Spectral Precision: The Added Value of Dual-Energy CT for Axillary Lymph Node Characterization in Breast Cancer

Area of Science:

• Radiology and Medical Imaging
• Oncology
• Biomedical Engineering

Background:

• Accurate differentiation of metastatic from benign axillary lymph nodes is crucial for breast cancer (BC) staging and treatment planning.
• Current non-invasive methods often have limitations in distinguishing nodal status.
• Dual-energy CT (DECT) offers advanced tissue characterization beyond conventional imaging.

Purpose of the Study:

• To develop and validate a predictive model integrating morphological features and DECT parameters for non-invasive axillary lymph node assessment in BC patients.
• To evaluate the added value of DECT-derived parameters, specifically water concentration, in differentiating metastatic from benign nodes.

Main Methods:

• Retrospective analysis of 117 breast cancer patients (375 lymph nodes) who underwent DECT followed by lymphadenectomy.
• Morphological criteria (e.g., adipose hilum, cortical appearance, extranodal extension, short-axis diameter) and DECT parameters (e.g., water concentration, iodine concentration) were assessed.
• Multivariate logistic regression with cross-validation was employed to build predictive models.

Main Results:

• All assessed DECT parameters and morphological criteria showed significant differences between metastatic and benign nodes (p < 0.01).
• Water concentration was identified as an independent DECT predictor of metastasis (OR=0.97, p=0.002), alongside morphological abnormalities.
• The integrated model demonstrated a high diagnostic performance (AUC=0.883), with stable internal cross-validation.

Conclusions:

• A combined model using morphological criteria and DECT-derived water concentration accurately differentiates metastatic from benign axillary lymph nodes in breast cancer.
• Water concentration provides valuable tissue composition information, complementing perfusion indicators like iodine concentration.
• Further multicenter prospective studies are warranted to validate and refine this DECT-based approach for clinical application.