Table 1.

The mean difference and variability of novice measurements of the abdominal aorta

Aortic measurement	Novice 1	Novice 2	Novice 3
Suprarenal
Mean difference	-0.46 (-0.52, -0.41)	-0.36 (-0.42, -0.31)	-0.32 (-0.37, -0.27)
Variability	0.81	0.76	0.63
LOA	-1.28, 0.35	-1.12, 0.40	-0.95, 0.31
n	196	193	161
Mid infrarenal
Mean difference	-0.13 (-0.18, 0.07)	-0.08 (-0.1, -0.02)	-0.004 (-0.05, 0.04)
Variability	0.83	0.83	0.64
LOA	-0.95, 0.70	-0.91, 0.75	-0.65, 0.64
n	214	212	179
Distal infrarenal
Mean difference	-0.07 (-0.1, -0.03)	-0.13 (-0.17, 0.09)	0.1 (0.06, 0.13)
Variability	0.49	0.61	0.49
LOA	-0.56, 0.42	-0.74, 0.48	-0.39, 0.59
n	215	209	179
Max Coronal
Mean difference	-0.07 (-0.1, -0.03)	-0.05 (-0.09, -0.02)	0.05 (0.01, 0.08)
Variability	0.47	0.50	0.48
LOA	-0.54, 0.40	-0.56, 0.45	-0.44, 0.53
n	209	194	167

Measurement of the abdominal aorta were taken in the transverse plane at suprarenal, mid infrarenal and distal infrarenal sections and the maximal aortic measurement taken in the coronal plane. Mean difference (95% CI) (cm) of novice measurements from that of the assessors; variability of the mean difference; limits of agreement (LOA); n, number of interobserver pairs. Scans from which no measurement could be attained were discarded from the analysis and thus the numbers of inter-observer pairs are different in each aortic segment and each novice.