title: 3D/2D registration and segmentation of scoliotic vertebrae using statistical models.
abstract: We propose a new 3D/2D registration method for vertebrae of the scoliotic spine, using two conventional radiographic views (postero-anterior and lateral), and a priori global knowledge of the geometric structure of each vertebra. This geometric knowledge is efficiently captured by a statistical deformable template integrating a set of admissible deformations, expressed by the first modes of variation in Karhunen-Loeve expansion, of the pathological deformations observed on a representative scoliotic vertebra population. The proposed registration method consists of fitting the projections of this deformable template with the preliminary segmented contours of the corresponding vertebra on the two radiographic views. The 3D/2D registration problem is stated as the minimization of a cost function for each vertebra and solved with a gradient descent technique. Registration of the spine is then done vertebra by vertebra. The proposed method efficiently provides accurate 3D reconstruction of each scoliotic vertebra and, consequently, it also provides accurate knowledge of the 3D structure of the whole scoliotic spine. This registration method has been successfully tested on several biplanar radiographic images and validated on 57 scoliotic vertebrae. The validation results reported in this paper demonstrate that the proposed statistical scheme performs better than other conventional 3D reconstruction methods.
authors.affiliation: Laboratoire de recherche en imagerie et orthopédie, Centre de recherche, Centre hospitalier Universitaire de Montréal, Pavilion J.A. de Sève 1560, rue Sherbrooke est, Montréal, Que., Y-1615, Canada H2L 4M1. benameus@iro.umontreal.ca
authors.forename: Said
authors.initials: S
authors.lastname: Benameur
authors.forename: Max
authors.initials: M
authors.lastname: Mignotte
authors.forename: Stefan
authors.initials: S
authors.lastname: Parent
authors.forename: Hubert
authors.initials: H
authors.lastname: Labelle
authors.forename: Wafa
authors.initials: W
authors.lastname: Skalli
authors.forename: Jacques
authors.initials: J
authors.lastname: de Guise
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*; D015233:Models, Statistical; D011859:Radiography; D012600:Scoliosis / Q000000981:diagnostic imaging / Q000473:pathology*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology*