Ischemic stroke is the most common type of stroke in humans. The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI) in a canine model of stroke. Ischemic stroke was induced by using prepared autologous thrombus. The dogs were placed in lateral recumbency on the operation table and the cervical area of each dog was sterilized by using alcohol. After making a cervical incision, the common carotid artery and internal carotid artery (a branch of the common carotid artery that supplies an anterior part of the brain) were exposed. A 200 μL injection of the autologous thrombus prepared 24 hr prior to surgery was delivered with a 20 gauge venous catheter through an internal carotid artery. After successful delivery of the autologous thrombus, the venous catheter was removed, and the cervical incision was sutured. Neurologic signs including generalized seizures, tetraparesis, and altered mental status, were observed in all 3 dogs after induction of ischemic stroke and the signs manifested immediately after awakening from anesthesia. T1- and T2-weighted images and fluid-attenuated inversion recovery (FLAIR) images of the brain were acquired 1 day before and 1 day after surgery. On the day following ischemic stroke induction, MRI revealed multifocal lesions in the cerebral cortex and subcortex such as T1 hypointensity, T2 hyperintensity, FLAIR hyperintensity, and diffusion-weighted hyperintensity in all 3 dogs. Upon postmortem examination, ischemic lesions were found to be consistent with the MRI findings and they were unstained with 2% triphenyltetrazolium chloride. Histologic features of the earliest neuronal changes such as cytoplasmic eosinophilia with pyknotic nuclei were identified. Neuropil spongiosis and perivascular cuffing were also prominently observed at the infarcted area. The present study demonstrated the features of MRI and histopathologic findings in canine ischemic stroke models.

Introduction
 Materials and Methods
  Animals
  Autologous thrombus preparation
  Animal preparation, monitoring, and surgical procedure
  Magnetic resonance imaging analysis
  Staining with 2,3,5-triphenyltetrazolium chloride and histopathologic examination
 Results
  Postsurgical management and observed neurologic signs
  Magnetic resonance imaging findings
  Staining with 2,3,5-triphenyltetrazolium chloride and histopathologic examination
 Discussion
 Acknowledgements
 References

• Joon-Hyeok Jeon(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University)
• Hae-Won Jung(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University)
• Hee-Chun Lee(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University)
• Byeong-Teck Kang(Laboratory of Veterinary Dermatology and Neurology, College of Veterinary Medicine, Chungbuk National University)
• Jung-Hyang Sur(Department of Pathobiology, Small Animal Tumor Diagnostic Center, College of Veterinary Medicine, Konkuk University)
• Dong-In Jung(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University) Corresponding author