Ultrasonic Doppler study of the hormonal response of blood flow in the normal human breast

The breasts of seven normal female volunteers were examined using a continuous wave, directional 10 MHz ultrasonic Doppler system. A range of quantitative features were extracted from recorded Doppler signals by first computing an average, single cardiac cycle sonogram from 4-6 overlayed cardiac cycles of sonogram data taken from each recording. Substantial variations were observed to occur in both frequency and amplitude characteristics of the Doppler signals during the menstrual cycle and pregnancy. For each subject the two breasts behaved similarly and the fluctuations correlated with known variations in blood hormone levels and breast surface temperature. In the one case of pregnancy, the mammary blood flow appeared to increase throughout pregnancy, beginning very shortly after conception. It is concluded that the normal fluctuations of the blood flow in the breast may make a large contribution to the variance of Doppler-derived blood flow features for the pre-menopausal breast. Use of the contralateral breast as a control is advocated for studies of the application of the Doppler method to the diagnosis and measurement of therapeutic response of breast cancer in young women. The usefulness of the contralateral breast as such a control might be enhanced by performing Doppler examinations only at about the midcycle. If the presence of a tumour were to alter these fluctuations there may be a possibility of using the effect to advantage alongside other methods for early diagnosis of breast cancer.