Structure alterations in left-sided trigeminal neuralgia: A voxel-based morphometry and diffusion tensor imaging study

Background: This study aimed to scrutinize alterations in brain structure in individuals afflicted with primary trigeminal neuralgia (TN), and to elucidate the relationship between these modifications and the clinical symptoms exhibited by TN patients. Methods: Utilizing 3.0 T magnetic resonance imaging (MRI), T1-weighted structural images and diffusion tensor imaging data were acquired from 64 participants. Variations in gray matter volume (GMV) and white matter (WM) were assessed through voxel-based morphometry (VBM) and tract-based spatial statistics, respectively. Furthermore, we explored the correlations between structural metrics and both the visual analogue scale (VAS) scores and the disease duration. Furthermore, a multi-model diffusion imaging approach combined with support vector machine (SVM) was utilized for classification purposes. Results: VBM analysis revealed a significant reduction in GMV within the right thalamus in the TN cohort. Additionally, we observed notable fluctuations in fractional anisotropy (FA) and radial diffusivity (RD) within the genu and body of corpus callosum (CC), anterior corona radiata (CR), and superior CR. Notably, alterations in FA and RD within certain affected brain regions demonstrated correlations with clinical metrics. By combining the significant features of FA and RD in the affected brain regions, the classification accuracy reached 0.783, with an AUC of 0.862. Conclusions: This study provides compelling evidence of structural changes in the brain of individuals with primary TN, notably the significant decrease in GMV in the right thalamus and variations in WM integrity, as indicated by changes in FA and RD in key brain regions such as the CC and CR. These structural alterations correlate significantly with clinical measures of pain intensity and disease duration. The use of a multi-modal diffusion imaging approach combined with a SVM classifier demonstrated high effectiveness, suggesting potential utility in diagnosing and understanding the neuropathology of TN.