title: Topographical variations in zonal properties of canine tibial articular cartilage due to early osteoarthritis: a study using 7-T magnetic resonance imaging at microscopic resolution.
abstract: OBJECTIVE
  Our aim was to determine topographical variations in zonal properties of articular cartilage over the medial tibia in an experimental osteoarthritis (OA) model using 7-T magnetic resonance imaging (MRI).
  
  
  METHODS
  An anterior cruciate ligament (ACL)-transection canine model was subjected to study at 8 (six) and 12 (seven) weeks after the surgery. Each medial tibia was divided into five topographical locations. For each specimen, T2 relaxation (at 0° and 55°) was quantified at microscopic resolution. The imaging data grouped the five locations into two topographical areas (meniscus-covered and -uncovered).
  
  
  RESULTS
  The T2 (55°) bulk values from the meniscus-covered area were significantly lower than those from the uncovered area. The total cartilage thicknesses on the meniscus-covered area were significantly thinner than those on the meniscus-uncovered area. Significant differences in the T2 (0°) values were observed in most thicknesses of the four subtissue zones and whole-tissue from the uncovered area, while the same significant changes were detected in the superficial zone from the meniscus-covered area.
  
  
  CONCLUSIONS
  By quantifying high-resolution imaging data both topographically and depth-dependently (zonal-wise), this study demonstrates that the rate of disease progression varies topographically over the medial tibia. Future correlation with OA pathology could lead to better detection of early OA.
authors.affiliation: Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI, 48309, USA.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI, 48309, USA.
authors.forename: Farid
authors.initials: F
authors.lastname: Badar
authors.affiliation: Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Matyas
authors.affiliation: Department of Mathematics and Statistics, Oakland University, Rochester, MI, 48309, USA.
authors.forename: Xianggui
authors.initials: X
authors.lastname: Qu
authors.affiliation: Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI, 48309, USA. xia@oakland.edu.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging; D000070598:Anterior Cruciate Ligament Injuries / Q000000981:diagnostic imaging; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging; D008297:Male; D010003:Osteoarthritis / Q000000981:diagnostic imaging*; D013977:Tibia / Q000000981:diagnostic imaging*
keywords: Anterior cruciate ligament; Cartilage; Microscopic MRI (µMRI); Osteoarthritis; T2 relaxation time