The Research Value Of 3D-FIESTA And DTI In Detecting Morphological And Microstructural Changes In Primary Trigeminal Neuralgia Patients

Objective: This study was to discuss the changes of morphological parameters and microstructural metrics in cistern segment of trigeminal nerve in PTN patients and correlate the morphological parameters and microstructural metrics.Materials and methods: This study was conducted between January 2017 and February 2018.We recruited 25 PTN patients with unilateral NVC,the diagnosis of all TN patients was confirmed in accordance with the diagnosis criteria of typical TN and was treated with MVD.To validate the study,25 sex-and age-matched healthy participants were also recruited in the study as HC.HC had no history of facial pain.Patients with disorders that could affect central nervous system function or those with metal implants were excluded.All participants were imaged with a 3.0 T MRI scanner using 3D-FIESTA and DTI.3D-FIESTA images were transferred to a post-processing workstation.All patients’ images were observed in axial,coronal,sagittal and oblique planes to evaluate the relationship between the nerve and surrounding structures.The morphological measurements were done on the axial images where the trigeminal nerve is best and longest displayed,including the length of the cisternal segment of trigeminal nerve,the trigeminal-pontine angle and the cross-sectional area of CPA cistern.The original DTI data were processed with functool software in the AW4.4workstation.Box-shaped ROI were placed over the NVC of the trigeminal nerve.The site of ROI is locate in the center of the nerve and the surrounding cerebrospinal fluid components are avoided as much as possible.All the morphological parameters were compared between the affected side and the unaffected side by Wilcoxon signed rank test.The morphological parameters were compared between the affected side and HC using Mann Whitney U-test.The values of FA and ADC were compared between the affected and unaffected side using paired t-test.The values of FA and ADC were compared between the affected and HC by independent t-test.Pearson correlation analyses were used to compare the morphological parametric and diffusion metrics,A p ≤ 0.05 was considered statistically significant.Results: The trigeminal-pontine angle and the value of FA on the affected side was significantly less than the unaffected side and HC(P<0.05).The value of ADC on the affected side was significantly increased compared with the unaffected and HC.There was no difference in the cross-sectional area of CPA and the length of the cistern segment of the trigeminal nerve between the affected and unaffected side and HC.Correlation analysis revealed that the trigeminal-pontine angle was significantly and positively correlated with the FA and negatively correlated with the ADC.Conclusion: A sharp trigeminal-pontine angle may increase the probability of NVC,focal nerve is more incline to demyelination,thus more likely to result in the genesis of TN.