title: Diffusion-weighted imaging in kainic acid-induced complex partial status epilepticus in dogs.
abstract: OBJECTIVE
  To investigate diffusion-weighted imaging (DWI) in status epilepticus, a canine model of kainic acid (KA)-induced complex partial status epilepticus (CPSE) was produced. In order to validate its usefulness, MR imaging was carried out at various times following onset of CPSE followed by histopathology.
  
  
  METHODS
  Six normal dogs were used in this study. In each dog, a cannula was stereotactically inserted into the left amygdala. One week after surgery, all dogs were imaged at MRI. Pre-injection imaging consisted of T2 weighted (T2W) imaging, fluid attenuated inversion recovery (FLAIR), and DWI. Two weeks after surgery, five dogs received intraamygdaloid KA microinjections. One dog was used as a control. MRI was carried out at 3, 6, 12, 24 and 48 h after onset of CPSE. Animals were euthanized immediately after MRI for histopathological evaluation. The average of each apparent diffusion coefficient (ADC) in the regions of interest was calculated from each DWI.
  
  
  RESULTS
  At 3 and 6 h, DWI hyperintensity and low ADC were found in the injected amygdala, without any T2W and FLAIR imaging changes. At 12 and 24 h, all imaging showed hyperintensity with higher ADC in the amygdala and the hippocampus. At 48 h, all imaging techniques showed continued hyperintensity, but ADC showed a trend towards normalization. This increasing hyperintensity in DWIs were in agreement with the degree of histopathology during CPSE.
  
  
  CONCLUSIONS
  This study suggests that DWI is a useful imaging method for finding the epileptic focus or for examining potential epileptic brain damage in status epilepticus.
authors.affiliation: Department of Veterinary Radiology, Nippon Veterinary and Animal Science University, 1-7-1 Kyounanchou, Musashino-shi, 180-8602, Tokyo, Japan. dj-die@td5.so-net.ne.jp
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hasegawa
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Orima
authors.forename: Michio
authors.initials: M
authors.lastname: Fujita
authors.forename: Shinichirou
authors.initials: S
authors.lastname: Nakamura
authors.forename: Kimimasa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohkubo
authors.forename: Hironaka
authors.initials: H
authors.lastname: Igarashi
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Hashizume
mesh_terms: D000465:Algorithms; D000818:Animals; D004285:Dogs; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D007091:Image Processing, Computer-Assisted; D007608:Kainic Acid / Q000494:pharmacology*; D012640:Seizures / Q000139:chemically induced / Q000473:pathology; D013226:Status Epilepticus / Q000139:chemically induced / Q000473:pathology*; D013238:Stereotaxic Techniques; D013997:Time Factors
chemical_list: D018690:Excitatory Amino Acid Agonists; D007608:Kainic Acid