Table 2.

Evaluation of axial vertebral rotation in 3D images

Method [ref.]	Degreea	Reported variability [ref.]b
3D reconstruction methods	2	RMS: (φ a, φ c, φ s) = (1.9°, 1.9°, 1.0°) [30] MAD: 1.9°–4.0° [59] SD: 3.6° [86] • 1.2°–2.4° [27, 29] • (φ a, φ c, φ s) = (6.4°, 3.6°, 3.7°) [73] • 0.9° (intra), 1.0° (inter) [36]
Aaro–Dahlborn [1]	1	MAD: 0.6°–2.0° [1] • 0.5° [2] SD: 1.6° [44] • 1.6° [50] • 1.8° (intra), 4.7° (inter) [37] • 2.8° (intra), 2.6° (inter) [2]
Ho [44]	2	MAD: 2.6° (intra), 3.0° (inter) [13] • 0.7° [2] SD: 1.2° [44] • 1.3° (intra), 1.9° (inter) [45] • 1.3° [12] • 1.2° (intra), 2.4° (inter) [37] • 3.3° (intra), 2.4° (inter) [2]
Krismer et al. [50]	1	SD: 2.2° [50] • 3.3° (intra), 6.1° (inter) [37]
Göçen et al. [38]	1	SD: 1.1° (intra), 1.8° (inter) [38]
Haughton et al. [41]	4	SD: 0.9° (man), 0.2° (comp) [75] • 0.1° [76]
Adam-Askin [2]	4	MAD: 0.25° [2]
Kouwenhoven et al. [48]	4	ICC: 0.99 (intra), 0.96 (inter) [49] • 0.91 (intra), 0.87 (inter) [48]
Vrtovec et al. CT [90]	4	–
Vrtovec et al. MR [91]	4	SD: 0.9° [91]
Vrtovec et al. CT & MR [92]	4	RMS: (φ a, φ c, φ s) = (0.53°, 0.53°, 0.58°) [92] SD: (φ a, φ c, φ s) = (0.26°, 0.26°, 0.28°) [92]

^aDegree of automation

^b Man manual measurement, comp computerized measurement, intra intra-observer, inter inter-observer