Current Status and Future of BI-RADS in Multimodality Imaging, From the AJR Special Series on Radiology Reporting and Data Systems.

BI-RADS is a communication and data tracking system that has evolved since its inception as a brief mammography lexicon and reporting guide into a robust structured reporting platform and comprehensive quality assurance tool for mammography, ultrasound, and MRI. Consistent and appropriate use of the BI-RADS lexicon terminology and assessment categories effectively communicates findings, estimates the risk of malignancy, and provides management recommendations to patients and referring clinicians. The impact of BI-RADS currently extends internationally through six language translations. A condensed version has been proposed to facilitate a phased implementation of BI-RADS in resource-constrained regions. The primary advance of the 5th edition of BI-RADS is harmonization of the lexicon terms across mammography, ultrasound, and MRI. Harmonization has also been achieved across these modalities for the reporting structure, assessment categories, management recommendations, and data tracking system. Areas for improvement relate to certain common findings that lack lexicon descriptors and a need for further clarification of proper use of category 3. BI-RADS is anticipated to continue to evolve for application to a range of emerging breast imaging modalities.

The Impact of Breast Density Notification Laws on Supplemental Breast Imaging and Breast Biopsy.

BACKGROUND: Dense breast tissue increases breast cancer risk and lowers mammography sensitivity, but the value of supplemental imaging for dense breasts remains uncertain. Since 2009, 37 states and Washington DC have passed legislation requiring patient notification about breast density. OBJECTIVE: Examine the effects of state breast density notification laws on use of supplemental breast imaging and breast biopsies. DESIGN: Difference-in-differences analysis of supplemental imaging and biopsies before and after notification laws in 12 states enacting breast density notification laws from 2009 to 2014 and 12 matched control states. Supplemental imaging/biopsy within 6 months following an index mammogram were evaluated during four time periods related to legislation: (1) 6 months before, (2) 0-6 months after, (3) 6-12 months after, and (4) 12-18 months after. PARTICIPANTS: Women ages 40-64 years receiving an initial mammogram in a state that passed a breast density notification law or a control state. INTERVENTION: Mandatory breast density notification following an index mammogram. MAIN MEASURES: Use of breast biopsies and supplemental breast imaging (breast ultrasound, tomosynthesis, magnetic resonance imaging, scintimammography, and thermography), overall and by specific test. KEY RESULTS: Supplemental breast imaging and biopsy increased modestly in states with notification laws and changed minimally in control states. Adjusted rates of supplemental imaging and biopsy within 6 months of mammography before legislation were 8.5% and 3.1%, respectively. Compared with pre-legislation in intervention and control states, legislation was associated with adjusted difference-in-differences estimates of + 1.3% (p < 0.0001) and + 0.4% (p < 0.0001) for supplemental imaging and biopsies, respectively, in the 6-12 months after the law and difference-in-differences estimates of + 3.3% (p < 0.0001) and + 0.8% (p < 0.0001) for supplemental imaging and biopsies, respectively, 12-18 months after the law. CONCLUSIONS: As breast density notification laws are considered, policymakers and clinicians should expect increases in breast imaging/biopsies. Additional research is needed on these laws' effects on cost and patient outcomes.

Downstream Breast Imaging Following Screening Mammography in Medicare Patients with Advanced Cancer: A Population-Based Study.

