Prediction of Bone Quality and Quantity in 90-day Bed Rest Using Confocal Scanning Ultrasound System and Dexa Measurement

+*Qin, Y-X., *Xia, Y., *Lin, W., Adler, B., *Rubin, C. *Department of Biomedical Engineering, SUNY Stony Brook, Stony Brook, NY email: [email protected] INTRODUCTION: Musculoskeletal complications induced by age-related diseases like osteoporosis, and in long-term disuse osteopenia such as a lack of microgravity during extended space missions and long-term bed rest, represent a key health problem. Such a skeletal disorder changes both the structural and strength properties of bone, and the latter plays a critic role in ultimately leading to fracture [1]. Early diagnosis of progressive bone loss or subtle changes of bone quality would allow prompt treatment and thus would dramatically reduce the risk of bone fracture. Most osteoporotic fractures occur in cancellous bone. Hence, noninvasive assessment of trabecular strength is extremely important in evaluating bone quality. The principal diagnostic method for osteoporosis is currently dual-energy X-ray absorptiometry (DEXA), which provides an index of bone mineral density (BMD) and/or content, but not the bone's physical properties. Recently, advancements in ultrasonic techniques provide a method for characterizing the material properties of bone in a manner which is non-invasive, non-destructive, repeatable, safe and relatively accurate. Limitations with this approach, however, include the tissue boundary interaction, influence of soft tissue and cortical shell, and accuracy. These leave quantitative ultrasound (QUS) in its current configuration as a first order screening tool, rather than a highly accurate diagnostic for true fracture risk [2]. To overcome these hurdles and improve the specificity of non-invasive ultrasonic assessment, we have initiated a new modality of QUS by developing a scanning confocal acoustic diagnostic (SCAD) technology particularly for identifying the strength of trabecular bone [3]. The ultrasound resolution and sensitivity can be significantly improved by its configuration. The objective of this work was to longitudinally evaluate bone mass changes in a 90-day bed rest. The correlations between QUS parameters and DEXA determined BMD were performed.