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Interictal hippocampal benzodiazepine receptors in temporal lobe epilepsy: comparison with coregistered hippocampal metabolism and volumetry
Author(s) -
Szelies B.,
WeberLuxenburger G.,
Mielke R.,
Pawlik G.,
Kessler J.,
Pietrzyk U.,
Bauer B.,
Heiss W.D.
Publication year - 2000
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1046/j.1468-1331.2000.00077.x
Subject(s) - hippocampal formation , ictal , temporal lobe , medicine , epilepsy , hippocampus , neuroscience , hippocampal sclerosis , magnetic resonance imaging , nuclear medicine , psychology , radiology
The significance of benzodiazepine receptor (BZR) concentration in comparison with hippocampal metabolism and volumetry was assessed in 14 patients diagnosed with temporal lobe epilepsy (TLE) without hippocampal signal change on T2‐weighted magnetic resonance imaging (MRI) scans. Focus lateralization was achieved by clinical, electroencephalographic and neuropsychological examinations. Three‐dimensional positron emission tomography (PET) and MRI scans were coregistered for determination of hippocampal 11 C‐flumazenil (FMZ) binding, normalized to average cortical values for glucose metabolism (rCMR glc ) and volume. The hippocampi were individually outlined on T1‐weighted MRI. Volumes of interest (VOI) were used for calculation of asymmetries between clinically affected and unaffected sides. Eleven out of 14 TLE patients presented a significant reduction in hippocampal volume. In nine of these 11 patients hippocampal FMZ binding and in seven cases hippocampal CMR glc was also reduced. In two patients without hippocampal volume asymmetry FMZ binding was markedly reduced in the mesial temporal lobe appropriately to the clinically diagnosed side. In our study volumetry is therefore the most sensitive tool for the detection of hippocampal abnormality in TLE. However, in cases without hippocampal atrophy the reduction of FMZ may indicate functional impairment of BZR before neuronal loss becomes evident. Our results emphasize the complementary nature of these tests in TLE patients.