CT And Pathological Features And Follow-up Study Of Lung Adenocarcinoma With Diameter <3cm

BackgroundAccording to the estimation of GLOBOCAN 2020,lung cancer is still the main cause of cancer death,especially lung adenocarcinoma.With the classification of lung adenocarcinoma by IASLC/ATS/ERS in 2011,lung adenocarcinoma is divided into preinvasive lesions(AAH,AIS),minimally invasive adenocacinoma(MIA),and invasive adenocacinoma(IAC).The prognosis of different types varies greatly.With the popularity of CT examination,more and more small pulmonary nodules are found,which means that lung cancer can be diagnosed and treated in the early stage.At the same time,challenges are coming.How to correctly identify these nodules and avoid over diagnosis and treatment has become the current focus.Follow up is a good method for the initial diagnosis of benign and malignant pulmonary nodules.However,at present,there are few indicators to judge the growth of pulmonary nodules,and more sensitive and simple indicators need to be found.Objective1.To analyze the CT imaging features of early lung adenocarcinoma and pulmonary interstitial fibrosis nodules,in order to help clinical doctors correctly distinguish between benign and malignant pulmonary nodules.2.To retrospectively analyze the early lung cancer cases with CT follow-up data in order to find the sensitive index to judge the growth of nodules.Method1.CT images of patients with early lung cancer and pulmonary interstitial fibrosis were collected.The signs of nodules were observed and recorded on CT images.2.Electronic caliper was used to measure the longest diameter and its vertical diameter on the cross section of the nodule,and the maximum plane of the nodule was drawn manually to obtain the average CT value and relative CT value.3.Spss-20 was used to analyze the data.Result1.The nodule size,mean CT value and relative CT value were different in AIS,MIA,IAC and interstitial fibrosis;2.The average diameter of 12.0 mm was used as the cutoff value of AIS,MIA,pulmonary interstitial fibrosis and IAC(sensitivity 72.9%,specificity 85.3%).The average CT value of-441.5 Hu could be used as the cutoff value of AIS,Mia,pulmonary interstitial fibrosis and IAC(sensitivity 91.8%,specificity 72.2%);3.Pulmonary nodules(<3cm)with lobulation sign,spicule sign and pleural indentation sign are more likely to be IAC than MIA or AIS;vacuole sign is more common in AIS and MIA,and its appearance may indicate the progress of the disease;vascular bundle sign may be an imaging feature to differentiate fibrosis from early lung cancer.4.The higher the average CT value,the higher the possibility of micropapillary,solid or invasive mucinous adenocarcinoma.5.In this study,79 patients with AIS and 43 patients with MIA were included.The preoperative follow-up time of AIS was 1-84 months,and 40 patients underwent surgical resection in the month after the diagnosis of pulmonary nodules.43 cases of AIS were followed up for 1-72 months,and 23 of them underwent surgical resection in the month of diagnosis.6.In 12 cases of IAC follow-up data,only 3 cases of average diameter difference>2 mm,while at the same time,10 cases of average CT value>50 Hu,9 cases of relative average CT value>50 Hu.Conclusion1.The average diameter of 12.0 mm and the average CT value of-441.5 Hu can be used as cut-off values of AIS,MIA,focal pulmonary fibrosis and IAC;2.Lobulation sign,prickle sign,pleural indentation sign,vascular bundle sign and vacuole sign are significant in differentiating benign and malignant pulmonary nodules;3.For incidental pulmonary nodules,clinicians should strengthen communication with patients,and both sides should jointly decide the treatment plan;4.The average CT value and relative CT value have potential to be used as indicators for monitoring the growth of pulmonary nodules during follow-up.