title: Knee cartilage thickness measurements using MRI: a 4(1/2)-month longitudinal study in the meniscectomized guinea pig model of OA.
abstract: OBJECTIVE
  The aim of this study was to follow, over a 4(1/2)-month period, the medial tibia cartilage thickness on a meniscectomy (MNX) guinea pig osteoarthritis (OA) model and to compare with control animals, using three-dimensional high-resolution magnetic resonance imaging (3D HR-MRI).
  
  
  METHODS
  MRI experimentations were performed in vivo at 7 T on guinea pig knee joints. 3D HR-MR images were acquired in 60 controls (SHAM) and 45 osteoarthritic animals (MNX) at four time-points (15, 45, 90 and 135 days) after surgery. Medial tibial cartilage thickness was measured from MRI images using in-house dedicated 3D software followed by a statistical analysis. At each time-point 15 SHAM and 15 MNX animals were sacrificed for histomorphometric assessments.
  
  
  RESULTS
  No significant difference of mean cartilage thickness between the groups was found at early stage (D45) using MRI; however, significant differences were found between the groups at D90 (P<0.001) and D135 (P<0.001). Histomorphometry data confirmed the pathological status of the animals and was well correlated with MRI at D15 (r=0.79, P<0.01), D45 (r=0.67, P<0.01), and D135 (r=0.39, P<0.05) for SHAM, and at D45 (r=0.63, P<0.01), and D135 (r=0.81, P<0.01) for MNX.
  
  
  CONCLUSIONS
  Medial tibial cartilage measurement based on HR-MR images enables the monitoring of longitudinal cartilage thickness changes. This technique showed significant differences between SHAM and MNX as from D90 after surgery. It could be used as a noninvasive and reproducible tool to monitor therapeutic response in this OA model.
authors.affiliation: Plate-forme ANIMAGE, Université Claude Bernard Lyon I, Rhône-Alpes Genopole, Lyon, France.
authors.forename: R
authors.initials: R
authors.lastname: Bolbos
authors.forename: H
authors.initials: H
authors.lastname: Benoit-Cattin
authors.forename: J-B
authors.initials: JB
authors.lastname: Langlois
authors.forename: A
authors.initials: A
authors.lastname: Chomel
authors.forename: E
authors.initials: E
authors.lastname: Chereul
authors.forename: C
authors.initials: C
authors.lastname: Odet
authors.forename: P
authors.initials: P
authors.lastname: Pastoureau
authors.forename: M
authors.initials: M
authors.lastname: Janier
authors.forename: O
authors.initials: O
authors.lastname: Beuf
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology / Q000648:ultrastructure*; D004195:Disease Models, Animal; D006168:Guinea Pigs; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008592:Menisci, Tibial / Q000473:pathology / Q000648:ultrastructure*; D010003:Osteoarthritis / Q000473:pathology*