Quantitative MR spectroscopy reveals metabolic changes in the dorsolateral prefrontal cortex of patients with temporal lobe epilepsy
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To characterize possible metabolic changes of the dorsolateral prefrontal cortex (DLPFC) in patients with temporal lobe epilepsy (TLE).
Quantitative proton magnetic resonance spectroscopy (1H-MRS) studies were performed on 24 TLE patients and 22 healthy controls. Metabolite concentrations were calculated using a linear combination model (LCModel) and corrected for cerebrospinal fluid contamination. Comparisons were performed between the TLE patients and the controls and between the left DLPFC and right DLPFC in each group. Pearson correlation coefficients were calculated between the metabolite concentrations and epilepsy duration and between the metabolite concentrations and voxel tissue composition: [gray matter (GM)/(GM+white matter (WM))].
Metabolic asymmetry was found in controls between the left and right DLPFC, i.e., the NAA concentration of the left DLPFC was significantly higher than that of the right. However, such metabolic asymmetry was not observed in TLE patients. Compared with the controls, TLE patients showed significantly decreased NAA and Ins, and the reductions were greater in the left DLPFC. No significant correlation was found between the metabolite concentrations and epilepsy duration or between the metabolite concentrations and voxel tissue composition [GM/(GM+WM)].
This study suggests that TLE can produce metabolic changes to DLPFC that is remote from the seizure focus.
• Magnetic resonance spectroscopy probes the brain metabolism noninvasively.
• Dorsolateral prefrontal reductions in NAA (a neuronal marker) and Ins are observed in TLE.
• Temporal lobe epilepsy can result in metabolic changes remote from the seizure focus.
KeywordsMagnetic resonance spectroscopy Temporal lobe epilepsy Dorsolateral prefrontal cortex Brain Metabolism
Proton magnetic resonance spectroscopy
One-way analysis of variance
Advanced normalization tools
Chemical shift selective
Choline, including glycerophosphocholine and phosphocholine
Contralateral to the epileptic focus
Creatine + phosphocreatine
Dorsolateral prefrontal cortex
Glutamate + glutamine
Ipsilateral to the epileptic focus
Average value of the left and right DLPFCs
Left TLE subgroup
Linear combination model
Least significant difference
Magnetization prepared rapid gradient echo
Right TLE subgroup
Temporal lobe epilepsy
Volumes of interest
We acknowledge Dr. Richard A.E. Edden for his assistance during the revision of the manuscript.
This study was funded by National Science Foundation of China (grant nos. 81371528 and 8130118) and the Sichuan Provincial Foundation of Since and Technology (grant no. 2013SZ0047).
Compliance with ethical standards
The scientific guarantor of this publication is Dr. Yue.
Conflict of interest
The authors of this manuscript declare no relationships with any companies.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Institutional Review Board approval was obtained.
Written informed consent was obtained from all patients in this study.
• cross-sectional study
• performed at one institution
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