Nipple Discharge: Current Clinical and Imaging Evaluation.

OBJECTIVE. Nipple discharge is a common complaint that is first evaluated with clinical assessment. Physiologic discharge does not require imaging other than routine screening mammography. Initial evaluation of pathologic nipple discharge involves mammography and ultrasound. evaluation of pathologic nipple discharge involves mammography and ultrasound. Because of its high sensitivity in detecting breast malignancy and its biopsy capability, MRI is increasingly used in lieu of ductography. CONCLUSION. The problem-solving algorithm for evaluating suspicious nipple discharge is evolving. When diagnostic imaging for evaluation of pathologic nipple discharge is negative, management is based on clinical suspicion. If additional imaging is warranted, MRI is preferred because of its increased sensitivity, specificity, and patient comfort. Although central duct excision is the current standard for evaluation of malignancy in patients with pathologic nipple discharge, studies suggest that, given the high negative predictive value of MRI, surveillance may be a reasonable alternative to surgery.

Artificial Intelligence in Breast Imaging: Potentials and Limitations.

OBJECTIVE: The purpose of this article is to discuss potential applications of artificial intelligence (AI) in breast imaging and limitations that may slow or prevent its adoption. CONCLUSION: The algorithms of AI for workflow improvement and outcome analyses are advancing. Using imaging data of high quality and quantity, AI can support breast imagers in diagnosis and patient management, but AI cannot yet be relied on or be responsible for physicians' decisions that may affect survival. Education in AI is urgently needed for physicians.

Three-dimensional Automated Breast US: Facts and Artifacts.

As automated breast (AB) US becomes more integrated into the daily practice of breast imaging, the need to address the artifacts that interfere with AB US image interpretation is becoming more important. Learning methods to detect and subsequently resolve artifacts such as shadowing can enhance the reader's confidence and ability to differentiate artifacts and true abnormalities. Understanding the basic principles of AB US and its image acquisition process are key elements in resolving artifacts. Gaining familiarity with the common patterns of AB US artifacts and placing them into categories of technical, software, physiologic, and breast lesion-related causes can aid in image interpretation. Recognizing specific artifacts, such as dropout and lack of contact, and the ability to distinguish them from true abnormalities, such as surgical scars and suspicious lesions, can help minimize preventable false-positive interpretations. Applying methods to confirm shadowing as artifactual, including the use of a second view, additional planes, and software-related tools such as the rotational tool, can aid the radiologist in resolving artifacts and avoiding preventable recalls, potentially resulting in increased specificity. Presented is a methodical approach to recognizing AB US artifacts and their causes; analyzing shadowing, a challenging entity in the interpretation of AB US imaging studies; differentiating artifact from true abnormality; and reviewing characteristic patterns and basic techniques to resolve artifacts. The goal of this article is to enable the radiologist in applying these methods to help reduce preventable false-positive recommendations and increase efficiency in AB US image interpretation. Online supplemental material is available for this article. ©RSNA, 2019.

MR imaging appearance of noncalcified and calcified DCIS.

To evaluate the MR appearance of noncalcified ductal carcinoma in situ (DCIS), with comparison to calcified DCIS. A retrospective, IRB-approved review of all DCIS diagnosed via MR biopsy between 2007 and 2011 was performed. DCIS was categorized as noncalcified based on the absence of calcifications on mammography and specimen radiography. MR morphology (focus, mass, nonmass enhancement [NME]) and enhancement kinetics (initial and delayed) for noncalcified DCIS were recorded and compared based on nuclear grade (1-3), size (<1.5 cm, 1.5-5 cm, >5 cm), and presence of necrosis. Imaging features of noncalcified and calcified DCIS were also compared. 115 cases of MR biopsy-proven DCIS were identified: 65 (56%) noncalcified and 50 (44%) calcified. For noncalcified DCIS, NME morphology was more common than mass or focus (60% vs 30.8% and 9.2%). There was a significant association between morphology and enhancement kinetics, with NME more likely demonstrating medium and persistent kinetics, and foci or masses demonstrating rapid and plateau or washout kinetics (P < .05). There was also a significant association between morphology and nuclear grade, with NME more likely seen with grade 3 DCIS (P = .024), and between size and initial enhancement, with lesions <1.5 cm more likely to have rapid initial enhancement (P = .0036). No significant difference was identified between calcified and noncalcified DCIS in terms of morphology, enhancement characteristics, nuclear grade, or presence of necrosis. The MR appearance of noncalcified DCIS closely mirrors that of calcified DCIS. Recognizing these imaging features may allow for improved identification of this MRI-detected abnormality, even in the absence of calcifications.

