CT differentiation of pulmonary neoplastic diseases which appear as focal ground-glass opacity

Objective To investigate the characteristic CT features in differentiation of pulmonary neoplastic diseases which appear as focal ground-glass opacity.Methods Forty-five cases of neoplastic diseases(including 17 cases of adenocarcinomas,19 cases of bronchioloalveolar carcinoma,5 cases of lymphoma,and 4 cases of atypical adenomatous hyperplasia) which appeared as focal ground-glass opacity were collected,and their CT manifestations including type of GGO,location,size,internal structure,margin and surrounding change,were analyzed.Results Pure GGO was mostly seen in atypical adenomatous hyperplasia(n=4) and bronchioloalveolar carcinoma(n=6);mixed GGO was mostly seen in adenocarcinoma(n=13) and bronchioloalveolar carcinoma(n=13).All the lesions were classified into two groups including ≤1 cm and 1 cm in size.There was significant difference in constituent ratio of different nature of lesion between two groups(χ2=9.12,P0.05).In ≤1 cm group,the common nature of disease was atypical adenomatous hyperplasia and bronchioloalveolar carcinoma,while in 1 cm group,the common diseases were adenocarcinoma and bronchioloalveolar carcinoma.All the lesions were classified into two groups including 50% group and ≤50% group according to the percentage of GGO in the entire lesion.There was significant difference in constituent ratio of different nature of lesion between two groups(χ2=8.24,P0.05).In 50% group,the common diseases were atypical adenomatous hyperplasia and bronchioloalveolar carcinoma,while in ≤50% group,the common disease was adenocarcinoma.Conclusion Comprehensively analyzing the type,internal structure,margin and size is very helpful for differentiation of focal GGO.In the pulmonary tumor which appears as GGO,small pure GGO is common in atypical adenomatous hyperplasia,air bronchogram is common in bronchioloalveolar carcinoma,and mixed GGO which had large area of solid lesion is common in adenocarcinoma.