The asymmetry of glymphatic system dysfunction in patients with temporal lobe epilepsy: A DTI-ALPS study

Xu Zhao; Yingying Zhou; Yuanhao Li; Shanshan Huang; Hongquan Zhu; Zhiqiang Zhou; Suiqiang Zhu; Wenzhen Zhu

doi:10.1016/j.neurad.2023.05.009

The asymmetry of glymphatic system dysfunction in patients with temporal lobe epilepsy: A DTI-ALPS study

J Neuroradiol. 2023 Nov;50(6):562-567. doi: 10.1016/j.neurad.2023.05.009. Epub 2023 Jun 8.

Authors

Xu Zhao¹, Yingying Zhou², Yuanhao Li¹, Shanshan Huang², Hongquan Zhu¹, Zhiqiang Zhou³, Suiqiang Zhu⁴, Wenzhen Zhu⁵

Affiliations

¹ Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
² Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
³ Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
⁴ Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address: zhusuiqiang@126.com.
⁵ Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. Electronic address: zhuwenzhen8612@163.com.

PMID: 37301366
DOI: 10.1016/j.neurad.2023.05.009

Abstract

Background and purpose: While the occurrence of glymphatic system dysfunction has been observed in temporal lobe epilepsy (TLE), the potential asymmetry of this system has yet to be investigated in the TLE context. We aimed to investigate the glymphatic system function in both hemispheres and to analyze asymmetric features of the glymphatic system in TLE patients using diffusion tensor image analysis along the perivascular space (DTI-ALPS) method.

Materials and methods: 43 patients (left TLE (LTLE), n = 20; right TLE (RTLE), n = 23) and 39 healthy controls (HC) were enrolled in this study. The DTI-ALPS index was calculated for the left (left ALPS index) and right (right ALPS index) hemispheres respectively. An asymmetry index (AI) was calculated by AI = (Right - Left)/ [(Right + Left)/2] to represent the asymmetric pattern. Independent two sample t-test, two-sample paired t-test or one-way ANOVA with Bonferroni correction were conducted to compare the differences in ALPS indices and AI among the groups.

Results: Both left ALPS index (p = 0.040) and right ALPS index (p = 0.001) of RTLE patients were significantly decreased, while only left ALPS index of LTLE patients (p = 0.005) was reduced. Compared to contralateral ALPS index, the ipsilateral ALPS index was significantly decreased in TLE (p = 0.008) and RTLE (p = 0.009) patients. Leftward asymmetry of the glymphatic system was found in HC (p = 0.045) and RTLE (p = 0.009) patients. The LTLE patients presented reduced asymmetric traits when compared to RTLE patients (p = 0.029).

Conclusion: The TLE patients exhibited altered ALPS indices, which could be triggered by glymphatic system dysfunction. Altered ALPS indices were more severe in ipsilateral than in the contralateral hemisphere. Moreover, LTLE and RTLE patients exhibited different change patterns of the glymphatic system. In addition, glymphatic system function presented asymmetric patterns in both normal adult brain and RTLE patients.

Keywords: Asymmetry index; DTI-ALPS; Glymphatic system; Temporal lobe epilepsy.

MeSH terms

Adult
Brain / diagnostic imaging
Brain Mapping
Epilepsy, Temporal Lobe* / diagnostic imaging
Glymphatic System* / diagnostic imaging
Humans
Magnetic Resonance Imaging / methods