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

Abstract

Idiopathic scoliosis is a three-dimensional deformity of the vertebral column and one of the common pediatric spinal diseases, while neuromuscular scoliosis is often associated with cerebral palsy. Especially during periods of growth, there is a high risk of progression of scoliosis. Thus, frequent clinical monitoring is important for proper treatment. X-rays are the Gold standard and the most commonly used method for follow-up of scoliosis. The spinal curvatures are measured by the Cobb angles from x-rays. Patients with scoliosis therefore accumulate higher ionizing radiation doses from repetitive x-rays over their life span. Hence, reducing exposure to ionizing radiation is an important consideration in the follow-up of adolescent scoliosis. For that purpose a body scanner system is proposed, in particular, for complementary diagnostics in children and adolescents with cerebral palsy. The system is non-invasive, free of ionizing radiation and provides three-dimensional scan images of the human torso. In this study, two intermediate steps are described that are useful for the development of analysis methods of the scan images. Two-dimensional transverse cross sections of the torso can be extracted from a scan image along the vertical body axis. Here, methods are described that will be useful for the shape analysis of the two-dimensional transverse body contours. Based on mathematical calculations in polar coordinates, the asymmetry between left and right side of the two-dimensional transverse cross sections is captured by a linear fitting of the course of the contour on either side. Further, the two-dimensional transverse contour data are fitted with an ellipse.