Table 2:

Reporting of temporal change between two MRI scans and inter-rater reliability of reporting temporal change for radiologists A and B (n=50)

MRI finding	“A” change “B” change	“A” change “B” no change	“A” no change “B” change	“A” no change “B” no change	Kappa (95% CI)	Prevalence and Bias Adjusted Kappa (PABAK)	Percent Agreement
Disc degeneration (Pfirrmann Grade)	0	6	17	227	−0.037 (−0.060 to −0.014)	0.816	90.8
Disc signal intensity	0	2	19	229	−0.015 (−0.033 to 0.004)	0.832	91.6
Disc height	0	0	17	233	N/A	0.864	93.2
High intensity zone	1	5	3	241	0.184 (−0.15 to 0.520)	0.936	96.8
Annular fissure	0	6	2	242	−0.012 (−0.025 to 0.001)	0.936	96.8
Modic changes*	0	0	2	498	N/A	0.992	99.6
Disc contour/herniation	3	6	10	231	0.240 (−0.010 to 0.491)	0.872	93.6
Facet joint arthropathy*	0	0	5	495	N/A	0.980	99
Central canal stenosis	0	1	5	244	0.007 (−0.018 to 0.004)	0.952	97.6
Spondylolisthesis	0	0	1	249	N/A	0.992	99.6
Bone marrow oedema	0	0	0	250	N/A	N/A	100
Nerve root compromise*	0	2	2	496	−0.004 (−0.008 to −0.000)	0.984	99.2

A and B refer to the 2 reporting radiologists. “A” change indicates radiologist A reported a change between the 2 MRIs. “B” change indicates radiologist B reported a change between the 2 MRIs.

50 patients were included in these analyses and all MRI findings reported at 5 lumbar levels. Therefore, there are 250 data points for most MRI findings apart from those indicated with an * where each MRI finding produced 2 data points per spinal level resulting in a total of 500 data points for Modic changes (upper and lower endplates), facet joint arthropathy (right and left) and nerve root compromise (right and left).