Faculty Bibliography

This article provides evidence-based guidance for imaging lactating women across screening, diagnostic, and staging scenarios. Imaging should not be deferred because of lactation; mammography with digital breast tomosynthesis, targeted ultrasound, and contrast-enhanced MRI have defined roles based on age, presenting complaint, and cancer risk and may be used similarly to nonlactating patients. Physiologic changes during lactation can alter breast appearance and complicate clinical and imaging assessment. Gadolinium contrast and most nuclear medicine procedures result in negligible infant exposure and do not require interruption of breastfeeding. Image-guided core biopsy and aspiration are safe and effective, with rare lactation-specific risks, which should be discussed during consent. Recommendations aim to standardize care, minimize diagnostic delay, preserve breastfeeding when possible, and support multidisciplinary decision-making. These guidelines inform clinicians, radiologists, and multidisciplinary teams in routine practice. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

For asymptomatic patients with saline implants, no imaging is recommended. If there is suspected saline implant rupture, ultrasound is usually appropriate, though saline implant rupture is often clinically evident. For asymptomatic patients with silicone implants, the FDA recommends that patients have an initial ultrasound or MRI examination without contrast 5 to 6 years after initial silicone implant surgery and then every 2 to 3 years thereafter. In a patient with silicone implants and suspected implant complication, MRI without contrast is usually appropriate and ultrasound and/or mammography may be appropriate, depending on age. In a patient with unexplained axillary adenopathy with current or prior silicone breast implants, ultrasound and/or mammography are usually appropriate, depending on age. In the setting of a patient with breast implants of any type and suspected implant-associated malignancy, ultrasound or MRI without and with contrast is usually appropriate as initial imaging test. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

There are physiologic and structural changes of the breast that occur during pregnancy that can make the clinical examination and imaging more challenging. Pregnancy-associated breast cancer (PABC) is uncommon but increasing as more women postpone childbearing. PABC can present clinically as a palpable lump, focal pain, nipple discharge, or diffuse breast enlargement. Mammography is safe to perform during pregnancy. Both high- and normal-risk women should continue their routine screening mammography examinations during pregnancy. Diagnostic mammography and/or ultrasound is tailored to evaluate the clinical symptoms and for locoregional staging of newly diagnosed PABC. Breast MRI is not advocated for screening or diagnostic evaluation of the breast during pregnancy due to unknown safety of gadolinium exposure to the fetus. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Routine screening substantially reduces the risk of mortality and morbidity of breast cancer with early detection. Multiple different imaging modalities may be used to screen for breast cancer. Screening recommendations differ based on an individual's risk of developing breast cancer. Numerous factors contribute to breast cancer risk, which is frequently divided into three major categories: average, intermediate, and high risk. For patients assigned female at birth with native breast tissue, mammography and digital breast tomosynthesis are recommended for breast cancer screening in all risk categories. In high-risk patients, screening with breast MRI is recommended starting as early as 25 to 30 years of age and mammography and digital breast tomosynthesis with a variable starting age between 25 and 40 years of age, depending on the type of risk. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Screening mammography has been proven to reduce the mortality from breast cancer by approximately 30%, however, it is less sensitive in women with dense breast tissue and certain risk groups. Supplemental screening may be considered based on the patient's risk level and breast density. In all women, digital breast tomosynthesis improves screening sensitivity. Average-risk women with heterogeneously dense tissue may also benefit from breast MRI, abbreviated breast MRI (AB-MRI) or breast ultrasound (US). In intermediate-risk women with nondense tissue, breast MRI and ABMRI may be appropriate. In intermediate-risk women with heterogeneously dense and extremely dense tissue, breast MRI and AB-MRI are usually appropriate, whereas US and contrast-enhanced mammography (CEM) may be appropriate. Breast MRI or ABMRI is usually appropriate in all high-risk women, regardless of density. Screening breast US or CEM could be considered in this population. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Ductal carcinoma in situ (DCIS) accounts for approximately 20% of diagnosed breast cancer. It is important to understand which imaging studies are appropriate in patients with a new diagnosis or history of DCIS. Initial imaging for a new diagnosis of DCIS, consists of diagnostic mammography and/or tomosynthesis, whereas breast ultrasound and breast MRI may be appropriate as complementary examinations. Routine surveillance with annual mammography and/or tomosynthesis is recommended to detect an in-breast recurrence or a new primary breast cancer in women who have completed breast conservation therapy for DCIS, and breast MRI may be appropriate. Advanced technologies such as contrast mammography or molecular breast imaging are usually not appropriate. In a patient with a history of mastectomy for DCIS, routine surveillance for ipsilateral recurrence with imaging is usually not appropriate. There is no role for imaging of the axilla in patients with known DCIS with or without microinvasion. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Breast density refers to the amount of fibroglandular tissue relative to fat on mammography and is determined either qualitatively through visual assessment or quantitatively. It is a heritable and dynamic trait associated with age, race/ethnicity, body mass index, and hormonal factors. Increased breast density has important clinical implications including the potential to mask malignancy and as an independent risk factor for the development of breast cancer. Breast density has been incorporated into breast cancer risk models. Given the impact of dense breasts on the interpretation of mammography, supplemental screening may be indicated.

As the proportion of women diagnosed with invasive breast cancer increases, the role of imaging for staging and surveillance purposes should be determined based on evidence-based guidelines. It is important to understand the indications for extent of disease evaluation and staging, as unnecessary imaging can delay care and even result in adverse outcomes. In asymptomatic patients that received treatment for curative intent, there is no role for imaging to screen for distant recurrence. Routine surveillance with an annual 2-D mammogram and/or tomosynthesis is recommended to detect an in-breast recurrence or a new primary breast cancer in women with a history of breast cancer, and MRI is increasingly used as an additional screening tool in this population, especially in women with dense breasts. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

3D imaging enables accurate diagnosis by providing spatial information about organ anatomy. However, using 3D images to train AI models is computationally challenging because they consist of 10x or 100x more pixels than their 2D counterparts. To be trained with high-resolution 3D images, convolutional neural networks resort to downsampling them or projecting them to 2D. We propose an effective alternative, a neural network that enables efficient classification of full-resolution 3D medical images. Compared to off-the-shelf convolutional neural networks, our network, 3D Globally-Aware Multiple Instance Classifier (3D-GMIC), uses 77.98%-90.05% less GPU memory and 91.23%-96.02% less computation. While it is trained only with image-level labels, without segmentation labels, it explains its predictions by providing pixel-level saliency maps. On a dataset collected at NYU Langone Health, including 85,526 patients with full-field 2D mammography (FFDM), synthetic 2D mammography, and 3D mammography, 3D-GMIC achieves an AUC of 0.831 (95% CI: 0.769-0.887) in classifying breasts with malignant findings using 3D mammography. This is comparable to the performance of GMIC on FFDM (0.816, 95% CI: 0.737-0.878) and synthetic 2D (0.826, 95% CI: 0.754-0.884), which demonstrates that 3D-GMIC successfully classified large 3D images despite focusing computation on a smaller percentage of its input compared to GMIC. Therefore, 3D-GMIC identifies and utilizes extremely small regions of interest from 3D images consisting of hundreds of millions of pixels, dramatically reducing associated computational challenges. 3D-GMIC generalizes well to BCS-DBT, an external dataset from Duke University Hospital, achieving an AUC of 0.848 (95% CI: 0.798-0.896).

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.