title: High resolution micro arthrography of hard and soft tissues in a murine model.
abstract: OBJECTIVE
  Recent developments on high resolution micro computed tomography (μCT) allow imaging of soft tissues in small animal joints. Nevertheless, μCT images cannot distinguish soft tissues from synovial fluid due to their similar mass density, limiting the 3D assessment of soft tissues volume and thickness. This study aimed to evaluate a lead chromate contrast agent for μCΤ arthrography of rat knee joints ex vivo.
  
  
  METHODS
  Intact tibiofemoral rat joints were injected with the contrast agent at different concentrations and imaged using a μCT at 2.7 μm isotropic voxel size. Cartilage thickness was measured using an automated procedure, validated against histological measurements, and analyzed as a function of μCT image resolution. Changes in hard and soft tissues were also analyzed in tibiofemoral joints 4 weeks after surgical destabilization of the medial meniscus (DMM).
  
  
  RESULTS
  The contrast agent diffused well throughout the whole knee cavity without penetrating the tissues, therefore providing high contrast at the boundaries between soft tissues and synovial fluid space. Thickness analysis of cartilage demonstrated a high similarity between histology and μ-arthrography approaches (R(2) = 0.90). Four weeks after surgical DMM, the development of osteophytes (Oph) and cartilage ulcerations was recognizable with μCT, as well as a slight increase in trabecular bone porosity, and decrease in trabecular thickness.
  
  
  CONCLUSIONS
  A lead chromate-based contrast agent allowed discriminating the synovial fluid from soft tissues of intact knee joints, and thus made possible both qualitative and quantitative assessment of hard and soft tissues in both intact and DMM tibiofemoral joints using high resolution μCT.
authors.affiliation: Department of Biomedical Engineering, The City College of New York of The City University of New York, NY 10013, USA.
authors.forename: X I
authors.initials: XI
authors.lastname: Gu
authors.forename: P E
authors.initials: PE
authors.lastname: Palacio-Mancheno
authors.forename: D J
authors.initials: DJ
authors.lastname: Leong
authors.forename: Y A
authors.initials: YA
authors.lastname: Borisov
authors.forename: E
authors.initials: E
authors.lastname: Williams
authors.forename: N
authors.initials: N
authors.lastname: Maldonado
authors.forename: D
authors.initials: D
authors.lastname: Laudier
authors.forename: R J
authors.initials: RJ
authors.lastname: Majeska
authors.forename: M B
authors.initials: MB
authors.lastname: Schaffler
authors.forename: H B
authors.initials: HB
authors.lastname: Sun
authors.forename: L
authors.initials: L
authors.lastname: Cardoso
mesh_terms: D000818:Animals; D001175:Arthrography / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology; D002840:Chromates; D003287:Contrast Media; D005260:Female; D006614:Hindlimb / Q000000981:diagnostic imaging* / Q000473:pathology; D007854:Lead; D008592:Menisci, Tibial / Q000000981:diagnostic imaging; D054850:Osteophyte / Q000000981:diagnostic imaging; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002840:Chromates; D003287:Contrast Media; D007854:Lead; C031895:lead chromate