In vivo visualization using MRI T2mapping of induced osteochondrosis and osteochondritis dissecans lesions in goats undergoing controlled exercise.
In vivo visualization of subclinical osteochondrosis (OC) lesions, characterized by necrosis of epiphyseal growth cartilage, is necessary to clarify the pathogenesis of this disease. Hence, our objectives were to demonstrate induced necrosis of the epiphyseal cartilage in vivo using MRI and to monitor progression or resolution of resulting lesions. We also aimed to improve the goat model of OC by introducing controlled exercise. Vascular supply to the epiphyseal cartilage was surgically interrupted in four 5-day-old goats to induce ischemic cartilage necrosis in a medial femoral condyle. Starting 3 weeks postoperatively, goats underwent daily controlled exercise until euthanasia at 6, 10, 11 (n = 2) weeks postoperatively. T2maps of operated and control femora were obtained in vivo at 3 (n = 4), 6 (n = 4), 9 (n = 3), and 11 (n = 2) weeks postoperatively using a 3 T MR scanner. In vivo MRI findings were validated against MRI results obtained ex vivo at 9.4 T in three goats and compared to histological results in all goats. Surgical interruption of the vascular supply caused ischemic cartilage necrosis in three out of four goats. T2maps obtained in vivo at 3 T identified regions of increased relaxation time consistent with discrete areas of cartilage necrosis 3-11 weeks postoperatively and demonstrated delayed progression of the ossification front at 9 (n = 1) and 11 (n = 2) weeks postoperatively. In vivo MRI findings were confirmed by ex vivo MRI at 9.4 T and by histology. Identification of cartilage necrosis in clinical patients in the early stages of OC using T2maps may provide valuable insight into the pathogenesis of this condition. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:868-875, 2017.
Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 435 AnSci/VetMed, 1988 Fitch Avenue, St. Paul, Minnesota, 55108.
Ferenc
F
Tóth
Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, Minnesota.
Frédéric H
FH
David
Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, Minnesota.
Elizabeth
E
LaFond
Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota.
Luning
L
Wang
Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota.
Jutta M
JM
Ellermann
Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 435 AnSci/VetMed, 1988 Fitch Avenue, St. Paul, Minnesota, 55108.
Cathy S
CS
Carlson
D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D004195:Disease Models, Animal; D005269:Femur / Q000473:pathology; D006041:Goats; D006132:Growth Plate / Q000098:blood supply; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009336:Necrosis; D010008:Osteochondritis Dissecans / Q000000981:diagnostic imaging*; D055034:Osteochondrosis / Q000000981:diagnostic imaging*; D010805:Physical Conditioning, Animal
MRI; T2 map; cartilage necrosis; osteochondritis dissecans; osteochondrosis