The EOS™ imaging system and its uses in daily orthopaedic practice

Abstract

Background The EOS™ X-ray machine, based on a Nobel prize-winning invention in physics in the field of particle detection, is capable of a simultaneous capture of biplanar X-ray images by slot scanning of the whole body in an upright, physiological load-bearing position, using ultralow radiation doses. The simultaneous capture of spatially calibrated anterioposterior and lateral images provides a three-dimensional (3D) surface reconstruction of the skeletal system using a special software. Parts of the skeletal system in X-ray images and 3D-reconstructed models appear in true 1:1 scale for size and volume, thus spinal and vertebral parameters, lower limb axis lengths and angles, as well as any relevant clinical parameters in orthopaedic practice can be very precisely measured and calculated. Visualisation of 3D reconstructed models in various views by sterEOS 3D software enables presentation of top view images to help analyse rotational conditions of lower limbs, joints and spine deformities in the horizontal plane, providing revolutionary novel possibilities in orthopaedic surgery, especially in spine surgery. Approach and conclusions Our department has been extensively using the very first commercially available EOS™ imaging system worldwide for routine orthopaedic diagnostics since June 2007. During this period of about 4.5 years, more than 5,700 standard examinations have been carried out, about a third of them in spine deformity cases and the rest in lower limb orthopaedic cases. In this mini-review, general principles and uses of this groundbreaking integrated orthopaedic solution is reviewed with a few highlighted examples from our own clinical practice.

Three-Dimensional Vertebral Wedging in Mild and Moderate Adolescent Idiopathic Scoliosis

“…This adjusted procedure was tested on 26 fiducial landmarks located in known positions within a calibration object measuring 140 mm by 210 mm by 410 mm. The average positional error was 1.35±0.79 mm and the angular error was 0.1±1.0°, which compare well with those reported by Ills and Somoskey [30] for the EOS® reconstruction software system. Since most wedging angles ranged between 3° and 5°, our average angular error of 0.1° should have little impact on the interpretations of the results.…”

Semiautomated 3D Spine Reconstruction from Biplanar Radiographic Images: Prediction of Intervertebral Loading in Scoliotic Subjects

“…Digitized images of the thoracolumbar spine and pelvis were simultaneously acquired in coronal and sagittal planes with EOS imaging system (EOS Imaging, France). Since EOS system provides spatially calibrated images (Illés and Somoskeöy, 2012), no further calibration procedures were required. The images pair was manually processed through SterEOS software (EOS Imaging, France), which allowed to identify as “scoliotic,” the spine curves characterized by CAs >5°, and provided in addition the identification of the anatomical parameters.…”

“…Those reference vertebral meshes were obtained through SterEOS software by reconstructing the spine of a 17-year-old adolescent male subject not affected by scoliosis. Specifically, those mesh models are created by SterEOS basing on a series of 3D CT models and a statistical finite element models (Illés and Somoskeöy, 2012) and are manually processed in the reconstruction procedure to match the vertebrae of the considered subject. The mesh dimensions were scaled to match the current vertebral body size.…”

Patient-specific 3D models created by 3D imaging system or bi-planar imaging coupled with Moiré–Fringe projections: a comparative study of accuracy and reliability on spinal curvatures and vertebral rotation data

“…The EOS imaging system, based on Nobel prize-winning Georges Charpak's Xenon multiwire proportional chamber, Digital images are secondarily processed on SterEOS Ò allowing 3D bone modeling and 3D measurements. Given its numerous advantages including simultaneous and very low-dose frontal and sagittal acquisitions, full view of patient skeleton including lower limbs, and the very good image quality without any stitching or vertical distortion, it is currently considered the gold standard for 2D and 3D measurements and reconstructions on weight-bearing patients [9,13,23,24]. Technology of the B3S method is different as an optical acquisition, based on the projection of a structured light pattern on the back of the patient, is performed simultaneously to the X-ray acquisition.…”

“…The EOS X-ray system allows simultaneous acquisition of frontal and sagittal views by slot scanning of the whole body in an upright, physiological load-bearing position, using ultra-low radiation doses. This allows three-dimensional (3D) surface reconstruction of the skeletal system using a special software program named SterEOS Ò , which offers excellent accuracy and reliability compared to 3D CT reconstructions, and the benefits of being performed in an upright position using only a fraction of the radiation dose [13]. Given its advantages, scoliosis evaluation is mainly performed by this technique.…”