Value-Based Reimbursement: Impact of Curtailing Physician Autonomy in Medical Decision Making.

OBJECTIVE: In this article, we define value in the context of reimbursement and explore the effect of shifting reimbursement paradigms on the decision-making autonomy of a women's imaging radiologist. CONCLUSION: The current metrics used for value-based reimbursement such as report turnaround time are surrogate measures that do not measure value directly. The true measure of a physician's value in medicine is accomplishment of better health outcomes, which, in breast imaging, are best achieved with a physician-patient relationship. Complying with evidence-based medicine, which includes data-driven best clinical practices, a physician's clinical expertise, and the patient's values, will improve our science and preserve the art of medicine.

Training and standards for performance, interpretation, and structured reporting for supplemental breast cancer screening.

OBJECTIVE. To compensate for the reduction of mammography's sensitivity in women with dense breasts, supplemental screening can increase the cancer detection rate. The modalities suggested are MRI, which is the most sensitive and is indicated for women with the highest risk of breast cancer, and ultrasound, which is suggested for dense-breasted average-risk women. CONCLUSION. For decades, ultrasound has been a focused examination. Extending a handheld ultrasound examination to depict the entire breast requires formal didactic training and hands-on scanning to learn suitable, efficient methods. Automated options also require intensive training in performance and interpretation.

Quantitative Maximum Shear-Wave Stiffness of Breast Masses as a Predictor of Histopathologic Severity.

OBJECTIVE: The objective of our study was to compare quantitative maximum breast mass stiffness on shear-wave elastography (SWE) with histopathologic outcome. SUBJECTS AND METHODS: From September 2008 through September 2010, at 16 centers in the United States and Europe, 1647 women with a sonographically visible breast mass consented to undergo quantitative SWE in this prospective protocol; 1562 masses in 1562 women had an acceptable reference standard. The quantitative maximum stiffness (termed "Emax") on three acquisitions was recorded for each mass with the range set from 0 (very soft) to 180 kPa (very stiff). The median Emax and interquartile ranges (IQRs) were determined as a function of histopathologic diagnosis and were compared using the Mann-Whitney U test. We considered the impact of mass size on maximum stiffness by performing the same comparisons for masses 9 mm or smaller and those larger than 9 mm in diameter. RESULTS: The median patient age was 50 years (mean, 51.8 years; SD, 14.5 years; range, 21-94 years), and the median lesion diameter was 12 mm (mean, 14 mm; SD, 7.9 mm; range, 1-53 mm). The median Emax of the 1562 masses (32.1% malignant) was 71 kPa (mean, 90 kPa; SD, 65 kPa; IQR, 31-170 kPa). Of 502 malignancies, 23 (4.6%) ductal carcinoma in situ (DCIS) masses had a median Emax of 126 kPa (IQR, 71-180 kPa) and were less stiff than 468 invasive carcinomas (median Emax, 180 kPa [IQR, 138-180 kPa]; p = 0.002). Benign lesions were much softer than malignancies (median Emax, 43 kPa [IQR, 24-83 kPa] vs 180 kPa [IQR, 129-180 kPa]; p < 0.0001). Usual benign lesions were soft, including 62 cases of fibrocystic change (median Emax, 32 kPa; IQR, 24-94 kPa), 51 cases of fibrosis (median Emax, 36 kPa; IQR, 22-102 kPa), and 301 fibroadenomas (median Emax, 45 kPa; IQR, 30-79 kPa). Eight lipomas (median Emax, 14 kPa; IQR, 8-15 kPa), 154 cysts (median Emax, 29 kPa; IQR, 10-58 kPa), and seven lymph nodes (median Emax, 17 kPa; IQR, 9-40 kPa) were softer than usual benign lesions (p < 0.0001 for lipomas and cysts; p = 0.007 for lymph nodes). Risk lesions were slightly stiffer than usual benign lesions (p = 0.002) but tended to be softer than DCIS (p = 0.14). Fat necrosis and abscesses were relatively stiff. Conclusions were similar for both small and large masses. CONCLUSION: Despite overlap in Emax values, maximum stiffness measured by SWE is a highly effective predictor of the histopathologic severity of sonographically depicted breast masses.

