Degenerative findings in lumbar spine MRI: an inter-rater reliability study involving three raters

Doktor, Klaus; Jensen, Tue Secher; Christensen, Henrik Wulff; Fredberg, Ulrich; Kindt, Morten; Boyle, Eleanor; Hartvigsen, Jan

doi:10.1186/s12998-020-0297-0

Chiropractic & Manual Therapies

Table 3 Inter-rater reliability coefficients and percent agreement with probabilistic benchmarking to the Landis and Koch scale in classification of MRI-findings at disc level

From: Degenerative findings in lumbar spine MRI: an inter-rater reliability study involving three raters

Diagnostic finding N = 177 disc levels	Reliability Rater 1 vs. 2	Reliability Rater 1 vs. 3	Reliability Rater 2 vs. 3	All	Landis and Koch scale
	95% C.I.	95% C.I.	95% C.I.		Probabilistic benchmark
Spondylolisthesis
Conger’s K	0.24 [−0.16:0.64]	0.36 [−0.01:0.72]	0.36 [− 0.01:0.72]	0.33	Slight
Gwet’s AC₂	0.998 [0.997:1.000]	0.998 [0.996:0.999]	0.998 [0.996:0.999]	0.99	Almost perfect
%-agreement	0.998 [0.997:1.000]	0.998 [0.996:0.999]	0.998 [0.996:0.999]	0.99	Almost perfect
Disc degeneration
Conger’s K	0.60 [0.51:0.70]	0.67 [0.58:0.76]	0.76 [0.69:0.82]	0.68	Moderate
Gwet’s AC₂	0.90 [0.87:0.94]	0.89 [0.85:0.93]	0.91 [0.88:0.95]	0.90	Substantial
%-agreement	0.95 [0.93:0.96]	0.94 [0.93:0.96]	0.96 [0.95:0.97]	0.95	Substantial
Nerve compromise
Conger’s K	0.55 [0.38:0.71]	0.56 [0.39:0.72]	0.52 [0.34:0.70]	0.54	Fair
Gwet’s AC₂	0.96 [0.93:0.98]	0.93 [0.90:0.96]	0.92 [0.89:0.96]	0.93	Substantial
%-agreement	0.96 [0.95:0.98]	0.95 [0.93–0.97]	0.94 [0.92:0.97]	0.95	Substantial
Spinal stenosis
Conger’s K	0.19 [0.08:0.29]	0.33 [0.22:0.45]	0.43 [0.34:0.53]	0.33	Fair
Gwet’s AC₂	0.98 [0.97:0.98]	0.98 [0.98:0.99]	0.98 [0.97:0.98]	0.98	Almost perfect
%-agreement	0.98 [0.98:0.99]	0.99 [0.98:0.99]	0.98 [0.98:0.99]	0.98	Almost perfect
Facet degeneration
Conger’s K	0.27 [0.16:0.38]	0.32 [0.21:0.42]	0.35 [0.25:0.46]	0.32	Slight
Gwet’s AC₂	0.79 [0.74:0.84]	0.79 [0.74:0.84]	0.76 [0.71:0.82]	0.78	Moderate
%-agreement	0.88 [0.86:0.90]	0.89 [0.86–0.91]	0.87 [0.85:0.90]	0.88	Moderate
Scoliosis
Cohen’s K	0.49 [0.06:0.92]	0.59 [0.22:0.96]	0.75 [0.40:1.00]	0.61	Fair
Gwet’s AC₁	0.98 [0.96:1.00]	0.98 [0.96:1.00]	0.99 [0.97:1.00]	0.98	Almost perfect
%-agreement	0.98 [0.96:1.00]	0.98 [0.96:1.00]	0.99 [0.97:1.00]	0.98	Almost perfect
Annular Fissure
Cohen’s K	0.50 [0.32:0.68]	0.45 [0.26:0.65]	0.61 [0.45:0.77]	0.53	Moderate
Gwet’s AC₁	0.87 [0.82:0.93]	0.88 [0.82:0.93]	0.88 [0.83:0.93]	0.88	Almost perfect
%-agreement	0.88 [0.83:0.93]	0.88 [0.83:0.93]	0.89 [0.84:0.93]	0.88	Almost perfect
Disc contour
Cohen’s K	0.36 [0.25:0.48]	0.27 [0.17:0.38]	0.39 [0.29:0.49]	0.34	Fair
Gwet’s AC₁	0.73 [0.65:0.80]	0.59 [0.50:0.68]	0.62 [0.53:0.70]	0.64	Moderate
%-agreement	0.75 [0.69:0.82]	0.64 [0.57:0.71]	0.67 [0.60:0.74]	0.69	Substantial

Inter-rater reliability using Gwet’s AC₁ (binominal/nominal data) and AC₂ (ordinal data) and percent agreement are presented
For comparison Cohen’s K (binominal/nominal data) and Conger’s K (ordinal data) also presented
Numbers in parentheses are 95% confidence intervals [95% CI]

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