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Table 4 Inter-observer agreements for spinal MRI changes

From: Spondyloarthritis-related and degenerative MRI changes in the axial skeleton - an inter- and intra-observer agreement study

  Observers Observed agreement (%) Expected agreement (%) Pairwise weighted Kappa (95% CI) Number of levels1
Type of signal change AB 95.70 88.65 .62 (.56–.68) 2208
AC 96.38 91.13 .59 (.51–.66) 2208
BC 95.70 89.73 .58 (.51–.65) 2208
Combined    .60 (.55–.65) 2208
  Signal change in the corner 2 AB 83.51 56.32 .62 (.46–.79) 97
AC 80.00 61.22 .48 (.28–.69) 70
BC 72.15 64.01 .23 (.00–.46) 79
Combined3    .53 (.42–.64) 114
  Location of signal change 2 AB 92.78 42.56 .87 (.78–.95) 97
AC 97.14 45.31 .95 (.86–1.00) 70
BC 94.94 46.37 .91 (.79–.98) 79
Combined    .90 (.83–.96) 66
  Size of signal change 2 AB 91.49 75.74 .65 (.45–.80) 97
AC 93.57 74.92 .74 (.54–.89) 70
BC 97.61 90.05 .76 (.64–.86) 79
Combined3    .66 (.58–.75) 114
Total size of BMO in the DVU AB 99.41 98.71 .54 (.32–.74) 1104
AC 99.23 99.07 .16 (.06–.33) 1104
BC 99.62 99.40 .43 (.24–.63) 1104
Combined3    .38 (.34–.41) 1104
Total size of FMD in the DVU AB 99.09 98.12 .52 (.36–.66) 1104
AC 99.25 98.27 .57 (.41–.72) 1104
BC 99.12 98.31 .47 (.32–.63) 1104
Combined3    .52 (.49–.56) 1104
Total size of mixed lesions in the DVU AB 99.39 98.99 .39 (.12–.65) 1104
AC 99.50 99.42 .13 (.00–.36) 1104
BC 99.59 99.19 .49 (.22–.74) 1104
Combined3    .36 (.32–.40) 1104
Erosions AB - - - -
AC - - - -
BC 99.83 99.72 .40 (.17–.56) 2208
Combined3     -
Syndesmophytes or vertebral fusion AB 99.71 99.17 .65 (0.00–.91) 1104
AC - - - -
BC - - - -
Combined3    - -
BMO at the apophyseal joint AB - - - -
AC 99.55 98.83 .61 (.30–.93) 1104
BC - - - -
Combined3    - -
Disc degeneration AB 98.61 94.73 .74 (.67–.79) 1104
AC 98.91 94.98 .78 (.72– .84) 1104
BC 98.97 95.61 .77 (.70–.82) 1104
Combined3    .76 (.74–.78) 1104
Disc contour AB 98.55 95.17 .70 (.63–.76) 1104
AC 98.44 94.29 .73 (.65–.79) 1104
BC 97.36 91.96 .67 (.60–.74) 1104
Combined3    .70 (.68–.73) 1104
Herniation in the vertebral endplate AB 98.73 96.27 .66 (.49–.83) 1104
AC 98.10 97.40 .27 (.06–.48) 1104
BC 98.28 97.75 .23 (.01–.46) 1104
Combined3    .43 (.40–.47) 1104
Scheurmann’s changes AB 98.46 98.47 -.01 (-.01–0.00) 1104
AC 98.92 97.58 .14 (-.05–.32) 1104
BC 98.55 98.20 .20 (-.04–.43) 1104
  Combined3    .12 (.08–.15) 1104
  1. BMO; Bone marrow oedema, DVU; Discovertebral unit, FMD; Fatty marrow deposition, - Too few positive ratings for one of the observers to be included in the analysis 1Discovertebral units or vertebral endplates. 2Only observations where both readers agreed on the presence of a signal change were included in the analyses. 3Intraclass correlation coefficient.