Technologist-performed handheld screening breast US imaging: how is it performed and what are the outcomes to date?

Breast density-inform legislation is increasing the need for data on outcomes of tailored screening. Dense parenchyma can mask cancers, and denser tissue is also more likely to develop breast cancer than fatty tissue. Digital mammography is standard for women with dense breasts. Supplemental screening magnetic resonance imaging should be offered to women who meet high-risk criteria. Supplemental screening ultrasonographic (US) imaging may be appropriate in the much larger group of women with dense breasts. Both physician- and technologist-performed screening US imaging increases detection of node-negative invasive breast cancer. To meet anticipated demand in the United States, screening US images will most likely be acquired by trained technologists rather than physicians. While automated US offers standard documentation, there are few data on outcomes. US has been used diagnostically for decades to characterize masses seen by using mammography, but training specific to screening has been lacking. Standard approaches to training and documentation of technologist-performed handheld screening US imaging are needed. This article reviews the current status of technologist-performed handheld screening breast US imaging.

Multiple bilateral circumscribed masses at screening breast US: consider annual follow-up.

PURPOSE: To determine prospectively the prevalence and rate of malignancy of multiple bilateral (MB) circumscribed breast masses detected at screening ultrasonography (US) compared with those of other US-depicted masses. MATERIALS AND METHODS: This institutional review board-approved, HIPAA-compliant prospective trial included women at elevated risk for breast cancer, who gave written informed consent to participate in a study evaluating cancer detection rates for three rounds of annual supplemental screening US at 21 international sites. After exclusions, 2662 participants and 7473 screening studies were included. Physician-performed US studies were interpreted, with blinding to mammography results. Simple cysts were noted. Breast Imaging Reporting and Data System features of all other findings were recorded, with addition of the descriptor MB similar-appearing circumscribed masses (minimum of three total and at least one in each breast), with details of the largest such mass recorded. Rates of malignancy were determined after biopsy or mammographic and US follow-up at a minimum of 11 months. For this analysis, 490 women (1370 screenings) with prior mastectomy were excluded. Descriptive statistics and exact 95% confidence intervals (CIs) were generated. RESULTS: Of 2172 evaluable participants (6103 screening studies; median age at study entry, 54.0 years; range, 25-91 years), 1454 had unique findings at US. One hundred thirty-five (6.2%) participants had 153 unique MB circumscribed masses, with no malignancies (0% [95% CI: 0%, 2.4%]; 95% CI: 0%, 2.9% for the 127 masses with at least 2 years of follow-up). There were 1319 (60.7%) participants with 2464 non-MB lesions, including 1038 solitary circumscribed masses with a malignancy rate of 0.8% (eight of 1038). Of 836 solitary circumscribed masses with at least 2 years of follow-up, the malignancy rate was 0.4% (three of 836; 95% CI: 0.1%, 1.0%). Of the 135 women with MB circumscribed masses, 82 (60.7%) also had a solitary lesion. Two of these 82 women (2.4%) had cancer. CONCLUSION: MB similar-appearing circumscribed masses seen at screening US are almost always benign, with no malignancies found among such lesions in this prospective, multicenter experience. These lesions are suitable for diagnostic follow-up in 1 year, with resumption of screening thereafter if they are stable.

Probably benign lesions at screening breast US in a population with elevated risk: prevalence and rate of malignancy in the ACRIN 6666 trial.

