The Value of Second-look Ultrasound and Mammography for Assessment and Biopsy of MRI-detected Breast Lesions.

Rationale and objectives: Suspicious lesions detected in multiparametric breast MRI can be further analyzed with second-look ultrasound (SLUS) and/or mammography. This study aims to assess the value of second-look imaging in selecting the appropriate biopsy method for different lesion characteristics.

Materials and methods: Between January 2021 and December 2023, 212 women underwent contrast-enhanced multiparametric breast MRI at 3 Tesla. A total of 241 suspicious lesions (108 malignancies, 44.8%) were further assessed with SLUS and second-look mammography. Subsequent image-guided biopsy of each lesion was performed using the most suitable modality. Size-dependent lesion detection rates in SLUS and mammography were compared by means of the McNemar test.

Results: Lesions referred to MRI-guided biopsy were predominantly ≤ 10 mm in size (52.8%). SLUS allowed for higher detection rates than mammography in mass lesions (55.6% [95% confidence interval 46.4-64.4%] versus 16.7% [10.6-24.3%]; p < 0.001) with a particularly high sensitivity for malignant mass lesions > 10 mm (88.5% [69.9-97.6%]). In contrast, the detection rate for malignant non-mass lesions was lower in SLUS than in second-look mammography (22.0% [11.5-36.0%] versus 38.0% [24.7-52.8%]; p < 0.001). The malignancy rates in ultrasound-, mammography-, and MRI-guided biopsies were 53.7%, 55.2%, and 35.0%, respectively.

Conclusion: SLUS is an excellent tool for further assessment and biopsy of suspicious mass lesions > 10 mm without associated calcifications. In contrast, supplemental ultrasound is of limited value in the evaluation and biopsy guidance of suspicious non-mass lesions compared to second-look mammography.