Multimodal MRI characterization of brain injury in heatstroke: integrating gray matter morphometry and advanced diffusion tractometry

Objective To investigate gray–white matter injury in heatstroke using multimodal MRI, and precisely localize damaged white matter segments via automated fiber quantification (AFQ) with clinical correlation. Results Compared with the healthy control group, VBM revealed reduced volume in bilateral cerebellar anterior lobes and left fusiform gyrus. TBSS showed widespread white matter abnormalities. AFQ identified: (a) Decreased fractional anisotropy in left corticospinal tract and right inferior fronto-occipital fasciculus; (b) increased mean diffusivity in left thalamic radiation, bilateral corticospinal tracts, corpus callosum forceps minor, bilateral inferior fronto-occipital fasciculus, left inferior longitudinal fasciculus, right superior longitudinal fasciculus, and bilateral uncinate fasciculi (false discovery rate – P < 0.05). Specific nodes in the left thalamic radiation, right corticospinal tract, right inferior fronto-occipital fasciculus, left inferior longitudinal fasciculus, and left uncinate fasciculus were correlated with Glasgow Coma Scale and coagulopathy markers. Conclusion Heatstroke involves cerebellar/cortical atrophy and segment-specific white matter damage, where AFQ-precise localization links microstructural alterations to clinical severity and coagulopathy.