~(18)F-FDG PET/CT in the Diagnosis of Mediastinal Lymph Node Metastasis of Non-small Cell Lung Cancer

Purpose To improve the diagnostic accuracy by analyzing the features of 18F-FDG PET/CT imaging in non-small cell lung cancer with mediastinal lymph node metastasis and nonspecific high uptake of lymph node in elderly.Materials and Methods For 127 non-small cell lung cancer patients with mediastinal lymph node increased uptake revealed in 18F-FDG PET/CT examination were retrospective analyzed,including mediastinal lymph node metastasis in 58 cases with 161 lymph nodes and non-specific lymph node uptake in elderly in 69 cases with 160 lymph nodes,the diagnosis was confirmed by pathology or follow-up results,and the characteristics of lung cancer lymph node metastasis and nonspecific lymphatic high uptake in elderly was analyzed.Results Diameter of mediastinal lymph node metastases was larger(2.22±1.00) cm,with higher metabolism and no obvious pattern in its distribution,59 of them located in district 4 and 31 located in district 7;while there was certain pattern for the distribution of non-specific lymph nodes in elderly,mainly as symmetric distribution in mediastinal and hilar,with smaller diameter(1.37±0.48) cm,higher density,and mild unusually high metabolism in PET images.Lymph node diameter and SUVmax(7.45±4.49) in mediastinal metastasis were significantly higher than those of the non-specific lymph nodes in elderly which were(1.37±0.48) cm and 3.94±1.36(t=-7.50 and-7.37,P0.01),but CT value of the mediastinal metastasis lymph nodes(30.73±4.31) Hu was significantly less than that of the elderly non-specific lymph nodes(81.27±14.24) Hu(t=- 24.47,P0.01).Conclusion According to the distribution pattern,size,density and metabolism of mediastinal lymph nodes in 18F-FDG PET/CT imaging,non-small cell lung cancer with mediastinal lymph node metastasis and non-specific lymph nodes in elderly can be distinguished,which is beneficial to make the correct clinical diagnosis.