Table 4.

Differences in UGAP values among the three groups of BMI < 24 kg/m², 24 ≤ BMI < 28 kg/m² and BMI ≥ 28 kg/m².

Parameters	BMI < 24 (n = 13) (dB/cm/MHz)	24 ≤ BMI < 28 (n = 27) (dB/cm/MHz)	BMI ≥ 28 (n = 23) (dB/cm/MHz)	F /Z value	p value
Distance from skin to liver capsule (cm)	1.48 ± 0.27	1.82 ± 0.25	2.17 ± 0.42	30.130‡	< 0.001*
Fasting (SP, S5, 1)	0.60 ± 0.12	0.66 ± 0.14	0.71 ± 0.11	10.249‡	0.006*
Fasting (SP, EI)	0.60 ± 0.15	0.68 ± 0.13	0.73 ± 0.12	7.512§	0.001*
Fasting (SP, EE)	0.60 ± 0.13	0.64 ± 0.14	0.70 ± 0.13	7.125‡	0.028*
Fasting (LP)	0.56 ± 0.14	0.64 ± 0.18	0.73 ± 0.13	9.087§	< 0.001*
Fasting (SP, S5, 2)	0.60 ± 0.14	0.66 ± 0.12	0.71 ± 0.12	5.865§	0.005*
Fasting (SP, S5, another radiologist)	0.59 ± 0.15	0.67 ± 0.12	0.72 ± 0.13	6.857§	0.002*
2 h after a meal (SP, S5)	0.61 ± 0.13	0.68 ± 0.13	0.65 ± 0.22	6.695‡	0.035*

SP supine position, S5 segment V, ROI PLC region of interest (ROI) perpendicular to liver capsule, EI end of inspiration, EE end of expiration. LP lateral position, BMI body mass index, UGAP ultrasound-guided attenuation parameter.

*p < 0.05.

^‡Kruskal–Wallis H test.

^§One Way ANOVA.