High-resolution diffusion tensor imaging for the detection of diffusion abnormalities in the trigeminal nerves of patients with trigeminal neuralgia caused by neurovascular compression.

PURPOSE To detect diffusion abnormalities in the trigeminal nerves of patients with trigeminal neuralgia (TN) caused by neurovascular compression (NVC) by using a high-resolution diffusion tensor imaging (HR-DTI) technique. METHODS Thirteen patients with TN and 14 healthy controls underwent HR-DTI scanning. After extracting the trigeminal nerve using a tractography technique, we measured the fractional anisotropy (FA) and apparent diffusion coefficient (ADC), and compared the contralateral ratios (CR) of these parameters between the patients and controls, and correlated these ratios with the cross-sectional areas of the nerves. RESULTS The CRs of the FA values for the trigeminal nerves of the patients (1.00 ± 0.15) had significantly higher variance than those of healthy controls (1.00 ± 0.05) (P < .05) and showed a positive correlation with the cross-sectional area of the nerves (r= 0.81). In contrast, the CRs of the ADC values were not significantly different between the two groups (1.02 ± 0.10 and 1.01 ± 0.08, respectively) and had no significant correlation with cross-sectional area. CONCLUSION HR-DTI can detect an alteration in the relative FA values of affected trigeminal nerves and a correlation with atrophic changes in patients with NVC-induced TN.