CT image acquisition
CAVITY
The CT examination was performed on a Definition AS 40-detector (Siemens Healthineers, Erlangen, Germany), a Definition Flash 64-detector and Dual-energy Force (Siemens Healthineers), a Somatom EMOTION 16-detector (Siemens Healthineers), and an IQon 64-detector and Dual-energy Force (Philips Healthcare, Amsterdam, Netherlands). Scans covered the area between the thorax inlet and the bilateral adrenal glands in the supine position. The scanning parameters were as follows: 120 kV, automatic tube current, pitch 0.75–1.5, field of view 336 × 336 mm, and resolution 512 × 512. CT images were interpreted by two experienced pulmonologists who were blinded to the histopathological diagnosis in the lung and mediastinal windows. The following subjective features of the lesion were recorded: (1) component of the lesion (part solid or non-solid), (2) lesion diameter (the maximum diameter in the largest slice), (3) lesion location, and (4) the characteristics of the lesion, including lobulation (absent, present), spiculation (absent, present), bubble-like lucency (absent, present), cavity (absent, present), pleural indentation sign (absent, present), vascular breakthrough sign (absent, present), sharp (round or oval, irregular or polygonal), and margin (clear, unclear).