Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053, PR China.
Eur J Radiol. 2013 May;82(5):783-6. doi: 10.1016/j.ejrad.2012.11.027. Epub 2012 Dec 21.
To investigate microstructural tissue changes of trigeminal nerve (TGN) in patients with unilateral trigeminal neuralgia (TN) by multiple diffusion metrics, and correlate the diffusion indexes with the clinical variables.
16 patients with TN and 6 healthy controls (HC) were recruited into our study. All participants were imaged with a 3.0 T system with three-dimension time-of-flight (TOF) magnetic resonance angiography and fluid attenuated inversion recovery (FLAIR) DTI-sequence. We placed regions of interest over the root entry zone of the TGN and measured fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The mean values of FA, MD, AD and RD were compared between the affected and unaffected sides in the same patient, and to HC values. The correlation between the side-to-side diffusion metric difference and clinical variables (disease duration and visual analogy scale, VAS) was further explored.
Compared with the unaffected side and HC, the affected side showed significantly decreased FA and increased RD; however, no significant changes of AD were found. A trend toward significantly increased MD was identified on the affected side comparing with the unaffected side. We also found the significant correlation between the FA reduction and VAS of pain (r=-0.55, p=0.03).
DTI can quantitatively assess the microstructural abnormalities of the affected TGN in patients with TN. Our results suggest demyelination without significant axonal injury is the essential pathological basis of the affected TGN by multiple diffusion metrics. The correlation between FA reduction and VAS suggests FA as a potential objective MRI biomarker to correlate with clinical severity.
通过多项扩散指标研究单侧三叉神经痛（TN）患者三叉神经（TGN）的微观组织变化，并将扩散指标与临床变量相关联。
本研究纳入了 16 例 TN 患者和 6 例健康对照者（HC）。所有参与者均在 3.0T 系统上进行三维时间飞跃（TOF）磁共振血管造影和液体衰减反转恢复（FLAIR）DTI 序列扫描。我们在 TGN 的神经根进入区放置感兴趣区，并测量各向异性分数（FA）、平均扩散系数（MD）、轴向扩散系数（AD）和径向扩散系数（RD）。比较了同一患者患侧和健侧之间，以及与 HC 值之间 FA、MD、AD 和 RD 的平均值。进一步探讨了侧方扩散指标差异与临床变量（病程和视觉类比量表，VAS）之间的相关性。
与健侧和 HC 相比，患侧 FA 值显著降低，RD 值显著升高；然而，AD 没有明显变化。与健侧相比，患侧 MD 值有升高的趋势。我们还发现 FA 值降低与疼痛 VAS 之间存在显著相关性（r=-0.55，p=0.03）。
DTI 可以定量评估 TN 患者 TGN 的微观结构异常。我们的结果表明，脱髓鞘而无明显轴索损伤是 TGN 发生病变的主要病理基础。FA 值降低与 VAS 之间的相关性提示 FA 可能是与临床严重程度相关的潜在 MRI 客观生物标志物。
