NONINVASIVE BONE-BIOPSY - A NEW METHOD TO ANALYZE AND DISPLAY THE 3-DIMENSIONAL STRUCTURE OF TRABECULAR BONE

Three-dimensional structure is one of the main factors influencing the mechanical behaviour of cancellous bone, To analyse the trabecular bo ne structure non-destructively we used a peripheral QCT system and app lied a special thin-slice technique to create high-resolution volumetr ic data sets serving as a basis for something we would like to call no n-invasive bone biopsy. In order to obtain binary data sets, the miner alized bone in the CT volume was separated from bone marrow and muscle tissue with the help of a sophisticated three-dimensional segmentatio n algorithm based on the analysis of directional derivatives, which ar e computed from a locally approximated fit function of the original CT volume. Binary volumes including either a solid representation of tra becular plates and rods or a topological representation of the cancell ous bone architecture were acquired. Such volumes can be processed non -destructively and, even more important, repetitively. By using a surf ace reconstruction algorithm based on interpolating triangulation it w as possible to visualize the three-dimensional surface of the trabecul ar bone structure. The results showed that surface representation and visualization in combination with a multiple thin-slice measuring tech nique are valuable tools in studying three-dimensional bone architectu re. In the future, the non-invasive bone biopsies will be evaluated by means of three-dimensional mechanical analysis incorporating finite e lement modelling and direct morphological investigations of the cancel lous bone architecture for a better prediction of bone strength as an index for fracture risk or osteoporosis.