Abstract:
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Purpose: There is strong evidence that age induces a decrease of bone mineral density (BMD) while the age-related changes of non-invasively determined trabecular bone structure are less understood. The purpose of this study was to investigate age-related changes of trabecular bone structure in healthy female patients applying our new 3D-based scaling index method on high resolution magnetic resonance (HR-MR) images of the distal radius and to compare these with the correlation of age and BMD.
Methods and Materials: HR-MR imaging of the distal radius was performed at 1.5 T in 60 healthy women, aged 39 to 76 years, using a receive-only wrist coil. We applied a three-dimensional gradient-echo sequence with a slice thickness of 0.5 mm, a TE of 6.7 ms, a TR of 24 ms, a flip angle of 20°, 2 acquisitions and an acquisition time of 7.16 min in an axial orientation. A matrix of 512x512 pixels was used with a field of view (FOV) of 10 cm corresponding to a pixel size of 195x195 μm. After normalization and segmentation of each MR-image structure analysis was performed using a new non-linear texture measure (3D scaling index method) as well as standard morphological 2D parameters, which included apparent measures of trabecular bone volume fraction, trabecular thickness, trabecular spacing, and trabecular number. For all subjects BMD measurements of the spine were obtained using quantitative computed tomography (QCT).
Results: Linear regression was applied to the data to describe age-related changes. There was a significant decrease with age for BMD and apparent trabecular bone volume fraction in HR-MR images. However, there was no correlation found for age versus the 3D structure measure based on the local scaling index method. A fairly high correlation with age was calculated for BMD (r=-.642, p<0.01), while the 2D structure parameter trabecular bone volume fraction showed only a moderate correlation (r=-.319, p<0.05).
Conclusion: In contrast to BMD there was no correlation found between our newly developed scaling index parameter and the age of healthy subjects. Since this parameter shows a high diagnostic performance in differentiating post-menopausal patients with and without osteoporotic fractures, we conclude that this non-linear measurement may determine different non-age-related entities that are important for the prediction of individual fracture risk and are not reflected by BMD.
Questions about this event email: dmueller@roe.med.tu-muenchen.de
Mueller MD, D,
Age-related Changes of 3D-Trabecular Structure Parameters in Comparison with Bone Mineral Density. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3104473.html