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Diffusion tensor imaging (DTI) has been used to detect microstructural alteration and effect of surgical treatment of the trigeminal nerve root (TR) in patients with classical trigeminal neuralgia (CTN) underwent microvascular decompression (MVD). Patients with CTN without neurovascular compression (woNVC) is a special population of TN, however, the pathogenesy of CTN woNVC and the mechanism of internal neurolysis (IN) remain unknown. 21 patients with CTN woNVC who underwent IN and 20 healthy controls were included in this study. The differences in the means, kurtosis and skewness of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) between the affected and unaffected nerves in patients and both nerves in controls were investigated by independent t -test and paired t- test respectively. Longitudinal changes of FA and ADC were correlated with outcome of IN via Spearman correlation coefficient. Significant differences were found in preoperative mean and kurtosis values for both FA and ADC of the affected side TR, compared to the unaffected side and control group respectively. However, these differences remarkably reduced postoperatively. Further, the Spearman correlation coefficient showed a strong negative correlation between decrease of ADC in the affected side and the surgical outcome in BNI total score. The changes of diffusive property of TR, especially the FA and ADC, provide alternative radiological evidence for evaluating the mechanism of CTN woNVC. The modification of DTI metrics could be an effective factor for providing potential noninvasive biomarkers for determining the prognosis of patients with CTN woNVC underwent IN. [ABSTRACT FROM AUTHOR]

Purpose: Previous researches have reported gray and white matter microalterations in primary trigeminal neuralgia (TN) with neurovascular compression (NVC). The central mechanism underlying TN without NVC are unknown but may include changes in specific brain regions or circuitries. This study aimed to investigate abnormalities in the gray matter (GM) and white matter (WM) of the whole brain and the possible pathogenetic mechanism underlying this disease. Methods: We analyzed brain morphologic images of TN patients, 23 with NVC (TN wNVC) and 22 without NVC (TN wNVC) compared with 45 healthy controls (HC). All subjects underwent 3T-magnetic resonance imaging and pain scale evaluation. Voxel-based morphometry (VBM) and surface-based morphometry (SBM) were used to investigate whole brain grey matter quantitatively; graph theory was applied to obtain network measures based on extracted DTI data based on DTI data of the whole brains. Sensory and affective pain rating indices were assessed using the visual analog scale (VAS) and short-form McGill Pain Questionnaire (SF-MPQ). Results: The VBM and SBM analyses revealed widespread decreases in GM volume and cortical thickness in TN wNVC compared to TN woNVC, and diffusion metrics measures and topology organization changes revealed DTI showed extensive WM integrity alterations. However, above structural changes differed between TN wNVC and TN woNVC, and were related to specific chronic pain modulation mechanism. Conclusion: Abnormalities in characteristic regions of GM and WM structural network were found in TN woNVC compared with TN wNVC group, suggesting differences in pathophysiology of two types of TN. [ABSTRACT FROM AUTHOR]

• We determined the correspondence between the thalamus and the cortex. • The anisotropy of thalamocortical fiber bundles in patients generally declined. • The abnormalities may be related to damage to the myelin sheath of nerve fibers. • The longer the disease duration, the more serious the damage. Epilepsy is one of the most common diseases of the nervous system. Approximately one-third of epilepsy cases are drug-resistant, among which generalized-onset seizures are very common. The present study aimed to analyze abnormalities of the thalamocortical fiber pathways in each hemisphere of the brains of patients with drug-resistant generalized epilepsy. The thalamocortical structural pathways were identified by diffusion tensor imaging (DTI) in 15 patients with drug-resistant generalized epilepsy and 16 gender/age-matched controls. The thalami of both groups were parcellated into subregions according to the local thalamocortical connectivity pattern. DTI measures of thalamocortical connections were compared between the two groups. Probabilistic tractography analyses showed that fractional anisotropy of thalamocortical pathways in patients with epilepsy decreased significantly, and the radial diffusivity of the left thalamus pathways with homolateral motor and parietal-occipital cortical regions in the drug-resistant epilepsy group increased significantly. In addition to the right thalamus pathway and prefrontal cortical region, fractional anisotropy of all other pathways was inversely correlated with disease duration. The results provide evidence indicating widespread bilateral abnormalities in the thalamocortical pathways in epilepsy patients and imply that the degree of abnormality in the pathway increases with the disease duration. [ABSTRACT FROM AUTHOR]