MRI Breast Dynamic contrast-enhanced MRI may be useful for staging prior to systemic therapy and for restaging of the axilla after systemic therapy if the preoperative axillary staging was positive [7,48]. However, most of the data focuses on the tumor within the breast and not of the axillary nodes. Current breast MRI protocols do not adequately image the entire axilla (level I, II, III) in up to 30% of cases based on a retrospective study of 803 newly diagnosed breast cancer patients [79]. However, contrast-enhanced breast MRI is more accurate than noncontrast imaging with a FNR of 12% to 19% and NPV of 97% to 99% based on 6 studies designed to evaluate the accuracy of MRI in patients with histologically positive nodes [52]. In a meta-analysis of 21 eligible studies evaluating the efficacy of MRI versus FDG-PET/CT, the pooled sensitivity of MRI was significantly better (82% versus 64%, respectively), and the pooled specificity of MRI was similar (93%) [69]. A negative MRI does not exclude metastatic nodal disease on final histopathology, but a positive MRI finding suggests high tumor burden (>3 abnormal nodes) [15,69,79]. DWI is a noninvasive imaging technique that does not require contrast injection, measures the mobility of water molecules, and may complement contrast-enhanced MRI. In a meta-analysis of 13 studies from a literature search of 159 articles, apparent diffusion coefficient value of metastatic nodes are lower than nonmetastatic nodes with Imaging of the Axilla pooled sensitivity of 86% and specificity of 86% using a b-value of 800 [80]. There is insufficient data to support the use of DWI for detecting metastatic disease in axillary nodes at this time. In summary, although current breast MRI protocols do not consistently image the entire axilla in patients with newly diagnosed breast cancer over 2 cm in size and clinical node-positive, breast MRI can be beneficial for evaluation of tumor within the breast and may be helpful for the axilla in some circumstances.
Imaging of the Axilla. MRI Breast Dynamic contrast-enhanced MRI may be useful for staging prior to systemic therapy and for restaging of the axilla after systemic therapy if the preoperative axillary staging was positive [7,48]. However, most of the data focuses on the tumor within the breast and not of the axillary nodes. Current breast MRI protocols do not adequately image the entire axilla (level I, II, III) in up to 30% of cases based on a retrospective study of 803 newly diagnosed breast cancer patients [79]. However, contrast-enhanced breast MRI is more accurate than noncontrast imaging with a FNR of 12% to 19% and NPV of 97% to 99% based on 6 studies designed to evaluate the accuracy of MRI in patients with histologically positive nodes [52]. In a meta-analysis of 21 eligible studies evaluating the efficacy of MRI versus FDG-PET/CT, the pooled sensitivity of MRI was significantly better (82% versus 64%, respectively), and the pooled specificity of MRI was similar (93%) [69]. A negative MRI does not exclude metastatic nodal disease on final histopathology, but a positive MRI finding suggests high tumor burden (>3 abnormal nodes) [15,69,79]. DWI is a noninvasive imaging technique that does not require contrast injection, measures the mobility of water molecules, and may complement contrast-enhanced MRI. In a meta-analysis of 13 studies from a literature search of 159 articles, apparent diffusion coefficient value of metastatic nodes are lower than nonmetastatic nodes with Imaging of the Axilla pooled sensitivity of 86% and specificity of 86% using a b-value of 800 [80]. There is insufficient data to support the use of DWI for detecting metastatic disease in axillary nodes at this time. In summary, although current breast MRI protocols do not consistently image the entire axilla in patients with newly diagnosed breast cancer over 2 cm in size and clinical node-positive, breast MRI can be beneficial for evaluation of tumor within the breast and may be helpful for the axilla in some circumstances.