How Often Does Retrieval of a Clipped Lymph Node Change Adjuvant Therapy Recommendations? A Prospective, Consecutive, Patient Cohort Study.

BACKGROUND: Prior studies examining sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NAC) for cN1 patients have demonstrated that 20% of biopsied, clipped lymph nodes (cLNs) are nonsentinel lymph nodes (non-SLNs). Our goal was to determine how often the cLN was a non-SLN among both cN0 and cN1 patients and how often cLN pathology impacted management. METHODS: Overall, 238 patients treated with NAC and surgery January 2019 to June 2020 were prospectively examined. Patients underwent routine axillary ultrasound, biopsy of suspicious nodes, and clip placement. Radioactive iodine-125 seed localization of the cLN was performed in cN1 patients only. Isolated tumor cells (ITCs) were considered node positive (ypN+) for both cN0 and cN1 cohorts. Chart review was performed to determine if cLNs were non-SLN and their ypN status. RESULTS: Of 118 cN0 patients, 115 of 118 (97%) underwent successful SLNB, 33 of whom had a cLN present; 21 of 33 (64%) cLNs were non-SLNs. Overall, 9 of 118 (8%) were ypN+; no cLN was ypN+ without additional +SLNs. Of 120 cN1 patients, 104 of 120 (87%) converted to cN0, 98 of 104 (94%) of which had attempted SLNB, and 95 of 98 (97%) successfully mapped. The cLN was a non-SLN in 18 of 95 (19%). Overall, 58 of 104 (56%) cN1 patients were ypN+. One patient had a positive cLN in the absence of +SLNs. This patient underwent axillary lymph node dissection (ALND); adjuvant treatment recommendations were unchanged. CONCLUSIONS: The cLN was a non-SLN in 19% of cN1 patients. cLN pathology did not impact adjuvant therapy recommendations, calling into question the utility of routinely clipping biopsied lymph nodes.

The Breast Imager's Approach to Nonmammary Masses at Breast and Axillary US: Imaging Technique, Clues to Origin, and Management.

Ultrasonography (US) of the breast and axilla is primarily used to evaluate a symptomatic patient or to further investigate findings identified with other imaging modalities. Breast imagers are generally familiar with US evaluation of level I, II, and III axillary lymph nodes in the diagnosis and staging of breast cancer. However, the axilla contains nonlymphatic tissue as well, including muscle, fat, and vascular and neurologic structures, and anatomically the breast lies on the chest wall. Therefore, lesions of nonmammary and non-lymph node origin in the axilla or chest wall are not infrequently encountered during US evaluation of the breast or axilla. In fact, such lesions may be the reason that the patient presents to the breast imaging department for evaluation. Understanding the anatomy of the chest wall and axilla and using a systematic US approach will help radiologists expedite accurate diagnosis, suggest optimal additional imaging, and streamline appropriate clinical referral. Key imaging features of nonmammary non-lymph node masses are highlighted, and case examples are provided to illustrate these features. Appropriate patient management is critical in these cases because referral to a breast surgeon may not be the best next step. Depending on institutional referral patterns, other subspecialty surgeons will be involved. Online supplemental material is available for this article.

Papilloma on core biopsy: excision vs. observation.

BACKGROUND: Intraductal papillomas (IPs) are commonly seen breast lesions with variable clinical presentation. For a palpable lesion and/or evidence of cellular atypia and/or pathologic nipple discharge, excision is warranted to rule out adjacent carcinoma, while for asymptomatic IPs lacking atypia current data for excision vs. observation are controversial. We reviewed outcomes of IPs diagnosed at our institution. METHODS: With IRB approval, we reviewed consecutive patients with IPs seen on core biopsy (CBx) between 2005 and 2013. All patients had an excision, with subspecialty breast pathology review of CBx and excisions. The rate of upgrade to cancer on excision was recorded. Differences between atypia and no-atypia groups were determined by two-tailed t test and Fisher's exact test. RESULTS: We identified 97 patients (age range 31-83 years) with IPs on CBx. Among 52 atypical IPs, DCIS was seen in 11 (upgrade 21 %). In 45 IPs without atypia, 3 cancers were seen (upgrade 6. %): 2 had palpable lesions and were found to have DCIS, and 1 invasive cancer was found in a non-palpable mammographically detected BIRADS 4C lesion, whose Cbx result was discordant. If the 2 palpable lesions are excluded, the upgrade rate for IPs without atypia is 2.2 %. CONCLUSIONS: This series shows a low upgrade rate for IP without atypia seen on CBx in the absence of a palpable mass and radiographic/pathologic discordance, suggesting that a surgical biopsy may not be necessary. Further prospective studies to better estimate the upgrade rate for IPs without atypia may be helpful.

Breast density: clinical implications and assessment methods.

