THE CHARACTERIZATION OF BROAD-BAND ULTRASOUND ATTENUATION AND FRACTALANALYSIS BY BIOMECHANICAL PROPERTIES

The purpose of this study was to show how the difference in structure affects the mechanical properties of bone and if BUA or fractal analys is is able to detect these changes in mechanical properties, A total o f 38 cancellous bone cubes were obtained from seven bovine tibiae (32 specimens) and one human tibia (6 specimens), BUA was measured in the superior/inferior (SI), medial/lateral (ML), and anterior/posterior (A P) directions for each specimen, The fractal dimension was estimated b y using the continuous alternating sequential filter (CASF) pyramid ap proach to handle fractal dimension estimation of small images, Nondest ructive compressive tests were also performed in the three orthogonal directions for each sample, The correlations between BUA and density w ere statistically significant for all three directions, The correlatio n between BUA and elastic modulus varied depending on the direction in which the two parameters were measured, The best correlation was in t he AP directions (r = 0.75, p < 0.0001), followed by the ML direction (r = 0.52, p = 0.0006), and finally the SI direction (r = 0.18, p = 0. 28), The only significant correlation between fractal dimension and de nsity was in the SI direction (r = 0.39, p = 0.015), There was signifi cant correlation between fractal dimension and elastic modulus in all three directions, but the direction that exhibited the best correlatio n was the SI direction (r = 0.61, p < 0.0001), The correlation coeffic ients for the AP and ML directions were 0.45 (p = 0.0046) and 0.34 (p = 0.0377), respectively, A multivariate model, carried out to predict the elastic modulus from the BUA or fractal dimension including densit y, demonstrated that the correlation coefficient significantly increas ed in all three directions for BUA and fractal dimension, After adjust ment for density, significant relationships between elastic modulus an d BUA or fractal dimension were still found (p < 0.05). (C) 1997 by El sevier Science Inc.