ABSTRACT
<p><b>OBJECTIVE</b>To 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).</p><p><b>METHODS</b>Ninety-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.</p><p><b>RESULTS</b>All 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.</p><p><b>CONCLUSION</b>Comprehensive 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.</p>