title: Imaging of non-osteochondral tissues in osteoarthritis.
abstract: OBJECTIVE
  The aim of this review is to describe imaging techniques for evaluation of non-osteochondral structures such as the synovium, menisci in the knee, labrum in the hip, ligaments and muscles and to review the literature from recent clinical and epidemiological studies of OA.
  
  
  METHODS
  This is a non-systematic narrative review of published literature on imaging of non-osteochondral tissues in OA. PubMed and MEDLINE search for articles published up to 2014, using the keywords osteoarthritis, synovitis, meniscus, labrum, ligaments, plica, muscles, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), scintigraphy, and positron emission tomography (PET).
  
  
  RESULTS
  Published literature showed imaging of non-osteochondral tissues in OA relies primarily on MRI and ultrasound. The use of semiquantitative and quantitative imaging biomarkers of non-osteochondral tissues in clinical and epidemiological OA studies is reported. We highlight studies that have compared both imaging methodologies directly, and those that have established a relationship between imaging biomarkers and clinical outcomes. We provide recommendations as to which imaging protocols should be used to assess disease-specific changes regarding synovium, meniscus in the knee, labrum in the hip, and ligaments, and highlight potential pitfalls in their usage.
  
  
  CONCLUSIONS
  MRI and ultrasound are currently the most useful imaging modalities for evaluation of non-osteochondral tissues in OA. MRI evaluation of any tissue needs to be performed using appropriate MR pulse sequences. Ultrasound may be particularly useful for evaluation of small joints of the hand. Nuclear medicine and CT play a limited role in imaging of non-osteochondral tissues in OA.
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston, MA, USA. Electronic address: guermazi@bu.edu.
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston, MA, USA; Department of Radiology, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: F W
authors.initials: FW
authors.lastname: Roemer
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston, MA, USA; Department of Radiology, Hospital do CoraÇão (HCor) and Teleimagem, São Paulo, SP, Brazil.
authors.forename: M D
authors.initials: MD
authors.lastname: Crema
authors.affiliation: Department of Orthopedics, Clinical Sciences Lund, Lund University, Lund, Sweden; Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, Boston, MA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Englund
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston, MA, USA; Department of Radiology, Bridgeport Hospital, Yale University School of Medicine, Bridgeport, CT, USA.
authors.forename: D
authors.initials: D
authors.lastname: Hayashi
mesh_terms: D006801:Humans; D003952:Diagnostic Imaging / Q000379:methods; D008022:Ligaments / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008592:Menisci, Tibial / Q000000981:diagnostic imaging / Q000473:pathology; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology; D015207:Osteoarthritis, Hip / Q000175:diagnosis; D020370:Osteoarthritis, Knee / Q000175:diagnosis; D049268:Positron-Emission Tomography; D011877:Radionuclide Imaging; D013583:Synovial Membrane / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
keywords: Ligaments; MRI; Meniscus; Osteoarthritis; Synovitis; Ultrasound