title: Parallax-free intra-operative X-ray image stitching.
abstract: We present a novel method to generate parallax-free panoramic X-ray images during surgery by enabling the mobile C-arm to rotate around its X-ray source center, relative to the patient's table. Rotating the mobile C-arm around its X-ray source center is impractical and sometimes impossible due to the mechanical design of mobile C-arm systems. In order to ensure that the C-arm motion is a relative pure rotation around its X-ray source center, we propose to move the table to compensate for the translational part of the motion based on C-arm pose estimation. For this we employ a visual marker pattern and a Camera Augmented Mobile C-arm system that is a standard mobile C-arm augmented by a video camera and mirror construction. We are able to produce a parallax-free panoramic X-ray image independent of the geometric configuration of imaged anatomical structures. Our method does not require a fronto-parallel setup or any overlap between the acquired X-ray images. This generated parallax-free panoramic X-ray image preserves the linear perspective projection property. It also presents a negligible difference (below 2 pixels) in the overlapping area between two consecutive individual X-ray images and has a high visual quality. This promises suitability for intra-operative clinical applications in orthopedic and trauma surgery. The experiments on phantoms and ex-vivo bone structure demonstrate both the functionality and accuracy of the method.
authors.affiliation: Computer Aided Medical Procedures (CAMP), Technische Universität München, Fakultät für Informatik / I16 Boltzmannstrasse 3 85748 Garching bei München, TU Munich, Germany. wangle@in.tum.de
authors.forename: Lejing
authors.initials: L
authors.lastname: Wang
authors.forename: Joerg
authors.initials: J
authors.lastname: Traub
authors.forename: Simon
authors.initials: S
authors.lastname: Weidert
authors.forename: Sandro Michael
authors.initials: SM
authors.lastname: Heining
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Euler
authors.forename: Nassir
authors.initials: N
authors.lastname: Navab
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D006801:Humans; D010363:Pattern Recognition, Automated / Q000379:methods*; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015641:Radiography, Interventional / Q000295:instrumentation / Q000379:methods*; D011862:Radiography, Panoramic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D025321:Surgery, Computer-Assisted / Q000379:methods*