. 2017 Aug 10;12(8):e0182596. doi: 10.1371/journal.pone.0182596

Table 1. Comparison of measured volume using three-dimensional ultrasound and estimated volume from 2D diameters $(V= \frac{4}{3} π r_{1} r_{2} r_{3})$ with the true volume of tumor phantoms.

	Measured Volume (observer 1)	Measured Volume (observer 2)	Estimated volume from 2D diameters $(V= \frac{4}{3} π r_{1} r_{2} r_{3})$
Mean volume^a	7.18 ± 5.44	8.31 ± 6.32	9.10 ± 8.47
Mean difference from reference volume (95% CI)	-0.24 (-0.79 to 0.32)	0.89 (0.38 to 1.40)	1.69 (0.55 to 2.82)
SD of differences between measured volume and reference volume	1.75	1.58	3.56
Upper limit of agreement	3.19 (2.23 to 4.15)	3.99 (3.12 to 4.86)	8.66 (6.70 to 10.62)
Lower limit of agreement	-3.66 (-4.63 to -2.70)	-2.21 (-3.08 to 1.34)	-5.29 (-7.25 to 3.33)

^a The mean reference volume was 7.42 ± 5.76 mL

Table 1. Comparison of measured volume using three-dimensional ultrasound and estimated volume from 2D diameters (V=43πr1r2r3) with the true volume of tumor phantoms.