Mammographic density (MD) is a major independent risk factor for breast cancer. As such, it is a promising target for risk-modifying interventions. Mammographically dense breast tissue contains a large proportion of fibroglandular tissue, while low-density tissue is predominantly adipose. Traditionally MD is evaluated using X-ray mammography, where mammographically dense breast tissue appears radiopaque. However, the use of ionising radiation makes X-ray mammography unsuitable for high-frequency monitoring of MD. There is a significant interest in the development of an affordable and accurate method for quantifying MD that is free of ionising radiation, e.g. for the screening of cancer risk factors in younger women and for the monitoring of response to interventional cancer treatments.
This project aims to investigate the feasibility of non-invasive sensing of MD using single-sided portable NMR. We have used a commercially available portable-NMR instrument (NMR-Mouse) to study slices of human breast tissue from prophylactic mastectomies, smaller excised samples from both high- and low-MD regions, as well as artificial phantoms.
We have found that quantitative T1 measurements enable reliable differentiation between areas of high and low MD in breast tissue slices. Phantom measurements are underway to determine if an accurate quantification of the relative amounts of fibroglandular and adipose tissue on the basis of portable-NMR measurements is feasible. We have also investigated the dependence of the portable-NMR signal-to-noise ratio on the dimensions of the tissue sample in order to ascertain the sensitivity implications for measurements in vivo.
This project is part of an ongoing investigation to determine whether portable NMR is capable of providing a safe, affordable and accurate methodology for the measurement of MD in vivo. The results are highly encouraging so far. Future work will include evaluation of different quantitative measurement modalities (especially diffusion and spin-relaxation) for non-invasive quantification of fibroglandular and adipose tissue in the breast.