Bone microstructure and elastic tissue properties are reflected in QUS axial transmission measurements

Femur ultrasound (FemUS)—first clinical results on hip fracture discrimination and estimation of femoral BMD

“…A "guided wave" through the proximal shaft could be evaluated to achieve information about the cortical bone. This kind of wave has previously been evaluated in axial transmission measurements (typically at the radius and the tibia) and transverse measurements (at the finger phalanges) [28][29][30][31]. Taking the experience from these measurements, one might expect that the guided waves at the femur are influenced by geometric aspects like bone diameter as well as cortical properties like mineralization, porosity and thickness.…”

Low-frequency axial ultrasound velocity correlates with bone mineral density and cortical thickness in the radius and tibia in pre- and postmenopausal women

“…In this approach, two or more ultrasonic transmitters and receivers are placed on the same side of the bone, and the apparent propagation velocity of the first arriving signal (FAS) is determined [1,8,9,20,29]. Sensitivity of this FAS velocity to diagnostically useful information about bone has been debated by a number of modeling [5,23,33], in vitro [7,19,25,26,31,35], and in vivo studies [22,34,37].…”

“…The FAS velocity has in modeling and in vitro studies shown to be sensitive to elastic anisotropy, mineralization, intracortical porosity, and acoustic impedance [5,7,35]. More recently, porosity and material property gradients through the cortical layer have been shown to greatly affect the FAS velocity [12].…”

“…A number of in vivo studies have also reported sensitivity to volumetric bone mineral density [9,22,39]. Essentially, certain phantom and in vitro studies have demonstrated that sufficient sensitivity to endosteal bone properties is indeed associated with long-enough wavelengths and the resulting deep enough penetration depths [25,35,42]. However, what is still needed is clear in vivo evidence of such an advantage related to an LF approach.…”

Quantitativer Ultraschall

“…Die verschiedenen QUS-Ge- [18,19]. Mithilfe der SAM konnte auch ein Modell entwickelt werden, welches Struktur-und Elastizitätsparameter mit der auch in vivo messbaren, axialen Transmission verknüpft [20]. Einerseits konnten so die Parameter identifiziert werden, welche die Schallgeschwindigkeit bei der axialen Transmission beeinflussen, andererseits hilft dies bei der Entwicklung von Methoden, Knochenparameter wie Porosität und Kortikalisdicke separat abzuschätzen [21,22] …”