Table 1 Baseline patients’ characteristics before RFA

Age(years)

45.83 ± 11.12 (18–69)

Sex (F/M)

39/13

No. of patients

52

No. of nodules

52

Initial nodule largest diameter(cm)

1.10 ± 1.18 (0.30–5.80)

Initial nodule volume(cm³)

5.83 ± 19.17 (0.02–111.59)

Location

 Left lobe

25

 Right lobe

25

 Isthmic

2

Location close to critical structures (Y/N)

21/31

Composition

 Solid (fluid component ≤ 10%)

46

 Predominantly solid (fluid component 11–50%)

4

 Predominantly cystic (fluid component 51–80%)

2

Echogenicity

 Hypoechoic

40

 Isoechoic

10

 Hyperechoic

2

Vascularity

 Grade 1

22

 Grade 2

6

 Grade 3

20

 Grade 4

4

CEUS enhancement degree

 Hypoenhancement

28

 Isoenhancement

11

 Hyperenhancement

2

 Mixed enhancement

9

 Unidentified enhancement

2

Calcification

 PEF

22

 Macrocalcification

30

  Weak

12

  Strong

18