High-Resokution Three-Dimensional-pQCT Images Can Be An Adequate Basis for In-Vivo FE Analysis of Bone  

Oleh:

Ruegsegger, P. ; Pistoia, W. ; Laib, A. ; Rietbergen, B. van

Jenis: Article from Bulletin/Magazine
Dalam koleksi: Journal of Biomechanical Engineering vol. 123 no. 2 (2001), page 176-183.
Topik: basis; high - resolution; three - dimensional; adequate basis; in - vivo; FE; analysis; bone

Ketersediaan

Perpustakaan Pusat (Semanggi) Nomor Panggil: JJ52.2 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

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Isi artikel

Micro - finite element (µFE) models based on high-resolution images have enabled the calculation of elastic properties of trabecular bone in vitro. Recently, techniques have been developed to image trabecular bone structure in vivo, albeit at a lesser resolution. The present work studies the usefulness of such in - vivo images for µFE analyses, by comparing their µFE results to those of models based on high - resolution micro -CT (µCT) images. Fifteen specimens obtained from human femoral heads were imaged first with a 3D - pQCT scanner at 165 µm resolution and a second time with a µCT scanner at 56 µm resolution. A third set of images with a resolution of 165 µm was created by downscaling the µCT measurements. The µFE models were created directly from these images. Orthotropic elastic properties and the average tissue von Mises stress of the specimens were calculated from six FE - analyses per specimen. The results of the 165 µm models were compared to those of the 56 µm model, which was taken as the reference model. The results calculated from the pQCT - based models, correlated excellent with those calculated from the reference model for both moduli (R(2) > 0.95) and for the average tissue von Mises stress (R(2) > 0.83). Results calculated from the downscaled micro - CT models correlated even better with those of the reference models (R(2) > 0.99 for the moduli and R(2) > 0.96 for the average von Mises stress). In the case of the 3D - pQCT based models, however, the slopes of the regression lines were less than one and had to be corrected. The prediction of the Poisson's ratios was less accurate (R(2) > 0.45 and R(2) > 0.67) for the models based on 3D - pQCT and downscaled µCT images respectively). The fact that the results from the downscaled and original µCT images were nearly identical indicates that the need for a correction in the case of the 3D - pQCT measurements was not due to the voxel size of the images but due to a higher noise level and a lower contrast in these images, in combination with the application of a filtering procedure at 165 micron images. In summary : the results of µFE models based on in - vivo images of the 3D - pQCT can closely resemble those obtained from µFE models based on higher resolution µCT system.

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