Assessment of Breast Composition With a Transmission-Based Microwave Imaging System.

[UNLABELLED] Breast density is a key risk factor for breast cancer, but it is typically unknown before a first mammogram. Microwave imaging, proposed for cancer detection and monitoring, offers potential for measuring the composition of the breast.

[OBJECTIVE] Assess the potential of microwave imaging as a method for estimating breast composition via correlation with mammogram metrics.

[METHODS] Transmission based microwave imaging was applied to a cohort of 110 participants with prior mammograms. Several techniques were developed to estimate breast composition from microwave images, including average permittivity calculation, image thresholding and segmentation, and estimation of the fraction of glandular tissue in each pixel. These measures were compared to breast density category and percent density available from mammograms.

[RESULTS] Average permittivity from microwave images correlated strongly with mammogram-based metrics. For the average permittivity, statistical analysis using one-way ANOVA revealed significant group differences across the various breast density categories. Thresholding and segmentation involved more detailed analysis of the images, and showed potential as alternative approaches to differentiating between breast composition categories.

[CONCLUSIONS] This study represents the largest cohort of healthy participants in which microwave breast images were compared with breast composition data available from clinical imaging. The cohort is well balanced across all categories. It highlights microwave imaging as a safe, portable, and affordable tool for non-invasive breast composition assessment and early cancer risk detection.

[SIGNIFICANCE] The correlation between microwave imaging and mammogram-based breast density metrics highlights the potential for microwave imaging as a novel method for assessment of breast composition.