PURPOSE: To prospectively validate predefined breast ultrasonographic (US) Breast Imaging Reporting and Data System (BI-RADS) category 3 criteria in a multicenter setting in an elevated-risk population. MATERIALS AND METHODS: The American College of Radiology Imaging Network 6666 database was reviewed for prospectively defined BI-RADS category 3 lesions. Patient characteristics, lesion US features at initial detection, and work-up recommendations were analyzed with descriptive statistics. Exact 95% confidence intervals (CIs) were given, where appropriate. Lesion reference standard was biopsy or a minimum of 1-year follow-up. In addition, malignancy rate for lesions that had at least 2 years of follow-up data or that had biopsy data was calculated. RESULTS: Of 2662 participants, 519 (19.5%) had 745 BI-RADS category 3 lesions (25.5% of 2916 US lesions other than simple cysts), with a median size of 7 mm (range, 2-135 mm). The number of new BI-RADS category 3 lesions decreased with year 2-3 screening, but the percentage of new BI-RADS category 3 lesions was stable at 26.4% (506 of 1920 lesions), 23.6% (142 of 601 lesions), and 24.6% (97 of 395 lesions), respectively. Of 745 BI-RADS category 3 lesions, 124 (16.6%) were ultimately sampled for biopsy. Six malignancies (0.8% of BI-RADS category 3 lesions; 95% confidence interval [CI]: 0.3%, 1.7%) occurred in five (1.0%) of 519 participants: Five malignancies were invasive (median size, 10 mm; size range, 2-18 mm), and one was node positive. When the analysis is limited to lesions with at least 2-year follow-up or biopsy, the malignancy rate among BI-RADS category 3 lesions is 0.9% (95% CI: 0.3%, 2.0%). Three malignant BI-RADS category 3 lesions were sampled for biopsy because of a suspicious change at follow-up (two N0 lesions, one each at 6- and 12-month follow-up; one N1 lesion at 24-month follow-up), one was sampled for biopsy because of an upgrade after additional mammography (NX), one was found at mastectomy for another cancer (N0), and one was found at prophylactic contralateral mastectomy in the same patient (NX). CONCLUSION: As BI-RADS category 3 lesions have a low malignancy rate (0.8%; 95% CI: 0.3%, 1.7%) and only 0.1% of the cancers had suspicious changes at 6-month follow-up and only one (17%; 95% CI: 0.4%, 64%) of six malignancies were node positive at detection (24-month follow-up), a recommendation of 1-year diagnostic follow-up may be appropriate for BI-RADS category 3 lesions detected at screening US. Online supplemental material is available for this article.

US appearance of ductal carcinoma in situ.

Ductal carcinoma in situ (DCIS) is a noninvasive cancer that accounts for 25% of all breast cancers diagnosed in the United States. DCIS is a heterogeneous disease process with varied clinical manifestations and a broad spectrum of imaging findings. With advances in technology, the ability to detect early-stage cancers has improved, and understanding the role of ultrasonography (US) in the multimodality era of detection and diagnosis is paramount. When calcifications are identified at mammography, US can be performed to evaluate for an invasive component and to allow possible US-guided biopsy. Use of high-frequency transducers, spectral compounding, and speckle reduction algorithms can aid in the detection of calcifications. Calcified DCIS most commonly manifests as echogenic foci located within a mass or duct, associated with internal microlobulations, or distributed in a branch pattern. Noncalcified DCIS, which is more often identified in symptomatic patients, may manifest as a hypoechoic mass with microlobulated margins and no posterior acoustic features, or it may have a "pseudomicrocystic" appearance. Harmonic imaging and coronal reconstruction may improve detection of noncalcified DCIS. The appearance of DCIS at "second-look" US can be subtle and may warrant a lower threshold for detection, given a higher pretest probability of malignancy. US features are nonspecific, and careful correlation with respect to lesion location, size, shape, and depth is needed. The presence of internal vascularity can help increase the positive predictive value of US in this setting. US is a useful adjunct to mammography and magnetic resonance imaging, and recognizing the US appearance of DCIS will aid in the detection and diagnosis of this disease entity.

Shear-wave elastography improves the specificity of breast US: the BE1 multinational study of 939 masses.

