Conspicuity of Screen-Detected Malignancies on Full Field Digital Mammography vs. Synthetic Mammography.

Rationale And Objectives: To evaluate conspicuity of screen-detected cancers on two-dimensional synthetic mammography (SM) reconstructed from digital breast tomosynthesis (DBT) compared to two-dimensional full field digital mammography (FFDM).

Materials And Methods: IRB-approved retrospective review of consecutive screen-detected cancers from October 1, 2015 to June 30, 2017 was performed. All examinations were reviewed by three radiologists in consensus (n = 224); a score of 1-3 was given to each screen-detected cancer on SM vs. FFDM [1 = FFDM more conspicuous than SM, 2 = FFDM equivalent to SM, and 3 = SM more conspicuous than FFDM]. Findings considered only visible on tomosynthesis (n = 40), without medical history (n = 2), and with skin thickening only (n = 1) were excluded, leaving 181 cases as the study population. The longitudinal medical record was reviewed to determine patient demographics and outcomes of imaging surveillance and biopsy.

Results: Mammographic features on SM (n = 181) were calcifications (n = 68, 37.8%), masses (n = 51, 27.8%), asymmetries (n = 50, 27.6% [11 focal asymmetries]), and distortion (n = 12, 6.8%). The majority (76%, 137/181) of findings were equal or more conspicuous on SM vs. FFDM. However, calcifications and distortion greater than 2 cm were more conspicuous on SM and asymmetries were less conspicuous on SM vs. FFDM, controlling for menopausal status, family or personal history of breast cancer, BRCA status, and breast density.

Conclusion: Although the majority of screen-detected cancers are equal to more conspicuous on SM when compared to FFDM, calcifications and asymmetries <2cm were less conspicuous on SM than FFDM. When SM + DBT is used as an alternative to FFDM + DBT in breast cancer screening, caution should be taken when assessing one-view asymmetries and findings <2cm on SM.