Contribution of Statistical Iterative Reconstruction Algorithm for Orthopaedic Applications: A Study with a Cone-Beam CT Prototype
Author(s): Stéphanie UK, Fanny Morin, Valérie Bousson, Rémy Nizard, Guillaume Bernard, Christine Chappard
Three-dimensional reconstruction for image-guidance in orthopaedic surgery necessitates a high degree of geometrical precision but not necessary structure details. With the aim to reduce as much as possible the dose, a cone beam CT prototype was tested with decreasing intensities, the number of projections or different angular range. We tested two methods of reconstruction: Feldkamp-Davis-Kress (FDK) reconstruction and the Simultaneous Algebraic Reconstruction Technic with Total Variation (SART-TV). Based on this protocol, on a knee cadaveric specimen, we combined qualitative assessment performed by radiologists and orthopedic surgeons, objective metrics of image quality such as signal-to-noise ratio, or related to bone geometric contour, grey level restitution and texture of trabecular bone, and finally the quality of joint space segmentation. Objective indicators related to signal-to-noise ratio, the quality of geometry and segmentation have shown better results for SART-TV than FDK in case of decrease projections number and angular range. On the contrary, qualitative assessment, and indexes about grey level restitution and textural quality of trabecular bone produced the best results for FDK reconstruction. These results showed that SART-TV reconstruction has a good capability to restore the geometry in case of low dose protocol and consequently could be a good candidate for orthopaedic surgery.