Control Study Of Molecular Imaging Features And Pathology Of Pulmonary Nodules

Objective:The treatment of lung cancer is developing towards individualization and precision.The choice of treatment modality for different pathological types of lung cancer varies greatly.Therefore,for pulmonary nodules,accurate diagnosis and prediction of their benignity and malignancy and different pathological classifications play an important role in selecting different treatment strategies and assessing prognosis.In view of this,we used molecular imaging methods to evaluate the potential correlation between ¹⁸F-FDG and ^99mTc-3PRGD₂metabolic parameters and different pathological types and immunohistochemical indicators TTF-1,CK5/6,CK7,Napsin A,Ki-67 expression levels.In order to predict the pathological classification and immunohistochemical index level of pulmonary nodules by metabolic parameters before operation,so as to better assist the clinic in developing individualized treatment plans for patients.Methods:This study analyzed 40 patients who underwent simultaneous ¹⁸F-FDG PET/CT imaging and ^99mTc-3PRGD₂SPECT/CT imaging from June 2020 to June2021 and underwent surgical resection to obtain histopathological and immunohistochemical results.The clinical data of patients,semi-quantitative metabolic parameters of PET images including SUVmax1,SUVmax2（delay）,MTV（metabolic tumor volume）and TLG（total glycolysis）,semi-quantitative parameters of SPECT images SUVmax R（SUVmax of RGD）,pathological types and immunohistochemical indicators TTF-1,CK5/6,CK7,Napsin A,Ki-67 expression levels were collected.T test was used to analyze whether there were statistical differences in metabolic parameters between different pathological types.To compare the diagnostic value of ¹⁸F-FDG with ^99mTc-3PRGD₂by drawing ROC curves using postoperative pathological results as the gold standard,as well as the combined diagnostic efficacy of the two.The optimal thresholds for the diagnosis of benign and malignant nodules were analyzed for both imaging agents,and AUC values,sensitivity and specificity were calculated.Spearman correlation analysis was used to assess the correlation between metabolic parameters and immunohistochemical indices,P<0.05 was considered statistically significant.Results:1.There were 40 patients with pulmonary nodules,with an average age of（62.86±12.68）years.There were 35 cases of malignant lesions,including 15 cases of squamous cell carcinoma and 20 cases of adenocarcinoma.There were 5 cases of benign lesions,including 2 cases of organizing pneumonia,1 case of pulmonary abscess,1 case of pulmonary interstitial fibrosis and 1 case of inflammatory pseudotumor.There was no statistical difference in the comparison of general information between the two groups.2.Comparing the metabolic parameters between the malignant lesion group and the benign lesion group,only SUVmax2 was statistically significant（P<0.05）.Comparing the differences in each metabolic parameter between the squamous carcinoma group and the adenocarcinoma group,the differences in SUVmax1,SUVmax2,MTV,and TLG were statistically significant（P<0.05）.3.SUVmax R was positively correlated with SUVmax1,SUVmax2,MTV and TLG（r=0.412,0.49,0.518,0.655,P<0.05）.4.Comparing the diagnostic efficacy of each metabolic parameter,the best parameter was delayed SUVmax2 with an optimal threshold of 4.40,which had a sensitivity and specificity of 85.7%and 80%for the diagnosis of pulmonary nodules,respectively.In addition,the parameters with higher diagnostic efficiency were SUVmax1 and TLG,and the optimal thresholds were 7.3 and 25.3,respectively.The sensitivity and specificity of the diagnosis of pulmonary nodules were 68.6%,80.0%and 65.7%,80.0%.5.The diagnostic efficacy of the combined ¹⁸F-FDG PET/CT and ^99mTc-3PRGD₂SPECT/CT images for the diagnosis of benign and malignant pulmonary nodules was improved compared to the single image（from 0.774 and 0.417 to 0.823）.6.There was a negative correlation between SUVmax1,SUVmax2 and TTF-1,CK7,Napsin A（r=-0.560,-0.539,-0.668;-0.550,-0.507,-0.645,P<0.05）,and positively correlated with CK5/6 and Ki-67（r=0.471,0.622;0.428,0.550,P<0.05）.MTV value was negatively correlated with TTF-1 and CK7（r=-0.389,-0.539,P<0.05）,but not with CK5/6,Napsin A and Ki-67（P>0.05）.TLG value was negatively correlated with TTF-1,CK7 and Napsin A（r=-0.644,-0.596,-0.570,P<0.05）,and positively correlated with CK5/6（r=0.424,P<0.05）.There was no correlation between TLG value and Ki-67（P>0.05）.There was a negative correlation between SUVmax R and TTF-1（r=-0.338,P<0.05）.Conclusions:1.The delayed metabolic parameter SUVmax2 can predict the benign and malignant,pathological type and immunohistochemical expression level of pulmonary nodules,and provide certain reference value for clinical formulation of individualized programs.2.^99mTc-3PRGD₂SPECT/CT metabolic parameter SUVmax R was positively correlated with ¹⁸F-FDG PET/CT metabolic parameters SUVmax1,SUVmax2,MTV and TLG.The diagnostic efficiency of delayed imaging SUVmax2 in pulmonary nodules was the highest,and the combination of the two improved the diagnostic efficiency.3.Patients with high SUVmax,MTV and TLG are more likely to have CK5/6 positive,suggesting that squamous cell carcinoma is more likely.It is expected to predict the expression level of each immunohistochemical index by the size of metabolic parameters,and further predict the pathological classification of lung cancer.