A systematic review of brain structural and functional alterations in pediatric mild traumatic brain injury

Abstract

Introduction Pediatric mild traumatic brain injury (pmTBI) constitutes 70–90% of childhood traumatic brain injury cases. While magnetic resonance imaging (MRI) reveals subtle brain alterations, fragmented evidence across modalities limits understanding of long-term neurobiological consequences. Methods This systematic review synthesized 42 studies from MEDLINE/PubMed, Web of Science, Cochrane Library, and Scopus (inception to December 2025) employing structural MRI and functional MRI (fMRI). Methodological quality was assessed using a modified GRADE framework. Results White matter investigations (n = 18) suggested widespread microstructural alterations in limbic and commissural pathways-alongside reduced global network efficiency and disrupted hub connectivity in executive and salience networks. Gray matter studies (n = 9) identified regional cortical thinning in prefrontal and parietal regions, hippocampal atrophy persisting up to 1 year. Resting-state fMRI studies (n = 5) revealed diminished default mode network (DMN) integrity and elevated striatal spontaneous activity. Task-based fMRI studies (n = 10) demonstrated compensatory hyperactivation during working memory and inhibitory tasks-manifesting as enhanced preparatory activation but resource depletion during execution-alongside lower DMN deactivation and persistent cerebrovascular reactivity abnormalities extending to chronic phases. Discussion In sum, multimodal MRI provides evidence suggesting systematic structural and functional alterations in pmTBI encompassing white matter disruption, gray matter vulnerability, and network reorganization.