| Objective:Through the comparative analysis of imaging and pathological results of pulmonary subcentimeter ground glass nodules(ground glass nodule,GGN)to summary the correlation between imaging features and the nature of lesions,in order to initially judge the nature of lesions through imaging features,further improve the accuracy of differential diagnosis of pulmonary subcentimeter GGN,better guide preoperative evaluation,and provide a basis for clinical decision-making.method:The imaging and pathological data of 52 patients(70 lesions)with subcentimeter GGN resected by high resolution CT(high-resolution CT,HRCT)scan in the second Hospital of Jilin University from January 2016 to November 2019 were analyzed retrospectively,and the subcentimeter GGN of all patients were resected surgically.The HRCT images of all patients were reconstructed by multiplanar reconstruction(multiplanar reconstructions,MPR),maximum intensity projection(maximum intensive projection,MIP)and volume rendering technique(volume rendering technique,VRT).the size of lesion,the average value of CT,the location of lesion,the location of type,the boundary,spiculation sign,vacuole sign,three-dimensional shape,lobulation sign,air bronchus sign,pleural indentation sign and the relationship between lesions and peripheral blood vessels were evaluated by two experienced doctors.A total of 70 subcentimeter GGN of the lung were included in this study,including benign lesions(n=12)and lung adenocarcinomas(n=58)(including atypical adenomatous hyperplasia(n=11),adenocarcinoma in situ(n=29),minimally invasive adenocarcinoma(n=9)and invasive adenocarcinoma(n=9)).To analyze the relationship between the imaging characteristics and pathological results of subcentimeter GGN.The data were analyzed statistically by SPSS 25.0 software.Results:The results of comparison between benign group and malignant group: a total of 52 patients were included in this study,including 22 cases of men and 30 cases of women,ranging in age from 35 to 77 years old,there was no statistical difference in sex and age between the two groups(p> 0.05).A total of 70 subcentimeter GGN were detected in 52 patients,including 12 cases in benign group and 58 cases in malignant group.The locations of lesions were as follows:right upper lobe(n=25),right middle lobe(n=4),right lower lobe(n=13);left upper lobe(n=18)and left lower lobe(n=10).Using Fisher exact probability method,there was no statistical difference in the location of lesions between the two groups.The size of lesions in benign group and malignant group were 6.50(5.13 ~ 8.53)mm and 7.05(6.00 ~ 9.00)mm respectively,and the average value of CT were-606.50(-707.00 ~-150.25)Hu and-609.00(-683.00-385.25)Hu,respectively,using rank sum test,there was no statistical difference in lesion size and the average value of CT between the two groups(p>0.05).There was significant difference in air bronchial sign and lobulation sign between the two groups(p<0.001),but there was no statistical difference in lesion type,boundary,spiculation sign,vacuole sign,three-dimensional shape and pleural indentation sign between the two groups(p>0.05).The relationship between lesions and peripheral vessels was divided into three types,Fisher exact probability method was used for statistical analysis,and there was statistical difference between the two groups(p<0.05).Among of them,type?was the most common in the benign group(75%),while type ? and type ? were more common in the malignant group(48.3%?27.6%).The results of comparison between pre-infiltration group and post-infiltration group:In this study,58 malignant nodules were collected and divided into pre-infiltration group(including AAH(n=11),AIS(n=29))and post-infiltration group(including MIA(n=9),IAC(n= 9)),according to whether they were infiltrative or not.There was no statistical difference in sex between the two groups by chi square statistics(p>0.05),and there was no statistical difference in age by the test statistical analysis(p>0.05).The locations of lesions were as follows:right upper lobe(n=23),right middle lobe(n=4),right lower lobe(n=9);left upper lobe(n=15)and left lower lobe(n=7),Fisher exact probability method was used for statistical analysis,P>0.05,there was no significant difference in the location of lesions between the two groups.The size of lesions in pre-infiltration group and post-infiltration group were(6.99±1.75)mm and(8.14±1.57)mm respectively,and the average value of CT were-633.00(-692.75 ~-561.00)HU and-326.00(-627.50 ~-203.00)HU,respectively,using T-test and rank sum test,the difference of the lesion size and the average value of CT was statistically significant(P<0.05).Using ROC curve,the best critical values of lesion size and the average value of CT were 6.95 mm and-502 HU,respectively.Chi-square test showed that there were significant differences in lesion type,boundary,spiculation sign,vacuole sign,lobulation sign,air bronchial sign and pleural indentation sign between the two groups(p<0.05),but there was no significant difference in three-dimensional shape between the two groups(p> 0.05).Most of the lesions in the pre-infiltration group were p GGN(80%),and the boundary was clear(55%),while in the post-infiltration group,most of the lesions were m GGN(83.3%),and the boundary was blurred(77.8%).The incidences of spiculation sign,vacuole sign,lobulation sign,air bronchial sign and pleural indentation sign in the post-infiltration group were 66.7%,66.7%,88.9%,88.9% and55.6%,respectively,which were significantly higher than those in the pre-infiltration group.The frequency of the above five signs was counted and the ROC curve was drawn,it was found that the frequency of 2.5 was the best threshold for the diagnosis of infiltrative lesions,that is,in malignant lesions,3 or more of the above five signs were found,indicating that the lesions were likely to be infiltrative lesions.According to the statistical analysis of the relationship between lesions and peripheral blood vessels by Fisher exact probability method,there was a significant difference between the two groups(p<0.001).Type ? was the most common in the pre-invasion group (52.5%)and type III was the most common in the post-invasion group(61.1%).MPR has a certain advantage in displaying the position of pulmonary nodules.MIP has a clearer image of pulmonary vessels than HRCT.VRT can display the three-dimensional shape of pulmonary nodules.The combination of CT images and various reconstruction technologies can provide more comprehensive and accurate information of pulmonary subcentimeter GGN.Conclusion:1.The lobulation sign and air bronchial sign in the subcentimeter ground glass nodules of the lung suggest that there is a high possibility of malignant lesions.2.Among the malignant subcentimeter ground glass nodules,if the nodule is pure ground glass nodule and the boundary is clear,it indicates that it is likely to be a pre-infiltration lesion;if the nodule is mixed ground glass nodule and the boundary is blurred,it indicates that it is likely to be infiltrative lesions.When the lesion size >6.95 mm and the average value of CT >-502 HU,or there are three or more signs of spiculation sign,vacuole sign,lobulation sign,air bronchial sign and pleural indentation sign in the malignant lesions,it is more likely to be considered as infiltrative lesions,otherwise they are more likely to be pre-infiltrative lesions.3.The classification of the relationship between lesions and peripheral vessels has a certain significance in distinguishing the benign from the malignant and the infiltrative features of the subcentimeter ground glass nodule of the lung.If the blood vessel is not related to the lesions,it is more likely to be benign.If the the shape of blood vessels in the lesions is naturally,it is more likely to be pre-infiltrative.If the blood vessel is twisted,thickened,rigid or gathered in the lesions,it is more likely to be infiltrative.4.Image post-processing technology is a supplementary means of two-dimensional imaging,and the accuracy of diagnosis depends on the organic combination of image post-processing technology and two-dimensional images.There is a complementary relationship between different reconstruction techniques.Only by combining the advantages of various reconstruction techniques can the images provide more comprehensive,accurate and objective information for clinical diagnosis. |
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