Assessing the diagnostic value of hemodynamic distinctions between axillary lymph nodes and adjacent vessels in breast cancer axillary lymph node metastasis via breast magnetic resonance imaging

Background: Axillary lymph node metastasis (ALNM) is pivotal for breast cancer treatment and prognosis. Invasive tests may carry complications, while non-invasive methods like physical examination have poor accuracy. Existing AI-based models rely mostly on tumor-centric features. However, metastatic lymph nodes show neoangiogenesis and altered hemodynamics, leading to time-intensity curve (TIC) profiles similar to those of adjacent vessels. This study aimed to quantify these hemodynamic disparities from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and enhance ALNM prediction accuracy. Methods: A retrospective study included 186 patients (92 ALNM+, 94 ALNM−). Axillary vessels and lymph nodes were semi-automatically segmented via Hessian matrix algorithms. Four TIC-derived features [lymph-node TIC area (LNTICA), difference in TIC area between vessel ROI and lymph-node ROI (DIFF), non-negative area difference (NON-NEG DIFF), ratio of area difference to lymph node TIC area (RATIO TO LYMPH)] were extracted. ResNet50 extracted image features, and a Stacking framework integrated image, clinical, and TIC features, using support vector machine (SVM) and nomogram as classifiers. Statistical tests (F-test, t-test, and Kolmogorov-Smirnov test) validated feature discriminability. Results: All TIC features differed significantly between groups (P