title: Imaging research results from the osteoarthritis initiative (OAI): a review and lessons learned 10 years after start of enrolment.
abstract: The Osteoarthritis Initiative (OAI) is a multicentre, prospective, observational, cohort study of knee osteoarthritis (OA) that began recruitment in 2004. The OAI provides public access to clinical and image data, enabling researchers to examine risk factors/predictors and the natural history of knee OA incidence and progression, and the qualification of imaging and other biomarkers. In this narrative review, we report imaging findings and lessons learned 10 years after enrolment has started. A literature search for full text articles published from the OAI was performed up to 31 December 2013 using Pubmed and the OAI web page. We summarise the rationale, design and imaging protocol of the OAI, and the history of OAI publications. We review studies from early partial, and later full OAI public data releases. The latter are structured by imaging method and tissue, reviewing radiography and then MRI findings on cartilage morphology, cartilage lesions and composition (T2), bone, meniscus, muscle and adipose tissue. Finally, analyses directly comparing findings from MRI and radiography are summarised. Ten years after the first participants were enrolled and first papers published, the OAI has become an invaluable resource to the OA research community. It has fuelled novel methodological approaches of analysing images, and has provided a wealth of information on OA pathophysiology. Continued collection and public release of long-term observations will help imaging measures to gain scientific and regulatory acceptance as 'prognostic' or 'efficacy of intervention' biomarkers, potentially enabling shorter and more efficient clinical trials that can test structure-modifying therapeutic interventions (NCT00080171).
authors.affiliation: Institute of Anatomy, Paracelsus Medical University, Salzburg, Austria Chondrometrics GmbH, Ainring, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Eckstein
authors.affiliation: Division of Rheumatology and University of Arizona Arthritis Center, University of Arizona, Tucson, Arizona, USA.
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
authors.affiliation: Department of Radiology and Biomedical Imaging, Musculoskeletal and Quantitative Imaging Research, UCSF, San Francisco, California, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
mesh_terms: D006801:Humans; D000273:Adipose Tissue / Q000000981:diagnostic imaging / Q000473:pathology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D015331:Cohort Studies; D018450:Disease Progression; D007717:Knee / Q000000981:diagnostic imaging / Q000473:pathology; D007719:Knee Joint / 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; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors; D064887:Observational Studies as Topic; D015337:Multicenter Studies as Topic
keywords: Knee Osteoarthritis; Magnetic Resonance Imaging; Osteoarthritis