Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Department of Radiology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Epilepsia. 2019 Jan;60(1):121-130. doi: 10.1111/epi.14614. Epub 2018 Nov 26.
The epileptogenic network underlying secondarily generalized tonic-clonic seizures (sGTCS) in mesial temporal lobe epilepsy (mTLE) is not well understood. Here, we investigated alterations in the probabilistic hippocampal-thalamic pathway (pHTP) underlying sGTCS using diffusion tensor imaging and resting-state functional magnetic resonance imaging in a cohort of TLE patients with hippocampal sclerosis (HS).
We consecutively recruited 51 unilateral TLE-HS patients (26 with and 25 without sGTCS) and 22 healthy controls. Probabilistic tractography was used to track the pHTP. Raw fractional anisotropy (FA) and mean diffusivity (MD) of the pHTP were corrected by the FA/MD of the hemispheric white matter on the same side. The volume of the thalamic subregion connected to the hippocampus (TSCH) was investigated. Fractional amplitude of low-frequency fluctuations of the hippocampus, the TSCH, and the thalamic subregion unconnected to the hippocampus in resting-state functional magnetic resonance imaging were also calculated.
After correction, the sGTCS group showed lower FA than the non-sGTCS group (P = 0.03), and lower FA as well as higher MD than controls in the ipsilateral pHTP. The non-sGTCS group only showed higher corrected MD in the ipsilateral pHTP relative to controls. Corrected FA or MD in the contralateral pHTP did not differ among groups. The TSCH was located in the mesial aspect of the thalamus, and it was atrophied in the sGTCS group compared to the non-sGTCS group and controls. The sGTCS group had lower fractional amplitude of low-frequency fluctuations in the ipsilateral hippocampus and TSCH compared to controls.
In TLE-HS, sGTCS was associated with impaired integrity of the pHTP as well as structural and functional abnormalities in the medial thalamus. The medial thalamus is important in seizure generalization in mTLE.
内侧颞叶癫痫（MTLE）继发全面强直阵挛发作（sGTCS）的致痫网络尚不清楚。本研究使用扩散张量成像和静息态功能磁共振成像，对伴有海马硬化（HS）的 TLE 患者队列中的 sGTCS 潜在的海-丘脑概率性通路（pHTP）改变进行了研究。
我们连续招募了 51 例单侧 TLE-HS 患者（26 例伴有 sGTCS，25 例不伴有 sGTCS）和 22 例健康对照者。使用概率追踪技术来追踪 pHTP。对 pHTP 的原始各向异性分数（FA）和平均扩散系数（MD）进行了同侧半球白质 FA/MD 的校正。还研究了与海马相连的丘脑亚区（TSCH）的体积。计算了静息状态功能磁共振成像中海马、TSCH 和与海马不相连的丘脑亚区的低频振幅。
校正后，sGTCS 组的 FA 低于非 sGTCS 组（P=0.03），且 FA 低于对照组，MD 高于对照组，均为同侧 pHTP。非 sGTCS 组仅在同侧 pHTP 中校正 MD 高于对照组。各组间对侧 pHTP 的校正 FA 或 MD 无差异。TSCH 位于丘脑的内侧，sGTCS 组较非 sGTCS 组和对照组萎缩。sGTCS 组同侧海马和 TSCH 的低频振幅低于对照组。
在 TLE-HS 中，sGTCS 与 pHTP 的完整性受损以及内侧丘脑的结构和功能异常有关。内侧丘脑在 MTLE 中的癫痫发作泛化中起重要作用。
