Objective To discuss the pathological classification and lesion's inner imaging features of lung adenocarcinoma presented as pure ground-glass opacity.Methods CT imaging features of 156 pGGO lesions which confirmed by surgery and pathology were analyzed in retrospectively.There were 58 lesions of pre-invasive (including atypical adenomatous hyperplasia and adenocarcinoma in situ),32 lesions of minimally invasive adenocarcinoma and 66 lesions of invasive adenocarcinoma.CT features were analyzed including lesion density,vacuole sign,air bronchogram and abnormal vascular changes (vascular dilatation,distortion or rigid).Results There were statistical difference in lesions density and abnormal vascular changes in 3 different pathological types (P ＜ 0.05),with increase of lesions invasive,the incidence of uneven density and abnormal vascular changes increase,its mean the more invasive of the lesion,the lesion tent to be more uneven and higher incidence of the dilation,twist or rigid of the vascular happened;while the incidence of the air bronchogram will be higher when the lesions invasive degree increased,but there was statistical difference only between the pre-invasive and invasive groups (including minimally invasive adenocarcinoma and invasive adenocarcinoma) (x2 =4.868,P =0.027).Conclusions The uneven density and abnormal vascular changes had certain value in differential diagnosis of lung adenocarcinoma presented as pGGO.

Objective To investigate the diffevential diagnostic value of preinvasive and invasive lung adenocarcinoma (including minimally invasive adenocarcinoma and invasive adenocarcinoma) presented as pure ground-glass nodules(pGGN) by CT.Methods One hundred and fifty-six cases of pGGN verified by operative pathology were retrospectively analyzed,including 58 ca ses of preinvasive adenocarcinoma and 98 cases of invasive adenocarcinoma(TNM staging were T1N0M0).The CT features and sex were statistically processed.The difference between the CT features and sex were performed by thex2 test.The ROC curve of lesion focus size was drawn.Results Statistically significant differences were found in the lesion shape,vacuole sign,air bronchogram,blood vessel through,tumor-lung interface and vascular cluster sign between the two groups(all P＜0.05).The ROC curve showed that the accuracy rate of invasive adenocarcinoma was 75.0％ when the size of the pGGN lesions was larger than 15.35 mm.Conclusion The lesion size,shape,vacuole sign,air bronchogram,blood vessels through and vascular cluster sign have some predictive value.