title: Use of magnetic resonance imaging in detecting subclinical synovitis in rheumatoid arthritis and correlation of imaging findings with interleukin-18 levels.
abstract: OBJECTIVE
  We studied the usefulness of magnetic resonance imaging (MRI) in detecting subclinical inflammation in patients with asymptomatic RA and tested the hypothesis of interleukin (IL)-18 as a marker of disease activity.
  
  
  METHODS
  Thirteen RA patients with Disease Activity Score of 28 joints (DAS28) < 2.6 were evaluated. The patients underwent clinical evaluation, laboratory tests and MRI assessment. Imaging of bilateral hands and wrists was performed using validated acquisition and scoring techniques. Serum IL-18 levels were concurrently measured.
  
  
  RESULTS
  MRI assessments showed that 92.3% and 76.9% of patients had synovitis and bone marrow edema, respectively, despite being in clinical remission. Eight out of 12 patients (66.7%) had erosions on MRI which were not visualised on plain radiographs. Of all the 182 joints studied for synovitis on MRI, only one had clinical evidence of joint swelling. Comparison of the total sum scores of synovitis between the right and left hand and wrist joints of individual patients showed a significant difference between the two sides. Measurements of IL-18 indicated that a large proportion (54%) of the patients had undetectable or very low levels of the cytokine.
  
  
  CONCLUSIONS
  MRI is more sensitive in detecting erosions compared with X-rays, and is superior in its ability to detect subclinical inflammation in RA patients. Despite being in clinical remission, a large majority of patients had imaging-detected synovitis and bone marrow edema. Our study highlights the usefulness of MRI for the accurate evaluation of disease activity. In the utility of MRI, it may be important to assess bilateral hands and wrists, instead of limiting to the dominant side.
authors.affiliation: Department of Rheumatology and Immunology, Singapore General Hospital, Singapore.|Duke-NUS Graduate Medical School, Singapore.|Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Li-Ching
authors.initials: LC
authors.lastname: Chew
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore.|Department of Diagnostic Radiology, Singapore General Hospital, Singapore.
authors.forename: P
authors.initials: P
authors.lastname: Chandra Mohan
authors.affiliation: Department of Diagnostic Radiology, Singapore General Hospital, Singapore.
authors.forename: Lai Peng
authors.initials: LP
authors.lastname: Chan
authors.affiliation: Department of Rheumatology and Immunology, Singapore General Hospital, Singapore.|Duke-NUS Graduate Medical School, Singapore.|Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Kok Yong
authors.initials: KY
authors.lastname: Fong
authors.affiliation: Department of Rheumatology and Immunology, Singapore General Hospital, Singapore.|Duke-NUS Graduate Medical School, Singapore.|Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Julian
authors.initials: J
authors.lastname: Thumboo
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000000981:diagnostic imaging* / Q000628:therapy; D058070:Asymptomatic Diseases; D015415:Biomarkers / Q000097:blood; D001855:Bone Marrow Diseases / Q000097:blood / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D004487:Edema / Q000097:blood / Q000000981:diagnostic imaging; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D020382:Interleukin-18 / Q000097:blood*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012074:Remission Induction; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012846:Singapore; D013583:Synovial Membrane / Q000000981:diagnostic imaging*; D013585:Synovitis / Q000097:blood* / Q000000981:diagnostic imaging* / Q000628:therapy
chemical_list: D015415:Biomarkers; C000589760:IL18 protein, human; D018836:Inflammation Mediators; D020382:Interleukin-18
keywords: interleukin-18; magnetic resonance imaging; remission; rheumatoid arthritis; subclinical; synovitis