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Proton MR Spectroscopy in Patients with Structural MRI‐Negative Temporal Lobe Epilepsy
Author(s) -
Xu Michael Y.,
Ergene Erhan,
Zagardo Michael,
Tracy Patrick T.,
Wang Huaping,
Liu WenChing,
Machens Nancy A.
Publication year - 2015
Publication title -
journal of neuroimaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.822
H-Index - 64
eISSN - 1552-6569
pISSN - 1051-2284
DOI - 10.1111/jon.12263
Subject(s) - medicine , temporal lobe , epilepsy , magnetic resonance imaging , pathological , creatine , gliosis , nuclear medicine , parietal lobe , choline , radiology , pathology , psychiatry
ABSTRACT BACKGROUND AND PURPOSE With conventional magnetic resonance imaging (MRI), 20–30% of patients with temporal lobe epilepsy (TLE) have negative pathological MRI findings. Further investigations of the role of magnetic resonance spectroscopy (MRS) in the pre‐surgical evaluation of patients with MRI‐negative TLE are important to avoid intracranial EEG recording and to better understand the mechanism of the epileptogenic process. This study aimed to compare the measurements of N‐acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the hippocampi of MRI‐negative TLE patients and normal subjects. METHODS Twenty patients with MRI‐negative TLE and 10 age‐matched healthy control subjects underwent MRI and MRS. The concentrations of NAA, Cr, and Cho and the ratios of NAA/Cr and NAA/(Cr+Cho) were measured. Seven of these 20 patients also underwent surgical treatment for TLE. Their pathological results and surgical outcomes were evaluated. RESULTS In the hippocampi ipsilateral to the seizure side, the NAA/Cr and NAA/(Cr+Cho) ratios were significantly decreased compared with the ratios of the hippocampi contralateral to the seizure side and the normal control hippocampi. There was no significant difference between the hippocampi contralateral to the seizure side and the normal control hippocampi. The pathological results from the patients who underwent temporal lobe resection indicated mild to moderate gliosis and minimal loss of neurons. Five patients were seizure‐free during the follow‐up period of 9‐ 47 months (mean 27.7 months). CONCLUSIONS In MRI‐negative TLE, significant reductions in the NAA/Cr and NAA/(Cr+Cho) ratios ipsilateral to the seizure side may help lateralize and localize the epileptogenic zone.