title: Guidelines for Dual Energy X-Ray Absorptiometry Analysis of Trabecular Bone-Rich Regions in Mice: Improved Precision, Accuracy, and Sensitivity for Assessing Longitudinal Bone Changes.
abstract: Trabecular bone is frequently studied in osteoporosis research because changes in trabecular bone are the most common cause of osteoporotic fractures. Dual energy X-ray absorptiometry (DXA) analysis specific to trabecular bone-rich regions is crucial to longitudinal osteoporosis research. The purpose of this study is to define a novel method for accurately analyzing trabecular bone-rich regions in mice via DXA. This method will be utilized to analyze scans obtained from the International Space Station in an upcoming study of microgravity-induced bone loss. Thirty 12-week-old BALB/c mice were studied. The novel method was developed by preanalyzing trabecular bone-rich sites in the distal femur, proximal tibia, and lumbar vertebrae via high-resolution X-ray imaging followed by DXA and micro-computed tomography (micro-CT) analyses. The key DXA steps described by the novel method were (1) proper mouse positioning, (2) region of interest (ROI) sizing, and (3) ROI positioning. The precision of the new method was assessed by reliability tests and a 14-week longitudinal study. The bone mineral content (BMC) data from DXA was then compared to the BMC data from micro-CT to assess accuracy. Bone mineral density (BMD) intra-class correlation coefficients of the new method ranging from 0.743 to 0.945 and Levene's test showing that there was significantly lower variances of data generated by new method both verified its consistency. By new method, a Bland-Altman plot displayed good agreement between DXA BMC and micro-CT BMC for all sites and they were strongly correlated at the distal femur and proximal tibia (r=0.846, p<0.01; r=0.879, p<0.01, respectively). The results suggest that the novel method for site-specific analysis of trabecular bone-rich regions in mice via DXA yields more precise, accurate, and repeatable BMD measurements than the conventional method.
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Jiayu
authors.initials: J
authors.lastname: Shi
authors.affiliation: 2 Department of Orthopedic Surgery, CHA Bundang Medical Center, CHA University , School of Medicine, Gyeonggi-do, Republic of Korea.|3 Department of Orthopedic Surgery and the Orthopedic Hospital Research Center, University of California , Los Angeles, Los Angeles, California.
authors.forename: Soonchul
authors.initials: S
authors.lastname: Lee
authors.affiliation: 3 Department of Orthopedic Surgery and the Orthopedic Hospital Research Center, University of California , Los Angeles, Los Angeles, California.|4 Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine, University of California , Los Angeles, Los Angeles, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Uyeda
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Justine
authors.initials: J
authors.lastname: Tanjaya
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Jong Kil
authors.initials: JK
authors.lastname: Kim
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Hsin Chuan
authors.initials: HC
authors.lastname: Pan
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Patricia
authors.initials: P
authors.lastname: Reese
authors.affiliation: 5 Aerospace Engineering Sciences, University of Colorado , Boulder, Colorado.
authors.forename: Louis
authors.initials: L
authors.lastname: Stodieck
authors.affiliation: 6 Institute for Digital Research and Education Statistical Consulting Group, University of California , Los Angeles, Los Angeles, California.
authors.forename: Andy
authors.initials: A
authors.lastname: Lin
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.|3 Department of Orthopedic Surgery and the Orthopedic Hospital Research Center, University of California , Los Angeles, Los Angeles, California.
authors.forename: Kang
authors.initials: K
authors.lastname: Ting
authors.affiliation: 1 Division of Growth and Development and Section of Orthodontics, School of Dentistry, University of California , Los Angeles, Los Angeles, California.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kwak
authors.affiliation: 3 Department of Orthopedic Surgery and the Orthopedic Hospital Research Center, University of California , Los Angeles, Los Angeles, California.|4 Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine, University of California , Los Angeles, Los Angeles, California.
authors.forename: Chia
authors.initials: C
authors.lastname: Soo
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000818:Animals; D015519:Bone Density; D000071556:Cancellous Bone / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D008137:Longitudinal Studies; D051379:Mice; D008807:Mice, Inbred BALB C; D010024:Osteoporosis / Q000517:prevention & control; D055114:X-Ray Microtomography / Q000379:methods*