1. Department of Radiology and Biomedical Imaging, Musculoskeletal Quantitative Imaging Research Group, University of California San Francisco, 185 Berry St, Ste 350, San Francisco, CA 94107.
2. Department of Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
3. Department of Radiology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.
4. Center for Musculoskeletal Health, UC Davis Medical Center, Sacramento, CA.
5. Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA.