Postictal Magnetic Resonance Spectroscopic (1H-MRS) Metabolite Changes in Temporal Lobe Epilepsy
Abstract number :
1.214
Submission category :
Year :
2000
Submission ID :
2418
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Bruno Maton, Ana Londono, Edward R Faught, Robert C Knowlton, Ruben I Kuzniecky, Univ of Alabama, Birmingham, AL.
RATIONALE: 1H-MRS is increasingly used for lateralization of temporal lobe epilepsy especially in patients with no lateralized MRI abnormality. Since N-acetyl-aspartate (NA) has been shown to be a functional marker, it is possible that this metabolite may fluctuate. It is unknown whether the interictal and postictal concentrations of NA fluctuate. In this study we evaluated the postictal changes in metabolite peak areas and compared it with the interictal levels. We also evaluated postictal lactate (Lac) increase as a marker for seizure lateralization in patients with temporal lobe epilepsy. METHODS: Seven patients (4M/3F; 17-28y) with ictal and interictal unitemporal EEG abnormalities (L=5, R=1) were scanned at the level of the hippocampus after a mean delay of 2.5 h (1-5.5) after the last seizure and during the interictal state (2-30 days after the last seizure). MRI showed mesial temporal sclerosis in 5/7 patients. Ratios of N-acetylaspartate/(Choline + Creatine), and presence of Lac (+lipids) were measured in both 1H-MRS studies and compared using paired t-test. RESULTS:_Lactate (+lipids) was absent in all the interictal 1H-MRS studies and detected in the temporal lobe of 3/7 postictal studies. Lactate detection was associated with postictal confusion in all cases. Patients were confused during the study in the three cases. Lateralization was concordant with EEG and MRI in 2/3 cases. In one patient, lactate was recorded in an arachnoid cyst without other 1H-MRS abnormality. Lact (+lipids) was recorded bilaterally in one patient. No significant difference was noted between the interictal and postictal NA/(Cr+Cho). In one patient, NA ratio decreased (p=0.02) was noted during the postictal period. CONCLUSIONS:_No significant NA/(Ch+Cr) changes occurred between postictal and interictal states. Postictal Lact (+lipids) was detected in half of our patients with high concordance with MRI and EEG findings. Postictal 1H-MRS can provide additional information to lateralize the epileptogenic zone in patients with TL