ABSTRACT
Objective@#To evaluate 99mtechnetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid ( 99mTc-3PRGD2) singlephoton emission computed tomography (SPECT)/computed tomography (CT) imaging for diagnosing lymph node metastasis of primary malignant lung neoplasms. @*Materials and Methods@#We prospectively enrolled 26 patients with primary malignant lung tumors who underwent 99mTc-3PRGD2 SPECT/CT and 18F-fluorodeoxyglucose ( 18F-FDG) positron emission tomography (PET)/CT imaging. Both imaging methods were analyzed in qualitative (visual dichotomous and 5-point grades for lymph nodes and lung tumors, respectively) and semiquantitative (maximum tissue-to-background radioactive count) manners for the lymph nodes and lung tumors. The performance of the differentiation of lymph nodes with and without metastasis was determined at the per-lymph node station and perpatient levels using histopathological results as the reference standard. @*Results@#Total 42 stations had metastatic lymph nodes and 136 stations had benign lymph nodes. The differences between metastatic and benign lymph nodes in the visual qualitative and semiquantitative analyses of 99mTc-3PRGD2 SPECT/CT and18F-FDG PET/CT were statistically significant (all P < 0.001). The area under the receiver operating characteristic curve (AUC)in the semi-quantitative analysis of 99mTc-3PRGD2 SPECT/CT was 0.908 (95% confidence interval [CI], 0.851–0.966), and the sensitivity, specificity, positive predictive value, and negative predictive value were 0.86 (36/42), 0.88 (120/136), 0.69 (36/52), and 0.95 (120/126), respectively. Among the 26 patients (including two patients each with two lung tumors), 15 had pathologically confirmed lymph node metastasis. The difference between primary lung lesions in patients with and without lymph node metastasis was statistically significant only in the semi-quantitative analysis of 99mTc-3PRGD2 SPECT/CT (P = 0.007), with an AUC of 0.807 (95% CI, 0.641–0.974). @*Conclusion@#99mTc-3PRGD2 SPECT/CT imaging may notably perform in the direct diagnosis of lymph node metastasis of primary malignant lung tumors and indirectly predict the presence of lymph node metastasis through uptake in the primary lesions.
ABSTRACT
Objective:To explore the values of dynamic 18F-FDG PET/CT semi-quantitative parameters in the differentiation of histological subtypes of non-small cell lung cancer (NSCLC) and the diagnosis of lymph node metastasis. Methods:Twenty-three patients (10 males, 13 females, age (61.5±8.1) years) with NSCLC in Shengjing Hospital of China Medical University were prospectively enrolled between October 2020 and June 2021. All patients underwent 40 min of dynamic PET/CT scan and static scan at 60 min post-injection of 18F-FDG. SUV max, SUV mean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary lesions at different stages of PET/CT imaging were evaluated. SUV max of lymph nodes were also analyzed. The histopathological results were considered as the gold standard. Parameters of primary lesions and lymph nodes at different PET/CT imaging stages in different groups were compared by independent-sample t test or Mann-Whitney U test. The diagnostic efficiencies of those parameters were tested by ROC curve and compared by DeLong test. Results:A total of 24 lesions in 23 patients were pathologically confirmed as NSCLC, of which 11 were squamous cell carcinoma and 13 were adenocarcinoma. The SUV max (13.5±3.4 vs 9.6±5.1), SUV mean (8.1±2.2 vs 5.8±3.2) at the third stage of dynamic PET/CT (33-40 min) between squamous cell carcinoma and adenocarcinoma were both significantly different ( t values: 2.20, 2.10, P values: 0.039, 0.048). SUV max, TLG of static PET/CT between the 2 groups were also different ( t=2.22, P=0.037; z=-2.17, P=0.030). ROC curves of those parameters showed that AUCs were between 0.727 and 0.762. Fourteen patients underwent surgery and lymph node dissection. According to the pathological results, lymph nodes in 15 areas were metastatic, the rest in 70 areas were benign. There were significant differences in SUV max at the second stage of dynamic PET/CT (19-26 min) between metastatic and benign lymph nodes (4.0(2.8, 6.2) vs 2.3(1.8, 2.8); z=-4.31, P<0.001), as well as SUV max at the third stage of dynamic PET/CT and static PET/CT between the 2 groups ( z values: -4.59, -4.10, both P<0.001). ROC curves of those 3 parameters showed that the AUCs were 0.856, 0.879 and 0.838 respectively, with no significant differences ( z values: 0.78, 0.34, 1.27, P values: 0.434, 0.734, 0.205). The sensitivity, specificity, and accuracy of the SUV max of the third dynamic imaging stage were 13/15, 90.0%(63/70) and 89.4%(76/85), respectively. Conclusion:Dynamic 18F-FDG PET/CT semi-quantitative parameters have certain clinical significance in the identification of histological subtypes of NSCLC and the diagnosis of metastatic lymph nodes, especially the third stage dynamic imaging has a better diagnostic performance.