Table 2 Comparison of the qualitative image analysis between the standard and RPP groups

Arterial phase

Qualitative image noise

3.51 ± 0.30 (3.00, 4.00)

3.93 ± 0.45 (2.50, 4.75)

3.89 ± 0.42 (2.50, 4.75)

< 0.001

0.001

Quantitative image noise

10.4 ± 1.71 (6.13, 13.04)

8.66 ± 1.28 (6.20, 11.42)

7.74 ± 0.95 (6.26, 10.01)

< 0.001

< 0.001

Image contrast

3.09 ± 0.43 (2.25, 4.00)

3.60 ± 0.65 (1.75, 4.50)

3.75 ± 0.60 (1.75, 4.50)

0.002

< 0.001

SNR of aorta

33.63 ± 8.45 (20.66, 59.60)

57.09 ± 14.29 (24.81, 78.55)

67.45 ± 17.66 (26.34, 100.75)

< 0.001

< 0.001

Image texture

4.48 ± 0.35 (3.75, 5.00)

4.06 ± 0.32 (3.50, 4.50)

3.56 ± 0.53 (3.50, 4.50)

< 0.001

< 0.001

Overall image quality

3.20 ± 0.47 (2.25, 4.00)

3.88 ± 0.58 (2.25, 4.75)

3.57 ± 0.56 (2.25, 4.50)

< 0.001

0.012

Portal venous phase

Qualitative image noise

3.60 ± 0.26 (3.25, 4.25)

4.12 ± 0.29 (3.50, 4.75)

3.98 ± 0.27 (3.25, 4.50)

< 0.001

< 0.001

Quantitative image noise

11.22 ± 1.56 (7.99, 14.85)

9.13 ± 1.76 (6.65, 13.40)

8.04 ± 1.05 (6.61, 11.04)

< 0.001

< 0.001

Image contrast

3.21 ± 0.31 (2.75, 4.00)

4.01 ± 0.49 (2.25, 4.75)

3.86 ± 0.42 (3.25, 4.75)

< 0.001

< 0.001

SNR of portal vein

15.90 ± 3.16 (9.99, 24.0)

24.71 ± 5.70 (15.11, 36.54)

29.29 ± 6.30 (19.15, 43.83)

< 0.001

< 0.001

SNR of liver

10.23 ± 2.06 (6.50, 15.42)

14.61 ± 3.39 (6.60, 21.33)

14.61 ± 3.39 (6.60, 21.33)

< 0.001

< 0.001

CNR of liver

5.66 ± 1.75 (2.56, 9.31)

10.11 ± 3.01 (5.56, 15.21)

12.34 ± 3.19 (5.29, 19.45)

< 0.001

< 0.001

Image texture

4.47 ± 0.31 (3.75, 5.00)

4.09 ± 0.23 (3.75, 4.50)

3.50 ± 0.42 (3.00, 4.50)

< 0.001

< 0.001

Overall image quality

3.44 ± 0.36 (2.75, 4.25)

4.16 ± 0.35 (3.25, 4.75)

3.63 ± 0.44 (3.00, 4.50)

< 0.001

0.095