Table 6. Intergroup comparison of the indices in different dose groups.

Index	Group C	Group D	t/Z value	P value
LE10	1.78±0.16	2.07±0.22	−4.201	<0.01
PE10	1.40±0.13	1.85±0.25	−6.226	<0.01
SE10	1.42±0.11	1.71±0.13	−6.614	<0.01
LE15	1.81 (1.78–1.97)	2.15 (2.06–2.44)	−3.7541	<0.011
PE15	1.24±0.18	1.51±0.19	−3.955	<0.01
SE15	1.46±0.14	1.72±0.14	−5.182	<0.01
LE20	1.94±0.20	2.27±0.29	−3.655	<0.01
PE20	1.25±0.24	1.46±0.20	−2.539	0.017
SE20	1.48±0.14	1.71±0.15	−4.330	<0.01
LPC	1.73±0.16	1.73±0.18	−0.058	0.954
LSC	0.94±0.09	0.93±0.12	0.423	0.676
LPC10	2.19±0.18	1.94±0.17	4.001	<0.01
LSC10	1.17±0.09	1.11±0.12	1.527	0.138
LPC15	2.67±0.33	2.61±0.21	0.507	0.616
LSC15	1.22±0.13	1.22±0.13	0.099	0.922
LPC20	2.74±0.37	2.72±0.27	0.158	0.875
LSC20	1.24±0.12	1.23±0.13	0.213	0.833

¹, a significant difference at a P value <0.05 was observed using the Mann-Whitney U test. Indices were presented as mean ± standard deviation when the samples followed the normal distribution and median (lower quartile – upper quartile) when the samples did not follow the normal distribution. Group C: low-dose group; Group D: conventional-dose group. LE10/15/20, the relative tissue enhancement of liver, ratio of hepatic parenchymal signal in the corresponding phases to hepatic parenchymal signal in the plain scan; PE10/15/20, the relative tissue enhancement of portal vein, ratio of portal vein signal in the corresponding phases to portal vein signal in the plain scan; SE10/15/20, the relative tissue enhancement of spleen, ratio of splenic parenchymal signal in the corresponding phases to splenic parenchymal signal in the plain scan; LPC and LPC10/15/20, the contrast between liver and portal vein, ratio of hepatic parenchymal signal to portal vein signal in the plain scan and corresponding phases; LSC and LSC10/15/20, the contrast between liver and spleen, ratio of hepatic parenchymal signal to splenic parenchymal signal in the plain scan and corresponding phases.