| Parameters | Variables | Fluid type: USG | Fluid type: Biochemical | ||||
| Transudate (n = 14) | Exudate (n = 29) | P value | Transudate (n = 11) | Exudate (n = 32) | P value | ||
| Side | ・ Left | 4 (28.6%) | 8 (27.6%) | 0.014* | 4 (36.4%) | 8 (25%) | 0.014* |
| ・ Right | 5 (35.7%) | 20 (69%) | 3 (27.3%) | 22 (68.8%) | |||
| ・ Bilateral | 5 (35.7%) | 1 (3.4%) | 4 (36.4%) | 2 (6.3%) | |||
| Axial diameter | ・ 1 - 5 cm | 9 (64.3%) | 16 (55.2%) | 0.570 | 7 (63.6%) | 18 (56.3%) | 0.736 |
| ・ 6 - 10 cm | 5 (35.7%) | 13 (44.8%) | 4 (36.4%) | 14 (43.8%) | |||
| Septation | ・ Absent | 14 (100%) | 8 (27.6%) | <0.001** | 11 (100%) | 11 (34.4%) | <0.001** |
| ・ Present | 0 (0%) | 21 (72.4%) | 0 (0%) | 21 (65.6%) | |||
| Internal echoes | ・ Absent | 14 (100%) | 11 (37.9%) | <0.001** | 11 (100%) | 14 (43.8%) | 0.001** |
| ・ Present | 0 (0%) | 18 (62.1%) | 0 (0%) | 18 (56.3%) | |||
| PL thickening | ・ Absent | 11 (78.6%) | 16 (55.2%) | 0.137 | 9 (81.8%) | 18 (56.3%) | 0.166 |
| ・ Present | 3 (21.4%) | 13 (44.8%) | 2 (18.2%) | 14 (43.8%) | |||
| Parenchymal lesion | ・ Absent | 11 (78.6%) | 25 (86.2%) | 0.665 | 8 (72.7%) | 28 (87.5%) | 0.347 |
| ・ Present | 3 (21.4%) | 4 (13.8%) | 3 (27.3%) | 4 (12.5%) | |||
| Abnormal vascularity | ・ Absent | 14 (100%) | 27 (93.1%) | 1.000 | 11 (100%) | 30 (93.8%) | 1.000 |
| ・ Present | 0 (0%) | 2 (6.9%) | 0 (0%) | 2 (6.3%) | |||
| Fluid color | ・ Straw colored | 12 (85.7%) | 23 (79.3%) | 1.000 | 9 (81.8%) | 26 (81.3%) | 0.809 |
| ・ Hemorrhagic | 2 (14.3%) | 4 (13.8%) | 2 (18.2%) | 4 (12.5%) | |||
| ・ Others | 7 (50%) | 14 (48.3%) | 0 (0%) | 2 (6.3%) | |||