Effects of angular range on lesion margin assessment in contrast-enhanced digital breast tomosynthesis

Contrast-Enhanced Digital Breast Tomosynthesis (CEDBT) provides quasi three-dimensional contrast enhancement of breast lesions and has been investigated for breast cancer detection and lesion assessment. The acquisition geometry of CEDBT may affect its ability to detect and assess contrast-enhanced lesions. In this study, we investigate the effects of angular range of CEDBT on lesion margin assessment. The CIRS BR3D phantom with iodine inserts was imaged for four angular ranges between 15 and 45 degrees with same total glandular dose using a prototype CEDBT system. The artifact spread functions of iodine objects with various sizes were measured. The detectability of iodine objects overlaid in the depth direction with different separation distances was evaluated using signal-difference-to-noise ratio. Clinical images of malignant lesions were acquired with 25 projections over approximately 50 degrees, and CEDBT for various angular ranges were generated using a subset or all of the projection images and were assessed for lesion margins. Our results show that increasing angular range of CEDBT improves the separation of overlapping iodine signals in phantom images, and the margins of malignant mass lesions are better identified. In conclusion, CEDBT with wide angular range may improve lesion characterizations, e.g. lesion size, morphology and location, and provide better performance than contrast enhanced digital mammography (CEDM) for applications such as guidance of biopsy and evaluation of treatment response.