The clinical use of low-dose multidetector row computed tomography for breast cancer patients in the prone position

Purpose: To investigate the clinical use of low-dose multidetector row computed tomography (MDCT) for staging of invasive breast cancers with patients in the prone position. Methods: Three hundred twenty-two patients with 334 pathologically-verified breast cancers had low-dose MDCT breast imaging in the prone position for tumor staging before treatment between May 2006 and June 2010. We designed an additional computed tomography table pad with a hole for prone positioning. Patients lay prone on the table pad and the breasts were positioned within the rectangular hole. We obtained dynamic breast imaging from the lower neck to the lung base with the following parameters: 120 kVp, 50 mAs, and 3-mm reconstruction intervals. We evaluated the extent of the primary tumor, lymph nodal status, and distant metastasis in lung or bone, then assessed tumor staging based on the TNM classification of breast cancer. The assessed staging compared to the pathologic results for diagnostic accuracy. Results: Among the 334 invasive breast cancers, the overall diagnostic accuracy of tumor staging was 88.3% and the accuracy values of each tumor stage were 89.6% in T1, 90.8% in T2, 81.0% in T3, and 89.3% in T4. The overall diagnostic accuracy of lymph nodal staging was 86.3% and the accuracy values in each nodal stage were 82.9% in N0, 88.0% in N1, 89.7% in N2, and 93.3% in N3. Based on breast computed tomography scans, we detected distant metastases in 30 cases (7 lungs, 10 bones, 7 lungs and bones, and 6 livers). Conclusion: Lowdose MDCT scanning for invasive breast cancer patients in the prone position is a feasible imaging technique for tumor staging before treatment to evaluate primary breast tumors, lymph nodes, lungs, or thoracic bones with reduced radiation doses.