PURPOSE: To determine whether adding shear-wave (SW) elastographic features could improve accuracy of ultrasonographic (US) assessment of breast masses. MATERIALS AND METHODS: From September 2008 to September 2010, 958 women consented to repeat standard breast US supplemented by quantitative SW elastographic examination in this prospective multicenter institutional review board-approved, HIPAA-compliant protocol. B-mode Breast Imaging Reporting and Data System (BI-RADS) features and assessments were recorded. SW elastographic evaluation (mean, maximum, and minimum elasticity of stiffest portion of mass and surrounding tissue; lesion-to-fat elasticity ratio; ratio of SW elastographic-to-B-mode lesion diameter or area; SW elastographic lesion shape and homogeneity) was performed. Qualitative color SW elastographic stiffness was assessed independently. Nine hundred thirty-nine masses were analyzable; 102 BI-RADS category 2 masses were assumed to be benign; reference standard was available for 837 category 3 or higher lesions. Considering BI-RADS category 4a or higher as test positive for malignancy, effect of SW elastographic features on area under the receiver operating characteristic curve (AUC), sensitivity, and specificity after reclassifying category 3 and 4a masses was determined. RESULTS: Median participant age was 50 years; 289 of 939 (30.8%) masses were malignant (median mass size, 12 mm). B-mode BI-RADS AUC was 0.950; eight of 303 (2.6%) BI-RADS category 3 masses, 18 of 193 (9.3%) category 4a lesions, 41 of 97 (42%) category 4b lesions, 42 of 57 (74%) category 4c lesions, and 180 of 187 (96.3%) category 5 lesions were malignant. By using visual color stiffness to selectively upgrade category 3 and lack of stiffness to downgrade category 4a masses, specificity improved from 61.1% (397 of 650) to 78.5% (510 of 650) (P<.001); AUC increased to 0.962 (P=.005). Oval shape on SW elastographic images and quantitative maximum elasticity of 80 kPa (5.2 m/sec) or less improved specificity (69.4% [451 of 650] and 77.4% [503 of 650], P<.001 for both), without significant improvement in sensitivity or AUC. CONCLUSION: Adding SW elastographic features to BI-RADS feature analysis improved specificity of breast US mass assessment without loss of sensitivity.

Training the ACRIN 6666 Investigators and effects of feedback on breast ultrasound interpretive performance and agreement in BI-RADS ultrasound feature analysis.

OBJECTIVE: Qualification tasks in mammography and breast ultrasound were developed for the American College of Radiology Imaging Network (ACRIN) 6666 Investigators. We sought to assess the effects of feedback on breast ultrasound interpretive performance and agreement in BI-RADS feature analysis among a subset of these experienced observers. MATERIALS AND METHODS: After a 1-hour didactic session on BI-RADS: Ultrasound, an interpretive skills quiz set of 70 orthogonal sets of breast ultrasound images including 25 (36%) malignancies was presented to 100 experienced breast imaging observers. Thirty-five observers reviewed the quiz set twice: first without and then with immediate feedback of consensus feature analysis, management recommendations, and pathologic truth. Observer performance (sensitivity, specificity, area under the curve [AUC]) was calculated without feedback and with feedback. Kappas were determined for agreement on feature analysis and assessments. RESULTS: For 35 observers without feedback, the mean sensitivity was 89% (range, 68-100%); specificity, 62% (range, 42-82%); and AUC, 82% (range, 73-89%). With feedback, the mean sensitivity was 93% (range, 80-100%; mean increase, 4%; range of increase, 0-12%; p < 0.0001), the mean specificity was 61% (range, 45-73%; mean decrease, 1%; range of change, -18% to 11%; p = 0.19), and the mean AUC was 84% (range, 78-90%; mean increase, 2%; range of change, -3% to 9%; p < 0.0001). Three breast imagers in the lowest quartile of initial performance showed the greatest improvement in sensitivity with no change or improvement in AUC. The kappa values for feature analysis did not change, but there was improved agreement about final assessments, with the kappa value increasing from 0.53 (SE, 0.02) without feedback to 0.59 (SE, 0.02) with feedback (p < 0.0001). CONCLUSION: Most experienced breast imagers showed excellent breast ultrasound interpretive skills. Immediate feedback of consensus BI-RADS: Ultrasound features and histopathologic results improved performance in ultrasound interpretation across all experience variables.

