Diagnostic accuracy of apparent diffusion coefficient value in differentiating metastatic form benign axillary lymph nodes in cancer breast

Abstract

Purpose: To detect axillary lymph node metastasis based on diffusion Weighted MR and apparent diffusion coefficient (ADC) in the known breast cancer cases. Patient and methods: Forty-four patients were included in this study for preoperative MRI staging of the breast cancer and axillary lymph node assessment. The lymph node criteria (long/short-axis ratio, T2WI, DWI and ADC value) were included in the analysis. Images were obtained with diffusion sensitizing gradients of 0 and 750 mm2/s. The ADC was calculated. Results: Thirty-two patients had metastatic axillary lymph nodes and 12 cases had no malignant LN involvement. There was no significant difference between both in S/L ratio, T2WISI (p < 0.140 & p = 0.079, respectively), while statistically significant difference between benign and malignant lymph nodes in both DWI and ADC mean values (p < 0.0001 & p < 0.007, respectively). The optimal ADC cut off value was ⩽.8 × 10−3 mm2/s for differentiation between benign and malignant lymph nodes with accuracy 96.7%, sensitivity 100%, specificity 87%, PPV 95.4% and NPV 100%. Conclusion: Compared with lymph node size or routine magnetic resonance sequences, DWI and ADC are promising techniques for differentiating metastatic and non metastatic axillary lymph nodes in known breast cancer patients.

Keywords

• Axillary lymph node
• Diffusion-weighted imaging
• Apparent diffusion coefficient (ADC)