BACKGROUND: Screening tests are generally not recommended in patients with advanced cancer and limited life expectancy. Nonetheless, screening mammography still occurs and may lead to follow-up testing. OBJECTIVE: We assessed the frequency of downstream breast imaging following screening mammography in patients with advanced colorectal or lung cancer. DESIGN: Population-based study. PARTICIPANTS: The study included continuously enrolled female fee-for-service Medicare beneficiaries ≥65 years of age with advanced colorectal (stage IV) or lung (stage IIIB-IV) cancer reported to a Surveillance, Epidemiology, and End Results (SEER) registry between 2000 and 2011. MAIN MEASURES: We assessed the utilization of diagnostic mammography, breast ultrasound, and breast MRI following screening mammography. Logistic regression models were used to explore independent predictors of utilization of downstream tests while controlling for cancer type and patient sociodemographic and regional characteristics. KEY RESULTS: Among 34,127 women with advanced cancer (23% colorectal; 77% lung cancer; mean age at diagnosis 75 years), 9% (n = 3159) underwent a total of 5750 screening mammograms. Of these, 11% (n = 639) resulted in at least one subsequent diagnostic breast imaging examination within 9 months. Diagnostic mammography was most common (9%; n = 532), followed by ultrasound (6%; n = 334) and MRI (0.2%; n = 14). Diagnostic mammography rates were higher in whites than African Americans (OR, 1.6; p <0.05). Higher ultrasound utilization was associated with more favorable economic status (OR, 1.8; p <0.05). CONCLUSIONS: Among women with advanced colorectal and lung cancer, 9% continued screening mammography, and 11% of these screening studies led to at least one additional downstream test, resulting in costs with little likelihood of meaningful benefit.

The Changing World of Breast Cancer: A Radiologist's Perspective.

Compared with other fields of medicine, there is hardly an area that has seen such fast development as the world of breast cancer. Indeed, the way we treat breast cancer has changed fundamentally over the past decades. Breast imaging has always been an integral part of this change, and it undergoes constant adjustment to new ways of thinking. This relates not only to the technical tools we use for diagnosing breast cancer but also to the way diagnostic information is used to guide treatment. There is a constant change of concepts for and attitudes toward breast cancer, and a constant flux of new ideas, new treatment approaches, and new insights into the molecular and biological behavior of this disease. Clinical breast radiologists and even more so, clinician scientists, interested in breast imaging need to keep abreast with this rapidly changing world. Diagnostic or treatment approaches that are considered useful today may be abandoned tomorrow. Approaches that seem irrelevant or far too extravagant today may prove clinically useful and adequate next year. Radiologists must constantly question what they do, and align their clinical aims and research objectives with the changing needs of contemporary breast oncology. Moreover, knowledge about the past helps better understand present debates and controversies. Accordingly, in this article, we provide an overview on the evolution of breast imaging and breast cancer treatment, describe current areas of research, and offer an outlook regarding the years to come.

Screening breast ultrasound: past, present, and future.

OBJECTIVE. This article discusses breast ultrasound for the detection of breast cancer in the screening environment, as well as strategies for integrating screening breast ultrasound, including automated breast ultrasound. CONCLUSION. Breast density is an increasingly pertinent issue in breast cancer diagnosis. Breast density results in a decrease in the sensitivity of mammography for cancer detection, with a significant increase in the risk of breast cancer. Ultrasound detects additional cancers.

[New trends and novel possibilities in the diagnostic imaging of breast cancer]. / Újdonságok, új lehetoségek az emlodaganatok képalkotó diagnosztikájában.

Complex tumor therapy development and new opportunities in surgery, which take into account both oncological principles as well as esthetic aspects, have set the requirements far higher for diagnostic imaging of the breast and for radiologists. Despite these new opportunities, X-ray mammography remains the basic examination. However, part of the cancers is hidden on the mammogram, which is partly a consequence of the dense glandular tissue and may also be influenced by the histological type of cancer. Besides reducing radiation dose, digital X-ray mammography improves the examination sensitivity of the dense breast. State of the art digital examination methods, such as tomosynthesis and contrast-enhanced mammography, increase the accuracy of examination. Ultrasound mammography is the most important supplementary method of X-ray mammography. Among the new applications of ultrasound mammography, US elastography, which is based on different tissue elasticity, as well as automatic 3D ultrasound, can be highlighted. Furthermore, among imaging methods that provide functional or metabolic data, MR mammography is the most appropriate non-invasive, non-ionising method for the detection of malignancy and for structure examination. MR mammography is the most sensitive method for the detection of breast cancer and in 20-30% of cases, results in changes of the therapy, and it is also effective in the examination of the dense breast. High level of evidence proves that MR mammography is very useful in the screening of women at risk of breast cancer. Promising results prove that MR mammography will play more considerable role in the evaluation of the effectiveness of the therapy. Diffusion-weighted MR imaging is based on the different diffusion of tissue water, qualitative analysis and quantitative evaluation can be performed. DCE-MR examines that contrast enhancement over time, which can mainly be useful for the qualitative and quantitative evaluation of perfusion changes which may indicate the biological response to tumor therapy. The MR spectroscopic (MRSI) biochemical analysis increases the characterization of the lesions. Multimodal imaging techniques provide more accurate analysis, which is confirmed by more and more evidence, but none of the imaging methods are sufficiently specific to provide histological diagnosis. However, imaging-guided biopsies enable precise histological or cytological confirmation. Technical development, new imaging methods, experienced radiologists and multi-disciplinary cooperation increase the accuracy of the diagnosis and the effectiveness of personalized therapy.

