Do ultrasound measurements reflect bone microarchitecture rather than bone mass?: An in vitro study of the rat femur with the use of ultrasound, densitometry, and histomorphometry.

RATIONALE AND OBJECTIVES

In an experimental study in 40 rat femurs, the authors correlated the amplitude-dependent speed of bone ultrasound (Ad-SOS) with the bone mineral content and density and with the bone trabecular connectivity: trabecular bone volume, trabecular number, trabecular thickness, and trabecular separation to evaluate and compare the usefulness of the Ad-SOS to determine bone quantity and/or quality.

METHODS

Bone mineral content and density were determined with dual-energy x-ray absorptiometry. Trabecular connectivity was determined with histomorphometric techniques.

RESULTS

There was a strong correlation between the Ad-SOS and the other parameters studied, with a particularly high positive correlation with trabecular bone volume and trabecular thickness, and an inverse correlation with trabecular separation. The correlation was weaker with the bone mineral content and bone mineral density and with the trabecular number. For the trabecular separation, the correlation was significant in all cases, but it was negative.

CONCLUSIONS

Bone ultrasound, in this case Ad-SOS, defines the quality of the bone in terms of trabecular architecture rather than bone density; however, this conclusion is valid only for the rat femur model that the authors used.