The effect of system geometry and dose on the threshold detectable calcification diameter in 2D-mammography and digital breast tomosynthesis

Abstract

Digital breast tomosynthesis (DBT) is under consideration to replace or to be used in combination with 2D-mammography in breast screening. The aim of this study was the comparison of the detection of microcalcification clusters by human observers in simulated breast images using 2D-mammography, narrow angle (15°/15 projections) and wide angle (50°/25 projections) DBT. The effects of the cluster height in the breast and the dose to the breast on calcification detection were also tested. Simulated images of 6 cm thick compressed breasts were produced with and without microcalcification clusters inserted, using a set of image modelling tools for 2D-mammography and DBT. Image processing and reconstruction were performed using commercial software. A series of 4-alternative forced choice (4AFC) experiments was conducted for signal detection with the microcalcification clusters as targets. Threshold detectable calcification diameter was found for each imaging modality with standard dose: 2D-mammography: 2D-mammography (165 ± 9 µm), narrow angle DBT (211 ± 11 µm) and wide angle DBT (257 ± 14 µm). Statistically significant differences were found when using different doses, but different geometries had a greater effect. No differences were found between the threshold detectable calcification diameters at different heights in the breast. Calcification clusters may have a lower detectability using DBT than 2D imaging.

The threshold detectable mass diameter for 2D-mammography and digital breast tomosynthesis

“…For consistency with the methods followed by Hadjipanteli et al [18], we used six realistic mathematical breast phantoms validated for 4-AFC studies [25]. The breast phantoms were produced using a biological approach in which breast components were simulated using features extracted from clinical DBT images.…”

“…Alternatively, simulation methods are sensitive and useful for investigating the imaging technology. Observer studies with lesions inserted into physical phantoms (anthropomorphic or structured) [15,16] or fully simulated breast images [17][18][19][20] have yielded useful results, while image metrics such as contrast-to-noise ratio (CNR), CNR/ASF (artefact spread function) [21][22][23] have also been used successfully.…”

“…Simulation studies have shown that masses were visible at a lower contrast than with 2D-mammography in comparison to DBT [17,20]. In the recent work of Hadjipanteli et al [18] three commercially-implemented geometries (2D-mammography, narrow angle (15°/15 projections) and wide angle (50°/25 projections)) were compared. It was shown that 2D-mammography demonstrated a smaller minimum detectable calcification diameter than either DBT geometry, and narrow angle DBT showed a smaller minimum detectable calcification diameter than wide angle DBT.…”

“…An advantage of this approach is that the same breast can be imaged using different acquisition methods, unlike clinical studies. We aimed to expand on the results of a previous observer study [18] conducted for the detection of calcifications and used the same methods to assess the same systems for the detection of masses. Knowledge of the threshold detectable mass diameter, in addition to calcification diameter, of the three imaging systems would help quantify the differences between DBT (narrow and wide angle) and 2D-mammography imaging and make a clinically relevant comparison between different imaging systems for different forms of breast cancer.…”

Evaluating the simulation of radiation dose reduction in a digital breast tomosynthesis system featuring an amorphous silicon (a-Si) detector

“…As DBT relies on the acquisition of multiple projections, with approximately the same combined radiation dose as stated for 2D mammography, the relative noise is higher in each projection. A number of works investigated the relationship between radiation dose and diagnostic performance, showing that noise can negatively impact the detection of subtle signs of breast cancer, decreasing diagnostic accuracy [6][7][8][9][10][11][12] .…”