Breast ultrasonography: state of the art.

Ultrasonography (US) is an indispensable tool in breast imaging and is complementary to both mammography and magnetic resonance (MR) imaging of the breast. Advances in US technology allow confident characterization of not only benign cysts but also benign and malignant solid masses. Knowledge and understanding of current and emerging US technology, along with the application of meticulous scanning technique, is imperative for image optimization and diagnosis. The ability to synthesize breast US findings with multiple imaging modalities and clinical information is also necessary to ensure the best patient care. US is routinely used to guide breast biopsies and is also emerging as a supplemental screening tool in women with dense breasts and a negative mammogram. This review provides a summary of current state-of-the-art US technology, including elastography, and applications of US in clinical practice as an adjuvant technique to mammography, MR imaging, and the clinical breast examination. The use of breast US for screening, preoperative staging for breast cancer, and breast intervention will also be discussed.

Emerging breast imaging modalities.

Current limitations in mammography have impelled the development of alternative imaging modalities for general and/or high-risk screenings, problem-solving, diagnosis, staging, pre-surgical planning, and determination of treatment efficacy. From initial studies, emerging breast modalities may overcome the inherent weaknesses of current imaging procedures. Among the modalities discussed here are digital breast tomosynthesis (DBT), molecular breast imaging, automated breast ultrasound, breast elasticity ultrasound imaging, and cone beam breast CT (CBBCT).

CAD and AI for breast cancer-recent development and challenges.

Computer-aided diagnosis (CAD) has been a popular area of research and development in the past few decades. In CAD, machine learning methods and multidisciplinary knowledge and techniques are used to analyze the patient information and the results can be used to assist clinicians in their decision making process. CAD may analyze imaging information alone or in combination with other clinical data. It may provide the analyzed information directly to the clinician or correlate the analyzed results with the likelihood of certain diseases based on statistical modeling of the past cases in the population. CAD systems can be developed to provide decision support for many applications in the patient care processes, such as lesion detection, characterization, cancer staging, treatment planning and response assessment, recurrence and prognosis prediction. The new state-of-the-art machine learning technique, known as deep learning (DL), has revolutionized speech and text recognition as well as computer vision. The potential of major breakthrough by DL in medical image analysis and other CAD applications for patient care has brought about unprecedented excitement of applying CAD, or artificial intelligence (AI), to medicine in general and to radiology in particular. In this paper, we will provide an overview of the recent developments of CAD using DL in breast imaging and discuss some challenges and practical issues that may impact the advancement of artificial intelligence and its integration into clinical workflow.

Trends in breast cancer screening and diagnosis.

Screening mammography is the single most effective method of early breast cancer detection and is recommended on an annual basis beginning at age 40 for women at average risk of breast cancer. In addition to traditional film-screen mammograms, digital mammograms now offer digital enhancement to aid interpretation, which is especially helpful in women with dense breast tissue. Useful emerging adjuncts to mammography include ultrasonography, which is particularly helpful for further assessment of known areas of interest, and magnetic resonance imaging, which shows promise for use in high-risk populations. Image-guided biopsy--directed by ultrasonograpy or stereotactic mammography views--plays a critical role in histologic confirmation of suspected breast cancer.

