Application Value Of ¹⁸F-FDG PET/CT Metabolic Parameters In Staging Nasopharyngeal Carcinoma And Predicting Metastasis

Objective To explore the application value of ¹⁸F-FDG PET/CT imaging metabolic parameters in the diagnosis and staging of nasopharyngeal carcinoma and its metastasis.Methods The clinical data and PET/CT data of 50 patients with pathologically confirmed nasopharyngeal carcinoma were retrospectively analyzed,including 35 males and 15 females,with an average age of（53.62±13.80）years.They were divided into two groups according to the presence or absence of lymph node metastasis and/or distant metastasis,of which 35 patients were in the metastatic group and 15 patients were in the non-metastatic group.They were divided into two groups according to the clinical stage of patients with nasopharyngeal carcinoma,including 8 cases of early nasopharyngeal carcinomaand 42 cases of advanced stage.Siemens Biography 16 HR PET/CT scanner was used to collect whole-body images of patients with nasopharyngeal carcinoma.All image data was processed at Siemens Syngo.via workstation,and MM oncology software was used to automatically outline VOI using 40%of SUVmax value as the threshold.Measure PET/CT metabolic parameters of the primary lesion:maximum standard uptake（SUVmax）,average standard uptake（SUVmean）,peak standard uptake（SUVpeak）,total glycolysis（TLG）,and tumor metabolic volume（MTV）.Make statistical analysis and comparison of general clinical data（age,gender）and various metabolic parameters between patients in metastasis group and non-metastatic group,earlyand advanced stage.Count data use?²test and measurement data use independent sample t test.Draw ROC curve for statistically significant parameters,then calculate the area under the curve（AUC）,and find the corresponding optimal diagnostic threshold by calculating the Jordan index,and calculate the relevant sensitivity and specificity,then analyze the results.Results There were statistically significant differences in TLG and MTV of primary lesion between the metastatic and non-metastatic groups（all P<0.05）,and no significant differences in gender,age,SUVmax,SUVpeak,and SUVmean（all P>0.05）.In the ROC curve analysis,the predicted transfer efficiency of TLG（AUC 0.817）is better than MTV（AUC 0.783）.Calculating the Jordan index is 0.571.When the TLG value is 73.240,the predictive efficiency of nasopharyngeal carcinoma metastasis is the highest.The sensitivity and specificity are 57.1%and 100%respectively.The Jordan index of MTV is 0.467.At 6.600,the predictive power for nasopharyngeal carcinoma metastasis is the highest,when sensitivity and specificity are 60%and 86.7%,respectively.There was a statistically significant difference in MTV between primary nasopharyngeal carcinomaand advanced stage（P<0.05）.There were no significant differences in gender,age,SUVmax,SUVpeak,SUVmean,and TLG（all P>0.05）.In the ROC curve analysis,MTV（AUC 0.771）has a certain degree of accuracy in predicting clinical staging.The calculated Jordan index of MTV is0.482.When the MTV value is 2.685,it has the highest predictive effect on clinical staging of nasopharyngeal carcinoma.The sensitivity and specificity are respectively62.5%and 85.7%.Conclusion The PET/CT metabolic parameters TLG and MTV in primary tumors of patients with nasopharyngeal carcinoma have certain value in predicting metastasis of nasopharyngeal carcinoma,and TLG is better than MTV in predicting metastasis.MTV of primary lesions in nasopharyngeal carcinoma patients is related to the clinical stage of nasopharyngeal carcinoma.Using MTV,¹⁸F-FDG PET/CT can predict the clinical stage of nasopharyngeal carcinoma.