Breast density assessment is an important component of the screening mammography report and conveys information to referring clinicians about mammographic sensitivity and the relative risk for developing breast cancer. These topics have gained substantial attention because of recent legislation in several states that requires patients to be informed of dense breast tissue and the potential for associated breast cancer risk and decreased mammographic sensitivity. Because of the considerable implications of diagnosing a woman with dense breast tissue, radiologists should strive to be as consistent as possible when assessing breast density. Commonly used methods of breast density assessment range from subjective visual estimation to quantitative calculations of area and volume density percentages made with complex computer algorithms. The basic principles of currently available commercial methods of calculating fibroglandular density are described and illustrated. There is no criterion standard for determining breast density, but understanding the pros and cons of the various assessment methods will allow radiologists to make informed decisions. Radiologists should understand the basic factors involved in breast density assessment, the changes related to density assessment described in the fifth edition of the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) lexicon, and the capabilities of currently available software. Online supplemental material is available for this article.

Patient compliance and diagnostic yield of 18-month unilateral follow-up in surveillance of probably benign mammographic lesions.

OBJECTIVE: The purpose of this study is to determine the patient compliance with and diagnostic yield of 18-month unilateral mammography in surveillance of probably benign (BI-RADS category 3) lesions. MATERIALS AND METHODS: This retrospective study identified lesions prospectively classified BI-RADS 3 in asymptomatic women from January 1, 2004, to December 31, 2008. Surveillance protocol for BI-RADS 3 lesions included 6-month (unilateral), 12-month (bilateral), 18-month (unilateral), and 24-month (bilateral) imaging, with subsequent annual screening. Demographics, surveillance data, BI-RADS upgrades and downgrades, and biopsy results were abstracted from the longitudinal medical record. RESULTS: One thousand one hundred eighty-eight lesions in 1077 patients (mean age, 51.5 years; age range, 26-89 years) had BI-RADS 3 assessment, representing 1.07% of all screening examinations. The compliance rates for follow-up at 6, 12, 18, and 24 months were 83.3%, 75.9%, 54.8%, and 53.9%, respectively. Sixty lesions were upgraded to BI-RADS 4 or 5 during surveillance. Biopsy revealed 15 cancers (cancer yield of 1.47%) from 1017 lesions with either 24-month imaging stability or tissue diagnosis available. Five, six, one, and three cancers were detected at 6, 12, 18, and 24 months, respectively. Cancers were all stage 0 or 1 except for one stage 2A cancer. Seven hundred forty-four of 1188 (62.6%) BI-RADS 3 lesions were downgraded before completing 2-year surveillance. CONCLUSION: Most (11/15 [73%]) breast cancers initially assessed as BI-RADS 3 are diagnosed at up to 12 months' surveillance. Eighteen-month unilateral mammography performed as BI-RADS 3 surveillance contributes minimally to cancer detection and has poor patient compliance.

Background parenchymal enhancement at breast MR imaging: normal patterns, diagnostic challenges, and potential for false-positive and false-negative interpretation.

At magnetic resonance (MR) imaging, both normal and abnormal breast tissue enhances after contrast material administration. The morphology and temporal degree of enhancement of pathologic breast tissue relative to normal breast tissue form the basis of MR imaging's diagnostic accuracy in the detection and diagnosis of breast disease. Normal parenchymal enhancement at breast MR imaging is termed background parenchymal enhancement (BPE). BPE may vary in degree and distribution in different patients as well as in the same patient over time. Typically BPE is minimal or mild in overall degree, with a bilateral, symmetric, diffuse distribution and slow early and persistent delayed kinetic features. However, BPE may sometimes be moderate or marked in degree, with an asymmetric or nondiffuse distribution and rapid early and plateau or washout delayed kinetic features. These patterns cause diagnostic difficulty because these features can be seen with malignancy. This article reviews typical and atypical patterns of BPE seen at breast MR imaging. The anatomic and physiologic influences on BPE in women undergoing diagnostic and screening breast MR imaging are reviewed. The potential for false-positive and false-negative interpretations due to BPE are discussed. Radiologists can improve their interpretive accuracy by increasing their understanding of various BPE patterns, influences on BPE, and the potential effects of BPE on MR imaging interpretation.

Positioning in breast MR imaging to optimize image quality.

