European Radiology

, Volume 28, Issue 11, pp 4570–4577 | Cite as

Sagittal balance measures are more reproducible when measured in 3D vs in 2D using full-body EOS® images

  • Masashi OkamotoEmail author
  • Fouad Jabour
  • Kenichiro Sakai
  • Shun Hatsushikano
  • J. C. Le Huec
  • Kazuhiro Hasegawa
Computer Applications



An innovative low-dose X-ray biplanar imager (EOS®) allows measurement of the whole-body in standing-position which is necessary for the evaluation of spinal deformities.


A total of 60 asymptomatic subjects (ages 20–81 years) were evaluated using the 3D workflow called postural assessment and 2D measures. Subjects were measured twice each by two new observers following training, including: lordosis/kyphosis, pelvic parameters, sagittal-vertical axis, and spinal-sacral angle. Intra- and inter-observer reproducibility and similarity were compared between 2D and 3D measures.


The intraclass correlation coefficient (ICC) was very high for the 3D measures (>0.9) and excellent for the 2D measures (>0.75). In all cases, the overall mean absolute difference between repeated 3D measures was less than 2°, or 2 mm. For all parameters, the inter- and intra-observer reproducibility in 3D measures were significantly superior to 2D measures (p < 0.03).


This study demonstrated that 3D measures have better reproducibility than 2D for sagittal balance.

Key Points

• Reproducibility of sagittal balance 2D/3D measurements was evaluated using EOS® full-body radiographs.

• Inter- and intra-observer reproducibility were significantly superior for 3D measures vs. 2D.

• 3D measures have better reproducibility than 2D for sagittal balance.


Whole-body imaging Postural balance Standing position Radiography Reproducibility of results 





Seventh cervical vertebra


Full-body index


Intra-class correlation coefficient


Pelvic incidence


Pelvic tilt


Quality of life


Sacral slope


Spinal sacral angle


Sagittal vertical axis



The authors state that this work has not received any funding.

Compliance with ethical standards


The scientific guarantor of this publication is Masashi Okamoto.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors has significant statistical expertise.

Informed consent

Written informed consent was obtained from all subjects (patients) in this study.

Ethical approval

Institutional review board approval was obtained.


• retrospective

• cross-sectional study

• multicentre study


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Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  1. 1.Niigata Spine Surgery CenterNiigataJapan
  2. 2.Ortho-Spine DepartmentBordeaux University HospitalBordeauxFrance

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