Advances in breast imaging: a review on where we are and where we are going

Breast radiology has undergone significant advances in recent years, and, naturally, several possibilities open up for attending physicians. Concomitantly, it increases the responsibility to keep up to date and provide the best care for each patient. Aware of the complex implications that the implementation of some of the technological advances may bring, such as increased costs, limited availability of equipment, and a potential increase in examination time, the objective of this study is to carry out a narrative review and provide a collection of advances that, in our opinion, are already gaining ground and should be consolidated in clinical practice. We will discuss new breast imaging methods that can be used both for screening and for the diagnostic investigation of breast lesions and we will summarize the most relevant aspects of each of them, addressing the technique, applicability, positive aspects, and limitations of each modality in a standardized way. (AU)

Association between mammographic density and tumor marker-defined breast cancer subtypes: a case-control study.

High mammographic density (MD) is the most important risk factor for breast cancer. This study aimed to clarify the relationship between MD and breast cancer subtypes defined by tumor markers. We enrolled 642 women with breast cancer (69% premenopausal) and 1241 controls matched for age and menopausal status. Absolute mammographic dense area (ADA), percent mammographic dense area (PDA), and nondense area were assessed using a computer-assisted thresholding technique. We classified breast cancer cases into four subtypes using information on tumor marker expression such as estrogen receptor (ER), progesterone receptor (PR), and Cerb2 receptor (HER2); luminal A (ER+ and/or PR+, HER2-), luminal B (ER+ and/or PR+, HER2+), HER2-overexpressing (ER-, PR-, and HER2+), and triple-negative (ER-, PR-, and HER2-). Analysis was carried out using a conditional logistic regression model with adjustment for covariates. ADA and PDA were associated positively with the risk of breast cancer overall. Both ADA and PDA tended to have a positive association with breast cancer with any ER, any PR, or HER2-, but not for HER2+. The risk of luminal A breast cancer increased significantly 1.11 times (95% confidence interval: 1.01-1.23) for ADA and 1.12 times (95% confidence interval: 1.01-1.24) for PDA, estimated per 1 SD of the age and BMI-adjusted MD. However, the risk of breast cancer with luminal B, HER2-overexpressing, and triple-negative subtypes did not differ (P>0.10). Differential associations between MD measures and breast cancer by tumor marker status or tumor marker-defined subtypes were not detected. These findings suggested that the association between MD and breast cancer subtype may be because of other causal pathways.

MR Imaging: Future Imaging Techniques.

Breast MR imaging is the most sensitive modality for breast cancer detection. This high sensitivity has led to widespread adoption of this technique, particularly in screening women at elevated risk for breast cancer. Despite its high sensitivity, standard breast MR imaging protocols are limited by moderate specificity and relative higher cost, longer examination time, longer interpretation time, and lower availability compared with mammography and ultrasound. As such, new techniques in MR imaging, including abbreviated breast MR imaging, pharmacokinetic modeling, and diffusion-weighted imaging, are active areas of research. This article discusses the rationale, current evidence, and limitations of these new MR imaging techniques.

Ultrasound as the Primary Screening Test for Breast Cancer: Analysis From ACRIN 6666.

BACKGROUND: Mammography is not widely available in all countries, and breast cancer incidence is increasing. We considered performance characteristics using ultrasound (US) instead of mammography to screen for breast cancer. METHODS: Two thousand eight hundred nine participants were enrolled at 20 sites in the United States, Canada, and Argentina in American College of Radiology Imaging 6666. Two thousand six hundred sixty-two participants completed three annual screens (7473 examinations) with US and film-screen (n = 4351) or digital (n = 3122) mammography and had biopsy or 12-month follow-up. Cancer detection, recall, and positive predictive values were determined. All statistical tests were two-sided. RESULTS: One hundred ten women had 111 breast cancer events: 89 (80.2%) invasive cancers, median size 12 mm. The number of US screens to detect one cancer was 129 (95% bootstrap confidence interval [CI] = 110 to 156), and for mammography 127 (95% CI = 109 to 152). Cancer detection was comparable for each of US and mammography at 58 of 111 (52.3%) vs 59 of 111 (53.2%, P = .90), with US-detected cancers more likely invasive (53/58, 91.4%, median size 12 mm, range = 2-40 mm), vs mammography at 41 of 59 (69.5%, median size 13 mm, range = 1-55 mm, P < .001). Invasive cancers detected by US were more frequently node-negative, 34 of 53 (64.2%) vs 18 of 41 (43.9%) by mammography (P = .003). For 4814 incidence screens (years 2 and 3), US had higher recall and biopsy rates and lower PPV of biopsy (PPV3) than mammography: The recall rate was 10.7% (n = 515) vs 9.4% (n = 453, P = .03), the biopsy rate was 5.5% (n = 266) vs 2.0% (n = 97, P < .001), and PPV3 was 11.7% (31/266) vs 38.1% (37/97, P < .001). CONCLUSIONS: Cancer detection rate with US is comparable with mammography, with a greater proportion of invasive and node-negative cancers among US detections. False positives are more common with US screening.

