Application of Microvascular Flow (MV-Flow) Ultrasound in the Differential Diagnosis of Benign and Malignant Lymph Nodes.

OBJECTIVE: To investigate the value of Microvascular Flow (MV-Flow) vascular pattern and quantitative parameter vascular index (VI) in differentiating benign from malignant lymph nodes. METHODS: A total of ninety-five patients who underwent ultrasound-guided lymph node aspiration biopsy at the First Hospital of Sun Yat-sen University between February 2023 and September 2023 were prospectively enrolled. Conventional ultrasound and MV-Flow examinations were performed, and the diagnostic efficacy was analyzed. The influencing factors of the VI were investigated. RESULTS: Among grayscale features, lymph node hilum, shape, liquefaction, and calcification differed significantly between benign and malignant nodes (p < 0.05). In the vascular pattern of Color Doppler Flow Imaging (CDFI) and MV-Flow, benign nodes mainly showed hilar flow, while malignant nodes mainly showed mixed flow (p < 0.05 for both). MV-Flow and CDFI demonstrated comparable overall diagnostic performance (AUC: 0.682 vs. 0.646), with no statistically significant difference (p > 0.05). MV-Flow vascular pattern classification showed good interobserver agreement (κ = 0.801), and the vascular index (VI) demonstrated high reliability (ICC = 0.811). A moderate negative correlation was observed between lymph node depth and VI across all four sections. CONCLUSIONS: MV-Flow provided superior qualitative visualization of microvascular flow compared to CDFI, but this did not translate into a statistically significant improvement in quantitative diagnostic performance for differentiating benign from malignant lymph nodes. Therefore, it should serve as a secondary diagnostic adjunct for lymph nodes with indeterminate CDFI findings, particularly to microvascular architecture that traditional Doppler fails to detect.