Abstract:Objective: To investigate the diagnostic efficacy of the combined application of Superb Microvascular Imaging (SMI) and Shear Wave Elastography (SWE) in the preoperative evaluation of cervical lymph node metastasis in patients with lung cancer. Methods: A total of 187 patients (with 187 lymph nodes) with suspected lung cancer and cervical lymph node enlargement were selected as the study subjects. All patients underwent conventional ultrasound, superb microvascular imaging (SMI), and shear wave elastography (SWE) before surgery. Using cervical lymph node aspiration/biopsy pathology or pathological staging after radical lung cancer surgery as the gold standard, differences in conventional ultrasound, SMI blood flow parameters, and SWE elastography parameters were compared between the two groups at both the patient level (114 cases in the metastatic positive group and 73 cases in the metastatic negative group) and the lymph node level (114 lymph nodes in the metastatic group and 73 lymph nodes in the non-metastatic group). Receiver operating characteristic (ROC) curves were plotted to evaluate the diagnostic efficacy of different examination methods and their combined application. Results: At the patient level, the proportion of poor differentiation was higher in the metastatic positive group than in the metastatic negative group (P<0.05). At the lymph node level, metastatic nodes more frequently exhibited features on conventional ultrasound such as a long-axis/short-axis ratio < 2, larger short-axis diameter, indistinct margins, loss of corticomedullary differentiation, heterogeneous internal echogenicity, and microcalcifications (P <0.05). SMI revealed that metastatic nodes predominantly showed peripheral or mixed vascular patterns, while non-metastatic nodes mainly showed hilar vascular patterns (P<0.05). The proportion of nodes with Adler blood flow grade II~III was higher in the metastatic group than that in the non-metastatic group (P<0.05). SWE quantitative parameters showed that the maximum Young’s modulus (Emax), mean Young’s modulus (Emean), minimum Young’s modulus (Emin), and standard deviation (SD) were higher in the metastatic group compared to the non-metastatic group (P<0.05). The sensitivity, specificity, and accuracy of the combined SMI and SWE diagnosis were 95.60%, 90.40%, and 93.60%, respectively, with an AUC of 0.938 (95%CI:0.892~0.973), which were higher than those of any single method (P<0.05). Conclusion: SMI can finely depict the internal vascular architecture of lymph nodes, while SWE can quantitatively assess lymph node stiffness. Both techniques reflect the pathological characteristics of metastatic lymph nodes from different dimensions. Their combined application can improve the diagnostic accuracy for preoperative cervical lymph node metastasis in lung cancer.