Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Rui Jin Er Rd., Shanghai, 200025, China.
Department of Radiology, Fudan University Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
Acta Neurochir (Wien). 2019 Jul;161(7):1407-1413. doi: 10.1007/s00701-019-03851-2. Epub 2019 May 8.
Several recent studies have focused on microstructural changes in the trigeminal nerve in trigeminal neuralgia using diffusion tensor imaging (DTI). However, alterations after microvascular decompression (MVD) have rarely been investigated. Furthermore, the trigeminal nerve of asymptomatic individuals also presenting with neurovascular contact/compression (NVC) has not yet been studied.
Thirty-four patients suffering from trigeminal neuralgia and 34 healthy age-matched controls, who were identified as having unilateral NVC signs, underwent both DTI and high-resolution magnetic resonance imaging (MRI) for comparison. All trigeminal neuralgia patients underwent a post-surgical MRI scan after 7 days and a follow-up MRI scan within 6-8 months after surgery. The apparent diffusion coefficients (ADCs) and fractional anisotropy (FA) values were measured from coronal images in which the nerves from the root exit point to the distal segment were clearly shown.
In 34 trigeminal neuralgia patients, the absolute FA value was significantly lower on the affected side (mean FA, 0.34 ± 0.03) than on the unaffected side (mean FA, 0.37 ± 0.05, p < 0.001). The FA ratio was also significantly different between the trigeminal neuralgia group (Rs, 0.92 ± 0.06) and the control group (Rs, 0.99 ± 0.09) (p = 0.001). The absolute ADC value between the two sides in patients and the ratios of ADC between the trigeminal neuralgia and control groups did not show any significant differences (p = 0.21 and 0.29, respectively). However, in 34 healthy subjects presenting with signs of NVC, neither the FA value nor the ADC showed a difference between sides (p > 0.05). The FA ratio of patients showed a significant increase on two follow-up MRI scans compared to the preoperative FA (p = 0.02 and 0.002, respectively), while the ADC ratio showed a significant decrease at 6 months after MVD (p = 0.004).
This study of trigeminal neuralgia due to NVC found that DTI indexes could reflect alterations in the affected trigeminal nerve. Furthermore, a reversible change after MVD surgery could be potentially valuable for monitoring the change in white matter of the trigeminal nerve.
多项近期研究使用弥散张量成像（DTI）聚焦于三叉神经痛患者三叉神经的微观结构变化。然而，微血管减压术（MVD）后的改变很少被研究。此外，还没有研究无症状个体的三叉神经，这些个体也存在神经血管接触/压迫（NVC）。
34 例患有三叉神经痛的患者和 34 例年龄匹配的健康对照组，这些患者均被确定为单侧存在 NVC 征象，分别进行 DTI 和高分辨率磁共振成像（MRI）检查进行比较。所有三叉神经痛患者在术后 7 天进行术后 MRI 扫描，并在术后 6-8 个月进行随访 MRI 扫描。在冠状图像上测量从神经根出口点到远端节段的神经，测量表观扩散系数（ADC）和各向异性分数（FA）值。
在 34 例三叉神经痛患者中，患侧的绝对 FA 值明显低于健侧（患侧平均 FA 值，0.34±0.03；健侧平均 FA 值，0.37±0.05，p<0.001）。三叉神经痛组和对照组之间的 FA 比值也有显著差异（Rs，0.92±0.06；Rs，0.99±0.09，p=0.001）。患者双侧之间的绝对 ADC 值和 ADC 比值在三叉神经痛组和对照组之间没有显示出任何显著差异（p=0.21 和 0.29）。然而，在 34 例有 NVC 征象的健康受试者中，FA 值和 ADC 值在两侧均无差异（p>0.05）。与术前 FA 相比，患者的 FA 比值在两次随访 MRI 扫描中均有显著增加（分别为 p=0.02 和 0.002），而 ADC 比值在 MVD 后 6 个月时显著降低（p=0.004）。
这项针对 NVC 引起的三叉神经痛的研究发现，DTI 指标可以反映受影响的三叉神经的变化。此外，MVD 手术后的可逆变化可能对监测三叉神经白质的变化具有潜在价值。
