Current standard MRI of the breast has some technical challenges that do not allow simultaneous optimal imaging of both the breast and axilla, with approximately 30% of the MRI examination excluding the axilla because of technical challenges or incomplete axillary visualization in a retrospective study of 803 newly diagnosed breast cancer patients [79]. When comparing contrast-enhanced breast MRI with noncontrast breast MRI, contrast-enhanced breast MRI is more accurate than noncontrast MRI, based on Imaging of the Axilla a summary of 6 studies evaluating the accuracy of MRI in detecting pathologically proven positive axillary 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]. Based on the review of the literature, there was disagreement for the role of breast MRI in this clinical scenario. Diffusion-weighted imaging (DWI) is a noninvasive imaging technique that does not require contrast injection, measuring 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 are 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 Tc-99m sestamibi MBI for staging of the axilla in breast cancer patients. US Axilla US is the most established noninvasive imaging test for assessing the axilla.
Imaging of the Axilla. Current standard MRI of the breast has some technical challenges that do not allow simultaneous optimal imaging of both the breast and axilla, with approximately 30% of the MRI examination excluding the axilla because of technical challenges or incomplete axillary visualization in a retrospective study of 803 newly diagnosed breast cancer patients [79]. When comparing contrast-enhanced breast MRI with noncontrast breast MRI, contrast-enhanced breast MRI is more accurate than noncontrast MRI, based on Imaging of the Axilla a summary of 6 studies evaluating the accuracy of MRI in detecting pathologically proven positive axillary 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]. Based on the review of the literature, there was disagreement for the role of breast MRI in this clinical scenario. Diffusion-weighted imaging (DWI) is a noninvasive imaging technique that does not require contrast injection, measuring 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 are 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 Tc-99m sestamibi MBI for staging of the axilla in breast cancer patients. US Axilla US is the most established noninvasive imaging test for assessing the axilla.