Neurochemical characteristics of pathological tissues in epilepsy: A preliminary 1H MR spectroscopy study at 7 T

Abstract

Background and purpose: This study aims to evaluate the neurochemical characteristics of pathological tissues by ¹H magnetic resonance spectroscopy (MRS) in patient with pharmaco-resistant focal epilepsy at 7 T.

Methods: Thirteen patients with drug-resistant epilepsy and focal seizure successfully underwent MRS examinations at 7 T MRI scanners. ¹H MR spectra were acquired from two voxels (lesion side and contralateral side) using the semi-adiabatic spin-echo full-intensity localized spectroscopy (sSPECIAL) sequence. Metabolite levels were quantified from LCModel and reported as to total creatine ratio.

Results: In comparison to the contralateral side, lesions in focal cortical dysplasia demonstrated significantly reduced macromolecule and N-acetyl aspartate, significantly increased total choline and glycine + myo-inositol, and a distinct reduction trend of glutamate.

Conclusions: We conclude that performing MRS at high magnetic field offered the potential to reveal metabolic alterations in epilepsy lesions that may help to further understand the underlying pathophysiology of the disease.

Keywords: 7 T; Cortical dysplasia; Epilepsy; MR spectroscopy; Non lesional.

Fig. 1

MRS voxel positions and ¹H MR spectra from the control and lesion side of patient #2 with focal cortical dysplasia. Glu: glutamate, NAA: N-acetyl aspartate, tCr: creatine+phosphocreatine, tCho, total choline, Ins: myo-inositol.

Fig. 2

Neurochemical changes between lesion and contralateral side in epilepsy patients with the focal cortical dysplasia and MRI non-detectable lesion (* p < 0.05, + p = 0.057). The plot shows the mean percentage difference between lesion and contralateral side and error bars represent standard errors of the mean.