Evaluation of Lymph Nodes Using a Combination of Advanced Sonographic Techniques: Superb Microvascular Imaging and Shear Wave Elastography

Abstract

Purpose: To evaluate the diagnostic performance of a novel combination of advanced sonographic techniques in distinguishing between malignant and benign lymph nodes. Methods: A total of 59 patients with enlarged lymph nodes were evaluated with conventional ultrasound (US), superb microvascular imaging (SMI), and shear wave elastography (SWE) even before ultrasound-guided percutaneous biopsy. Following the development of regression models, the diagnostic utility of univariate and multivariate parameters was evaluated using receiver operating characteristic (ROC) analysis. Results: Forty-one of the 59 lymph nodes were benign. The shortest diameter, longest diameter, elasticity (kPa), velocity (m/s), and vascularity index (VI) of malignant lymph nodes were all significantly higher than those of benign lymph nodes. In univariate analysis, the AUC values for VI and SDkPa were 0.793 and 0.818, respectively, with the short axis having the highest AUC of 0.910. The diagnostic accuracy value for SDkPa was the highest (0.88). The regression model with short axis, SDkPa, and VI variables had the best diagnostic performance in the multivariate analysis (AUC 0.967; 0.89 sensitivity, 0.95 specificity, 0.89 PPV, 0.95 NPV, and 0.93 accuracy). Conclusion: The combination of SMI and SWE results in a highly reliable diagnostic model for differentiating between malignant and benign lymph nodes.