血管压迫性三叉神经痛的扩散张量成像研究

目的 研究血管压迫性三叉神经痛（TN）患者三叉神经根部扩散张量成像（DTI）的磁共振表现及临床应 用。方法 49 例经手术证实的血管压迫引起单侧 TN 患者行常规 MRI 检查和横轴面 DTI 成像，根据血管与神经相 互关系分为 A 组（接触，22 例）、B 组（移位，11 例）、C 组（压迫，16 例），分别测量患侧及健侧三叉神经根部的横截面 积（CSA）、平均扩散系数（MD）值、部分各向异性分数（FA）值、轴向扩散系数（AD）值和径向扩散系数（RD）值，比较患 侧及健侧三叉神经以及 TN 患者组间患侧三叉神经各参数值的差异。结果 患侧三叉神经 CSA、FA 值明显低于健 侧，患侧 MD 值及 RD 值明显高于健侧，且差异均有统计学意义（P＜0.05），患侧 AD 值与健侧比较差异无统计学意 义（P＞0.05）。A、B 和 C 组的 CSA、FA 值、RD 值之间差异有统计学意义，其中 A 组 CSA 和 FA 值高于 C 组，RD 值低 于 C 组；B 组 FA 值高于 C 组，差异有统计学意义（P＜0.05）。结论 磁共振 DTI 序列可以反映三叉神经微观结构的 改变，提示三叉神经脱髓鞘是由血管压迫引起的，为揭示 TN 的发病机制以及评估 TN 严重程度提供了可靠的依据。

The study of diffusion tensor imaging of trigeminal neuralgia with vascular compression

Objective To study the findings and clinical application of the diffusion tensor imaging (DTI) of the trigeminal nerve root in patients with trigeminal neuralgia (TN). Methods Forty-nine patients with unilateral TN caused by vascular compression and surgically confirmed were collected in this study. The subjects were divided into group A (contact, n=22), group B (displacement, n=11) and group C (atrophy, n=16), according to the relationship between blood vessels and nerves. Conventional MRI and horizontal DTI were performed to measure cross-sectional area (CSA), mean diffusivity (MD) value, fractional anisotropy (FA) value, axial diffusivity (AD) value and radial diffusivity (RD) value in nerve roots of affected side and unaffected side. The trigeminal indexes of both affected and unaffected trigeminal nerves and data of the affected trigeminal indexes of TN patients were compared between the groups. Results The CSA and FA values were significantly lower, MD and RD values of trigeminal nerves were significantly higher in affected side than those of unaffected side (P＜ 0.05). But there was no significant difference in AD value between affected side and unaffected side of TN patients (P＞ 0.05). Values of CSA and FA were significantly higher in group A than those of group C. The value of RD was significantly lower in group A than that of group C. FA value was significantly higher in group B than that of group C (P＜0.05). Conclusion The magnetic resonance DTI sequence can reflect changes in trigeminal nerve microstructure, suggesting that trigeminal demyelination is caused by vascular compression, and altered diffusion indexes of trigeminal nerve are reliable basis for the pathogenesis and the severity evaluation of TN.