Abstract: Objective To investigate the value of lymphatic contrast-enhanced ultrasound (LCEUS) with intra-glandular injection of contrast agent for diagnosis of central compartment lymph node metastasis of thyroid cancer. Methods From November, 2020 to May, 2022, the patients suspected of having thyroid cancer and scheduled for biopsy at our center received both conventional ultrasound and LCEUS examinations of the central compartment lymph nodes before surgery. All the patients underwent surgical dissection of the lymph nodes. The perfusion features in LCEUS were classified as homogeneous enhancement, heterogeneous enhancement, regular/irregular ring, and non-enhancement. With pathological results as the gold standard, we compared the diagnostic ability of conventional ultrasound and LCEUS for identifying metastasis in the central compartment lymph nodes. Results Forty-nine patients with 60 lymph nodes were included in the final analysis. Pathological examination reported metastasis in 34 of the lymph nodes, and 26 were benign lymph nodes. With ultrasound findings of heterogeneous enhancement, irregular ring and non-enhancement as the criteria for malignant lesions, LCEUS had a diagnostic sensitivity, specificity and accuracy of 97.06%，92.31% and 95% for diagnosing metastatic lymph nodes, respectively, demonstrating its better performance than conventional ultrasound (P<0.001). Receiver-operating characteristic curve analysis showed that LCEUS had a significantly greater area under the curve than conventional ultrasound for diagnosing metastatic lymph nodes (94.7% [0.856-0.988] vs 78.2% [0.656-0.878], P=0.003). Conclusion LCEUS can enhance the display and improve the diagnostic accuracy of the central compartment lymph nodes to provide important clinical evidence for making clinical decisions on treatment of thyroid cancer.

Key words: thyroid carcinoma; ultrasound; contrast-enhanced ultrasound; lymph nodes