Analysis of bone structure for an improved diagnosis of osteoporosis

Osteoporosis is the most frequent disease of the skeletal system. It is defined by reduced (mineral) bone density and changes in the microarchitecture of the bone leading to an increased risk of bone fractures. The measurement of the bone mineral density (BMD) is a well established method in the diagnosis of osteoporosis. But since the fracture risk does not only depend on the bone density, this parameter is only of limited use for assessing the fracture risk. Nowadays it is possible to visualize the complex, three-dimensional (trabecular) bone structures using high resolution imaging techniques (CT and MR). If one compares the morphology of the microarchitecture of the bone with the large scale structure of the galaxies in the universe, one can find similarities: In both cases one deals with filaments and wall-like structures, which enclose empty regions ("voids"). An interdisciplinary research project of the MPE in cooperation with the department of radiology of the TU Munich within the framework of the recently initiated TANDEM-projects has been established. In this project new methods for the quantitative description of complex structures, which were originally developed in the field of astrophysics, are applied to the analysis of three-dimensional images of the trabecular bone structure in order to improve the diagnosis of osteoporosis. The results obtained so far show that the newly developed structure measures are very well suited to predict the mechanical strength of bones in human specimen and the risk of fractures in patients.