Table 3 Comparison of baseline data between training and validation group

Patients number

96

57

Age (year)

57.5 ± 12.3

58.2 ± 10.6

0.750

Sex (male/female)

54/42

33/24

0.843

Smoker

39

29

0.217

 Size (mm)

18.6 ± 5.7

17.8 ± 6.0

0.434

 Solid/sub-solid

94/2

55/2

0.992

 Spiculation

47

29

0.818

 Pleural retraction sign

39

20

0.496

 Cavity

8

7

0.427

 Calcification

15

3

0.054

 Enlarged hilar or mediastinal lymph nodule (≥ 10 mm)

21

9

0.359

 Emphysema

20

14

0.592

 Right lung/left lung

48/48

32/25

0.462

 Upper lobe/non-upper lobe

45/51

28/29

0.788

 Lesion — pleura distance (mm)

16.1 ± 14.6

17.5 ± 13.8

0.558

 Needle — pleura angle (degrees)

68.3 ± 20.1

67.2 ± 19.4

0.733

 Number of specimen

1.5 ± 0.7

1.4 ± 0.5

0.381

 Pneumothorax

15

8

0.790

 Hemoptysis

21

14

0.702

 Abnormal CEA (normal: 0–5 ug/L)

11

7

0.879

 Abnormal Cyfra21-1 (normal: 0–3.3 ng/ml)

9

7

0.570

 Abnormal SCC (normal: 0–2.5 ug/L)

4

2

1.000

 Abnormal NSE (normal: 0–16.3 ng/ml)

2

2

0.992

 Granulomatous inflammation

46

30

0.948

 Chronic inflammation with alveolar epithelial hyperplasia

17

13

0.442

 True negative/false negative

82/14

47/10

0.626