Can PET/CT show heterogeneous distribution of tumor’s proliferative and infiltrative area in malignant solitary pulmonary nodule?

1357 Objectives: To study if 18F-FDG distribution is in difference on various edge signs of malignant solitary pulmonary nodule, and further explore the reason of heterogeneous distribution by of tumor’s biological characteristic behavior. METHODS Retrospectively collected cases of preoperative PET/CT images due to malignant solitary pulmonary nodule (SPN) from August 2015 to July 2017 in our institution to analyze the distribution characteristics of radioactive 18F-FDG on its corresponding edge sign region. 50 cases were enrolled in this study according to inclusion and exclusion criterion as follows: 1) Cases who had not underwent chemotherapy, radiotherapy, or other invasive examination or treatment before the PET/CT scan; 2) Cases who had confirmed pathological results of carcinoma postoperatively after PET/CT scan; 3) Cases whose SPN located on peripheral lung field were in the study except for the SPN occurring hilum or pleura for its edge signs were overlapped with surrounding structure and could not be well recognized; 4) Cases whose SPN with shorter diameter more than 1.0cm were in the study to avoid the volume effect; 5) Cases whose SPN with less than 2 edge signs were not included in this study. All cases underwent PET/CT scan according to routine procedure, and the fused images obtained on workstation were analyzed by 2 senior PET/CT physicians who were unaware of the final results. The edge signs including lobulation sign, spicule sign, vessel convergence sign and pleural retraction sign were determined according to diagnostic criteria of positive edge signs, and 18F-FDG uptake values on its corresponding areas were measured followed the definition of region of interest (ROI). Analyzed the data by SAS 8.0 software, the differences among 18F-FDG uptake values on various SPN edge sign areas were analyzed by using variance analysis of GLM procedure, and mean values of two-two comparison in 4 groups were made by DUNCAN Methods: RESULTS SUVave/SUVmax in corresponding areas of lobulation sign, spicule sign, pleural retraction sign and vessel convergence sign were 6.87 ± 3.29/8.33±3.98, 5.02 ± 3.93/5.86±3.44, 4.42 ± 2.04/5.40±2.45 and 6.37±3.93/7.77±5.22 respectively (p