title: Gaussian mixture models based 2D-3D registration of bone shapes for orthopedic surgery planning.
abstract: In orthopedic surgery, precise kinematics assessment helps the diagnosis and the planning of the intervention. The correct placement of the prosthetic component in the case of knee replacement is necessary to ensure a correct load distribution and to avoid revision of the implant. 3D reconstruction of the knee kinematics under weight-bearing conditions becomes fundamental to understand existing in vivo loads and improve the joint motion tracking. Existing methods rely on the semiautomatic positioning of a shape previously segmented from a CT or MRI on a sequence of fluoroscopic images acquired during knee flexion. We propose a method based on statistical shape models (SSM) automatically superimposed on a sequence of fluoroscopic datasets. Our method is based on Gaussian mixture models, and the core of the algorithm is the maximization of the likelihood of the association between the projected silhouette and the extracted contour from the fluoroscopy image. We evaluated the algorithm using digitally reconstructed radiographies of both healthy and diseased subjects, with a CT-extracted shape and a SSM as the 3D model. In vivo tests were done with fluoroscopically acquired images and subject-specific CT shapes. The results obtained are in line with the literature, but the computational time is substantially reduced.
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, via Colombo 40, 20133, Milan, Italy. marta.valenti@polimi.it.
authors.forename: Marta
authors.initials: M
authors.lastname: Valenti
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, via Colombo 40, 20133, Milan, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Ferrigno
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, via Colombo 40, 20133, Milan, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Martina
authors.affiliation: Universität Bern, Staffaucherstr. 78, 3014, Bern, CH, Switzerland.
authors.forename: Weimin
authors.initials: W
authors.lastname: Yu
authors.affiliation: Universität Bern, Staffaucherstr. 78, 3014, Bern, CH, Switzerland.
authors.forename: Guoyan
authors.initials: G
authors.lastname: Zheng
authors.affiliation: University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
authors.forename: Mohsen Akbari
authors.initials: MA
authors.lastname: Shandiz
authors.affiliation: University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Anglin
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, via Colombo 40, 20133, Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: De Momi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001842:Bone and Bones / Q000473:pathology* / Q000601:surgery*; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016011:Normal Distribution; D019637:Orthopedic Procedures; D010347:Patient Care Planning; D012399:Rotation; D014584:User-Computer Interface
keywords: 2D/3D registration; Gaussian mixture models; Image processing; Orthopedic surgery; Statistical shape models