An ultrasonic bone assessment technique based on the spectral difference of signals from cortical and cancellous bone: an in vivo study

Ultrasonic backscatter may be able to detect changes in bone caused by osteoporosis. This study assesses the relative in vivo performance of three ultrasonic backscatter parameters: cortical-cancellous mean (CCM), cortical-cancellous slope (CCS), and cortical-cancellous intercept (CCI). Measurements were performed at the left and right femoral necks of 88 healthy volunteers. CCM was determined by frequency averaging the spectral power difference in decibels between echoes from the outer cortical surface and backscatter from underlying cancellous bone. CCS and CCI were determined from the slope and intercept, respectively, of a line fitted to the spectral power difference. Linear regression analysis was used to compare measurements performed at the left and right femur. CCM demonstrated highly significant (p < 0.0001) correlations between left and right side measurements across nine choices of gate delay and width for analysis of both ten and thirty adjacent signals centered on the bone (0.41 < R < 0.53). CCS and CCI showed significant correlations only for five and three gate choices, respectively, for the ten signal analysis (0.001 < p < 0.05). These results indicate that CCM is sensitive to naturally occurring variations in bone tissue and may be sensitive to changes in bone tissue caused by osteoporosis.