Affiliations: [a] Institute for Biomedical Engineering, University of Zürich and Swiss Federal Institute of Technology (ETH), Moussonstrasse 18, CH-8044 Zürich, Switzerland | [b] Departement of Rheumatology, University Hospital, Gloriastrasse 25, CH-8091 Zürich, Switzerland
Correspondence:
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Address for correspondence: Andres Laib, Institute for Biomedical Engineering, Moussonstrasse 18, CH-8044 Zürich, Switzerland. Tel.: +41 1 632 45 92; Fax: +41 1 632 12 14; E-mail: [email protected].
Abstract: In vivo examinations of bone microarchitecture have become available recently through high resolution computed tomography (3D-QCT) and magnetic resonance imaging. The spatial resolution of the resulting images, however, is not sufficient to depict individual trabeculae in their true shape. Nevertheless, structural indices such as relative bone volume, trabecular number, mean thickness and mean separation can be extracted with the help of a ridge detection algorithm. Precision of the procedure is of the order of 1%, accuracy is ascertained using a micro-CT based calibration. In this work we report first results of time serial examinations. Eighteen healthy postmenopausal women (no HRT) were measured at months 0, 6, and 12, and the temporal changes were analyzed. Examination site was the distal radius. The above mentioned structural indices, the average densities and the thickness of the cortical shell were determined. Of the 18 women 6 showed no significant bone loss of any kind, 5 lost primarily cancellous bone, 4 lost primarily cortical bone, and 3 had a substantial loss of cortical as well as cancellous bone. We conclude that even in a homogenous group such as postmenopausal women, there are considerable differences in the reason why bone is weakend and that high resolution 3D-QCT allows to differentiate between various types of bone loss.
Keywords: Computed tomography (CT), bone microarchitecture, trabecular bone structure, quantitative bone morphology
