title: Minimizing Interpolation Bias and Precision Error in In Vivo µCT-Based Measurements of Bone Structure and Dynamics.
abstract: In vivo µCT imaging allows for high-resolution, longitudinal evaluation of bone properties. Based on this technology, several recent studies have developed in vivo dynamic bone histomorphometry techniques that utilize registered µCT images to identify regions of bone formation and resorption, allowing for longitudinal assessment of bone remodeling. However, this analysis requires a direct voxel-by-voxel subtraction between image pairs, necessitating rotation of the images into the same coordinate system, which introduces interpolation errors. We developed a novel image transformation scheme, matched-angle transformation (MAT), whereby the interpolation errors are minimized by equally rotating both the follow-up and baseline images instead of the standard of rotating one image while the other remains fixed. This new method greatly reduced interpolation biases caused by the standard transformation. Additionally, our study evaluated the reproducibility and precision of bone remodeling measurements made via in vivo dynamic bone histomorphometry. Although bone remodeling measurements showed moderate baseline noise, precision was adequate to measure physiologically relevant changes in bone remodeling, and measurements had relatively good reproducibility, with intra-class correlation coefficients of 0.75-0.95. This indicates that, when used in conjunction with MAT, in vivo dynamic histomorphometry provides a reliable assessment of bone remodeling.
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Chantal M J
authors.initials: CMJ
authors.lastname: de Bakker
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Allison R
authors.initials: AR
authors.lastname: Altman
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Connie
authors.initials: C
authors.lastname: Li
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Tribble
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Carina
authors.initials: C
authors.lastname: Lott
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA.
authors.forename: Wei-Ju
authors.initials: WJ
authors.lastname: Tseng
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 426C Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA, 19104, USA. xiaoweil@mail.med.upenn.edu.
authors.forename: X Sherry
authors.initials: XS
authors.lastname: Liu
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000000981:diagnostic imaging* / Q000378:metabolism; D003951:Diagnostic Errors; D005260:Female; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D010012:Osteogenesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D055114:X-Ray Microtomography / Q000379:methods*
keywords: 3D image registration; Animal models/rodent; In vivo μCT; Trabecular microstructure