Distribution of sonic plesio-velocity in a compact bone sample

Abstract

Since compact bone is demonstrably anisotropic and inhomogeneous, the measured quantities yield a plesio-velocity rather than a true sonic velocity, which makes it difficult to compare velocity measurements among several bone samples. Distribution of the plesio-velocity for 11 pairs of 2 mm thick specimens from a single mature bovine compact bone sample using 100-ns well-damped sonic pulses emitted by a 10-mHz transducer show that anisotropy exists in both axial and transverse directions and must be associated with the local structure and composition. Changes in the same specimens when wet, dry, and rehydrated show an increase in velocity and anisotropy of the dry over the wet state. The plesio-velocity is greater in the axial direction, along the bone axis, than in the transverse plane. The change in plesio-velocity from wet to dry bone is greatest along the bone axis and least in the transverse plane. Changes in dimension, when the bone specimens were dried, show the bone sample to be anisotropic in this parameter also, but in the reverse order from that for the plesio-velocity. Shrinkage is least along the osteons and a maximum in the transverse plane.

Towards Aberration Correction of Transcranial Ultrasound Using Acoustic Droplet Vaporization

“…A λ/4 shift in the arrival time corresponding to a decrease in the average speed of sound was also observed during hydration. The decrease in speed of sound with hydration has been reported by others for other bones (Duck, 1990;Lees et al, 1979;Lang, 1970). Since the arrival time and transmission appear to reach a steady state, it was assumed that the skull was fully hydrated after 48 hours.…”

“…Prior work has shown that skull preparation affects the acoustic properties of an ex vivo human skull (Lang, 1970;Fry and Barger, 1978;Lees et al, 1979). Therefore, prior to performing transcranial ADV and aberration correction, the effects of skull hydration and the gas content of the hydrating water on the ultrasound transmission were studied.…”

Bone fibrillogenesis and mineralization: Quantitative analysis and implications for tissue elasticity

“…Extracellular bone tissue mass densities as determined from Eqs. (1) and (2) have been documented by Lees et al [1979aLees et al [ , 1983; Lees [1987]; Lees and Page [1992]; Lees et al [1995]; Lees [2003]; Biltz and Pellegrino [1969]; Broz et al [1995]; Gong et al [1964a]; Burns [1929]; Hammett [1925], see Tables 1-5.…”

“…The experimental data of Lees et al [1979aLees et al [ , 1995Lees et al [ , 1983; Lees [1987Lees [ , 2003; Lees and Page [1992]; Biltz and Pellegrino [1969]; Gong et al [1964a]; Burns [1929]; Hammett [1925] refer to mass density determination according to Archimedes' principle: The mass of samples with a typical size of a few millimeters is measured in air. Hence, the respective value M air refers to a state of empty vascular and lacunar pores, but with wet extracellular (ec) bone matrix.…”

“…According to the protocols of Lees et al [1979aLees et al [ , 1983; Lees [1987]; Lees and Page [1992], Lees et al [1995]; Lees [2003], bone samples are dried in a vacuum dessicator at room temperature, until a constant mass is observed (typically after 7 days). This mass is the mass of the dehydrated extracellular bone tissue, M dry .…”