OBJECTIVETo explore the CT features of ground-glass nodules (GGN) including preinvasive lesions [atypical adenomatous hyperplasia (AAH) and adenocarcinoma in situ (AIS)], minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC).

METHODSNinety-seven GGN lesions confirmed by operation pathology were included in this study. The lesions were divided into three groups: preinvasive lesion group (24 cases), MIA group (39 cases), IAC group (34 cases). The lesion size, 3-dimensional ratio, 2-dimensional ratio in axial images, lesion density, shape, speculation, lobulation, air-containing space and pleural indentation on the preoperative CT images in the three groups were analyzed and compared with pathological results. The data were statistically analyzed using SPSS 17.0.

RESULTSAll preinvasive lesions presented as pure GGN on CT image, most showed round-like shape, clear and smooth border. MIA presented as pure GGN or mixed GGN on CT image, most showed round-like shape, with a clear and smooth border. IAC most presented as mixed GGN on CT image, often showed irregular shape. Speculation, lobulation, air-containing space and pleural indentation displayed gradually increasing from preinvasive lesions to MIA and IAC. There were statistically significant differences in lesion size, CT density, shape, air-containing space, speculation, pleural indentation and long diameter of solid component between the MIA and IAC groups (P < 0.05 for all). There were statistically significant differences in CT density values and long diameters of solid component of the lesions between the preinvasive lesion group and MIA group (P < 0.05). The AUC of solid component of the preinvasive lesion group and MIA group was 0.705, and that of the MIA and IAC groups was 0.814.

CONCLUSIONComprehensive analysis of the CT image features of GGNs, especially the solid component in the lesions, may help to the preoperative and differential diagnosis of preinvasive lesions, MIA and IAC.