| BackgroundLymph nodes play important roles in cancer TMN staging,the correct assessment of which affects the surgical approach and prognosis of cancer patients.With the innovation of imaging technology for mediastinal and intracavitary diseases,unknown lymph nodes have aroused concern.CT and MRI have low accuracy rates in diagnosis of lymph nodes.PET-CT hasn’t been used broadly because of its high cost.Thanks to the combination of the second generation contrast agent Sonovue and the low mechanical index(MI)ultrasound imaging technique,contrast-enhanced endoscopic ultrasound(CE-EUS)as a noninvasive method not only increases endoscopic ultrasound guided fine needle aspiration(EUS-FNA)diagnosis accuracy but aslo occupies a pivotal position in patients who cannot undergo EUS-FNA or provide little tissue during examination.Time-intensity curve(TIC)analysis is able to quantify perfusion patterns by depicting the parameters of blood perfusion to improve diagnostic accuracy.Nowadays,there are few studies on CE-EUS quantitative analysis in differential diagnosis of benign and malignant lymph nodes.ObjectiveThe aim of this study was to compare the CE-EUS blood perfusion patterns of benign and malignant lymph nodes in the mediastinal and abdominal cavity and compare the parameters of blood perfusion by TIC analysis,prospectively.MethodsA total of 48 patients with unknown lymph node manifestation revealed by conventional imaging techniques such as CT,MRI or transabdominal ultrasound(US)between October 2015 and December 2016 were prospectively included in our study,which was carried out in the Departmant of Gastroenterology of a local tetirary medical center.A total of 50 lymph nodes were observed by CE-EUS,in the mediastinum or in the abdomen.Final diagnosis was the results of EUS-FNA,pathology or follow-up.The diagnostic accuracy of CE-EUS quantitative analysis was evaluated.CE-EUS enhancement mode and TIC parameters were analyzed.ResultsThere were 23 malignant lymph nodes in total of 50 lymph nodes,19 benign lymph nodes and 8 normal lymph nodes.The sensitivity and specificity of CE-EUS quantitative diagnosis of benign and malignant lymph nodes were 94%and 82%,respectively.The sensitivity of CE-EUS quantitative diagnosis was much higher than EUS-FNA.Malignant lymph nodes showed heterogeneous enhancement or non enhancement,the majority of benign ones showed homogeneous enhancement.As for TIC analysis,malignant lymph nodes showed low peak enhancement,slow wash-in rate and slow wash-out rate,while the benign lymph nodes showed high peak enhancement,fast wash-in rate and fast wash-out rate.The difference was statistically significant(P<0.05).ConclusionsCE-EUS can identify benign and malignant lymph nodes,usefully.Heterogeneous enhancement and non enhancement have significant effects on the diagnosis of malignant lymph nodes.TIC quantitative analysis,in which malignant lymph nodes shows low peak enhancement,slow wash-in rate and slow wash-out rate,as a kind of auxiliary means can effectively improve diagnostic accuracy. |