Will supplemental screening ultrasound increase breast cancer overdiagnosis?

Overdiagnosis refers to the detection of cancers that would never come to light in a patient's lifetime and are only identified by means of screening. Exactly how much overdiagnosis currently exists with screening mammography is uncertain. Because we do not know for certain which tumors would ultimately lead to death if left untreated and which would not, we cannot directly measure overdiagnosis and how best to estimate it is a matter of controversy. A conservative estimate of overdiagnosis with mammography would be on the order of 10%, but estimates have ranged as high as 54%. We know from multiple studies that ultrasound (US) screening mostly detects small, invasive, node-negative cancers; and in the ACRIN 6666 study, there was a greater tendency for US-only-detected tumors to be low grade than those detected with mammography. However, the population of patients undergoing screening US can be expected to differ from the average screening mammography population in that they will have higher breast density, they will be younger, and they may also have higher breast cancer risk than the population undergoing screening mammography. These factors may be associated with more aggressive tumors. There is no way to know whether we will be increasing overdiagnosis without performing a large randomized controlled study with very long-term follow-up. Even if some cancers are overdiagnosed with US, there will be a greater proportion of lethal breast cancers that are successfully treated because of screening US. The more important task is to learn how to correctly diagnose and appropriately treat nonlethal cancers.

Advances in breast imaging.

Many exciting developments are occurring in breast imaging. Digital mammography holds the promise of telemammography and computer-aided diagnosis. Mammoscintigraphy may be helpful in identifying drug-resistant tumors before therapy. There is renewed interest in evaluating ultrasound as a potential adjunctive screening tool in women with radiographically dense breasts. Finally, contrast-enhanced magnetic resonance imaging may be used more extensively in the monitoring of tumor response to primary chemotherapy and in the preoperative workup of patients being considered for breast conservation therapy.

The evolving role of sonography in evaluating solid breast masses.

Many investigators have attempted to use ultrasound imaging to differentiate benign from malignant solid breast masses. Studies have evaluated several generations of gray-scale imaging, Doppler, color Doppler, and power Doppler imaging, and several unconventional ultrasound techniques. Although various individual studies have shown promise, ultrasound criteria for avoiding biopsy of solid lesions have not been widely adopted. Considerable observer variability also remains an important obstacle. This article reviews the results, strengths, and weaknesses of some of the key studies addressing this issue. Fundamental criteria for a successful ultrasound model are also specified.

Imaging axillary lymph nodes in patients with newly diagnosed breast cancer.

The presence of axillary lymph node metastasis in patients newly diagnosed with breast cancer carries significant prognostic and management implications. As a result, there is increasing interest to stage accurately the axilla with preoperative imaging to facilitate treatment planning. Currently, the most widespread imaging techniques for the evaluation of the axilla include ultrasound and magnetic resonance imaging. In many settings, the ability to detect axillary lymph nodes containing metastases with imaging and image-guided biopsy can allow surgeons to bypass sentinel lymph node dissection and proceed with full axillary lymph node dissection. However, no imaging modality currently has sufficient negative-predictive value to obviate surgical staging of the axilla if no abnormal lymph nodes are detected. Promising advanced imaging technologies, such as diffusion-weighted imaging and magnetic resonance lymphangiography, hold the potential to improve the accuracy of axillary staging and thereby transform management of the axilla in patients newly diagnosed with breast cancer.