Regional neocortical thinning in mesial temporal lobe epilepsy.
OBJECTIVE
To determine the nature and extent of regional cortical thinning in patients with mesial temporal lobe epilepsy (MTLE).


METHODS
High-resolution volumetric MRIs were obtained on 21 patients with MTLE and 21 controls. Mean cortical thickness was measured within regions of interest and point-by-point across the neocortex using cortical reconstruction and parcellation software.


RESULTS
Bilateral thinning was observed within frontal and lateral temporal regions in MTLE patients relative to controls. The most striking finding was bilateral cortical thinning in the precentral gyrus and immediately adjacent paracentral region and pars opercularis of the inferior frontal gyrus, extending to the orbital region. Within the temporal lobe, bilateral thinning was observed in Heschl's gyrus only. Ipsilateral only thinning was observed in the superior and middle temporal gyri, as well as in the medial orbital cortex. Greater asymmetries in cortical thickness were observed in medial temporal cortex in patients relative to controls. Individual subject analyses revealed that this asymmetry reflected significant ipsilateral thinning of medial temporal cortex in 33% of patients, whereas it reflected ipsilateral thickening in 20% of MTLEs.


CONCLUSIONS
Patients with MTLE show widespread, bilateral pathology in neocortical regions that is not appreciated on standard imaging. Future studies are needed that elucidate the clinical implications of neocortical thinning in MTLE.
McDonald
Carrie R
CR
Department of Psychiatry, and Multimodal Imaging Laboratory, University of California, San Diego, CA 92093-0841, USA. camcdonald@ucsd.edu
Hagler
Donald J
DJ
Ahmadi
Mazyar E
ME
Tecoma
Evelyn
E
Iragui
Vicente
V
Gharapetian
Lusineh
L
Dale
Anders M
AM
Halgren
Eric
E
D000328:Adult; D001284:Atrophy / Q000473:pathology; D001931:Brain Mapping; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D005260:Female; D005625:Frontal Lobe / Q000473:pathology; D007839:Functional Laterality / Q000502:physiology; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000473:pathology*; D011300:Preoperative Care; D012598:Sclerosis / Q000473:pathology; D013702:Temporal Lobe / Q000473:pathology