Table 1 Demographic information and CT characteristics of training and testing cohorts

Gender

0.319

0.658

 Female

76 (65.5%)

65 (59.1%)

28 (56.0%)

29 (60.4%)

 Male

40 (34.5%)

45 (40.9%)

22 (44.0%)

19 (39.6%)

Age (years)

56.4 ± 10.7

55.6 ± 9.5

0.572

56.7 ± 9.1

55.8 ± 9.8

0.629

Smoking history

0.981

0.307

 Yes

22 (19.0%)

21 (19.1%)

12 (24.0%)

16 (33.3%)

 No

94 (81.0%)

89 (80.9%)

38 (76.0%)

32 (66.7%)

Diameter (mm)

6.7 ± 1.9

8.4 ± 1.5

 < 0.001

6.5 ± 1.8

7.9 ± 1.7

 < 0.001

Location

0.281

0.857

 RUL

23 (19.8%)

22 (20.0%)

7 (14.0%)

7 (14.6%)

 RML

19 (16.4%)

9 (8.2%)

10 (20.0%)

7 (14.6%)

 RLL

26 (22.4%)

24 (21.8%)

16 (32.0%)

13 (27.1%)

 LUL

17 (14.7%)

25 (22.7%)

8 (16.0%)

11 (22.9%)

 LLL

31 (26.7%)

30 (27.3%)

9 (18.0%)

10 (20.8%)

Enhancement degree

0.477

0.864

 Low

91 (78.4%)

93 (84.5%)

43 (86.0%)

41 (85.4%)

 Medium

13 (11.2%)

8 (7.3%)

3 (6.0%)

4 (8.3%)

 High

12 (10.3%)

9 (8.2%)

4 (8.0%)

3 (6.2%)

Nodule-lung interface

 < 0.001

0.003

 Clear

111 (95.7%)

84 (76.4%)

48 (96.0%)

36 (75.0%)

 Blurred/Halo

5 (4.3%)

26 (23.6%)

2 (4.0%)

12 (25.0%)

Lobulation

72 (62.1%)

93 (84.5%)

 < 0.001

22 (44.0%)

41 (85.4%)

 < 0.001

Spiculation

6 (5.2%)

49 (44.5%)

 < 0.001

4 (8.0%)

17 (35.4%)

0.001

Vacuole

2 (1.7%)

22 (20.0%)

 < 0.001

1 (2.0%)

4 (8.3%)

0.334

Pleural indentation

17 (14.7%)

54 (49.1%)

 < 0.001

6 (12.0%)

20 (41.7%)

0.001

Air bronchogram

1 (0.9%)

23 (20.9%)

 < 0.001

1 (2.0%)

11 (22.9%)

0.002

Vascular convergence 0 (0.0%)

6 (5.5%)

0.033

0 (0.0%)

5 (10.4%)

0.060