乳腺MRI具有很高的敏感性和阴性预测值，因此在其他影像学检查或体格检查无法确定是否存在乳腺癌时，它非常适用于问题解决。MRI问题解决的适应症包括：钼靶X线和/或超声检查中出现疑似或不确定的影像学结果；可疑的乳头溢液或皮肤变化被怀疑可能代表异常情况，而常规影像学结果对癌症呈阴性反应；被分为乳腺影像报告与数据系统（BI-RADS）4级的病变，无法进行活检；以及活检后放射学和病理学结果不一致。MRI不应在乳腺X线摄影和超声诊断工作仔细完成前使用，也不应在可以安全进行活检时使用。MRI在表征钙化方面的作用存在争议，钙化的处理应根据它们在钼靶X线摄影中的表现决定，因为导管内癌可能不在MR图像上显示强化。此外，仅通过MRI检测到的导管内癌与通过其他影像学检查检测到的导管内癌相比，并没有更高升级为浸润性癌症的可能性。对于高危病变的筛查MRI是一个正在进行研究的课题，未来可能通过MRI减少切除活检的数量。随着深度学习等先进技术的使用，MRI的准确性可能会提高，这将很可能扩大MRI问题解决的适应症。©RSNA，2023 本文的问题解答可在附加材料中找到。

Breast MRI has high sensitivity and negative predictive value, making it well suited to problem solving when other imaging modalities or physical examinations yield results that are inconclusive for the presence of breast cancer. Indications for problem-solving MRI include equivocal or uncertain imaging findings at mammography and/or US; suspicious nipple discharge or skin changes suspected to represent an abnormality when conventional imaging results are negative for cancer; lesions categorized as Breast Imaging Reporting and Data System 4, which are not amenable to biopsy; and discordant radiologic-pathologic findings after biopsy. MRI should not precede or replace careful diagnostic workup with mammography and US and should not be used when a biopsy can be safely performed. The role of MRI in characterizing calcifications is controversial, and management of calcifications should depend on their mammographic appearance because ductal carcinoma in situ may not appear enhancing on MR images. In addition, ductal carcinoma in situ detected solely with MRI is not associated with a higher likelihood of an upgrade to invasive cancer compared with ductal carcinoma in situ detected with other modalities. MRI for triage of high-risk lesions is a subject of ongoing investigation, with a possible future role for MRI in decreasing excisional biopsies. The accuracy of MRI is likely to increase with the use of advanced techniques such as deep learning, which will likely expand the indications for problem-solving MRI. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.