title: Identifying the affected hemisphere by (1)H-MR spectroscopy in patients with temporal lobe epilepsy and no pathological findings in high resolution MRI.
abstract: Up to 30% of patients with temporal lobe epilepsy (TLE) remain without remarkable changes in MRI. In this study we investigated the role of (1)H-MR spectroscopy ((1)H-MRS) in lateralizing the affected hemisphere in the mentioned patient group. Twenty-two consecutive patients diagnosed with TLE were investigated by high resolution MRI and (1)H-MRS. We examined the incidence and diagnostic accuracy of temporal metabolite alterations determined by Linear Combination of Model Spectra (L C Model) via water reference. Metabolite values of each hemisphere of TLE patients were compared with healthy controls. Results of metabolite alterations were related to intensive video EEG focus localization. Reduction of N-acetylaspartate + N-acetylaspartyl-glutamate (tNAA) in the affected hemisphere revealed identification in six of nine patients (66%) with unilateral TLE. Group comparison revealed a significant reduction of tNAA (6.1+/-0.8*) in the involved temporal lobe compared with controls (6.67+/-0.4*, P=0.026). Choline levels were significantly increased in the affected hemisphere (1.42+/-0.17*) compared with healthy controls (1.22+/-0.17*, P=0.035). The results of our study show that (1)H-MRS is able to identify the affected hemisphere of MRI negative TLE patients and can be used as an additive tool in multimodal focus localization.
authors.affiliation: Clinics of Neurology, Epilepsy Center (ZEE), University of Erlangen-Nuremberg, Erlangen, Germany. Thilo.Hammen@neurozentrum.imed.uni-erlangen.de
authors.forename: T
authors.initials: T
authors.lastname: Hammen
authors.forename: F
authors.initials: F
authors.lastname: Kerling
authors.forename: M
authors.initials: M
authors.lastname: Schwarz
authors.forename: A
authors.initials: A
authors.lastname: Stadlbauer
authors.forename: O
authors.initials: O
authors.lastname: Ganslandt
authors.forename: B
authors.initials: B
authors.lastname: Keck
authors.forename: B
authors.initials: B
authors.lastname: Tomandl
authors.forename: A
authors.initials: A
authors.lastname: Dörfler
authors.forename: H
authors.initials: H
authors.lastname: Stefan
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000473:pathology*; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012016:Reference Values