Background parenchymal enhancement on breast MRI: influence of menstrual cycle and breast composition

Abstract

Purpose: To evaluate the menstrual cycle and breast composition influence on background parenchymal enhancement of breast magnetic resonance imaging (MRI) and to investigate the optimal time for breast MR examinations.

Materials and methods: We evaluated the dynamic contrast-enhanced breast MR images of 238 women who had completed a questionnaire survey about menstrual status. On MRI, the degree of enhancement (DE) of normal parenchyma was measured in the images 2 minutes and 6 minutes after contrast injection. A comparison between premenopausal and postmenopausal women and a separate comparison between dense breasts and fatty breasts were analyzed according to the premenopausal women's menstrual cycle.

Results: Premenopausal women showed significantly higher DE than the postmenopausal women (P<0.001). In premenopausal women, overall DE of fatty breasts and dense breasts was not different. However, fatty breasts showed the highest DE in the 4th week and lowest DE in the 2nd week, while dense breasts showed the highest DE in the 3rd week and the lowest DE in the 4th week of menstrual cycle.

Conclusion: The influence of menstrual cycle on the enhancement of breast parenchyma is different according to the breast composition. The optimal time for breast MRI could be different for dense and fatty breasts.

Keywords: breast; magnetic resonance imaging; menstrual cycle; parenchymal enhancement.