Table 2

Imaging findings in MRI and radiograph of the SIJ and spine in the entire population, population 1, population 2, patients with confirmed PsA and patients with axial symptoms

VariableAll
n=93
Population 1
n=41
Population 2
n=52
PsA
n=63
Axial symptoms
n=76
SIJ MRI
 Sacroiliitis-ASAS6 (6.5%)6 (14.6%)06 (9.53%)5 (6.6%)
 Sacroiliitis-radiologist9 (9.7%)7 (17.1%)2 (3.9%)7 (11.1%)6 (7.9%)
Spine MRI
 Spondylitis-ASAS4 (4.3%)3 (7.3%)1 (1.9%)3 (4.8%)3 (3.9%)
 Spondylitis-radiologist4 (4.3%)3 (7.3%)1 (1.9%)3 (4.8%)3 (3.9%)
 Spondylitis without sacroiliitis3 (3.2%)2 (4.9%)1 (1.9%)2 (3.2%)2 (2.6%)
MRI-SpA
 ASAS-MRI-SpA9 (9.7%)8 (19.5%)1 (1.9%)8 (12.7%)7 (9.2%)
 Radiologist-MRI-SpA12 (12.9%)9 (22%)3 (5.8%)9 (14.3%)8 (10.5%)
Radiographic assessment
 Sacroiliitis (mNYC)13 (14%)6 (14.6%)7 (13.5%)12 (18.5%)12 (15.8%)
 Syndesmophytes9 (10%)7 (18.4%)2 (3.9%)9 (15%)7 (9.3%)
 RAD (sacroiliitis and/or spondylitis)18 (19.4%)11 (26.8%)7 (13.5%)17 (26.2%)15 (19.7%)
  • ASAS-MRI-SpA: sacroiliitis and/or spondylitis according to ASAS (sacroiliitis: presence of two or more inflammatory lesions (subchondral bone marrow oedema) on one slice or at least two inflammatory lesions in two consecutive slices; spondylitis: presence of anterior/posterior spondylitis (corner-based bone marrow oedema) in three or more sites). Radiologist-MRI-SpA sacroiliitis and/or spondylitis according to radiologist impression (taking into account inflammatory and structural lesions).

  • MRI-SpA: sacroiliitis and/or spondylitis according to ASAS or radiologist criteria.

  • mNYC for ankylosing spondylitis.

  • ASAS, Assessment of Spondyloarthritis International Society; mNYC, modified New York criteria; RAD, radiographic axial disease; SIJ, sacroiliac joint; SpA, spondyloarthritis.