title: Investigation of hippocampal substructures in focal temporal lobe epilepsy with and without hippocampal sclerosis at 7T.
abstract: To provide a more detailed investigation of hippocampal subfields using 7T magnetic resonance imaging (MRI) for the identification of hippocampal sclerosis in temporal lobe epilepsy (TLE).
  
  
  
  Patients (n = 13) with drug-resistant TLE previously identified by conventional imaging as having hippocampal sclerosis (HS) or not (nine without HS, four HS) and 20 age-matched healthy controls were scanned and compared using a 7T MRI protocol. Using a manual segmentation scheme to delineate hippocampal subfields, subfield-specific volume changes and apparent transverse relaxation rate ( R2*) were studied between the two groups. In addition, qualitative assessment at 7T and clinical outcomes were correlated with measured subfield changes.
  
  
  
  Volumetry of the hippocampus at 7T in HS patients revealed significant ipsilateral subfield atrophy in CA1 (P = 0.001) and CA4+DG (P < 0.001). Volumetry also uncovered subfield atrophy in 33% of patients without HS, which had not been detected using conventional imaging. R2* was significantly lower in the CA4+DG subfields (P = 0.001) and the whole hippocampus (P = 0.029) of HS patients compared to controls but not significantly lower than the group without HS (P = 0.077, P = 0.109). No correlation was found between quantitative volumetry and qualitative assessment as well as surgical outcomes (Sub, P = 0.495, P = 0.567, P = 0.528; CA1, P = 0.104 ± 0.171, P = 0.273, P = 0.554; CA2+CA3, P = 0.517, P = 0.952, P = 0.130 ± 0.256; CA4+DG, P = 0.052 ± 0.173, P = 0.212, P = 0.124 ± 0.204; WholeHipp, P = 0.187, P = 0.132 ± 0.197, P = 0.628).
  
  
  
  These preliminary findings indicate that hippocampal subfield volumetry assessed at 7T is capable of identifying characteristic patterns of hippocampal atrophy in HS patients; however, difficulty remains in using imaging to identify hippocampal pathologies in cases without HS.
  
  
  
  2 J. MAGN. RESON. IMAGING 2017;45:1359-1370.
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.
authors: Brendan G
authors: BG
authors: Santyr
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Maged
authors: M
authors: Goubran
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: Jonathan C
authors: JC
authors: Lau
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Benjamin Y M
authors: BYM
authors: Kwan
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Fateme
authors: F
authors: Salehi
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Donald H
authors: DH
authors: Lee
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: Seyed M
authors: SM
authors: Mirsattari
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: Jorge G
authors: JG
authors: Burneo
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: David A
authors: DA
authors: Steven
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: Andrew G
authors: AG
authors: Parrent
authors: Department of Clinical Neurological Sciences - London Health Sciences Centre, London, Ontario, Canada.
authors: Sandrine
authors: S
authors: de Ribaupierre
authors: Department of Pathology and Laboratory Medicine - London Health Sciences Centre, London, Ontario, Canada.
authors: Robert R
authors: RR
authors: Hammond
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Terry M
authors: TM
authors: Peters
authors: Schulich School of Medicine and Dentistry - Western University, London, Ontario, Canada.|Departments of Medical Biophysics and Medical Imaging - Western University, London, Ontario, Canada.
authors: Ali R
authors: 0000-0002-0760-8647
authors: AR
authors: Khan
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D016022:Case-Control Studies; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012598:Sclerosis; D016896:Treatment Outcome; D055815:Young Adult
keywords: hippocampal subfields; temporal lobe epilepsy; ultrahigh-field MR; volumetry