A device for in vivo measurements of quantitative ultrasound variables at the human proximal femur

Abstract

Quantitative ultrasound (QUS) at the calcaneus has similar power as a bone mineral density (BMD)- measurement using DXA for the prediction of osteoporotic fracture risk. Ultrasound equipment is less expensive than DXA and free of ionizing radiation. As a mechanical wave, QUS has the potential of measuring different bone properties than dual X-ray absorptiometry (DXA,) which depends on X-ray attenuation and might be developed into a tool of comprehensive assessment of bone strength. However, site-specific DXA at the proximal femur shows best performance in the prediction of hip fractures. To combine the potential of QUS with measurements directly at the femur, we developed a device for in vivo QUS measurements at this site. Methods comprise ultrasound transmission through the bone, reflection from the bone surface, and backscatter from the inner trabecular structure. The complete area of the proximal femur can be scanned except at the femoral head, which interferes with the ilium. To avoid edge artifacts, a subregion of the proximal femur in the trochanteric region was selected as measurement region. First, in vivo measurements demonstrate a good signal to noise ratio and proper depiction of the proximal femur on an attenuation image. Our results demonstrate the feasibility of in vivo measurements. Further improvements can be expected by refinement of the scanning technique and data evaluation method to enhance the potential of the new method for the estimation of bone strength.

Relationship between calcaneal quantitative ultrasound and hip dual energy X-ray absorptiometry in young healthy men

“…Specifically, assessment of calcaneal QUS against calcaneal DXA would seem worthwhile. QUS assessment at the femur [64] is still at the experimental stage but might be compared to femoral DXA data. In this regard, the loss of the significant yet modest correlation with exercise between the two modalities is an interesting finding given that both BUA and BMD (all femoral regions) significantly increased with exercise.…”

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

“…We developed an ultrasound device for direct in vivo measurements at the proximal femur, the FemUS (Femur Ultrasound Scanner) device [18,19]. Based on ex vivo measurements of excised femora, correlations between speed of sound (SOS) as QUS variable and femoral BMD around 0.8 to 0.9 with residual errors around 8% to 10% were reported [18].…”

A hybrid FDTD-Rayleigh integral computational method for the simulation of the ultrasound measurement of proximal femur

“…The measurement configuration considered is a model of the measurement of the upper extremity of the femur. In the QUS application, the probe is typically at a distance of more than 15 cm from the femur [5]. In first approach soft tissues and coupling medium between the probe and femur may be approximated by a homogeneous medium, e.g.…”

“…However, aBMD alone is not sufficient to account for bone strength [3,4]. The development of a quantitative ultrasound (QUS) hip scanner [5,6] aims at providing an alternative to aBMD measurements. Because the cortical shell at the proximal femur determines a large part of bone strength [7,8], there is substantial interest in developing QUS measurements with improved sensitivity to cortical bone geometrical and material properties.…”