Abstract: Objective The aim of this study was to investigate the value of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)in the diagnosis of mediastinal lymph node metastasis of lung cancer. Methods Thirty-two patients with lung cancer who underwent DCE-MRI before surgery from January 2019 to June 2020 were collected.A total of 116 mediastinal lymph nodes confirmed by surgery and pathology were removed,including 21 metastatic lymph nodes and 95 non-metastatic lymph nodes.The DCE-MRI quantitative parameters of mediastinal lymph nodes were following:volume transfer constant(K^trans),rate constant(K_ep),and extravascular extracellular volume fraction(V_e).The differences between the DCE-MRI quantitative parameter values of the metastatic lymph nodes and non-metastatic lymph nodes were compared.The diagnostic efficiency of each quantitative parameter value for mediastinal lymph node metastasis was evaluated. Results The K^trans and Ve values of metastatic lymph nodes were higher than those of non-metastatic lymph nodes,the difference was statistically significant(P＜0.05).The ROC curves of K^trans,K_ep and V_e with pathological results were used as the gold standard,showing that the areas under the curve were 0.764,0.549,and 0.816,respectively.The areas under the curve of K^trans and Ve were all over 0.7,which has a certain diagnostic power,and the best diagnostic cut-off values were 0.117 min^-1 and 0.074,respectively.The sensitivity and specificity of K^trans were 87.37% and 66.67%,respectively,and the sensitivity and specificity of Ve were 75.79% and 90.48%,respectively. Conclusion The quantitative parameters of K^trans and Ve(DCE-MRI)can distinguish whether the mediastinal lymph nodes of lung cancer have metastasis,and have a certain diagnostic efficiency,which can provide more useful information for guiding the clinical development of individualized treatment plans.

Key words: Lung cancer;Magnetic resonance imaging;Dynamic enhancement;Lymph nodes