title: High-resolution MRI and micro-CT in an ex vivo rabbit anterior cruciate ligament transection model of osteoarthritis.
abstract: OBJECTIVE
  The aim of this study was to investigate the potential of using non-invasive, multi-modality imaging techniques to quantify disease progression in a rabbit model of experimentally induced osteoarthritis (OA).
  
  
  METHODS
  High-resolution 4-T magnetic resonance imaging (MRI) and micro-computed tomography (micro-CT) techniques were implemented and validated in an ex vivo rabbit anterior cruciate ligament transection (ACLT) model of OA. A three-dimensional (3-D) rigid body registration technique was executed and evaluated to allow combined MR-CT analysis in co-registered image volumes of the knee.
  
  
  RESULTS
  The 3-D MRI and micro-CT data formats made it possible to quantify cartilage damage, joint-space, and osseous changes in the rabbit ACLT model of OA. Spoiled gradient-recalled echo and fast-spin echo (FSE) sequences were jointly used to evaluate femorotibial cartilage and determine the sensitivity (78.3%) and specificity (95.3%) of 4-T MRI to detect clinically significant cartilage lesions. Overall precision error of the micro-CT technique for analysis of joint-space, volumetric bone mineral density (vBMD), and bone volume fraction (BV/TV) was 1.8%, 1.2%, and 2.0%, respectively. Co-registration of the 3-D data sets was achieved to within 0.36 mm for completed intermodality registrations, 0.22 mm for extrapolated intramodality registrations, and 0.50mm for extrapolated intermodality registrations.
  
  
  CONCLUSIONS
  These results indicate that high-resolution 4-T MRI and micro-CT can be used to accurately quantify cartilage damage and calcified tissue changes in the rabbit ACLT model of OA. In addition, image volumes can be successfully co-registered to facilitate a comprehensive multi-modality examination of localized changes in both soft tissue and bone within the rabbit femorotibial joint.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, P.O. Box 5015, 100 Perth Drive, London, Ontario, Canada N6A 5K8.
authors.forename: Danika L
authors.initials: DL
authors.lastname: Batiste
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kirkley
authors.forename: Sheila
authors.initials: S
authors.lastname: Laverty
authors.forename: Lisa M F
authors.initials: LM
authors.lastname: Thain
authors.forename: Alison R
authors.initials: AR
authors.lastname: Spouge
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Gati
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Foster
authors.forename: David W
authors.initials: DW
authors.lastname: Holdsworth
mesh_terms: D000818:Animals; D000070598:Anterior Cruciate Ligament Injuries; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D015519:Bone Density; D004195:Disease Models, Animal; D018450:Disease Progression; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*; D011817:Rabbits; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods