3D reconstruction of a femoral shape using a parametric model and two 2D fluoroscopic images

In medical diagnostic imaging, an X-ray CT scanner or a MRI system have been widely used to examine 3D shapes or internal structures of living organisms or bones. However, these apparatuses are generally very expensive and of large size. A prior arrangement is also required before an examination, and thus, it is not suitable for an urgent fracture diagnosis in emergency treatment. This paper proposes a method to estimate a patient-specific 3D shape of a femur from only two fluoroscopic images using a parametric femoral model. Firstly, we develop a parametric femoral model by statistical analysis of a number of 3D femoral shapes created from CT images of 51 patients. Then, the pose and shape parameters of the parametric model are estimated from two 2D fluoroscopic images using a distance map constructed by the level set method. Experiments using synthesized images and fluoroscopic images of a phantom femur are successfully carried out and the usefulness of the proposed method is verified.