Validation of marker-based tracking with a biplanar fluoroscopy system optimized for the foot and ankle

• Published in: Medical engineering & physics Vol. 138; p. 104310
• Main Authors: Thorhauer, Eric D., Wukelic, Corey, Lin, Will, Entress, Nick, Grantham, Aerie, Ledoux, William R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2025
• Subjects: Algorithms; Ankle - diagnostic imaging; Ankle - physiology; Biomechanical Phenomena; Biplanar fluoroscopy; Computer vision; Fiducial Markers; Fluoroscopy - instrumentation; Fluoroscopy - methods; Foot - diagnostic imaging; Foot - physiology; Gait; Humans; Image Processing, Computer-Assisted; Marker-based tracking; Computer vision; Marker-based tracking; Biplanar fluoroscopy
• ISSN: 1350-4533; 1873-4030; 1873-4030
• DOI: 10.1016/j.medengphy.2025.104310

•We have developed custom software solutions (PISCES and CRUX) to rectify distortions in biplanar fluoroscopy images and model the imaging chains, and we quantified their performance empirically.•We have developed URSA, a custom solution for the marker-based tracking method, and we assessed its accuracy and repeatability empirically.•Via Monte Carlo simulation, we provide a novel contextualization of the propagation of marker localization errors into bone pose reconstruction errors in order to establish lower limits on the use of the marker-based tracking method for serving as the ground truth to compare future model-based tracking algorithms. Biplanar fluoroscopy is a powerful, maturing technique for providing clinicians and biomechanists with in vivo kinematic data of the human skeleton during a variety of tasks. Marker-based tracking with biplane systems has applications in both the in vivo and in vitro realms and serves as the established means of validating model-based tracking algorithms. We have developed a custom biplane system for dynamic imaging of the entire foot and ankle complex during gait as well as a custom software suite to perform the required data preprocessing and marker-based tracking. We demonstrate our ability to repeatably model the biplane imaging chains and then accurately and precisely reconstruct the positions of markers in the foot during static and dynamic motion trials. Finally, we simulate the effects of marker localization errors in reconstructing the poses of the calcaneus, navicular, and proximal phalanx during gait in order to contextualize the extent to which marker-based tracking may be considered ground truth compared to future model-based tracking algorithms.