怀孕和哺乳期间乳房发生的生理变化给乳房癌筛查和诊断带来了挑战。尽管存在这些挑战，但不应推迟影像评估，因为延迟诊断与怀孕相关的乳房癌会导致不良结果。根据年龄、乳腺癌风险和患者是否怀孕或哺乳，可以安全地执行基于协议的筛查和诊断影像。对于评估怀孕妇女的临床症状，超声是首选的初始影像学模式，如果超声检查结果怀疑为恶性肿瘤或未显示出临床症状的病因，则进行乳房X线摄影。由于使用了静脉注射的钆基造影剂，不建议在怀孕期间进行乳房MR检查。哺乳期妇女的诊断影像与非怀孕、非哺乳个体的诊断影像相同，年龄小于30岁的患者需要进行超声检查，30岁及以上的患者需进行乳房X线摄影，然后再进行超声检查。对于哺乳期妇女，可以进行高风险筛查和局部区域分期的乳房MR检查。放射科医师可能会遇到各种乳房异常，其中一些与怀孕和哺乳有关，包括正常生理变化，良性疾病和恶性肿瘤。尽管大多数遇到的肿块是良性的，但如果影像学特征怀疑为癌症或发现在短时间临床随访后没有消退，应进行活检。了解生理变化和常见良性病变在影像上的预期表现对区分这些发现与怀孕相关的乳房癌至关重要。©RSNA，2023此文章提供相关在线补充资料，可通过在线学习中心获取本文章的测验题。

Physiologic changes that occur in the breast during pregnancy and lactation create challenges for breast cancer screening and diagnosis. Despite these challenges, imaging evaluation should not be deferred, because delayed diagnosis of pregnancy-associated breast cancer contributes to poor outcomes. Both screening and diagnostic imaging can be safely performed using protocols based on age, breast cancer risk, and whether the patient is pregnant or lactating. US is the preferred initial imaging modality for the evaluation of clinical symptoms in pregnant women, followed by mammography if the US findings are suspicious for malignancy or do not show the cause of the clinical symptom. Breast MRI is not recommended during pregnancy because of the use of intravenous gadolinium-based contrast agents. Diagnostic imaging for lactating women is the same as that for nonpregnant nonlactating individuals, beginning with US for patients younger than 30 years old and mammography followed by US for patients aged 30 years and older. MRI can be performed for high-risk screening and local-regional staging in lactating women. The radiologist may encounter a wide variety of breast abnormalities, some specific to pregnancy and lactation, including normal physiologic changes, benign disorders, and malignant neoplasms. Although most masses encountered are benign, biopsy should be performed if the imaging characteristics are suspicious for cancer or if the finding does not resolve after a short period of clinical follow-up. Knowledge of the expected imaging appearance of physiologic changes and common benign conditions of pregnancy and lactation is critical for differentiating these findings from pregnancy-associated breast cancer. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.