Menstrual variation of breast volume and T2 relaxation times in cyclical mastalgia

PurposeHormonal activity causes breast volume to change during the menstrual cycle. One possible cause of this volume change is thought to be due to water retention or oedema within the tissues. We used magnetic resonance imaging (MRI) to study the variation in breast volume and 1H Magnetic Resonance Spectroscopy (MRS) to measure T2 relaxation times which are known to increase with increasing tissue water content. We hypothesised that an increase in breast volume will elevate T2 relaxation due to the presence of an increased water content within the breast. T2 Relaxation time and volume were studied in fifteen control subjects and in a cohort of eight patients with cyclical mastalgia in order to determine whether changes in breast volume and T2 relaxation times differed in controls and patients during menses, ovulation and premenses.MethodBreast volume was determined by the Cavalieri method in combination with point counting techniques on MR images and T2 relaxation times of the water and fat in a voxel of breast tissue were obtained using 1H Magnetic Resonance Spectroscopy (MRS).ResultsStatistical analysis (ANOVA) demonstrated highly significant differences in breast volume between the three stages of the cycle (p < 0.0005) with breast volume being greatest premenstrually. Patients did not exhibit an increase in volume premenstrually, significantly above controls. T2 of fat or water did not depend on stage of cycle. T-tests demonstrated no significant differences in T2 of water or fat between patient and control groups. The average T2 relaxation time of water was lowest in the patient and control groups during ovulation and highest in the patient group during premenses.ConclusionWe have performed the first combined volumetric and spectroscopic study of women with cyclical mastalgia and demonstrated that the global changes in volumes and T2 were not significantly different from normal menstrual variations.