3D Reconstruction of the Spine From Uncalibrated Biplanar Intra-Operative X-Ray Images

Abstract

A new technique for the intra-operative 3D reconstruction of the spine from biplanar chest radiographs was developed. The technique uses a self-calibration algorithm that does not require a calibration object; the radiographic set-up is calibrated from the natural content of the images (i.e. matched anatomical landmarks and surgical implants). Since no calibration object is required, the technique is suitable for the retrospective study of scoliosis surgical treatments in 3D.An automatic procedure for the selection of matched landmarks was implemented in order to improve the quality of the results. This algorithm selects a subset of the available landmarks that are to be used for the calibration procedure. The selection criteria are based on quality of stereo-correspondence and breadth of spatial distribution.In vitro and in vivo tests showed that the proposed technique is feasible and reaches the expected accuracy.