Improper positioning of the breasts in a dedicated breast coil causes inhomogeneous fat saturation as well as other artifacts that decrease the sensitivity of breast magnetic resonance imaging. Improper positioning can create artifacts that can obscure a malignancy or cause it to be missed. Goals of proper positioning include imaging the maximum area of breast tissue, minimizing skin folds, and achieving homogeneous fat suppression and nondeformed breast parenchyma. Review of prior images gives the technologist an impression of what the positioning and imaging challenges may be in each patient before the patient enters the imaging unit. Checking the triplane localizer images and repositioning as necessary before any diagnostic or interventional imaging is key. Using a fat saturation pad, changing the arm position, or "rolling" the patient may be considered in difficult cases. Padding to support the patient in an oblique position, using angled sponges to increase breast compression thickness, and raising the grid to access posterior lesions may be helpful in targeting difficult-to-access lesions for biopsy. Using the presented positioning techniques and suggestions, in addition to strict attention to detail before imaging, will improve image quality, decrease imaging time and suboptimal images, and limit the need for repeat imaging studies.

Immunosuppressant-induced acneiform eruption of the breast.

Acneiform eruptions are dermatoses that resemble true acne. They are almost always drug induced (Indian J Dermatol Venereol Leprol 2009;75:255). Unlike true acne, acneiform eruptions have sudden onset, widespread involvement, occur in unusual locations, occur beyond typical acne age, consist of monomorphous lesions, and clear after the offending drug has been discontinued. The most common culprits are corticosteroids, iodides, bromides, anticonvulsants, Isoniazid (Acta Derm Venereol Suppl (Stockh) 1975;74:119), and immunosuppressants. We present a case of immunosuppressant-induced acneiform eruption of the breast in a 36-year-old female renal transplant recipient. To our knowledge, this is the first description of this condition appearing in the breast. Both the mammographic and ultrasound features will be described.

MRI-guided breast needle core biopsies: pathologic features of newly diagnosed malignancies.

Magnetic resonance imaging (MRI) of the breast is used for select groups of patients. MRI-guided breast core needle biopsies performed over a 3-year period were retrospectively reviewed to determine the incidence and types of cancers found and to correlate the cancers with the MRI findings and the indication for the study. Patients were stratified based on indication for MRI examination including, evaluation of disease extent in patients with current ipsilateral carcinoma, surveillance for recurrence of prior ipsilateral carcinoma, as a problem-solving method and for screening high-risk patients. The high-risk screening group included those with family history (with or without germline mutations), prior chest wall radiation, and contralateral breast carcinoma (current or prior). Four-hundred and forty-five biopsies were performed on 386 patients. The majority of biopsies (79%) were benign. Biopsies demonstrating ductal carcinoma in situ (DCIS) and invasive carcinoma were more likely to present as nonmass-like and mass-forming enhancements respectively, but with only 52% specificity. The highest rate of malignancy (44%) was seen in the least frequently biopsied patient group (n = 25), those with prior ipsilateral carcinoma. Conversely, the most frequently biopsied group (n = 283), the high-risk screening group, demonstrated the lowest malignancy rate (16%). Within this group, most malignant cases were invasive carcinomas (n = 27), 67% of which were small (≤1 cm), well or moderately differentiated with a good prognostic receptor profile (estrogen receptor positive, human epidermal growth factor receptor 2 negative), and lacked nodal macrometastases. The remaining malignant cases in the high-risk screening group were DCIS with or without microinvasion (n = 18), 78% of which demonstrated high nuclear grade. Overall, enhancement pattern did not correlate with the likelihood of or type of malignancy. The most common types of carcinomas identified by screening were small estrogen receptor positive invasive tumors and high grade DCIS.

Patterns of nonmasslike enhancement at screening breast MR imaging of high-risk premenopausal women.

Current U.S. recommendations for breast cancer screening of women with at least a 20%-25% lifetime risk of developing breast cancer include contrast material-enhanced magnetic resonance (MR) imaging of the breasts. The cancer detection rate in high-risk women undergoing screening MR imaging is approximately 10 times higher than that in normal-risk women undergoing screening mammography. Many of these high-risk women commence MR imaging screening while they are premenopausal, when the breasts are most influenced by cyclical hormonal changes. Healthy premenopausal breast tissue enhances in a cyclical and variable manner. This enhancement is described as background enhancement. Typically, enhancement of normal breast tissue occurs in a symmetric and diffuse pattern, and there is little diagnostic difficulty in classifying it as normal background parenchymal enhancement. However, sometimes the pattern is more focal, asymmetric, or regional. It may then be described as nonmasslike enhancement, an observation associated with both benign and malignant breast pathologic conditions. A review of the morphologic features and internal enhancement patterns in normal but nondiffuse background enhancement and abnormal nonmasslike enhancement in high-risk premenopausal women can help improve interpretive specificity and decrease false-positive interpretations. MR imaging pitfalls and interpretation strategies for localized background enhancement and pathologic nonmasslike enhancement in this high-risk population are highlighted. In evaluating nonmasslike enhancement, the use of the Breast Imaging Reporting and Data System (BI-RADS) lexicon to perform careful analysis of morphologic features, along with an understanding of the role and limitations of kinetic information, will help balance early breast cancer detection against false-positive interpretation.

