Dr. Pedersen has received consultant fees, speaking fees, and/or honoraria (less than $10,000 each) from Abbott, MSD, and UCB.
Development and Validation of a Magnetic Resonance Imaging Reference Criterion for Defining a Positive Sacroiliac Joint Magnetic Resonance Imaging Finding in Spondyloarthritis
Article first published online: 30 MAY 2013
Copyright © 2013 by the American College of Rheumatology
Arthritis Care & Research
Volume 65, Issue 6, pages 977–985, June 2013
How to Cite
Weber, U., Zubler, V., Pedersen, S. J., Rufibach, K., Lambert, R. G. W., Chan, S. M., Østergaard, M. and Maksymowych, W. p. (2013), Development and Validation of a Magnetic Resonance Imaging Reference Criterion for Defining a Positive Sacroiliac Joint Magnetic Resonance Imaging Finding in Spondyloarthritis. Arthritis Care Res, 65: 977–985. doi: 10.1002/acr.21893
- Issue published online: 30 MAY 2013
- Article first published online: 30 MAY 2013
- Accepted manuscript online: 30 NOV 2012 12:00AM EST
- Manuscript Accepted: 23 OCT 2012
- Manuscript Received: 3 SEP 2012
- National Research Initiative Award from the Canadian Arthritis Society
- Alberta Innovates Health Solutions
- Walter L. and Johanna Wolf Foundation, Zurich, Switzerland
To validate a magnetic resonance imaging (MRI) reference criterion for a positive sacroiliac (SI) joint MRI finding based on the level of confidence in the classification of spondyloarthritis (SpA) by expert MRI readers.
Four readers assessed SI joint MRIs in 2 inception cohorts (cohorts A and B) of 157 consecutive patients with back pain ages ≤50 years and 20 age-matched healthy controls. Patients were classified according to clinical examination and pelvic radiography as having nonradiographic axial SpA (n = 51), ankylosing spondylitis (n = 34), or nonspecific back pain (n = 72). Readers indicated their level of confidence in their classification of SpA on a 0–10 scale, where 0 = definitely not SpA and 10 = definite SpA. The MRI reference criterion was prespecified by consensus as the majority of readers indicating a confidence score of 8–10; the absence of SpA required all readers to indicate non-SpA (a confidence score of 0–4). We calculated interreader reliability and agreement between MRI-based and clinical classification using kappa statistics. We estimated cutoff values for MRI lesions attaining a specificity of ≥0.90 for SpA.
In cohorts A and B, 76.4% and 71.6% of subjects met the MRI criterion, respectively. The kappa values for interreader agreement were 0.76 for cohort A and 0.80 for cohort B and between MRI-based and clinical assessment were 0.93 for cohort A and 0.57 for cohort B. Using this MRI reference criterion, the cutoff for the number of affected SI joint quadrants needed to reach a predefined specificity of ≥0.90 was ≥2 for bone marrow edema (BME) in both cohorts and ≥1 for erosion in both cohorts, and the BME and/or erosion lesions increased sensitivity without reducing specificity.
This data-driven study using 2 inception cohorts and comparing clinical and MRI-based classification supports the case for including both erosion and BME to define a positive SI joint MRI finding for the classification of axial SpA.