title: Reconstruction of 3-D geometry using 2-D profiles and a geometric prior model.
abstract: A method has been developed to reconstruct three-dimensional (3-D) surfaces from two-dimensional (2-D) projection data. It is used to produce individualized boundary element models, consisting of thorax and lung surfaces, for electro- and magnetocardiographic inverse problems. Two orthogonal projections are utilized. A geometrical prior model, built using segmented magnetic resonance images, is deformed according to profiles segmented from projection images. In our method, virtual X-ray images of the prior model are first constructed by simulating real X-ray imaging. The 2-D profiles of the model are segmented from the projections and elastically matched with the profiles segmented from patient data. The displacement vectors produced by the elastic 2-D matching are back projected onto the 3-D surface of the prior model. Finally, the model is deformed, using the back-projected vectors. Two different deformation methods are proposed. The accuracy of the method is validated by a simulation. The average reconstruction error of a thorax and lungs was 1.22 voxels, corresponding to about 5 mm.
authors.affiliation: Laboratory of Biomedical Engineering, Helsinki University of Technology, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Lötjönen
authors.forename: I E
authors.initials: IE
authors.lastname: Magnin
authors.forename: J
authors.initials: J
authors.lastname: Nenonen
authors.forename: T
authors.initials: T
authors.lastname: Katila
mesh_terms: D003952:Diagnostic Imaging / Q000379:methods* / Q000706:statistics & numerical data; D004548:Elasticity; D004562:Electrocardiography / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006334:Heart Function Tests / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008280:Magnetics; D008297:Male; D008433:Mathematics; D008954:Models, Biological; D013902:Radiography, Thoracic / Q000379:methods / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D013499:Surface Properties