Study Of Diffusion Spectrum Imaging And Morphometry Analysis In Primary Trigeminal Neuralgia

Objective: Diffusion spectrum imaging(DSI)was used to quantitatively study the changes in the trigeminal cistern segment and the voxel-based morphometry analysis was used to the volume changes of subcortical structures in patients with trigeminal neuralgia(TN),and to further evaluate the changes of different parameters and their correlation with clinical practice.Methods: To achieve high-resolution fiber tracking and voxel based morphological analysis,60 patients with TN and 35 healthy controls(HCs)were scanned by T1 WI conventional magnetic resonance imaging(MRI)and DSI.DSI Studio software was used to process the DSI data,manually place the region of interest(ROI)in the trigeminal cistern segment,and reconstruct the trigeminal nerve bundle with deterministic fiber tracking algorithm.Calculate the average quantitative anisotropy(QA),general fractional anisotropy(GFA),restricted diffusion imaging(RDI)and isotropic diffusion component(ISO)values of fiber bundles,as well as basic diffusion coefficients such as fractional anisotropy(FA),axial diffusivity(AD),mean diffusivity(MD)and radial diffusivity(RD).FIRST(FSL 4.1)was used to automatically segment T1 WI data and calculate the volume of subcortical areas of bilateral cerebral hemispheres,including bilateral nucleus accumbens,amygdala,globus pallidus,caudate nucleus,hippocampus,putamen and thalamus.To analyze the differences between TN patients and HCs in DSI parameters and subcortical structure volume,and the correlation between these differences and visual analogue scale(VAS)score,symptom duration and responsible vessel types.Results: Compared with the mean value of trigeminal nerve parameters in HCs group,the pain side QA(P < 0.001),FA(P = 0.001),and GFA(P < 0.001)in TN group decreased significantly,and the AD(P = 0.036)increased significantly.Compared with the mean parameter value of trigeminal nerve in HCs group,QA(P = 0.046)and FA(P= 0.008)on the healthy side of TN patients were significantly reduced.Compared with TN patients with vein(16,26.7%),the values of FA(P = 0.028)and GFA(P < 0.001)on the pain side were significantly lower in TN patients with artery(44,73.3%).The ISO(P = 0.021)and RDI(P = 0.021)on the pain side were significantly lower in the long course group(25,41.6%)than in the short course group(35,58.4%)of TN patients.The relative volume of thalamus(P = 0.031)on the pain side in TN group was significantly higher than that on the healthy side.The relative volume of thalamus(P <0.0001)and nucleus accumbens(P < 0.0001)on the left side in HCs group was significantly lower than that on the right side,while the relative volume of putamen on the left side(P = 0.023)was significantly higher than that on the right side.The relative volume of bilateral thalamus and amygdala on pain side(P = 0.041)in TN group was significantly lower than that in HCs group.Conclusion: Using high-resolution fiber tracking technology,DSI can provide quantitative information of white matter fibers,which can be used to detect the integrity of trigeminal white matter in patients with TN,and VBM analysis can detect the changes of gray matter,which provides an accurate imaging basis for explaining the clinical manifestations of TN.