title: Hippocampal volumes and diffusion-weighted image findings in children with prolonged febrile seizures.
abstract: OBJECTIVE
  To assess hippocampal volumes (HV) and signal changes on diffusion-weighted imaging (DWI) within 5 days of prolonged febrile seizures (PFS) and compare them with the PFS duration and EEG.
  
  
  METHODS
  We studied 12 children (mean age: 32 +/- 21 months, range 10 months-5 years) within 5 days of a first episode of PFS (a seizure or series of seizures lasting for 30 min or longer, without return of consciousness between the seizures). The HV measurements were carried out using high-resolution magnetic resonance imaging and signal intensity abnormalities were evaluated visually on DWI. HV in patients were compared with those of 13 neurologically normal controls (mean age 31 +/- 16 months, range 15 months-5 years). HV abnormalities correlated with PFS duration. HV and DWI abnormalities were compared with EEG abnormalities.
  
  
  RESULTS
  Seizure duration ranged from 40 to 95 min. In seven out of twelve patients, seizures were refractory and lasted for 60 min or longer despite intravenous infusion of diazepam. In the patients with PFS for 60 min or longer, HV were significantly larger than that of controls. In all patients, there was a positive correlation between HV and seizure duration. DWI showed hyperintensity in unilateral hippocampus in three patients with intractable seizures, ipsilateral thalamus in two, and cingulate in one. EEG showed abnormalities in temporal areas ipsilateral to the DWI abnormalities in these patients.
  
  
  CONCLUSIONS
  Large HV and hippocampal hyperintensity on DWI were seen in patients with refractory PFS. Our results suggest that medically refractory PFS lasting for 60 min or longer may cause structural changes in limbic structures that could promote later epileptogenesis.
authors.affiliation: Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan. junnatsu@med.nagoya-u.ac.jp
authors.forename: J
authors.initials: J
authors.lastname: Natsume
authors.forename: N
authors.initials: N
authors.lastname: Bernasconi
authors.forename: M
authors.initials: M
authors.lastname: Miyauchi
authors.forename: M
authors.initials: M
authors.lastname: Naiki
authors.forename: T
authors.initials: T
authors.lastname: Yokotsuka
authors.forename: A
authors.initials: A
authors.lastname: Sofue
authors.forename: A
authors.initials: A
authors.lastname: Bernasconi
mesh_terms: D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007223:Infant; D008297:Male; D003294:Seizures, Febrile / Q000473:pathology* / Q000503:physiopathology