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

Table 2

Comparison of the tube current necessary for each condition (target size, with or without QDS filter) to obtain approximately equivalent mean Az values. The last column shows the dose reduction possible with QDS for each target size at statistically equivalent performance levels based on mean Az values.

	Without QDS			With QDS
Target diameter	Tube current	Mean Az value	Exposure dose	Tube current	Mean Az value	Exposure dose	Dose reduction ratio
2 mm	320 mA	0.709	44.5 mGy	200 mA	0.760	27.8 mGy	38%
3 mm	180 mA	0.706	25.0 mGy	120 mA	0.704	16.7 mGy	33%
4 mm	140 mA	0.730	19.5 mGy	90 mA	0.759	12.5 mGy	36%
5 mm	100 mA	0.717	13.9 mGy	80 mA	0.721	11.1 mGy	20%