The Value Of HRCT In The Diagnosis Of Pulmonary Ground Glass Nodules

BackgroundLung cancer is currently an important cause of cancer deaths worldwide.Lung adenocarcinoma accounts for about 45%of all lung cancers,and its 5-year survival rate is only 14.6%.If accurate treatment strategies can be adopted in the early stages of lung cancer,the survival of the patients can be significantly improved,and the5-year survival rate can be increased to 50%.Low-dose computed tomography(LDCT)is widely used in lung cancer screening,making the detection rate of solitary pulmonary nodules(SPN)improved which not be obvious in chest radiographs.Some of the visible nodules are ground glass nodules(GGN).Its main manifestations are the increase in the density of the lungs and retention of the bronchi and vascular borders,caused by local gas filling,thickening of the stroma,partial collapse of the alveolar wall,or increased capillary blood volume.The majority of persistent GGNs on computed tomography(CT)are early lung adenocarcinomas.Therefore,it is important to predict the benign and malignant pathological subtypes of GGN by high-resolution CT(high resolution CT,HRCT)image features.Therefore,we conducted this study to analyze the HRCT characteristics of GGN.PurposeTo evaluate the value of HRCT in the auxiliary diagnosis of GGN.MethodRetrospective analysis of clinical data from 170 patients with pulmonary GGN who were diagnosed in at least one pulmonary GGN by HRCT or confirmed by pathology or clinical follow-up in our hospital from January 2012 to December 2017.In this study,71 males and 99 females,aged 18-80 years,averaged 54.27±12.75years old.According to the nature of the lesions,there were 2 groups:69 patients in the benign group,with an average age of 50.91±14.15years;101 patients in the malignant group,including 75 invasive adenocarcinomas(37 adherent-type,21acinar-based,14 patients nipple-based,3 solid-type with mucus),9 cases of microinvasive adenocarcinoma(MIA),1 case of adenosquamous carcinoma,14cases of carcinoma in situ(AIS),with an average age of 56.55±11.21 years.Adenocarcinoma,germ cell carcinoma,small cell carcinoma,large cell carcinoma,adenosquamous carcinoma,carcinoma in situ,atypical adenomatoid hyperplasia are classified as malignant nodules,benign nodules include focal inflammation,organizing pneumonia,local fibrosis,hamartoma,inflammatory edema,tuberculosis,lymphoproliferative lesions,bronchogenic cysts.Relevant medical history and clinical data were collected.Quantitative data were analyzed by independent sample t test and one-way ANOVA.The non-normal distribution of quantitative data was compared by Mann-Whitney U test or Kruskal-Wallis test.Qualitative data using Pearson?~2 or Fisher's exact probability method.Statistically significant variables were selected(P<0.05),multivariate unconditional logistic regression analysis was performed,ROC curves were drawn and optimal cutoff values were determined.Results1.There was no significant difference between malignant and benign nodules in the patient's gender(P>0.05).Of all 101 malignant nodules,there were 54 mGGN and 50 pGGNs.Of all 69 benign nodules,there were 19 mGGNs and 50 pGGNs.Chi-square test showed that mGGN was associated with malignancy(P<0.05).Malignant and benign nodules were statistically different(P<0.05)in the incidence of lobulation,vascular bundle sign,burr sign,and air bronchus/cavitation sign.Compared with the benign control group,the lesions in the malignant group were larger(14.19 mm±4.50 vs 12.20 mm±5.72,P<0.05).Patients in the malignant group were older compared with the benign group(56.55±11.21 years vs.benign group 50.91±14.15 years,P<0.05).The mean CT value of the GGN lesions in the malignant group(-523.54±99.45 HU)was significantly higher than that in the benign group GGN((-610.59±107.97 HU).2.In the binary logistic regression analysis,the malignant and benign of the nodule were the dependent variable,whether it contains solid components,lobulated sign,burr sign,vascular bundle sign,air bronchus/vacuole sign,GGN size,CT value were used as covariate in logistic regression analysis.The analysis showed that the CT value was an important sign for predicting malignant GGN(P<0.05).The ROC curve was made for benign and malignant GGN,and the diagnostic value of CT value for malignant GGN was evaluated.The results showed that the area under the ROC curve was 0.724(95%CI:0.646,0.803),and the optimal threshold for distinguishing the CT value of malignant lesions is-654.67HU with a sensitivity of93.1%and a specificity of 40.6%.3.There was a significant difference in lesion size between AAH/AIS/MIA and IAC(t=-2.632,P<0.05).The average lesion size of IAC patients was 14.59 mm,which was greater than that of patients with AAH/AIS/MIA.The mean CT value of GGN in patients with IAC was-507.92,which was higher than that in patients with AAH/AIS/MIA lesions(P<0.05).4.In patients with lung adenocarcinoma with pleural indentation in HRCT,the proportion of IAC was higher,which was 74.6%(P<0.05).Patients with mGGN in HRCT had a higher rate of IAC,59.2%(P<0.05),and patients with bronchial signs,lobes,and burrs in HRCT had no appeal characteristics.In patients,there was no significant difference in the type of lung adenocarcinoma(P>0.05).The differences in pathological types of lung adenocarcinoma were compared between patients with different nodule locations.The results showed that there was no significant difference in the final case types between patients with different nodule locations(P>0.05).5.Multivariate analysis showed that the average CT value of GGN,whether there was pleural indentation,and the presence or absence of vascular bundle sign were important factors in identifying AAH/AIS/MIA and IAC.Conclusion1.The average CT value of GGN is an important factor to identify benign and malignant GGN.The average CT value is greater than-654.67HU,which is more malignant,and mGGN,lobulated sign,burr sign,vascular bundle sign,air bronchus/empty Bubble signs,pleural indentation sign,as well as larger GGNs,are more likely to be prone to malignant GGN.2.The mean CT value,pleural indentation sign,and vascular bundle sign are important factors in identifying AAH/AIS/MIA and IAC,and mGGN and larger diameter GGN are more inclined to IAC.