Three-Dimensional Glenohumeral Joint Kinematic Analyses from Asynchronous Biplane Fluoroscopy Using an Interpolation Technique Mohsen Akbari-Shandiz, Joseph D. Mozingo, David R. Holmes III, and Kristin D. Zhao 1 Introduction The use of biplane fluoroscopic systems has become increasingly popular for evaluating joint kinematics in vivo [1–6]. Glenohumeral joint kinematics can be quantified from biplane fluoroscopic images using radiostereometric analysis (RSA) or a 3D–2D registration approach. Custom biplane fluoroscopic systems, which are not FDA-approved for clinical use, have been commonly used for these approaches [2, 7]. Clinical biplane systems are FDA-approved but are inherently not well- suited for biplane analyses due to the fact that images are acquired asynchronously. Asynchrony in image acquisition has the advantage of reducing cross-scattering effects of one X-ray source onto the other [8]; however, asynchronous acquisition introduces errors into the registration process, as there is joint movement between the two asynchronous images. Moreover, the magnitude of the error depends on the speed of movement which is not known prior to the scan and the fluoroscopy frame rate. Thus, achieving accurate 3D kinematics using conventional techniques on temporally offset data sets is challenging. In the present study, our goal was to improve the accuracy of image registra- tion by generating simulated corresponding fluoroscopy images. We introduce an interpolation algorithm to generate missing images in biplane image sequences thus producing interpolated-synchronous image pairs. The main objective of this study M. Akbari-Shandiz • J.D. Mozingo • K.D. Zhao () Assistive and Restorative Technology Laboratory, Rehabilitation Medicine Research Center, Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, USA e-mail: Zhao.Kristin@mayo.edu D.R. Holmes III Biomedical Imaging Resource, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA © Springer International Publishing AG 2017 A. Wittek et al. (eds.), Computational Biomechanics for Medicine, DOI 10.1007/978-3-319-54481-6_9 101