Table 1.
Results of Linear Regression Analysis.
| A. Measured PDFF Versus Reference Fat Fraction | ||||
|---|---|---|---|---|
| BMD | 0 mg/cm3 | 50 mg/cm3 | 100 mg/cm3 | 150 mg/cm3 |
| R2 | 0.989 | 0.998 | 0.991 | 0.998 |
| Slope | 1.03 ± 0.062 | 1.00 ± 0.026 | 0.99 ± 0.053 | 1.01 ± 0.029 |
| P = 0.59 | P = 0.90 | P = 0.85 | P = 0.71 | |
| Intercept | 0.018 ± 0.025 | 0.010 ± 0.011 | 0.0090 ± 0.021 | −0.008 ± 0.012 |
| P = 0.47 | P = 0.34 | P = 0.68 | P = 0.49 | |
| B. Measured R2* Versus Known BMD | |||||
|---|---|---|---|---|---|
| Reference FF | 0% | 20% | 40% | 50% | 60% |
| R2 | 0.956 | 0.985 | 0.841 | 0.941 | 0.997 |
| Slope | 0.00056 ± 8.5x10−5 | 0.00090 ± 7.7 × 10−5 | 0.00066 ± 0.00020 | 0.00080 ± 0.00014 | 0.0016 ± 6.3 × 10−5 |
| Baseline | P = 0.39 | P = 0.99 | P = 0.67 | P = 0.002 | |
| Intercept | 0.023 ± 0.0079 | 0.055 ± 0.0072 | 0.088 ± 0.019 | 0.085 ± 0.013 | 0.035 ± 0.0059 |
| Baseline | P = 0.27 | P = 0.014 | P = 0.026 | P = 0.88 | |
A. Measured PDFF values agreed closely with known FFs for all BMD values in the phantom.
B. Measured R2* values were linearly related to BMD (all slope values were significantly greater than 0), although the slope varied significantly depending on the FF. P‐values relate to comparison with the 0% FF vial using analysis of covariance.
BMD, bone mineral density; FF, fat fraction; PDFF, proton density fat fraction.