3D visualization of the scoliotic spine: longitudinal studies, data acquisition, and radiation dosage constraints

Abstract

Decision making in the treatment of scoliosis is typically based on longitudinal studies that involve the imaging and visualization the progressive degeneration of a patient's spine over a period of years. Some patients will need surgery if their spinal deformation exceeds a certain degree of severity. Currently, surgeons rely on 2-dimensional measurements, obtained from x-rays, to quantify spinal deformation. Clearly working only with 2D measurements seriously limits the surgeon's ability to infer 3-dimensional spinal pathology. Standard CT scanning is not a practical solution for obtaining 3D spinal measurements of scoliotic patients, because it would exposes the patient to a prohibitively high dose of radiation. We have developed 2 new CT-based methods of 3D spinal visualization that produce 3D models of the spine by integrating a very small number of axial CT slices with data obtained from CT scout data. In the first method the scout data are converted to sinogram data, and then processed by a tomographic image reconstruction algorithm. In the second method, the vertebral boundaries are detected in the scout data, and these edges are then used as linear constraints to determine 2D convex hulls of the vertebrae.