The Value And Mechanism Of PET/CT Imaging On Diagnosis And Staging Of Lung Cancer

Objective To investigate the value and mechanism of 11C-choline PET/CT imaging in diagnosis and N staging of lung cancer.Methods In this retrospective study, eighty-four patients between 2007.6-2010.2 who diagnosed as lung cancer or pulmonary nodules were examined by both enhanced CT and 11C-choline PET/CT before surgery. " C-choline PET data was analyzed by visual method and semiquantitative method. The standardized uptake value (SUV) were measured. This research were divided into two steps:â‘ The sensitivity, specificity, validity of enhanced CT and 11C-choline PET in diagnosis of primary tumor and lymph node metastases were speculated according to the postoperative pathological results, and the difference between enhanced CT and 11C-choline PET in diagnosis and N staging of lung cancer was discussed.â‘¡RT-PRC were used to investigate the expressions of choline kinase (Chok) gene and phosphorylcholine-cytidyl transferase (PCYT) gene in lesions and normal tissues. The differences of gene expressions between lesions and normal tissues were discussed and the correlations between gene expression and SUV were evaluated.Resultsâ‘ In diagnosis of primary tumor, the sensitivity, specificity, validity were 86.15%,73.68%,83.33% respectively for 11C-choline PET, and 78.46%,63.16%, 75.00% for enhanced CT. The differences between 11C-choline PET/CT and enhanced CT were not statistically significant (p=0.12, p=0.63, p=0.55). In diagnosis of lymph node metastases, the sensitivity, specificity, validity were 80.28%,83.67%,83.10% respectively for 11C-choline PET, and 61.97%,70.42%,69.01% for enhanced CT The differences between "C-choline PET/CT and enhanced CT were statistically significant(p=0.03, p<0.01, p<0.01). In the 65 lung cancer patients,81.54% were staged correctly,12.31% were overstaged,6.15% were understaged by 11C-choline PET/CT.58.46% were staged correctly,24.62% were overstaged,11.92% were understaged by enhanced CT.8 overstaged patients and 10 understaged patients by enhanced CT can be corrected by the "C-choline PET/CT. Only 1 overstaged patient and 2 understaged patients by11C-choline PET/CT can be corrected by enhanced CT.â‘¡78.75% of the 56 lung cancer patients who were diagnosed as malignant tumor by 11C-choline PET had an overexpression of Chok gene (P<0.01).71.43% of them had an overexpression of PCYT gene (P<0.01).64.29% of them had an overexpression of both Chok and PCYT genes; Expressions of Chok and PCYT in the 9 lung cancer patients who were diagnosed as benign tumor by11C-choline PET were at normal level; Only 10.53% of 19 benign tumor patients had an overexpression of Chok gene (P=0.07),15.79% of them had an overexpression of PCYT gene (P=0.08). But the overexpressions had no significance in statistics; In the 56 lung cancer patients diagnosed as malignant tumor by11C-choline PET, expression of Chok showed positive correlation with SUVmean (r=0.51, P<0.01).Expression of PCYT also showed positive correlation with SUVmean (r=0.50, P<0.01)Conclusionâ‘ 11 C-choline PET/CT is not significantly superior to enhanced CT in the diagnosis of primary tumor. However, it's obviously superior to enhanced CT in the staging of lymph node. "C-choline PET/CT can provide more accurate N staging for the following therapy.â‘¡The Mechanism Of "C-choline PET/CT Imaging is related to the increase of phosphatidylcholine in lung cancer cells, and the increase of phosphatidylcholine is a result of the overexpression of Chok and PCYT.