Relationships Between Static Histomorphometry and Ultrasound in the Human Calcaneus

Abstract

The aim of this study was to explore the relationship(s) between histomorphometric measurements of cancellous bone structure and ultrasound. Ultrasonic measurements were made using a CUBA research system consisting of a pair of 1 Mhz unfocused transducers. Speed of sound (SOS) and broadband ultrasonic attenuation (BUA) were determined in 15 human cadaveric heels, with mean precision for all measurements coefficients of variation (CV) = 0.6% and 12%, respectively. The calcaneus was dissected and a 7.5 mm transcortical cylinder was removed from the path of ultrasound (US) transmission. The cortices were removed and the remaining cancellous core was sectioned into approximately 5 mm blocks, numbered from 1 to 6 (medial-lateral). Histomorphometric measurements were performed on decalcified, 5 microm-thick sections from blocks 1-6 using an automatic color image analysis system. There were significant differences between blocks 1 and 3-6 for BS/TV, BV/TV, Tb.N, and Tb. Sp (all P < 0.001), all decreasing in a medial-lateral direction (except Tb.Sp), implying that the medial portion of the calcaneus had more trabeculae with less spacing between them than the lateral portion. Furthermore, Tb.Th and BS/BV variables were uniform across the calcaneus, suggesting that individual trabeculae were of similar dimension. We found no significant correlations between US and histomorphometric parameters either averaged over all blocks or by using each block region separately. In conclusion, this study does not support the notion that US measurements of SOS and BUA through the heel reflect calcaneal cancellous bone structure, however, further studies using larger sample sizes may be warranted.

Quantitative Ultrasound Assessment of Acute Bone Loss Following Spinal Cord Injury: A Longitudinal Pilot Study

“…However, these relationships were generally modest [23] or disappeared when adjusted for density [13]. More recently, Häusler et al [24] found no significant correlation between QUS variables and any structural properties measured by histomorphometry. Supporting this, Hans et al [13] suggested that only 2-6% of the variance in QUS could possibly be explained by bone properties other than density or elasticity.…”

Recent developments in trabecular bone characterization using ultrasound

“…Several studies have investigated the relationships of these QUS variables to bone microarchitecture [12][13][14][15][16][17][18][19]. The data generally agreed on the following: the strongest evidence of the independent impact of microstructure on QUS is acoustic anisotropy [13,15,[20][21][22][23]; when the orientation of the ultrasound beam axis is fixed, usually along the medio-lateral direction, thereby limiting the potential influence of anisotropy, unidirectional ultrasound measurements correlate strongly with density [24][25][26][27]; after adjustment for density, the impact of microarchitecture on QUS parameters is still significant but modest for unidirectional QUS parameters measured at the calcaneus [26,27], the vertebrae [18], or the femur (Unpublished data). However, the interpretation of these statistical multi-linear models is often obscured by the limited sample size, the large number of statistical relationships to be tested with multiple variables, and the usual strong covariance observed between bone quantity and microarchitecture.…”

Statistics of the envelope of ultrasonic backscatter from human trabecular bone

“…8 The length of this trabecula was set to 0.65 mm and was chosen because this value corresponds to a mean value of trabecular separation in calcaneus. 24,25 The power backscattering coefficients (PBSC) for the infinite cylinder and for the sphere were calculated using the theory of scattering of ultrasound, respectively, from an elastic cylinder and the elastic sphere proposed by Faran 26 and Flax et al 27 We have found that the variation of the normalized (to 1 MHz) power backscattering coefficient due to the frequency change from 0.5 to 1.5 MHz allows to approximate the finite-length cylinder scattering with the scattering on the sphere [ Fig. 3(A)].…”

“…Mean values and standard deviations for the diameters of the trabeculae were collected from literature. 8,13,24,28,29 Variations in the structural properties of cancellous bone were modeled by changing the mean value and variance of scatterers' diameters. Experimentally determined thickness distributions of trabeculae were reported to be right-skewed, and the published data 29 follow well the Gamma distribution.…”