title: Imaging of osteoarthritis: update from a radiological perspective.
abstract: OBJECTIVE
  Imaging plays an increasingly important role in the continuing effort to understand the pathogenesis of osteoarthritis and in the quest for disease-modifying osteoarthritis drugs. To assist investigators in choosing the appropriate imaging technique for a particular goal of a study, this review describes, from a radiological point of view, key studies that were published between May 2010 and May 2011.
  
  
  RESULTS
  MRI and ultrasound are the two key modalities for osteoarthritis research today. MRI offers semiquantitative, quantitative and compositional assessment. The importance of contrast-enhanced MRI for synovitis assessment has been demonstrated by several studies. Radiography still has a role in clinical trials in light of regulatory requirements, but investigators need to be aware of its inherent limitations. MRI is the best modality for imaging of osteoarthritis: its strengths and unique advantages include ability to visualize multiple individual tissue pathologies relating to pain and also to predict clinical outcome.
  
  
  CONCLUSIONS
  MRI enables multitissue morphologic and compositional assessment of the joint. Contrast-enhanced MRI is essential for evaluation of synovitis in knee osteoarthritis. Ultrasound is a useful technique for assessing synovitis and structural damage especially in hand osteoarthritis.
authors.affiliation: Quantitative Imaging Center, Department of Radiology, Boston University School of Medicine, Boston, Massachusetts 02118, USA. guermazi@bu.edu
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
authors.forename: Frank W
authors.initials: FW
authors.lastname: Roemer
authors.forename: Daichi
authors.initials: D
authors.lastname: Hayashi
mesh_terms: D001845:Bone Cysts / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D003952:Diagnostic Imaging / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging; D008592:Menisci, Tibial / Q000473:pathology; D010003:Osteoarthritis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011859:Radiography; D013585:Synovitis / Q000473:pathology; D014463:Ultrasonography