Topography of acoustical properties of long bones: from biomechanical studies to bone health assessment

Abstract

The article presents a retrospective view on the assessment of long bones condition using topographical patterns of the acoustic properties. The application of ultrasonic point-contact transducers with exponential waveguides on a short acoustic base for detailed measurements in human long bones by the surface transmission was initiated during the 1980s in Latvia. The guided wave velocity was mapped on the surface of the long bones and the topographical patterns reflected the biomechanical peculiarities. Axial velocity profiles obtained in vivo by measurements along the medial surface of tibia varied due to aging, hypokinesia, and physical training. The method has been advanced at Artann Laboratories (West Trenton, NJ) by the introduction of multifrequency data acquisition and axial scanning. The model studies carried out on synthetic phantoms and in bone specimens confirmed the potential to evaluate separately changes of the bone material properties and of the cortical thickness by multifrequency acoustic measurements at the 0.1 to 1 MHz band. The bone ultrasonic scanner (BUSS) is an axial mode ultrasonometer developed to depict the acoustic profile of bone that will detect the onset of bone atrophy as a spatial process. Clinical trials demonstrated a high sensitivity of BUSS to osteoporosis and the capability to assess early stage of osteopenia.

Dispersion characteristics of the flexural wave assessed using low frequency (50–150 kHz) point-contact transducers: A feasibility study on bone-mimicking phantoms

“…A solution to overcome this limitation is the selective excitation of the flexural wave. Seemingly, this was achieved by using dry point-contact transducers by Tatarinov et al [30], although there was no clear explanation to the fact that this approach actually favors the flexural mode, diminishing spurious waves propagating in the soft tissues. In this paper, we extend the technique by combining dry point-contact transducers approach to the SVD-enhanced 2-D Fourier transform [31].…”

“…Although this was an interesting study, it did not allow concluding that the waveguide properties could be obtained in vivo using pointcontact transducers. Dry point-contact transducers have also been tested in vivo [30]. A flexural wave, similar to the A0 mode, could be observed, despite the presence of the soft tissues between the contact point of the transducers and the bone surface.…”

Hybrid nanostructured hydroxyapatite–chitosan composite scaffold: bioinspired fabrication, mechanical properties and biological properties

“…12 In addition to the mass faction of mineral (or organic matrix) in bones, the apatite crystal orientation has a great effect on mechanical properties. 13,14 Inside each individual trabecular bone, the apatite c-axis preferentially aligns along the direction of the trabecula, which makes the trabecula mechanically anisotropic. 15,16 Moreover, the biological properties of scaffolds are related to the crystallographic texture of HA crystals.…”

Application of the dual-frequency ultrasonometer for osteoporosis detection

“…In contrast, the received waveform of an ultrasound pulse with 1 MHz carrier frequency is defined mainly by the propagation parameters of longitudinal wave. Velocity of the longitudinal wave is determined by the material properties, that by the bone Young’s modulus [17, 26, 27]. Axial scanning, a new feature implemented in BUSS, allows assessment of topography of acoustical properties of long bones.…”