Lipid composition changes in normal breast throughout the menstrual cycle.

The detection of breast cancer in women using magnetic resonance imaging (MRI) is increasingly used as a supplement to X-ray mammography. Furthermore, proton MR spectroscopy (1H MRS) has detected alterations in lipid profiles that are linked with tumor development and progression in human biopsy tissue. Because normal "resting" breast is highly active, it is necessary to consider that any alterations observed in lipid profiles may not be indicative of breast tumor development. The purpose of this study was to assess the changes in lipid composition in the breast throughout the menstrual cycle in "normals" using MRS at 4.0 T. Five women with no known history of breast disease were subject to biweekly MRS breast examinations. MRS results showing water and fat resonances revealed cyclic changes in the lipid content throughout the duration of the menstrual cycle. In particular, intensity changes were seen in methylene (-CH2-) and allylic methylene (CH2CH2*CH=) resonances at 2.1 ppm and 1.3 ppm, respectively. These intensity changes assumed a similar cyclic trend for each subject over the 28 days that correlate with the follicular, ovulatory, and luteal phases of the menstrual cycle. The results obtained may indicate cell synthesis or metabolic activity in the breast during the menstrual cycle and provide valuable information pertinent to lipid responses associated with breast disease.