# Comparison of Clinical Performance Between Digital Breast Tomosynthesis and MammouS-N

## TL;DR

A new standing automated ultrasound system (MammouS-N) complements digital breast tomosynthesis by better detecting non-calcified breast cancers in dense tissue.

## Contribution

The study introduces and evaluates MammouS-N, a novel automated ultrasound system for breast imaging, and compares its performance with digital breast tomosynthesis.

## Key findings

- MammouS-N showed significantly higher visibility scores for non-calcified lesions compared to digital breast tomosynthesis.
- Ultrasound provided superior visualization of non-calcified lesions without radiation exposure.
- MammouS-N is a promising complementary tool for breast cancer screening in women with dense breast tissue.

## Abstract

Dense breast tissue complicates breast cancer detection using mammography alone. This study compared digital breast tomosynthesis with a novel standing automated breast ultrasound system in women with biopsy-confirmed breast cancer. Tomosynthesis effectively detected calcified lesions, while ultrasound provided superior visualization of non-calcified lesions without radiation exposure. The ultrasound system offers automated and reproducible imaging that integrates seamlessly into existing workflows, making it a valuable complement to tomosynthesis, especially for women with dense breasts. These findings support further studies on combined imaging approaches to improve breast cancer screening and diagnosis.

Background/Objectives: We compared the visibility of breast cancer using the newly developed standing automated breast ultrasound system (MammouS-N) and digital breast tomosynthesis (DBT), and identified factors influencing lesion visibility. Methods: We prospectively enrolled 100 women (mean age: 51.6 years; range: 26–76 years) who were diagnosed with breast cancer and were scheduled to undergo DBT between January and July 2024. They underwent DBT and an ultrasound on the same day. Two radiologists evaluated the visibility scores (0–5) of lesions corresponding to biopsy-confirmed breast cancers identified using magnetic resonance imaging. The Wilcoxon signed-rank test was used to compare the visibility scores of cancers identified on DBT and/or MammouS-N images. Results: Among the 100 women, invasive ductal carcinoma was the most common malignancy (73%). DBT findings included negative findings (7%), masses (46%), masses with calcification (29%), calcifications only (15%), and architectural distortions (3%). On MammouS-N ultrasound, most lesions were classified as masses (93%), whereas 7% were non-mass lesions. For Reviewer 1, MammouS-N demonstrated significantly higher visibility scores (higher scores: 26 on MammouS-N, seven on DBT; equal scores: 67, z = −3.234, p = 0.001). For Reviewer 2, the two modalities showed no significant difference in visibility (higher scores: 27 on MammouS-N, 28 on DBT, equal scores: 45, z = −0.040, p = 0.968). Noncalcified lesions that were obscured on DBT were better visualized on MammouS-N (p < 0.001) by both reviewers. Conclusions: MammouS-N holds promise as an imaging modality complementary to DBT in women with dense breast tissue, particularly for non-calcified lesion detection.