Timing of DTI is not restricted by the menstrual cycle, but is sensitive to menopause and milk in lactating women.
The timing of diffusion-tensor imaging (DTI) for breast examinations is not dependent on the menstrual cycle of premenopausal women, according to the results of a new study published in Radiology. However, similar to other magnetic resonance exams, DTI was sensitive to menopause, long-term hormone replacement therapy use and the presence of milk in lactating women.
Based on these results, Noam Nissan, MD, of Weizmann Institute of Science, Israel, and colleagues, concluded that DTI imaging is not restricted by the menstrual cycle, but that hormone replacement therapy and lactation should be taken into consideration when scheduling a DTI evaluation.
“Hormonal-induced changes in normal breast parenchymal enhancement may influence the accuracy of breast cancer diagnosis, imposing restrictions on the selection and timing of the dynamic-contrast material-enhanced examination,” the researchers wrote in their study.
Therefore, imaging of premenopausal women should normally take place between day six and 16 of their menstrual cycle and postmenopausal women on hormone replacement therapy should not be imaged until after four weeks of treatment cessation.
In this study, Nissan and colleagues wanted to examine the parameters of diffusion-tensor imaging during various phases of the menstrual cycle, during lactation and after menopause to determine if hormone-induced changes affected the outcomes of the imaging studies.
The study included 45 healthy volunteers who underwent T2-weighted and diffusion-tensor imaging magnetic resonance sequences at 3 T. Those women who were premenopausal and those who were lactating underwent weekly imaging. Postmenopausal women underwent one round of imaging.
The 15 premenopausal women in the study showed similar DTI results throughout the four different imaging results taken during their menstrual cycle. Results showed a low mean within-subject coefficient of variance of Ê1, Ê2, Ê3 and apparent diffusion coefficient and fractional anisotropy.
“The high level of proximity between the results of the four DT imaging examinations along the menstrual cycle was further supported by the high intraclass correlation rates for the DT imaging parameters,” the researchers wrote. “These observations may suggest that DT parameters of the normal breast fibroglandular tissue are minimally affected by the histologic and vascular changes that occur during the menstrual cycle.”
In contrast, the results of the study showed significantly higher diffusion coefficients in the participants who used hormone replacement therapy compared with those postmenopausal women who did not (P<.01). The same was true when postmenopausal hormone therapy users were compared with premenopausal participants (P<.01).
Women who were lactating were also found to have significantly higher Ê1, Ê2, Ê3 and apparent diffusion coefficient compared with nonlactating premenopausal women (P<.005). Fractional anisotropy remained similar between the two groups.
The researchers pointed out that this study was small, and that a larger study is needed to confirm its findings.