Abstract
We previously developed an image analysis approach for the determination of local sites of bone remodelling using time-lapse in vivo HR-pQCT. The involved image filtering for removing noise was chosen rather aggressively, and also removed some effects of the bone remodelling. In this paper, we quantify these filtering settings using ex vivo reproducibility HR-pQCT images, and determine the least-detectable bone remodelling using in vivo reproducibility HR-pQCT images, as well as testing whether the approach is capable of capturing age-related bone remodelling by use of in vivo long-term HR-pQCT images. We found that a threshold value of 225 mg HA/cm3 for the filtering led to acceptable results with falsely determined bone remodelling of less than 0.5%, and that the least-detectable bone formation and bone resorption are 2.0 ± 1.0% and 2.2 ± 0.7% respectively. We also found that age-related local bone remodelling can be captured satisfactorily in postmenopausal women. The latter revealed new insights into the effect of ageing on bone remodelling, and showed that bone remodelling seems to take place through a few small formation packets and many large resorption volumes leading to a net bone loss. We conclude that local in vivo bone remodelling can be successfully assessed with time-lapse in vivo HR-pQCT capable of assessing age-related changes in bone remodelling.
Highlights
Bone remodelling is a tightly coupled mechanism consisting of repetitive cycles of bone resorption followed by bone formation, which is necessary to maintain mineral homeostasis and to repair damaged bone caused by daily physical activity
We found that the filtering approach developed here leads to acceptable results: the least-detectable in vivo bone formation and bone resorption are 2.0 ± 1.0% and 2.2 ± 0.7%, respectively, and the method is sensitive enough to detect age-related local bone remodelling in postmenopausal women over a 2-year follow-up period
Since the age-related local bone remodelling revealed in our study is higher than the reproducibility of bone morphometric parameters of in vivo High-resolution peripheral quantitative CT (HR-pQCT), our results indicate that age-related changes were found
Summary
Bone remodelling is a tightly coupled mechanism consisting of repetitive cycles of bone resorption followed by bone formation, which is necessary to maintain mineral homeostasis and to repair damaged bone caused by daily physical activity. The cells responsible for this adaptation process are known as osteocytes (the mechanosensing cells that produce cytokines and hormones), osteoblasts (the bone-forming cells), and osteoclasts (the bone-resorbing cells) [1]. Biochemical markers of bone turnover allow the evaluation of bone remodelling in the entire skeleton. Bone cell activity is usually assessed by two-dimensional (2D) dynamic histomorphometry using fluorescent labels to indicate newly formed bone.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
