Three-dimensional ultrasound imaging of mammary ducts in lactating women: a feasibility study.

OBJECTIVE The main function of the breast is to produce milk for offspring. As such, the ductal system, which carries milk from the milk-secreting glands (alveoli) to the nipple, is central to the natural function of the breast. The ductal system is also the region in which many malignancies originate and spread. In this study, we aimed to assess the feasibility of manual mapping of ductal systems from 3-dimensional (3D) ultrasound data and to evaluate the structures found with respect to conventional understanding of breast anatomy and physiology. METHODS Three-dimensional ultrasound data of the breast were acquired using a mechanical system, which captures data in a conical shape covering most of the breast without excessive compression. Manual mapping of the ductal system was performed using custom software for data from 4 lactating volunteers. RESULTS Observational results are presented for ultrasound data from the 4 lactating volunteers. For all volunteers, only a small number of ductal structures were engorged with milk, suggesting that the lactiferous activity of the breast may be localized. These enlarged ducts were predominantly found in the inferior lateral quadrant of each breast. The observation was also made that the enlarged, milk-storing parts of the duct were spread throughout the ductal system and not directly below the nipple as conventional anatomy suggests. CONCLUSIONS Ultrasound visualization of the 3D structure of milk-laden ducts in an uncompressed breast has been shown. Using manual tracing, it was possible to track milk-laden ducts of diameters less than 1 mm.