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Table 7 Intra-observer agreements for MRI changes in the SIJ and global assessment

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

MRI changes

Observers

Observed agreement (%)

Expected agreement (%)

Weighted Kappa (95% CI)

Number of SIJ regions

BMO

AA

99.57

89.42

.96 (.92–.98)

384

BB

98.99

89.19

.91 (.85–.95)

384

  Intensity of BMO 1

AA

92.42

67.36

.77 (.58–.96)

66

BB

95.95

83.97

.75 (.47–1.00)

74

  Depth of BMO 1

AA

95.45

51.93

.91 (.80–1.00)

66

BB

91.89

55.84

.82 (.68–.96)

74

FMD

AA

99.33

85.49

.95 (.92–.97)

384

BB

98.06

82.15

.89 (.84–.93)

384

  Depth of FMD 1

AA

95.57

52.40

.80 (.64–.97)

53

BB

87.88

52.25

.75 (.58–.91)

66

Erosions

AA

98.61

93.52

.79 (.60–.92)

348

BB

99.02

91.96

.88 (.80–.93)

384

Subchondral sclerosis

AA

99.62

96.84

.88 (.71–.96)

384

BB

99.62

96.48

.89 (.77–.95)

384

Ankylosis

AA

-

-

-

-

BB

99.54

97.26

.83 (.52–.95)

384

Global assessment2

AA

98.37

84.61

.89 (.82–.95)

463

 

BB

95.79

80.20

.79 (.52–.93)

463

  1. SIJ: sacroiliac joints, BMO: Bone marrow oedema, FMD: fatty marrow deposition, - Too few positive ratings for one of the observers to be included in the analysis 1Only observations where the reader on both the readings agreed on the presence of BMO/FMD were kept in the analysis. 2Assessed on the entire MRI scan, not only the SIJ. 3Number of patients assessed.