Background: Accurate axillary lymph node staging is crucial for breast cancer prognosis and treatment planning. This study compares the diagnostic efficacy of abbreviated MRI (AB-MRI) protocols with limited sequences and reduced time, against full-diagnostic MRI (FD-MRI) in staging axillary lymph node metastasis of breast cancer patients.

Methods: This was a retrospective cross-sectional diagnostic-accuracy study of 88 women with breast cancer who underwent MRI for axillary lymph node staging. MRI protocols included FD-MRI, non-contrast T1 sequence, and contrast-enhanced T1 sequence. Imaging findings, interpreted by two radiologists blinded to histopathological results, were correlated with findings from sentinel lymph node biopsy or axillary lymph node dissection as the gold standard. Data analysis comprised diagnostic performance parameters (sensitivity and specificity) and inter-protocol agreement using the kappa statistic.

Results: No statistically significant differences were detected among the three protocols (all McNemar's p-values > 0.05). The non-contrast abbreviated MRI protocol demonstrated a sensitivity of 84.9% (95% CI: 72.4%-93.3%) and a specificity of 85.7% (95% CI: 69.7%-95.2%). Unweighted Cohen’s Kappa demonstrated strong concordance between the non-contrast and contrast-enhanced AB-MRI protocols (κ = 0.931; 95% CI: 0.855–1.00), between the non-contrast AB-MRI protocol and the FD-MRI (κ = 0.930; 95% CI: 0.852–1.00), and between the contrast-enhanced AB-MRI protocol and the FD-MRI (κ = 0.907; 95% CI: 0.819–0.995), respectively.

Conclusion: Non-contrast AB-MRI provides a less invasive, cost-effective alternative to FD-MRI for staging axillary lymph nodes in breast cancer, with shorter scan times and fewer procedural risks. Further studies are needed for validation in larger cohorts.