title: Multiparametric MRI of Epiphyseal Cartilage Necrosis (Osteochondrosis) with Histological Validation in a Goat Model.
abstract: OBJECTIVE
  To evaluate multiple MRI parameters in a surgical model of osteochondrosis (OC) in goats.
  
  
  METHODS
  Focal ischemic lesions of two different sizes were induced in the epiphyseal cartilage of the medial femoral condyles of goats at 4 days of age by surgical transection of cartilage canal blood vessels. Goats were euthanized and specimens harvested 3, 4, 5, 6, 9 and 10 weeks post-op. Ex vivo MRI scans were conducted at 9.4 Tesla for mapping the T1, T2, T1ρ, adiabatic T1ρ and TRAFF relaxation times of articular cartilage, unaffected epiphyseal cartilage, and epiphyseal cartilage within the area of the induced lesion. After MRI scans, safranin O staining was conducted to validate areas of ischemic necrosis induced in the medial femoral condyles of six goats, and to allow comparison of MRI findings with the semi-quantitative proteoglycan assessment in corresponding safranin O-stained histological sections.
  
  
  RESULTS
  All relaxation time constants differentiated normal epiphyseal cartilage from lesions of ischemic cartilage necrosis, and the histological staining results confirmed the proteoglycan (PG) loss in the areas of ischemia. In the scanned specimens, all of the measured relaxation time constants were higher in the articular than in the normal epiphyseal cartilage, consistently allowing differentiation between these two tissues.
  
  
  CONCLUSIONS
  Multiparametric MRI provided a sensitive approach to discriminate between necrotic and viable epiphyseal cartilage and between articular and epiphyseal cartilage, which may be useful for diagnosing and monitoring OC lesions and, potentially, for assessing effectiveness of treatment interventions.
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Luning
authors.initials: L
authors.lastname: Wang
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, United States of America; Research Group of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland; Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Nissi
authors.affiliation: Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States of America.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Tóth
authors.affiliation: Laboratory of Nanostructures and Biosensing, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Jonah
authors.initials: J
authors.lastname: Shaver
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Casey P
authors.initials: CP
authors.lastname: Johnson
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Jinjin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
authors.affiliation: Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States of America.
authors.forename: Cathy S
authors.initials: CS
authors.lastname: Carlson
authors.affiliation: Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States of America.
authors.forename: Jutta M
authors.initials: JM
authors.lastname: Ellermann
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006041:Goats; D006132:Growth Plate / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D009336:Necrosis; D055034:Osteochondrosis / Q000000981:diagnostic imaging*; D011859:Radiography