Breast MRI: State of the Art

Authors: Ritse M. Mann, Nariya Cho, Linda Moy


MRI of the breast has the highest sensitivity for breast cancer detection among current clinical imaging modalities and is indispensable for breast imaging practice. While the basis of breast MRI consists of T1-weighted contrast-enhanced imaging, T2-weighted, ultrafast, and diffusion-weighted imaging may be used to improve lesion characterization. Such multiparametric assessment of breast lesions allows for excellent discrimination between benign and malignant breast lesions. Indications for breast MRI are expanding. In preoperative staging, multiple studies confirm the superiority of MRI to other imaging modalities for tumor size estimation and detection of additional tumor foci in the ipsilateral and contralateral breast. Ongoing studies show that in experienced hands this can be used to improve breast cancer surgery, although there is no evidence of improved long-term outcomes. Screening indications are likewise growing as evidence is accumulating that OncologicRI depicts cancers at an earlier stage than mammography in all women. To manage the associated costs for screening, the use of abbreviated protocols may be beneficial. In patients treated with neoadjuvant chemotherapy, MRI is used to document response. It is essential to realize that oncologic and surgical response are different, and evaluation should be adapted to the underlying question.

© RSNA, 2019

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Learning Objectives:
After reading the article and taking the test, the reader will be able to:

Describe how multiparametric breast MRI protocols can be modified to address a particular clinical indication

Identify the benefits and limitations of a preoperative breast MRI to stage local breast cancer, modify surgical approaches, and improve surgical outcomes

Assess some state-of-the-art breast MRI techniques such as diffusion-weighted imaging, ultrafast imaging, and abbreviated MRI protocols

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Summary
Indications for breast MRI are consolidating; MRI for screening leads to earlier cancer detection in virtually all evaluated populations; in the hands of experienced teams, MRI allows for improvement of surgical practice, reducing the number of re-excisions while preventing unnecessary mastectomies; and MRI allows for patient selection for neoadjuvant chemotherapy and is the technique of choice to support modification of therapeutic agents and for presurgical assessment of residual tumor size to determine breast conservation surgery candidacy.

Essentials
Breast MRI is a key imaging technique for breast imaging.

Multiparametric breast MRI protocols can be adapted to the clinical indication.

Translating preoperative MRI for extent of disease evaluation to better surgical outcomes requires experience in incorporating MRI findings for MRI-guided surgery, with lesion localization where appropriate.

Screening with breast MRI leads to earlier cancer detection in all women.

In the neoadjuvant setting, enhancement characteristics of lesions change, and assessment should be adapted to the clinical question that is to be answered.