European Radiology

, Volume 29, Issue 4, pp 1874–1881 | Cite as

A reduced micro-dose protocol for 3D reconstruction of the spine in children with scoliosis: results of a phantom-based and clinically validated study using stereo-radiography

  • Peter H. PedersenEmail author
  • Claudio Vergari
  • Abdulmajeed Alzakri
  • Raphaël Vialle
  • Wafa Skalli



The aim of this study was to validate the reproducibility of 3D reconstructions of the spine using a new reduced micro-dose protocol.


First, semi-quantitative image analysis was performed using an anthropomorphic child phantom undergoing low-dose biplanar radiography. This analysis was used to establish a “lowest dose” allowing for acceptable visibility of spinal landmarks. Subsequently, a group of 18 scoliotic children, 12 years of age or younger, underwent full-spine biplanar radiography with both micro-dose and the newly defined reduced micro-dose. An intra- and inter-observer reliability study of 3D reconstructions of the spine was performed according to the International Organization for Standardization (ISO)-5725 standard, with three operators.


The reduced micro-dose setting corresponded to a theoretical reduction of radiation dose exposure of approximately 58%. In vivo results showed acceptable intra- and inter-observer reliability (for instance, 3.8° uncertainty on Cobb angle), comparable to previous studies on 3D spine reconstruction reliability and reproducibility based on stereo-radiography.


A new reduced micro-dose protocol offered reliable 3D reconstructions of the spine in patients with mild scoliosis. However, the quality of 3D reconstructions from both reduced micro-dose and micro-dose was inferior to standard-dose protocol on most parameters. Standard-dose protocol remains the option of choice for most accurate assessment and 3D reconstruction of the spine. Still, this new protocol offers a preliminary screening option and a follow-up tool for children with mild scoliosis yielding extremely low radiation and could replace micro-dose protocol for these patients.

Key Points

We investigated the reliability of 3D reconstructions of the spine based on a new stereo-radiography protocol reducing radiation dose by 58% compared with established micro-dose imaging protocol.

The new reduced micro-dose protocol offers a reproducible preliminary screening option and a follow-up tool in the necessarily frequent repeat imaging of children with mild scoliosis yielding extremely low radiation and could replace existing micro-dose protocol for these patients.

EOS standard-dose protocol remains the option of choice for exact radiographic assessment of scoliosis, offering more exact 3D reproducibility of the spine compared to both micro-dose and the new reduced micro-dose protocols.


Three-dimensional imaging Scoliosis Radiation dosage Radiography Reproducibility of results 



Adolescent idiopathic scoliosis


As low as reasonable achievable


Apical vertebra rotation


Dose area product


Intra vertebral rotation


International organization for standardization


Posterior-anterior-lateral positioning


Pelvic tilt


Torsional index of the spine



Fondation ParisTech BiomecAM chair on subject specific modeling, with the financial support of Société Générale and Covea.

Compliance with ethical standards


The scientific guarantor of this publication is Prof. Raphaël Vialle.

Conflict of interest

Two authors of this manuscript declare relationship with the following company: EOS imaging®, Paris, France (Prof. Raphaël Vialle, consulting fees. Prof. Wafa Skalli, coinventor of the EOS system, with no personal financial benefice (royalties rewarded to research and education)).

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

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

Ethical approval

Institutional Review Board approval was obtained.


• Prospective validation study with technical notes

• Multicenter study


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Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  1. 1.Orthopedic DepartmentUniversity Hospital of AalborgAalborgDenmark
  2. 2.Arts et Metiers ParisTechLBM/Institut de Biomecanique Humaine Georges CharpakParisFrance
  3. 3.Department of PediatricsSorbonne UniversitéParisFrance
  4. 4.Orthopedic Department, College of MedicineKing Saud UniversityRiyadhSaudi Arabia

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