title: Hippocampal sclerosis in temporal lobe epilepsy: findings at 7 T¹.
abstract: OBJECTIVE
  To determine if ultrahigh-field-strength magnetic resonance (MR) imaging can be used to detect subregional hippocampal alterations.
  
  
  METHODS
  Subjects provided written consent to participate in this prospective institutional review board-approved HIPAA-compliant study. T1- and T2-weighted 7-T brain MR images were acquired in 11 healthy subjects and eight patients with temporal lobe epilepsy (TLE). In all subjects, images were qualitatively examined for evidence of hippocampal atrophy, signal change, and malrotation with the Bernasconi definition, and digitations of the hippocampal heads were counted (agreement was measured with the κ statistic). Data were analyzed quantitatively with manual subregional hippocampal body segmentation. Subregional data in individual subjects with TLE were compared with data in control subjects to detect deviation from the control range for volume measures on each side and with asymmetry indexes.
  
  
  RESULTS
  All eight patients with TLE had hippocampal abnormalities on the epileptogenic side. Subregional analysis revealed selective lateral Ammon horn atrophy in six patients and diffuse Ammon horn and dentate gyrus atrophy in one patient. Paucity of hippocampal digitations occurred on the epileptogenic side in all patients with TLE and also on the contralateral side in three patients (interrater κ value, 0.80). Hippocampal malrotation was observed in three patients with TLE and four control subjects.
  
  
  CONCLUSIONS
  Ultrahigh-field-strength MR imaging permitted detection of selectively greater Ammon horn atrophy in patients with TLE and hippocampal sclerosis. Paucity of digitations is a deformity of the hippocampal head that was detected independent of hippocampal atrophy in patients with mesial TLE.
authors: Department of Neurology, University of Minnesota, Minneapolis, MN 55455, USA. trhenry@umn.edu
authors: Thomas R
authors: TR
authors: Henry
authors: Marie
authors: M
authors: Chupin
authors: Stéphane
authors: S
authors: Lehéricy
authors: John P
authors: JP
authors: Strupp
authors: Michael A
authors: MA
authors: Sikora
authors: Zhiyi Y
authors: ZY
authors: Sha
authors: Kâmil
authors: K
authors: Ugurbil
authors: Pierre-François
authors: PF
authors: Van de Moortele
mesh_terms: D000328:Adult; D004833:Epilepsy, Temporal Lobe / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012598:Sclerosis; D055815:Young Adult