Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
The ECHOSPA MRI Module for Diagnosis of Early Spondyloarthritis (SpA): Preliminary Validation and Assessment of Diagnostic Utility.
Maksymowych4, Walter P., Loeuille2, Damien, Desvignes-Engelbert2, Alexandra, Judet3, Olivia, Chary-Valckenaere2, Isabelle, Lambert4, Robert, Breban1, Maxime A.
MRI is now accepted as an imaging criterion for the classification of axial SpA but its diagnostic utility using conventional sequences in early pre-radiographic SpA requires further study. In particular, it is unclear which features on MRI of the sacroiliac joints (SIJ) have greatest diagnostic utility.
We developed an atlas of reference MRI images depicting the entire range of abnormalities observed in the SIJ. This included various patterns of bone marrow edema (linear, subchondral, capsular, posterior ligamentous, extra-articular, transitional vertebra), entheseal (capsulitis, ligamentary) and joint space inflammation, and structural lesions. These were incorporated into an online data entry module that displays schematics of the SIJ allowing the recording of lesions in each SIJ quadrant of each slice. Three readers blinded to patient and diagnosis, independently assessed MRI scans (T1-weighted (TIW), short tau inversion recovery (STIR), and post-gadolinium fat-saturated T1W sequences) from the following subjects: 24 patients with AS, 20 age and sex-matched patients with mechanical causes of low back pain (NSBP), and 20 patients followed in the French multi-center ECHOSPA pre-radiographic SpA prospective cohort, in which patients were included for symptoms suggestive of SpA (i.e. IBP, arthritis, enthesitis or dactylitis, B27+ uveitis and family history of SpA). Semi-coronal slices through the synovial portion of the SIJ were read systematically from anterior to posterior as described in a standardized online training module developed by the Spondyloarthritis Research Consortium of Canada (SPARCC). Readers answered the following question dichotomously (yes/no): This SIJ scan confirms the presence of SpA? Sensitivity, specificity were calculated according to clinical diagnosis and reliability of detection of individual lesions was assessed using intra-class correlation coefficient (ICC).
Sensitivity/specificity of MRI for the diagnosis of SpA in confirmed AS patients was 87.5/100, 95.8/80, and 83.3/83.3 for the 3 readers, respectively. The specific inflammatory lesions seen by all 3 readers in >30% of AS patients were capsular edema, ligamentous edema, and capsulitis, and each was reliably detected (k= 0.76, 0.70, and 0.85, respectively). Sensitivity of MRI for the diagnosis of SpA in the pre-radiographic cohort was 5%, 20%, and 55% for the 3 readers respectively. There was no significant difference between readers in the detection of either specific inflammatory lesions or in the mean number of SIJ quadrants with bone edema. However, reliability for detection of erosions (ICC = 0.65) was less than for edema (ICC = 0.75) and fat infiltration (ICC = 0.75). Moreover, the reader who had the highest sensitivity (55%) rated abnormalities on T1W MRI as contributory to the diagnosis of SpA in 72.7% of patients diagnosed with SpA as compared to only one patient by either of the two other readers.
Our data shows that although various inflammatory features on MRI can be reliably detected, further improvement in diagnostic utility of MRI for early SpA may depend on further training of readers to recognize structural lesions on T1W MRI.
To cite this abstract, please use the following information:
Maksymowych, Walter P., Loeuille, Damien, Desvignes-Engelbert, Alexandra, Judet, Olivia, Chary-Valckenaere, Isabelle, Lambert, Robert, et al; The ECHOSPA MRI Module for Diagnosis of Early Spondyloarthritis (SpA): Preliminary Validation and Assessment of Diagnostic Utility. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :551