TABLE IV.
Mean ± standard deviation of the normalized mean of the backscatter difference spectrum (nMBD) for each transducer and gate separation τs. a
| Transducer center frequency fc (MHz) | nMBD (dB/μs) | ||
|---|---|---|---|
| τs = 0 | τs = 5/fc | τs = 10/fc. | |
| 2.25 | 2.1 ± 0.2 (0.79*) | 1.8 ± 0.2 (0.77*) | 1.7 ± 0.2 (0.70*) |
| 5 | 4.0 ± 0.7 (0.89*) | 3.7 ± 0.6 (0.90*) | 3.4 ± 0.5 (0.91*) |
| 7.5 | 5.7 ± 1.0 (0.94*) | 5.4 ± 0.9 (0.92*) | 4.9 ± 0.8 (0.90*) |
| 10 | 5.8 ± 1.3 (0.95*) | 5.8 ± 1.3 (0.95*) | 5.4 ± 1.1 (0.95*) |
a
Linear correlation coefficients with bone density are given in parentheses. *p < 0.001.