Correlation of ultrasound bone velocity with dual-energy x-ray bone absorptiometry in rat bone specimens

RATIONALE AND OBJECTIVES. To investigate bone mass measurements by ultrasound bone velocity (UBV) in bone specimens obtained from experimental animals. METHODS. The authors made UBV measurements in 40 femurs and tibias dissected from Sprague-Dawley rats (14 weeks-old, mean weight 290 g) and compared them with bone densitometric measurements made on the same material using dual-energy x-ray absorptiometry (DXA). RESULTS. The coefficient of variation for UBV measurements, based on values obtained in five femurs and five tibias at different times, was 0.2% and 03% respectively. Regression studies yielded a correlation between UBV and bone mineral density in femur of r = 0.87 (P < 0.0001) and with bone mineral content of r = 0.65 (P < 0.0001); in the tibia similar levels of significance were obtained. The correlation between femur weight and UBV was r = 0.51 (P < 0.0005) and with bone mineral content it was r = 0.79 (P < 0.0001). Partial correlation between UBV and femur bone mineral density, with respect to bone weight, was r = 0.68 (P < 0.001), and with femur bone mineral content was r = 0.71 (P < 0.0001). In the tibia measurements were similarly significant. CONCLUSIONS. Measurements of bone mass made with ultrasound transmission velocity are precise correlate well with DXA measurements.