Hippocampal Glutamate Levels and Their Correlation With Subregion Volume in School-Aged Children With MRI-Negative Epilepsy: A Preliminary Study

Donghao Xu; Qingfa Ren; Quanyuan Liu; Miaomiao Liu; He Gong; Yuwei Liu; Zhijie Yin; Zhen Zeng; Shuyuan Xia; Yanyan Zhang; Jie Li; Quansheng Gao; Jing Wang; Xianglin Li

doi:10.1002/jmri.29514

Hippocampal Glutamate Levels and Their Correlation With Subregion Volume in School-Aged Children With MRI-Negative Epilepsy: A Preliminary Study

J Magn Reson Imaging. 2024 Jul 6. doi: 10.1002/jmri.29514. Online ahead of print.

Authors

Donghao Xu¹, Qingfa Ren², Quanyuan Liu², Miaomiao Liu¹, He Gong¹, Yuwei Liu¹, Zhijie Yin², Zhen Zeng³, Shuyuan Xia², Yanyan Zhang⁴, Jie Li², Quansheng Gao⁵, Jing Wang², Xianglin Li¹

Affiliations

¹ School of Medical Imaging, Binzhou Medical University, Yantai, China.
² Department of Radiology, Binzhou Medical University Hospital, Binzhou, China.
³ Department of Radiology, Chongqing Traditional Chinese Medicine Hospital, Chongqing, China.
⁴ Department of Pediatric Neurology, Binzhou Medical University Hospital, Binzhou, China.
⁵ Environmental & Operational Medicine, Tianjin Institute of Environmental & Operational Medicine, Tianjin, China.

PMID: 38970314
DOI: 10.1002/jmri.29514

Abstract

Background: Abnormal levels of glutamate constitute a key pathophysiologic mechanism in epilepsy. The use of glutamate chemical exchange saturation transfer (GluCEST) imaging to measure glutamate levels in pediatric epilepsy is rarely reported in research.

Purpose: To investigate hippocampal glutamate level variations in pediatric epilepsy and the correlation between glutamate and hippocampal subregional volumes.

Study type: Cross-sectional, prospective.

Subjects: A total of 38 school-aged pediatric epilepsy patients with structurally normal MRI as determined by at least two independent radiologists (60% males; 8.7 ± 2.5 years; including 20 cases of focal pediatric epilepsy [FE] and 18 cases of generalized pediatric epilepsy [GE]) and 17 healthy controls (HC) (41% males; 9.0 ± 2.5 years).

Field strength/sequence: 3.0 T; 3D magnetization prepared rapid gradient echo (MPRAGE) and 2D turbo spin echo GluCEST sequences.

Assessment: The relative concentration of glutamate was calculated through pixel-wise magnetization transfer ratio asymmetry (MTR_asym) analysis of the GluCEST data. Hippocampal subfield volumes were computed from MPRAGE data using FreeSurfer.

Statistical tests: This study used t tests, one-way analysis of variance, Kruskal-Wallis tests, and Pearson correlation analysis. P < 0.05 was considered statistically significant.

Results: The MTR_asym values of both the left and right hippocampi were significantly elevated in GE (left: 2.51 ± 0.23 [GE] vs. 2.31 ± 0.12 [HCs], right: 2.50 ± 0.22 [GE] vs. 2.27 ± 0.22 [HCs]). The MTR_asym values of the ipsilateral hippocampus were significantly elevated in FE (2.49 ± 0.28 [ipsilateral] vs. 2.29 ± 0.16 [HCs]). The MTR_asym values of the ipsilateral hippocampus were significantly increased compared to the contralateral hippocampus in FE (2.49 ± 0.28 [ipsilateral] vs. 2.35 ± 0.34 [contralateral]). No significant differences in hippocampal volume were found between different groups (left hippocampus, P = 0.87; right hippocampus, P = 0.87).

Data conclusion: GluCEST imaging have potential for the noninvasive measurement of glutamate levels in the brains of children with epilepsy.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 1.

Keywords: GluCEST; epilepsy in children; glutamate; hippocampal subfields; hippocampus.

Abstract

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