Craniomaxillofacial Complex Injuries Sustained During Training in Alpine Environments: Multimodal MRI-Based Analysis...

Training activities in alpine environments, characterized by low temperatures, hypoxia, and high physical demand, predispose individuals to craniomaxillofacial (CMF) complex injuries with potential involvement of the central nervous system in the event of accidents. However, the imaging manifestations and multimodal features of brain injury within this specific environmental context remain insufficiently characterized. This study aimed to retrospectively analyze the brain injury patterns in patients with CMF injuries sustained during alpine training, utilizing multimodal magnetic resonance imaging (MRI) data from the acute phase. It further sought to explore the interrelationships among structural damage, white matter microstructural alterations, and functional brain network abnormalities, thereby providing an imaging foundation for clinical assessment and risk stratification.

This retrospective observational imaging study enrolled patients who sustained CMF injuries during alpine training and subsequently underwent multimodal MRI. All imaging data were derived from prior clinical examinations. MRI evaluations were performed during the acute post-injury period, with a median interval from injury to MRI of 2.6 days (interquartile range: 1.8-3.4 d). Short-term clinical follow-up data during the acute hospitalization phase were available for a subset of patients, with the endpoint defined as hospital discharge or completion of acute-phase treatment. No standardized longitudinal imaging follow-up was conducted. The MRI protocol encompassed conventional T1-weighted and T2-weighted imaging, diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI), diffusion tensor imaging (DTI), and resting-state functional MRI (rs-fMRI). Primary analysis metrics included cerebral contusion/laceration and structural injury burden, the quantity and spatial distribution of cerebral microbleeds detected by SWI, DTI-derived white matter microstructural parameters, and topological indices of structural and functional brain networks constructed through connectomics methods. Multimodal integrative analysis was used to assess the associative characteristics between structural injury, white matter microstructural changes, and brain network dysfunction.

The findings revealed that patients with CMF injuries from alpine training exhibited multilevel brain injury features during the acute phase, including cerebral contusions, microbleeds, and diminished white matter microstructural integrity. Microbleeds were predominantly distributed in the corpus callosum and subcortical deep white matter regions. Their burden was closely associated with reduced white matter fractional anisotropy (FA) and weakened functional network connectivity. Structural and functional connectivity analyses demonstrated a widespread reduction in global network efficiency and clustering coefficient among the injured individuals, alongside a relative enhancement of connectivity in certain frontal lobe-related networks, suggesting the presence of network reorganization and compensation during the acute phase. Multimodal analysis further indicated that, within the alpine training context, structural lesions, white matter injury, and brain network dysfunction exhibited significant coupling. The overall injury phenotype seemed more severe compared with general trauma backgrounds.

Craniomaxillofacial complex injuries sustained during training in alpine environments can induce environmentally sensitive, multiscale brain damage in the acute phase, manifesting as coordinated alterations in structural injury, white matter microstructural abnormalities, and brain network functional disruption. Combined multimodal MRI analysis facilitates a comprehensive delineation of the imaging phenotype associated with such injuries, enhances the detection rate of occult brain damage, and provides critical reference for the clinical assessment, risk stratification, and intervention decision-making related to alpine environment-associated brain injury.