Multi-volume Fusion Imaging of MR Ductography and MR Mammography for Patients with Nipple Discharge

Because nipple discharge is caused by carcinoma as well as benign disease, identification of intraductal abnormalities with ductography is important. Ductography is an invasive mammographic examination in which contrast material is injected directly into the duct. Failure to cannulate or extravasation may occur. Ductography shows evidence of lesions, such as filling defects, duct obstruction, or wall irregularity, but it does not reveal the lesion itself. Furthermore, ductography produces a two-dimensional image, so it does not show the shape of the dilated duct or the precise location of the intraductal lesion in the breast. We applied three-dimensional (3D) heavily T2-weighted imaging with fat suppression of the breast to produce MR ductography. The dilated ducts are seen in 3D as tubular structures with high signal, and intraductal abnormalities are seen as signal defects. Furthermore, MR ductography can show an obstructed duct that cannot be seen on ductography. We also performed 3D breast MRI with the intravenous infusion of contrast material to show the lesion itself. Finally, we fused these 2 volume images into a single 3D fused image that not only shows the existence of intraductal abnormality, but reveals the shape, size, and extent of lesion, allowing us to understand easily the relationship between the ducts with dilation and any intraductal lesions in the breast. We herein introduce and describe this noninvasive method and discuss various factors related to its diagnostic use.