title: (1)H MR spectroscopic imaging in patients with MRI-negative extratemporal epilepsy: correlation with ictal onset zone and histopathology.
abstract: Proton magnetic resonance spectroscopy ((1)H MRS) is beneficial in the lateralization of the epileptogenic zone in temporal lobe epilepsy; however, its role in extratemporal and, especially, MRI-negative epilepsy has not been established. This study seeks to verify how (1)H MRS could help in localizing the epileptogenic zone in patients with MRI-negative extratemporal epilepsy. Seven patients (8-23 years) with MRI-negative refractory focal epilepsy were studied using (1)H MRS on a 1.5T MR system. Chemical shift imaging sequence in the transversal plane was directed towards the suspected epileptogenic zone localized by seizure semiology, scalp video/EEG, ictal SPECT and (18)FDG-PET. Spectra were evaluated using the program CULICH, and the coefficient of asymmetry was used for quantitative lateralization. MRS detected lateralization in all patients and was able to localize pathology in five. The most frequent findings were decreased ratios of N-acetylaspartate to choline compounds characterized by increasing choline concentration. The localization of the (1)H MRS abnormality correlated well with ictal SPECT and subdural mapping. In all cases, histopathological analysis revealed MRI-undetected focal cortical dysplasias. (1)H MRS could be more sensitive for the detection of discrete malformations of cortical development than conventional MRI. It is valuable in the presurgical evaluation of patients without MRI-apparent lesions.
authors.affiliation: Department of Pediatric Neurology, Second Medical School, Motol Hospital, Charles University, Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Krsek
authors.forename: Milan
authors.initials: M
authors.lastname: Hajek
authors.forename: Monika
authors.initials: M
authors.lastname: Dezortova
authors.forename: Filip
authors.initials: F
authors.lastname: Jiru
authors.forename: Antonin
authors.initials: A
authors.lastname: Skoch
authors.forename: Petr
authors.initials: P
authors.lastname: Marusic
authors.forename: Josef
authors.initials: J
authors.lastname: Zamecnik
authors.forename: Martin
authors.initials: M
authors.lastname: Kyncl
authors.forename: Michal
authors.initials: M
authors.lastname: Tichy
authors.forename: Vladimir
authors.initials: V
authors.lastname: Komarek
mesh_terms: D000293:Adolescent; D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001931:Brain Mapping; D002648:Child; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline