Application of body MRI coil in advanced breast cancer

Abstract

Background: Breast MRI coil is usually used to detect breast cancer individually using nipple Level as the center reference. The axillary zones are nearly outside the coil and images are usually suboptimal with noise. On the contrary, body coil have wider field of view (FOV), it can center at the axillary fossa, so combining two coils could evaluate the lymph nodes and chest wall more thoroughly. Methods: When MRI sequences were completed using breast coil, patients were kept prone and were covered by body coil on the back. Delayed enhanced axial and coronal T1W and axial DWI (b=50, 400,800 s/mm2) sequences were performed by two coils, it took about 4 minutes altogether. Images of neck, axillary and chest were performed. Fifty three cases of pathologically proved breast cancer with axillay lymph nodes metastases were included in the study. A retrospective analysis and comparison of the positive rate of nodes on one and two coils images. The result were evaluated by Chi-square analyses with Fisher’s exact test. Result: The positive interpretation by single and two coils were 21 and 49 cases respectively, p=0.000. Two coils sequences could see the full mapping of axillary nodes, with 3 additional cases of supraclavicular nodes metastases, 4 internal mammary nodal chain enlargement and 2 rib lesions, which were missed by single coil sequences. Conclusions: Body MRI coil should be combined with breast coil for breast examination.