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

Table 4 Inter-rater measures agreement results

Measurement	n (slices)	Mean (mm)	Standard deviation (mm)	Mean difference (bias) [95% CI] (mm)	95% Limits of agreement (LOA) (mm)	LOA as proportion of mean values (%)
Length - AIVH	257	14.9	1.2	−0.5 [−0.7; –0.4]	−2.8; 1.8	30.9
Length - PIVH	257	9.6	1.2	−0.3 [−0.4; –0.2]	−2.6; 2.0	47.9
Length - IVDL	257	31.2	0.8	−0.7 [−0.8; –0.6]	−2.2; 0.8	9.7
Length - ADML	257	3.4	0.6	0.1 [0.0; 0.2]	−1.1; 1.4	73.6
Length - PDML	257	3.4	0.9	0.3 [−0.2; 0.4]	−1.5; 2.1	105.9
Length - ADSL	229	8	1.1	0.2 [0.0; 0.3]	−2.0; 2.3	53.8
	n (participants)	(mm2)	(mm²)	(mm²)	(mm²)	(%)
Area - CAIH	15	568.2	23.4	−18.7 [−31.7; –5.7]	−64.6; 27.1	16.2
Area - CPIH	15	362.8	17.3	−13.3 [−22.9; –3.7]	−47.3; 20.7	18.7
Area - CIVD	15	1190.4	13.7	−19.5 [−27.1; –11.9]	−46.4; 7.4	4.5
Area - CADM	15	126.2	7	2.8 [−1.1; 6.7]	−10.8; 16.4	21.6
Area - CPDM	15	121.7	15	6.4 [−2.0; 14.7]	−23.1; 35.8	48.4
Area - CDS	8	286	17.8	4.8 [−10.1; 19.7]	−30.1; 39.8	24.4
		(mm³)	(mm³)	(mm³)	(mm³)	(%)
Volume - VADM	15	1830.3	209	392 [277; 508]	−17; 801	44.7
Volume - VPDM	15	1117.6	297	131 [−33; 296]	−450; 713	104.1

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 (bias) 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