The potential use of ultra-low radiation dose images in digital mammography - a clinical proof-of-concept study in craniocaudal views

Objective: To estimate the potential of low-dose images in digital mammography by analysing the effect of substantial dose reduction in craniocaudal (CC) views on clinical performance. Methods: At routine mammography, additional CC views were obtained with about 10\% of the standard dose. Five radiologists retrospectively read the standard [mediolateral oblique (MLO)AC/a,!aEURdeg+AC/a,!aEURdegCC] and combination low-dose mammograms (standard MLO+low-dose CC). If present, lesion type, conspicuity, and suggested work-up were recorded. Final diagnoses were made by histology or follow-up. A t-test or Chi-square test was used to compare results. Results: 421 cases were included, presenting 5 malignancies, 66 benign lesions and multiple non-specific radiologic features. Using MLO with low-dose CC, all lesions were detected by at least one reader, but altogether less often than with standard mammography (sensitivity 73.9\% versus 81.5\%). Missed lesions concerned all types. Lesions detected with both protocols were described similarly (p=0.084) with comparable work-up recommendations (p=0.658). Conclusion: Mammography with ultra-low-dose CC images particularly influences detection. While sensitivity decreased, specificity was unaffected. In this proof-of-concept study a lower limit was to be determined that is not intended nor applicable for clinical practice. This should facilitate further research in optimisation of a low-dose approach, which has potential in a relatively young and largely asymptomatic population. Advances in Knowledge: Tungsten/silver-acquired mammography images might facilitate substantial dose reduction. Ultra-low-dose CC images reduce sensitivity, but not specificity. Low-dose images have potential in a largely young and asymptomatic population; a baseline is set for further research in optimization of a low-dose approach.