Effect of Edge-Preserving Adaptive Image Filter on Low-Contrast Detectability in CT Systems: Application of ROC Analysis

Table 1

95% confidence intervals of the differences in average Az values and P-values obtained using MRMC analysis for low-contrast detection task for each target size (2, 3, 4, 5 mm) using images with and without QDS filter. These results also list the tube current used for each condition (target size, with or without QDS filter) to obtain a mean Az value that just exceeded 0.7. In all cases, “0” was included in the 95% confidence intervals and the P-values were large.

Target diameter	QDS	Tube current	Mean Az value	Difference	95% confidence interval		P-value
2 mm	Without	320 mA	0.709	−0.051	−0.176	0.074	0.410
	With	200 mA	0.760
3 mm	Without	180 mA	0.706	0.002	−0.074	0.078	0.911
	With	120 mA	0.704
4 mm	Without	140 mA	0.730	−0.029	−0.133	0.075	0.566
	With	90 mA	0.759
5 mm	Without	100 mA	0.717	−0.004	−0.080	0.072	0.880
	With	80 mA	0.721