Electrical impedance measurement of the breast: effect of hormonal changes associated with the menstrual cycle.

The purpose of this study was to evaluate the influence of hormonal factors on electrical impedance measurement with a new device TS2000, which is a new method in diagnosis of breast disease. Twenty-one healthy pre-menopausal women volunteers (aged 24-39 years) were examined with the TS2000 once/week for two menstrual cycles. On average, at least one spot was present in 47% of images of women not taking oral contraceptives and in 44% of women taking oral contraceptives (OC). The number of spots varied over the menstrual cycle and had a maximum in week 3 and week 5. We found that after 1 week only 15% of spots were present and no spots persisted for three consecutive weeks. These data, if further supported by observations on other populations of women, show that false-positive results are common in pre-menopausal women; however, these false-positive spots do not persist for long periods of time. This information may provide a basis for discrimination between true-positive and false-positive spots on the TS2000 image, since the latter would be expected to disappear on short-term follow up.