Table 3 LUS Characteristics of patients with COVID-19 according to LUS score

LUS features

 Pleural line, n (%)

  Normal pleural line

181 (64.6)

152 (99.3)

29 (41.4)

0 (0.0)

 < 0.001

  Irregular pleural line

99 (35.4)

1 (0.7)

41 (58.6)

57 (100.0)

 < 0.001

  Blurred pleural line

31 (11.1)

0 (0.0)

0 (0.0)

31 (54.4)

 < 0.001

 B-lines, n (%)

  Well-spaced B-lines < 3

250 (89.3)

153 (100.0)

70 (100.0)

27 (47.4)

 < 0.001

  Well-spaced B-lines ≥ 3

176 (62.9)

49 (32.0)

70 (100.0)

57 (100.0)

 < 0.001

  Multiple coalescent B-lines

34 (12.1)

0 (0.0)

1 (1.4)

33 (57.9)

 < 0.001

  Consolidation, n (%)

46 (16.4)

0 (0.0)

3 (4.3)

43 (75.4)

 < 0.001

   Pleural effusion, n (%)

5 (1.8)

0 (0.0)

0 (0.0)

5 (8.8)

 < 0.001

Distribution of abnormal LUS features

 Irregular pleural line

  Anterior fields

55 (19.6)

1 (0.7)

8 (11.4)

46 (80.7)

 < 0.001

  Lateral fields

50 (17.9)

0 (0.0)

5 (7.1)

45 (78.9)

 < 0.001

  Posterior fields

76 (27.1)

0 (0.0)

31 (44.3)

45 (78.9)

 < 0.001

  No. of involved zones

0 [0 ~ 2]

0 [0 ~ 0]

1 [0 ~ 2]

6 [4 ~ 10]

 < 0.001

 Blurred pleural line

  Anterior fields

4 (1.4)

0 (0.0)

0 (0.0)

4 (7.0)

0.002

  Lateral fields

16 (5.7)

0 (0.0)

0 (0.0)

16 (28.1)

 < 0.001

  Posterior fields

28 (10.0)

0 (0.0)

0 (0.0)

28 (49.1)

 < 0.001

  No. of involved zones

0 [0 ~ 0]

0 [0 ~ 0]

0 [0 ~ 0]

1 [0 ~ 3]

 < 0.001

 Well-spaced B-lines ≥ 3

  Anterior fields

100 (35.7)

14 (9.2)

30 (42.9)

56 (98.2)

 < 0.001

  Lateral fields

109 (38.9)

9 (5.9)

44 (62.9)

56 (98.2)

 < 0.001

  Posterior fields

139 (49.6)

26 (17.0)

56 (80.0)

57 (100.0)

 < 0.001

  No. of involved zones

1 [0 ~ 4]

0 [0 ~ 1]

3 [2 ~ 4]

9 [7 ~ 11]

 < 0.001

 Multiple coalescent B-lines

  Anterior fields

33 (11.8)

0 (0.0)

1 (1.4)

32 (56.1)

 < 0.001

  Lateral fields

32 (11.4)

0 (0.0)

0 (0.0)

32 (56.1)

 < 0.001

  Posterior fields

34 (12.1)

0 (0.0)

1 (1.4)

33 (57.9)

 < 0.001

  No. of involved zones

0 [0 ~ 0]

0 [0 ~ 0]

0 [0 ~ 0]

1 [0 ~ 3]

 < 0.001

 Consolidation

  Anterior fields

17 (6.1)

0 (0.0)

0 (0.0)

17 (29.8)

 < 0.001

  Lateral fields

25 (8.9)

0 (0.0)

1 (1.4)

24 (42.1)

 < 0.001

  Posterior fields

41 (14.6)

0 (0.0)

2 (2.9)

39 (68.4)

 < 0.001

  No. of involved zones

0 [0 ~ 0]

0 [0 ~ 0]

0 [0 ~ 0]

2 [1 ~ 5]

 < 0.001

Left lung involved, n (%)

139 (49.6)

26 (17.0)

56 (80.0)

57 (100.0)

 < 0.001

Right lung involved, n (%)

140 (50.0)

23 (15.0)

60 (85.7)

57 (100.0)

 < 0.001

Bilateral involved, n (%)

103 (36.8)

0 (0.0)

46 (65.7)

57 (100.0)

 < 0.001