Quantitative MRI in temporal lobe epilepsy: evidence for fornix atrophy.
OBJECTIVE
To investigate whether the fornix and mamillary bodies, being part of the limbic system, are abnormal in patients with mesial temporal lobe epilepsy (MTLE).


BACKGROUND
The limbic system comprises the hippocampal formation, fornix, mamillary bodies, thalamus, and other integrated structures. This system is implicated in complex functions, including memory and emotion, and in diseases such as MTLE.


METHODS
The authors performed volumetric measurements of hippocampus, amygdala, fornix, and mamillary bodies in 50 patients with MTLE and compared the results with normal controls and patients with extratemporal lobe epilepsy.


RESULTS
Control (n = 17) measurements of the amygdala, hippocampus, and fornix revealed larger volumes of the right hemisphere structures (p < 0.001). Normalized fornix volumes revealed atrophy in 86% of studies concordant with hippocampal atrophy in all cases but one. Similarly, the mean hippocampal and fornix volumes for the group discriminated the epileptogenic temporal lobe (p < 0.001). Limbic volumes were normal in all patients with extratemporal lobe epilepsy.


CONCLUSIONS
Quantitative MRI findings support the concept that MTLE is not a process limited to the hippocampus but also involves other interrelated limbic system structures, in particular, the fornix.
Kuzniecky
R
R
Department of Neurology, University of Alabama at Birmingham, USA.
Bilir
E
E
Gilliam
F
F
Faught
E
E
Martin
R
R
Hugg
J
J
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001284:Atrophy / Q000473:pathology; D004833:Epilepsy, Temporal Lobe / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male