The Comparison of US and MRI in the Assessment of Metastatic Axillary Lymph Nodes.

Objective: Axillary lymph node (ALN) metastasis is the most significant prognostic factor for predicting overall survival in breast cancer patients. Ultrasonography (US) and magnetic resonance imaging (MRI) are commonly used imaging methods in the detection of breast cancer lymph node metastasis (1, 2). The accurate assessment of ALN at preoperative period will guide the choice of appropriate surgical approach to the axillary and prevent potential surgery-related complications such as lymphedema, seroma and nerve injury. In this study, we aimed to compare effectiveness of MRI and US in the assessment of axillary. Materials and Methods: We retrospectively screened 1004 patients, who underwent US and MRI between 2016 and 2019. There were 257 patients with category 4, 5 or 6 according to Breast Imaging Reported Data System classification. Patients with received neo-adjuvant therapy excluded from the study. The MRI and US results were compared with histopathologic results of sentinel lymph node biopsy or axillary lymph node dissection. Results: The lesion was identified as malignant in 209 patients. Patients with received neo-adjuvant therapy (n=48; 23%). The remaining 161 patients underwent surgery. Of these, histopathological examination of ALNs was reported as positive in 73 patients and negative in 88 patients. The sensitivity, specificity values were 94.81%, 88% according to US and 89.02%, 73.95% according to MRI for the detection of metastatic ALNs, respectively. Conclusion: Dynamic-enhancement breast MRI is highly effective in detection of multi-focal, multi-centric lesion, invasion of skin and pectoral muscle. But, the result is not the same in the assessment of metastatic ALN. Ultrasonography is readily available, inexpensive, practical and successful imaging modality in the assessment of ALN. Major disadvantage of US is highly dependent to experience of radiologist. In our study, we observed that both sensitivity and specificity of US was statistically superior than MRI for the detection of metastatic ALNs. [ABSTRACT FROM AUTHOR]