Clinical Application Of Endoscopic Ultrasonography In The Diagnosis Of Lung Neoplasm And Mediastinal Lymph Node Metastasis

Objective To set up a criteria for the diagnosis of metastaticmediastinal lymph nodes in lung neoplasm by means of EndoscopicUltrasonography (EUS) and to investigate the feasibility,safety andaccuracy of Endoscopic Ultrasonography guided fine-needle aspiration(EUS-FNA, EUS guided FNA) in patients with suspected lungneoplasm and metastatic mediastinal lymph nodes.Methods Twenty-one patients with lung neoplasm underwentpreoperative EUS on mediastinal lymph nodes. All 103 lymph nodesdetected by EUS were resected and received pathologic examination.The rate of detection for mediastinal lymph nodes was calculated. Thedifference between benign and malignant lymph nodes were studiedand statistically analysed.Using a linear array scanning endosonography (Pentax FG32-UA) and a22G GIP (Medi-Globe) needle, EUS-FNA was performed in 10 patients,includin 6 patients with lung mass and enlarged mediastinal lymph nodes,one patient with a mass in right lung, one patient with a mass besideesophagus and 2 patients with asystematic enlarged mediastinal lymph nodes.Data collected included lesions types, complications and diagnostic ascuracy.Results The rates of metastatic lymph nodes detected by EUS weresignificanly higher than non-metastatic lymph nodes (p<0.01) in levels5,7,8,and 9 of UICC mediastinal lymph node staging map (1997),especially in levels 5 and 7.The mean length of the long and short axisof metastatic lymph nodes were significanly longer than that ofnon-metastatic lymph nodes(p<0.01). As the length of the long andshort axis increased, the frequency of there being metastasissignificanly increased (p<0.01). Metastaic lymph nodes had fourcharacteristic ultrasonographic features, including short axis≥1.0cm,long axis3l.5cm, clear boundny and rounded shaPe. When Logisticregression was performed using the presence of malignan lymPh nodesas a response varable, and the long axis, the short axis, boundny andthe value of (long axis)/(short axis) as convarites, the short axis andclear boundmp were found to be significant predictors. According theequation p(,)=l/[l+C-(-, 963+2.o4l xl+l.681 ")], P(l)30.5, the lymPh nodewere assumed to be malignant. The accuracy, sensitivity specificitywere 72.8%, 72.7%, 72.9%, respectively, suPerior to those by CT doneof the same patiellts in levels 5, 7, 8 and 9. During EUS-FNA,diagnostic material was obtained in 9 of l0 patients. The accuraCXsensitivity SPecificfor positive predictive value, negative predictivevalue were l00%. None of the patients had complications related tOprocedure.Conchaions EUS is an effective mothod of diagnostic evaluation ofmediastinal lymph nodes of lung neoplasm. EUS-FNA is a safe, reliableand accurate method to obtain diagnostic tissue of suspicious lungneoplasm and mediastinal lymPh node.