Model-Based Radiation-Free Assessment of Scoliosis: A Principle Validation Study

Abstract

Purpose Adolescent scoliosis is one of the common pediatric spinal diseases which has a high risk of progression due to the rapid growth of the skeleton during the growing stage therefore needs regular clinical monitoring including X-rays. Because X-rays could lead to ionizing radiation-related health problems, an ionizing radiation-free, non-invasive method is presented here to estimate the degree of scoliosis and to potentially support the medical assessment. Methods The radiation-free body scanner provides a 3D surface scan of the torso. A basic 3D structure of the human ribcage and vertebral column was modeled and simulated with computer-aided design software and finite element method calculation. For comparison with X-rays, courses of vertebral columns derived from 3D torso images and 3D models were analyzed with respect to their apex positions and angles. Results The methods show good results in the estimation of the apex positions of scoliosis. Strong correlations (R = 0.8924) were found between the apex and Cobb angle from X-rays. Similar correlations (R = 0.8087) was obtained between the apex angles extracted from X-rays and the combination of torso scan images with 3D model simulations. Promising agreement was obtained between the spinal trajectories extracted from X-ray and 3D torso images. Conclusions Very strong correlations suggest that the apex angle could potentially be used for scoliosis assessment in follow-up examinations in complement to the Cobb angle. However, further improvements of the methods and tests on a larger number of data set are necessary before their introduction into the clinical application.

A new computational approach for scoliosis assessment from a non-invasive body scanner

“…Furthermore, specific points and characteristics of the ellipse (like focii, eccentricity, major-minor axes), or their relations might be helpful later on to correlate them with the vertebral bodies positions inside the slice. This is expected to be achieved with the inclusion of the model of rib-cage into the 3D torso scan [5,9,10] and need to be verified on available CT data [6].…”

Scoliosis assessment tools to reduce follow-up X-rays

“…The previously developed body scanner system is equipped with an infrared depth sensor and a RGB video camera. Using computer vision algorithms, the system provides a true colour 3D image of the patients torso upon scanning [ 33 , 34 ]. It is thus non-invasive and ionizing radiation free.…”

“…Further a so-called apex angle has been defined, in an attempt to transfer the results of the present methods and parameter settings into a measurement that also reflects the Cobb angle – a gold standard in X-ray analysis. The apex angle is defined as 180° ​− ​ θ , where θ is the included angle between the two legs from the main apex to the adjacent inflection points along the course of the vertebral column from back view [ 34 ]. In principle this apex angle can thus be derived both from images of coronal X-ray and from the back view of the model.…”

A non-invasive method for scoliosis assessment—A new mathematical concept using polar angle

“…To predict the exact locations of the vertebral bodies inside the slices, similar like CT and MRI images, and to account for their rotational effects on the shapes of the slices, as well as to reconstruct the curvature of vertebral column further developments are required for the present study. This is expected to be accomplished with the integration and simulation of the ribcage model [17,22,36]. In summary, the present method, based on mathematical calculations, has advantages in quantifying the changes in each and every transverse cross sections at different vertebral levels with time without markers, in a short time, in standing position and independently with patients' natural growth.…”

“…In the case of P1, after a brace treatment and scoliosis specific physiotherapy exercises, further, a body scan (P1S) and X-ray were done at the time of one of the follow-up examinations and the Cobb angle was found to be reduced to 20˚. Extracted courses of the vertebral columns from the two X-ray images of P1 after [16,17] are shown in Fig 1(c). In the case of P2, only one scan image was analyzed.…”