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Estimation of Trabecular Thickness Using Ultrasonic Backcatter
| Content Provider | CiteSeerX |
|---|---|
| Author | Padilla, Frederic Jenson, Frederic Laugier, Pascal |
| Abstract | We present a method to estimate trabecular thickness (Tb.Th) in trabecular bones from ultrasound backscatter measurements. The estimation scheme is based on a nonlinear adjustment of predictions from a model to experimental data. The model assumes weak scattering from bone, where scattering is assumed to arise from the elastic solid trabeculae. The fluctuations of acoustical properties between bone tissue and the saturating fluid are assumed to be random and are described by the 3-D spatial autocorrelation function of the medium. In this paper, a Gaussian autocorrelation function is used. The inversion procedure is applied to a set of data measured on 33 femoral bone specimens. Results show that the model can predict both the magnitude and the frequency-dependence of the backscatter coeffi-cient (root mean square error RMSE = I dB). The estimated trabecular thickness values are compared to the true trabecular thickness measured on high resolution microcomputed tomography 3-D reconstruc-tion of bones microarchitecture. A close agreement is obtained on average over the group of specimens between predictions and the reference values: true Tb.Th is 132 ± 12 urn and estimated Tb.Th is 134 ± 15 urn. However, a moderate correlation between actual and estimated Tb.Th values is found (R2 = 0.44, p< 10'4, RMSE = 8.7 urn) suggesting a modest predictability at the individual level. Sources for the vari-ability ofthe estimator are studied. U sing synthetic rf'signals, we demonstrate that the fundamental limi- |
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| Access Restriction | Open |
| Content Type | Text |
