SPIO-enhanced MRI for differentiating metastatic from reactive hyperplastic lymph nodes in breast cancer: diagnostic performance and association with VEGF-C expression

Background: Accurate assessment of lymph node status is essential for staging and treatment planning in breast cancer. Conventional morphological imaging criteria have limited sensitivity and specificity. Superparamagnetic Iron Oxide (SPIO)-enhanced MRI offers a functional imaging alternative exploiting macrophage-mediated iron uptake. This study evaluated the diagnostic performance of SPIO-enhanced MRI in differentiating metastatic from reactive hyperplastic lymph nodes and explored the association between MRI signal characteristics and Vascular Endothelial Growth Factor C (VEGF-C) expression. Methods: Sixty female breast cancer patients (January-May 2024) underwent preoperative plain and SPIO-enhanced MRI (Resovist, 0.2 mL/kg, 12-h delay). Among 112 harvested lymph nodes, Hematoxylin and Eosin staining, Prussian Blue staining, and VEGF-C immunohistochemistry were performed. The Percentage of Signal Intensity Loss (PSIL) was calculated on T2*-weighted images. The primary diagnostic analysis was patient-level using mean PSIL with receiver operating characteristic analysis. Results: < 0.001). Conclusion: SPIO-enhanced MRI demonstrated favorable diagnostic performance for differentiating metastatic from reactive hyperplastic lymph nodes at the patient level. The imaging characteristics were associated with supportive histopathological findings and VEGF-C expression patterns. These findings warrant validation in larger, multicenter studies using currently available iron oxide agents.