title: In vivo diagnostic imaging using micro-CT: sequential and comparative evaluation of rodent models for hepatic/brain ischemia and stroke.
abstract: BACKGROUND
  There is an increasing need for animal disease models for pathophysiological research and efficient drug screening. However, one of the technical barriers to the effective use of the models is the difficulty of non-invasive and sequential monitoring of the same animals. Micro-CT is a powerful tool for serial diagnostic imaging of animal models. However, soft tissue contrast resolution, particularly in the brain, is insufficient for detailed analysis, unlike the current applications of CT in the clinical arena. We address the soft tissue contrast resolution issue in this report.
  
  
  METHODS
  We performed contrast-enhanced CT (CECT) on mouse models of experimental cerebral infarction and hepatic ischemia. Pathological changes in each lesion were quantified for two weeks by measuring the lesion volume or the ratio of high attenuation area (%HAA), indicative of increased vascular permeability. We also compared brain images of stroke rats and ischemic mice acquired with micro-CT to those acquired with 11.7-T micro-MRI. Histopathological analysis was performed to confirm the diagnosis by CECT.
  
  
  RESULTS
  In the models of cerebral infarction, vascular permeability was increased from three days through one week after surgical initiation, which was also confirmed by Evans blue dye leakage. Measurement of volume and %HAA of the liver lesions demonstrated differences in the recovery process between mice with distinct genetic backgrounds. Comparison of CT and MR images acquired from the same stroke rats or ischemic mice indicated that accuracy of volumetric measurement, as well as spatial and contrast resolutions of CT images, was comparable to that obtained with MRI. The imaging results were also consistent with the histological data.
  
  
  CONCLUSIONS
  This study demonstrates that the CECT scanning method is useful in rodents for both quantitative and qualitative evaluations of pathologic lesions in tissues/organs including the brain, and is also suitable for longitudinal observation of the same animals.
authors.affiliation: Department of Anatomy and Neurobiology, Kinki University School of Medicine, Osaka-Sayama, Osaka, Japan. hayasaka@med.kindai.ac.jp
authors.forename: Naoto
authors.initials: N
authors.lastname: Hayasaka
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nagai
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kawao
authors.forename: Atsuko
authors.initials: A
authors.lastname: Niwa
authors.forename: Yoshichika
authors.initials: Y
authors.lastname: Yoshioka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shigeta
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kashiwagi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Miyazawa
authors.forename: Takao
authors.initials: T
authors.lastname: Satou
authors.forename: Hideaki
authors.initials: H
authors.lastname: Higashino
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsuo
authors.forename: Takamichi
authors.initials: T
authors.lastname: Murakami
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D003287:Contrast Media / Q000494:pharmacology; D004195:Disease Models, Animal; D020343:Hypertensive Encephalopathy; D007511:Ischemia / Q000473:pathology*; D008099:Liver / Q000473:pathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010539:Permeability; D051381:Rats; D020521:Stroke / Q000473:pathology*; D013997:Time Factors; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003287:Contrast Media