%) were discharged home from the ED. rMRI was predominantly used to evaluate ventricular shunt function (n = 2069, 86.1%) and traumatic brain injury (n = 214, 9.0%). Annual rMRI utilization increased by 80.8% between 2015 and 2023, with an average utilization rate increase of 46.1 scans annually between the years 2015 and 2019, and relatively static utilization rate from 2020 to 2023. Conclusions: This work supports the feasibility of widespread rMRI in the high-volume ED care setting, including for young children. rMRI utilization increased over time, with the technique most frequently used to evaluate ventricular shunt function and traumatic brain injury.