However, findings on CT do not influence the approach for axillary surgery, reduce the number of axillary surgeries, or reduce the reoperation rate [14,47]. MRI Breast Dynamic contrast-enhanced MRI is not routinely performed [7,92] for staging prior to systemic therapy and for restaging of the axilla after systemic therapy if preoperative axillary staging was negative [7,48]. Current breast MRI protocols do not adequately image the breast and entire axilla 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 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, the apparent diffusion coefficient value of metastatic nodes is lower than nonmetastatic nodes with pooled sensitivity of 86% and specificity of 86% using a b-value of 800 [80]. Sestamibi MBI There is no relevant literature supporting the routine use of sestamibi MBI for staging of the axilla in breast cancer patients.
Imaging of the Axilla. However, findings on CT do not influence the approach for axillary surgery, reduce the number of axillary surgeries, or reduce the reoperation rate [14,47]. MRI Breast Dynamic contrast-enhanced MRI is not routinely performed [7,92] for staging prior to systemic therapy and for restaging of the axilla after systemic therapy if preoperative axillary staging was negative [7,48]. Current breast MRI protocols do not adequately image the breast and entire axilla 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 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, the apparent diffusion coefficient value of metastatic nodes is lower than nonmetastatic nodes with pooled sensitivity of 86% and specificity of 86% using a b-value of 800 [80]. Sestamibi MBI There is no relevant literature supporting the routine use of sestamibi MBI for staging of the axilla in breast cancer patients.