A straightforward method for assessing the technical image quality of reconstructed and synthetic 2D images for Digital breast tomosynthesis systems.

Purpose: Digital Breast Tomosynthesis (DBT) is an advanced mammography technique for which there are currently no internationally agreed methods and reference values for image quality assessment. The aim of this multicentre study was to evaluate a simple method to assess the technical image quality of reconstructed and synthetic 2D (SM) images of different models of DBT systems using commercially available phantoms.

Methods: The signal difference to noise ratio (SDNR) was chosen as an index of technical image quality and was evaluated for three commercial phantoms, Tomophan, Tormam and CIRS model 015, on 55 DBT systems (six vendors, nine models).

Results: SDNR was found to depend on several factors: detail size, average glandular dose (AGD), reconstruction algorithm, software version and applied post-processing. In particular, an increase in SDNR was observed with increasing detail size, AGD, as well as with the use of contrast-enhanced post-processing and iterative reconstruction algorithms. Most systems showed higher SDNR values in SM images respect to DBT for the largest details and a decrease for smaller details.

Conclusions: This study proposes a straightforward method to assess the technical image quality of reconstructed DBT and SM images using three different commercial phantoms. The algorithms used to generate SM and DBT images might perform differently when applied to phantoms with homogeneous backgrounds compared to clinical breast structures. However this method could be used to establish reference values for technical image quality during quality control (QC) which could be used to monitor the consistency of the system's performance over time.