Brain White Matter Plasticity And Functional Reorganization Underlying The Central Pathogenesis Of Idiopathic Trigeminal Neuralgia

Objective:Through Multi-MRI, this study combines Tract-Based Spatial Statistics(TBSS) of diffusion kurtosis imaging and functional connectivity density(FCD) of Resting-state fMRI to detect both structural plasticity and functional reorganization in brain thus further benefiting clinical therapy.Materials and Methods:A total of 32 right-handed unilateral trigeminal neuralgia patients and 22 healthy controls were included in this study. All participants underwent MRI scanning to get original data of diffusion kurtosis imaging and Resting-state fMRI. A comprehensive evaluation of pain were obtained for each patients according to their answers in the short-form of McGill pain questionnaire(SF-MPQ). Fractional anisotropy(FA), axial diffusivity(AD), radial diffusivity(RD), mean diffusivity(MD), axial kurtosis(AK), radial kurtosis(RK), and mean kurtosis(MK) were obtained from whole brain analysis from DKI using DKE. And long-range FCD, local FCD maps were obtained from rsfMRI using SPM. Group differences in DKI analysis were compared using TBSS, and FCD differences were compared in a voxel-wise manner using two-sample t-tests(P < 0.05, corrected). We also tested relations between these functional and structural changes as well as relations between functional/structural changes and clinical data obtained from SF-MPQ of TN patients.Results:We found white matter abnormalities in TN patients, mainly marked by lower AK, higher FA and AD in the internal capsule, cerebral peduncle, corticospinal tract, external capsule, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, posterior thalamic radiation, uncinate fasciculus, and splenium of corpus callosum. Besides, TN patients exhibited significantly increased FCDs in bilateral hippocampus, contralesional caudate nucleus, and contralesional orbitofrontal cortex. We also found FCDs reduction in TN patients in the posterior cingulate cortex, bilateral angular gyrus, and contralesional supramarginal gyrus. Moreover, white matter and FCD changes were significantly correlated.Conclusion:Trigeminal patients exhibited structural and functional reorganizations, and there were correlations between them, which might be responsible for the persistence of pathologic algogenic state and further to result in long-term recurrent pain and sensory-related dysfunction. Our findings may contribute to systematic treatment options in neuropathic pain and provide valuable imaging markers for monitoring of therapeutic interventions.