Frequency of Arthritis-Like MRI Findings in the Forefeet of Healthy Volunteers Versus Patients With Symptomatic Rheumatoid Arthritis or Psoriatic Arthritis.

OBJECTIVE: The objective of the present study is to evaluate arthritis-like findings on MRI studies of the forefeet of healthy volunteers versus patients with symptomatic rheumatoid arthritis (RA) or psoriatic arthritis (PsA). MATERIALS AND METHODS: Two observers analyzed MR images of the forefeet of 31 healthy volunteers, 30 patients with symptomatic RA, and 30 patients with symptomatic PsA, to identify MRI patterns of RA or PsA (e.g., bone marrow edema [BME], erosions, tenosynovitis, joint effusion, periarticular soft-tissue edema, or bony proliferations) on the basis of the Outcome Measures in Rheumatoid Arthritis Clinical Trial RA MRI scoring system and the PsA MRI scoring system. The Mann-Whitney test with Bonferroni correction was used for statistical analysis. RESULTS: Reader 1 found BME in 14 healthy volunteers (45%), whereas reader 2 found BME in 10 volunteers (32%). Tenosynovitis was observed by reader 1 in three healthy volunteers (10%). Joint effusion was found by reader 1 in seven healthy volunteers (23%) and by reader 2 in three volunteers (10%); the mean intensity grades for these findings were low (range, 1-1.33). Erosions, soft-tissue edema, and bony proliferations were not found in the forefeet of healthy volunteers. Reader 1 and reader 2 observed all arthritis-like features on the MR images of patients with RA. The percentages of patients with RA who had such MRI features, as identified by reader 1 and reader 2, respectively, were as follows: BME, 83% and 80%; erosions, 40% and 40%; tenosynovitis, 33% and 17%; effusion, 87% and 53%; soft-tissue edema, 20% and 27%; and bony proliferations, 3% and 3%. The percentages of patients with PsA who were found to have arthritis-like findings on MR images, as determined by reader 1 and reader 2, respectively, were as follows: BME, 70% and 67%; erosions, 20% and 20%; tenosynovitis, 57% and 50%; effusion, 70% and 37%; and soft-tissue edema, 60% and 53%. Bony proliferations were observed by reader 2 only in 7% of patients with PsA. The mean minimum intensity grade was 1 (for tenosynovitis in patients with RA, as observed by reader 2), whereas the maximum intensity grade was 2.53 (for erosions in patients with RA, as observed by reader 1). Tenosynovitis and soft-tissue edema were observed more frequently in patients with PsA than in patients with RA (p = 0.001-0.059). CONCLUSION: On the forefoot of healthy volunteers, mild BME is a common finding, and tenosynovitis and joint effusion are occasional findings. The frequency and intensity of arthritis-like findings on MRI are similar in patients with RA and PsA, with the exception of tenosynovitis and soft-tissue edema, which are more frequently observed in patients with PsA than in patients with RA.

Whole Body Magnetic Resonance Imaging Features in Diffuse Idiopathic Skeletal Hyperostosis in Conjunction with Clinical Variables to Whole Body MRI and Clinical Variables in Ankylosing Spondylitis.

OBJECTIVE: Discrimination of diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) can be challenging. Usefulness of whole-body magnetic resonance imaging (WB-MRI) in diagnosing spondyloarthritis has been recently proved. We assessed the value of clinical variables alone and in combination with WB-MRI to distinguish between DISH and AS. METHODS: Diagnostic case-control study: 33 patients with AS and 15 patients with DISH were included. All patients underwent 1.5 Tesla WB-MRI scanning. MR scans were read by a blinded radiologist using the Canadian-Danish Working Group's recommendation. Imaging and clinical variables were identified using the bootstrap. The most important variables from MR and clinical history were assessed in a multivariate fashion resulting in 3 diagnostic models (MRI, clinical, and combined). The discriminative capacity was quantified using the area under the receiver-operating characteristic (ROC) curve. The strength of diagnostic variables was quantified with OR. RESULTS: Forty-eight patients provided 1545 positive findings (193 DISH/1352 AS). The final MR model contained upper anterior corner fat infiltration (32 DISH/181 AS), ankylosis on the vertebral endplate (4 DISH/60 AS), facet joint ankylosis (4 DISH/49 AS), sacroiliac joint edema (11 DISH/91 AS), sacroiliac joint fat infiltration (2 DISH/114 AS), sacroiliac joint ankylosis (2 DISH/119 AS); area under the ROC curve was 0.71, 95% CI 0.64-0.78. The final clinical model contained patient's age and body mass index (area under the ROC curve 0.90, 95% CI 0.89-0.91). The full diagnostic model containing clinical and MR information had an area under the ROC curve of 0.93 (95% CI 0.92-0.95). CONCLUSION: WB-MRI features can contribute to the correct diagnosis after a thorough conventional workup of patients with DISH and AS.