A method for quantitative measurement of lumbar intervertebral disc structures: an intra- and inter-rater agreement and reliability study

Table 2 Intra-rater measures agreement results

Measurement	n (slices)	Mean (mm)	Standard deviation (mm)	Mean difference (bias) [95% CI] (mm)	95% LOA (mm)	LOA as proportion of mean values (%)
Length - AIVH	258	14.7	1.1	0.2 [0.0; 0.3]	−2.0; 2.3	29.3
Length - PIVH	258	9.5	0.8	0.1 [0.0; 0.2]	−1.5; 1.6	32.6
Length - IVDL	258	31.1	0.5	−0.1 [−0.1; 0.0]	−1.1; 1.0	6.8
Length - ADML	258	3.5	0.6	0 [−0.1; 0.1]	−1.1; 1,1	62.9
Length - PDML	258	3.6	0.5	0 [−0.1; 0.1]	−1.0; 1.0	55.6
Length - ADSL	227	8.5	0.8	−0.1 [−0.2; 0.0]	−1.6; 1.4	35.3
	n (participants)	(mm²)	(mm²)	(mm²)	(mm²)	(%)
Area - CAIH	24	512.6	19.1	6.2 [−1.8; 14.3]	−31.2; 43.7	14.6
Area - CPIH	24	327.6	11.7	4.5 [−0.4; 9.4]	−18.4; 27.4	14.0
Area - CIVD	24	1101.3	10.2	−1.2 [−5.5; 3.1]	−21.3; 18.8	3.6
Area - CADM	24	118.8	10.2	1 [−3.3; 5.3]	−19.0; 21.1	33.8
Area - CPDM	24	121.8	12.5	−1.6 [−6.9; 3.7]	−26.0; 22.8	40.1
Area - CDS	25	267.9	18.6	−3.8 [−11.5; 3.9]	−40.3; 32.7	27.2
		(mm³)	(mm³)	(mm³)	(mm³)	(%)
Volume - VADM	24	2136.7	246	−100 [−204; 4]	−582; 382	45.1
Volume - VPDM	24	1314.8	126	−47 [−100; 6]	−293; 199	37.4

Number of slices measured for length, and participants measured for cross-sectional area and volume measurements, overall mean values, standard deviation, mean difference between measurements with 95% confidence intervals (CI), 95% limits of agreement (LOA), and LOA as a proportion of mean values. Due to absence of dural sac at certain otherwise measured slices, a lower number of slices were measured. Participants with unequal start- and end-slices were excluded from the analyses, leading to varying numbers of included participants.

ISSN: 2045-709X