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Table 3 Sensitivity ratios for the different CT densitometric parameters (whole lung; analysis of covariance model)a

From: Exploring the optimum approach to the use of CT densitometry in a randomised placebo-controlled study of augmentation therapy in alpha 1-antitrypsin deficiency

  Model with lung volume adjustment
Outcome measure LS mean change from baseline Standard error Sensitivity indexb F-testc
PD15 (g/L) -4.12 0.539 7.64 -
MLD (g/L) -3.31 0.801 4.14 < 0.05
VI-910 (%) 2.25 0.517 4.36 < 0.05
VI-950 (%) 2.36 0.420 5.61 NS
  Model without lung volume adjustment
Outcome measure LS mean change from baseline Standard error Sensitivity indexb Reduction in sensitivity indexd
PD15 (g/L) -4.24 0.771 5.50 2.14
MLD (g/L) -3.49 1.221 2.86 1.28
VI-910 (%) 2.34 0.687 3.41 0.95
VI-950 (%) 2.41 0.514 4.69 0.92
  1. LS mean, least squares mean; PD15, 15th percentile lung density; MLD, mean lung density;
  2. VI-910, voxel index at a threshold of -910 (measured in %); VI-950, voxel index at a threshold of -950 (measured in %); NS, not significant. aResults based on estimates from endpoint analysis for placebo group only. bRatio of absolute value of mean change divided by standard error. cRatio of outcome measure as compared to PD15. dSensitivity index from model with lung volume adjustment minus sensitivity index from model without lung volume adjustment.