Table 5.
Multi-centre pQCT cross-calibration with EFP. As per ISCD recommendations, linear regression models determined slopes and intercepts related the European Forearm Phantom (EFP) bone mimic variables between the referent Hamilton pQCT scanner (model: XCT2000) and each of the scanners at other sites. 95% confidence intervals (CI) (lower, upper) for slope and intercepts were reported. Calibration data were obtained from the Canadian Multicentre Osteoporosis Bone Quality Study[22].
| Bone variable | Slope (95%CI) | Intercept (95%CI) | Slope (95%CI) | Intercept (95%CI) |
|---|---|---|---|---|
| Vancouver XCT2000 | Vancouver XCT3000 | |||
| Tot.Ar (mm2) | 1.02 (1.01,1.02) | 5.90 (4.08,7.73) | 1.02 (1.01,1.02) | 5.31 (3.93,6.69) |
| vBMDi (mg/cm3) | 0.97 (0.94,1.00) | 23.16 (10.88,35.45) | 0.99 (0.97,1.00) | 13.85 (6.20,21.49) |
| Ct.Ar (mm2) | 0.98 (0.89,1.06) | 0.23 (-4.33,4.78) | 1.00 (0.93,1.08) | 1.04 (-2.76,4.83) |
| vBMDc (mg/cm3) | 0.98 (0.89,1.07) | 17.77 (-58.59,94.12) | 0.92 (0.84,1.00) | 69.70 (1.58,137.83) |
| Tb.Ar (mm2) | 1.02 (1.01,1.02) | 2.57 (1.72,3.43) | 1.02 (1.01,1.02) | 2.35 (1.75,2.94) |
| vBMDtr (mg/cm3) | 1.17 (1.10,1.24) | -27.17 (-44.85,-9.49) | 1.19 (1.09,1.28) | -31.15 (-53.34,-8.96) |
| Saskatoon XCT2000 | Toronto XCT2000 | |||
| Tot.Ar (mm2) | 1.00 (1.00,1.00) | -0.18 (-1.36,1.00) | 1.00 (1.00,1.00) | -0.75 (-1.76,0.25) |
| vBMDi (mg/cm3) | 1.00 (0.99,1.01) | -2.75 (-6.80,1.29) | 1.01 (1.00,1.01) | -8.21 (-10.65,-5.76) |
| Ct.Ar (mm2) | 0.99 (0.92,1.06) | 0.20 (-3.62,3.22) | 0.97 (0.87,1.07) | 0.65 (-4.57,5.86) |
| vBMDc (mg/cm3) | 0.96 (0.83,1.09) | 27.41(-80.22,135.04) | 0.91 (0.78,1.05) | 67.96 (-43.67,179.59) |
| Tb.Ar (mm2) | 1.00 (1.00,1.00) | -0.09 (-0.60,0.42) | 1.00 (1.00,1.00) | -0.40 (-0.85,0.05) |
| vBMDtr (mg/cm3) | 0.99 (0.97,1.01) | |||
| Kingston XCT2000 | ||||
| Tot.Ar (mm2) | 1.00 (1.00,1.00) | -0.57 (-1.45,0.32) | - | - |
| vBMDi (mg/cm3) | 0.98 (0.97,0.99) | -3.92 (-7.39,-0.44) | - | - |
| Ct.Ar (mm2) | 0.93 (0.84,1.02) | 0.62 (-4.32,5.56) | - | - |
| vBMDc (mg/cm3) | 0.92 (0.81,1.02) | 50.90 (-38.96,140.75) | - | - |
| Tb.Ar (mm2) | 1.00 (1.00,1.00) | -0.23 (-0.65,0.20) | - | - |
| vBMDtr (mg/cm3) | 0.97 (0.96,0.98) | -0.91 (-3.84,2.01) | - | - |