3444 Usefulness of contrast echolymphography using endoscopic ultrasonography-guided puncture.

BACKGROUND: The accuracy of EUS in the assessment of regional lymph node metastasis leaves to be desired. Although EUS-guided fine needle aspiration biopsy (EUS-FNAB). is a superior examination method, there are various problems, such as difficulty in collecting tissue specimens and collection of tissue specimens from noncancerous regions. AIM: To qualitatively improve the capability of diagnosing lymph node swelling, contrastenhanced echolymphography (CE-EL) was performed using EUS-guided puncture. SUBJECTS AND METHOD : In the present study, 8 malignant swollen lymph nodes surgically resected from patients with gastrointestinal cancers and 36 lymph nodes obtained from 36 patients in whom abdominal lymph node swelling was indicated by EUS (14 cases of metastatic lymph node swelling and 22 cases of benign lymph node swelling) were examined. Lymph nodes were punctured under real-time EUS guidance, and carbon dioxide microbubbles were topically injected to evaluate ultrasonograms before and after microbubble injection. RESULTS: CE-EL of freshly resected metastatic lymph nodes showed nonhomogeneous patterns. Resions in the lymph node demonstrating filling defects during CE-EL were pathologically correlated with resions showing neoplastic infiltration. When the results of EUS performed before CE-EL were clinically evaluated, there were no apparent differences in any echo features except the shape of lymph nodes between the malignant and benign groups (malignant lymph nodes showed rounded shapes). In contrast, CE-EL demonstrated nonhomogeneous patterns, poor distribution of contrast medium, and filling defects in 92.9 to 100% of subjects in the malignant group. However, CE-EL demonstrated uniform patterns in 68.2% of subjects in the benign group. Therefore, there were differences in CE-EL findings between the two groups. The sensitivity, specificity, rate of positivity and negativity, and accuracy of differentiation diagnosis by CEEL were 92.8%, 95.5%, 92.8%, 95.5%, and 94.4%, respectively. CONCLUSION: The diagnostic capability is expected to be improved by combining CE-EL with EUS-FNAB. Therefore, the combination of CE-EL and EUSFNAB is considered a favorable examination method for differentially diagnosing swollen lymph nodes.