using the GE LightSpeed VCT scanner or GE BrightSpeed Elite 16 scanner (GE
Healthcare, Milwaukee, USA). Scans were performed from the lung apex to the lung
base using the following parameters: tube voltage 120 kV, tube current automatic
mA, helical pitch 0.938, rotation speed 0.6 s, slice thickness, and spacing
5 mm. CT images were reconstructed with a slice thickness of 1.00 to 1.25 mm.
The images were reviewed by 2 chest radiologists with more than 10 years of
experience together. If there was a disagreement between the 2 radiologists, a
third radiologist with 20 years of experience conducted a further review. During
this procedure, the following image features were recorded, including maximum
lesion diameter, spicule sign, and vacuolation sign. In addition, some clinical
data of these patients were collected through the clinical information system,
including age, gender, interval to pulmonary nodules (ITP), carcino-embryonic
antigen (CEA), and carbohydrate antigen 125 (CA125). The above data were
summarized in a table consisting of clinical characteristics.