To analyze the value of abnormal air bronchogram for predicting the invasiveness of lung adenocarcinoma with pure ground-glass nodule (pGGN).

From April 2014 to February 2016, 157 patients with 165 pGGN lung adenocarcinomas confirmed by surgical pathology were selected. There were 30 pre-invasive lesions (AAH+AIS), 39 minimally invasive adenocarcinoma (MIA), and 96 invasive adenocarcinoma (IAC). CT characteristics including lesion size, density, abnormal air bronchogram were recorded. All lesions were divided into two groups: normal group (no air bronchogram or normal air bronchogram) and abnormal air bronchogram group. Chi-square test was used to analyze the difference of pathological subtypes between the two groups. Mann-Whitney rank test was used to analyze the size difference of pGGN between the two groups. Two-independent samples t-test was used to analyze the lesion density difference of pGGN between the two groups.

Of the 165 lesions, 85 were found to have air bronchogram, there were 12 lesions in 30 pre-invasive lesions (AAH+AIS), 17 in 39 MIAs, 56 in 96 IACs. Abnormal air bronchogram were demonstrated in 61 lesions which was 1 in 30 pre-invasive lesions (IACs+AIS), 13 in 39 MIAs and 47 in 96 IACs, significant differences were found between two groups (χ²=25.943, P<0.01). The mean size of the IACs were (10.8±4.2) mm for normal group, (17.0±6.7) mm for abnormal air bronchogram group, the mean density were (-519±118) HU and (-518±124) HU, respectively. There was a significant difference in lesion diameter between two groups (Z=-6.197, P<0.01), but not in density (t=-0.042, P=0.966).

Abnormal air bronchogram can be used to predict the invasiveness of pGGN lung adenocarcinoma, and is correlated with lesion size, but not with density.

Lung neoplasms; Pure ground glass nodule; Pathology; Tomography, X-ray computed