Detection of breast cancer with addition of annual screening ultrasound or a single screening MRI to mammography in women with elevated breast cancer risk.

CONTEXT: Annual ultrasound screening may detect small, node-negative breast cancers that are not seen on mammography. Magnetic resonance imaging (MRI) may reveal additional breast cancers missed by both mammography and ultrasound screening. OBJECTIVE: To determine supplemental cancer detection yield of ultrasound and MRI in women at elevated risk for breast cancer. DESIGN, SETTING, AND PARTICIPANTS: From April 2004-February 2006, 2809 women at 21 sites with elevated cancer risk and dense breasts consented to 3 annual independent screens with mammography and ultrasound in randomized order. After 3 rounds of both screenings, 612 of 703 women who chose to undergo an MRI had complete data. The reference standard was defined as a combination of pathology (biopsy results that showed in situ or infiltrating ductal carcinoma or infiltrating lobular carcinoma in the breast or axillary lymph nodes) and 12-month follow-up. MAIN OUTCOME MEASURES: Cancer detection rate (yield), sensitivity, specificity, positive predictive value (PPV3) of biopsies performed and interval cancer rate. RESULTS: A total of 2662 women underwent 7473 mammogram and ultrasound screenings, 110 of whom had 111 breast cancer events: 33 detected by mammography only, 32 by ultrasound only, 26 by both, and 9 by MRI after mammography plus ultrasound; 11 were not detected by any imaging screen. Among 4814 incidence screens in the second and third years combined, 75 women were diagnosed with cancer. Supplemental incidence-screening ultrasound identified 3.7 cancers per 1000 screens (95% CI, 2.1-5.8; P < .001). Sensitivity for mammography plus ultrasound was 0.76 (95% CI, 0.65-0.85); specificity, 0.84 (95% CI, 0.83-0.85); and PPV3, 0.16 (95% CI, 0.12-0.21). For mammography alone, sensitivity was 0.52 (95% CI, 0.40-0.64); specificity, 0.91 (95% CI, 0.90-0.92); and PPV3, 0.38 (95% CI, 0.28-0.49; P < .001 all comparisons). Of the MRI participants, 16 women (2.6%) had breast cancer diagnosed. The supplemental yield of MRI was 14.7 per 1000 (95% CI, 3.5-25.9; P = .004). Sensitivity for MRI and mammography plus ultrasound was 1.00 (95% CI, 0.79-1.00); specificity, 0.65 (95% CI, 0.61-0.69); and PPV3, 0.19 (95% CI, 0.11-0.29). For mammography and ultrasound, sensitivity was 0.44 (95% CI, 0.20-0.70, P = .004); specificity 0.84 (95% CI, 0.81-0.87; P < .001); and PPV3, 0.18 (95% CI, 0.08 to 0.34; P = .98). The number of screens needed to detect 1 cancer was 127 (95% CI, 99-167) for mammography; 234 (95% CI, 173-345) for supplemental ultrasound; and 68 (95% CI, 39-286) for MRI after negative mammography and ultrasound results. CONCLUSION: The addition of screening ultrasound or MRI to mammography in women at increased risk of breast cancer resulted in not only a higher cancer detection yield but also an increase in false-positive findings. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00072501.

Automated breast ultrasound: Supplemental screening for average-risk women with dense breasts.

OBJECTIVE: We review ultrasound (US) options for supplemental breast cancer screening of average risk women with dense breasts. CONCLUSION: Performance data of physician-performed handheld US (HHUS), technologist-performed HHUS, and automated breast ultrasound (AUS) indicate that all are appropriate for adjunctive screening. Volumetric 3D acquisitions, reduced operator dependence, protocol standardization, reliable comparison with previous studies, independence of performance and interpretation, and whole breast depiction on coronal view may favor selection of AUS. Important considerations are workflow adjustments for physicians and staff.