Table 1.
Baseline characteristics of the 63 subjects.
| Parameters | Group 1 (n = 13) | Group 2 (n = 50) | ALL (n = 63) | t/Z/χ2 value | p value |
|---|---|---|---|---|---|
| Age (years, mean ± SD) [range] | 29.4 ± 7.7 | 38.5 ± 11.3 | 36.5 ± 11.3 | − 3.256‡ | 0.001 |
| Sex (n, male: female) | 6: 7 | 24: 26 | 30: 33 | 0.014ℐ | 0.905 |
| BMI (kg/m2, mean ± sd) [range] | 20.5 ± 2.3 | 28.0 ± 2.8 | 26.4 ± 4.1 | − 8.848† | < 0.001 |
| Distance from skin to liver capsule (cm, mean ± sd) [range] | 1.4 ± 0.3 | 2.0 ± 0.4 | 1.9 ± 0.4 | − 4.647‡ | < 0.001 |
| UGAP (dB/cm/MHz) | |||||
| Fasting (SP, S5, 1) | 0.58 ± 0.09 | 0.69 ± 0.13 | 0.67 ± 0.13 | − 2.923‡ | 0.003 |
| Fasting (SP, S5, ROI PLC) | – | 0.70 ± 0.13 | – | ||
| Fasting(SP, EI) | 0.57 ± 0.10 | 0.71 ± 0.13 | 0.68 ± 0.13 | − 3.690† | < 0.001 |
| Fasting(SP, EE) | 0.58 ± 0.11 | 0.67 ± 0.13 | 0.65 ± 0.13 | − 2.413‡ | 0.016 |
| Fasting(LP) | 0.54 ± 0.12 | 0.70 ± 0.13 | 0.66 ± 0.15 | − 3.814† | < 0.001 |
| Fasting (SP, S5, 2) | 0.57 ± 0.11 | 0.69 ± 0.12 | 0.67 ± 0.13 | − 3.195† | 0.002 |
| Fasting (SP, non-S5) | – | 0.69 ± 0.13 | – | ||
| Fasting (SP, S5, another radiologist) | 0.56 ± 0.12 | 0.70 ± 0.13 | 0.67 ± 0.14 | − 3.467† | 0.001 |
| 2 h after a meal (SP, S5) | 0.59 ± 0.10 | 0.67 ± 0.18 | 0.65 ± 0.17 | − 2.584‡ | 0.010 |
| Fasting (SP, S5, 3) | 0.59 ± 0.10 | – | – | ||
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.
‡Wilcoxon Mann–Whitney rank-sum test.
†Paired sample T test.
ℐChi-square test.