Table 1 Baseline patient characteristics and descriptive statistics of Berlin and CA scores of the 25 patients evaluated in the study

 Characteristic

Patients (n = 25)

  Age at inclusion in years, mean (SD)

31.7 (8.3)

  Male, n (%)

12 (48)

  Duration of back pain in months, mean (SD)

14.4 (8.0)

  BP, n (%)

19 (76)

  HLA-B27 positivity, n (%)

15 (60)

  Elevated CRP, n (%)

6 (24)

  Sacroiliitis on MRI (ASAS definition), n (%)

8 (32)

  Sacroiliitis on radiograph, n (%)

3 (12)

  Positive MRI (ASAS definition), n (%)

2 (8)

  ASAS classification positive, n (%)

14 (56)

 Variable

Berlin method

(reader 1/reader 2)

CA method

(reader 1/reader 2)

  VU-level score at baseline, median (range)

0 (0, 1) / 0 (0, 1)

NA

  VU-level score at follow-up, median (range)

0 (0, 1) / 0 (0, 1)

NA

  Patient-level score at baseline, median (range)

0 (0, 5) / 0 (0, 3)

NA

  Patient-level score at follow-up, median (range)

1 (0, 5) / 0 (0, 4)

NA

  Change in VU-level score, median (range)

0 (−1, 1) / 0 (−1, 1)

0 (−1, 2) / 0 (−2, 2)

  Change in patient-level score, median (range)

0 (−2, 3) / 0 (−1, 2)

0 (−3, 3) / 0 (−11, 5)