International Interobserver Variability of Breast Density Assessment.

PURPOSE: The aim of this study was to determine variability in visually assessed mammographic breast density categorization among radiologists practicing in Indonesia, the Netherlands, South Africa, and the United States. METHODS: Two hundred consecutive 2-D full-field digital screening mammograms obtained from September to December 2017 were selected and retrospectively reviewed from four global locations, for a total of 800 mammograms. Three breast radiologists in each location (team) provided consensus density assessments of all 800 mammograms using BI-RADS® density categorization. Interreader agreement was compared using Gwet's AC2 with quadratic weighting across all four density categories and Gwet's AC1 for binary comparison of combined not dense versus dense categories. Variability of distribution among teams was calculated using the Stuart-Maxwell test of marginal homogeneity across all four categories and using the McNemar test for not dense versus dense categories. To compare readers from a particular country on their own 200 mammograms versus the other three teams, density distribution was calculated using conditional logistic regression. RESULTS: For all 800 mammograms, interreader weighted agreement for distribution among four density categories was 0.86 (Gwet's AC2 with quadratic weighting; 95% confidence interval, 0.85-0.88), and for not dense versus dense categories, it was 0.66 (Gwet's AC1; 95% confidence interval, 0.63-0.70). Density distribution across four density categories was significantly different when teams were compared with one another and one team versus the other three teams combined (P < .001). Overall, all readers placed the largest number of mammograms in the scattered and heterogeneous categories. CONCLUSIONS: Although reader teams from four different global locations had almost perfect interreader agreement in BI-RADS density categorization, variability in density distribution across four categories remained statistically significant.

MR imaging assessment of the breast after breast conservation therapy: distinguishing benign from malignant lesions.

Dynamic contrast material-enhanced magnetic resonance (MR) imaging has emerged as a valuable tool in evaluation of women who have undergone lumpectomy and whole-breast radiation therapy for breast cancer. Early diagnosis of local recurrence by means of close clinical and imaging follow-up is an important component of a breast-conserving strategy, as it may improve survival. In the post-breast conservation therapy (BCT) breast, resolving edema, fat necrosis, a small focal area of non-masslike enhancement (NMLE), and thin linear NMLE at the lumpectomy site can all be expected findings. In contrast, masslike enhancement or NMLE of ductal or segmental distribution can indicate recurrence. Therefore, at MR imaging of the post-BCT breast, it is important to identify lesions that are benign or appropriate for short-interval imaging surveillance to minimize unnecessary intervention, as well as to discern suspicious lesions and optimize the diagnosis of recurrence.

Downstream Mammary and Extramammary Cascade Services and Spending Following Screening Breast Magnetic Resonance Imaging vs Mammography Among Commercially Insured Women.

Importance: Increasing use of screening breast magnetic resonance imaging (MRI), including among women at low or average risk of breast cancer, raises concerns about resulting mammary and extramammary cascades (downstream services and new diagnoses) of uncertain value. Objective: To estimate rates of cascade events (ie, laboratory tests, imaging tests, procedures, visits, hospitalizations, and new diagnoses) and associated spending following screening breast MRI vs mammography among commercially insured US women. Design, Setting, and Participants: This cohort study used 2016 to 2018 data from the MarketScan research database (IBM Corporation), which includes claims and administrative data from large US employers and commercial payers. Participants included commercially insured women aged 40 to 64 years without prior breast cancer who received an index bilateral screening breast MRI or mammogram between January 1, 2017, and June 30, 2018. We used propensity scores based on sociodemographic, clinical, and utilization variables to match MRI recipients to mammogram recipients in each month of index service use. Data were analyzed from October 8, 2020, to October 28, 2021. Exposures: Breast MRI vs mammography. Main Outcomes and Measures: Mammary and extramammary cascade event rates and associated total and patient out-of-pocket spending in the 6 months following the index test. Results: In this study, 9208 women receiving breast MRI were matched with 9208 women receiving mammography (mean [SD] age, 51.4 [6.7] years). Compared with mammogram recipients, breast MRI recipients had 39.0 additional mammary cascade events per 100 women (95% CI, 33.7-44.2), including 5.0 additional imaging tests (95% CI, 3.8-6.2), 17.3 additional procedures (95% CI, 15.5-19.0), 13.0 additional visits (95% CI, 9.4-17.2), 0.34 additional hospitalizations (95% CI, 0.18-0.50), and 3.0 additional new diagnoses (95% CI, 2.5-3.6). For extramammary cascades, breast MRI recipients had 19.6 additional events per 100 women (95% CI, 8.6-30.7) including 15.8 additional visits (95% CI, 10.2-21.4) and no statistically significant differences in other events. Breast MRI recipients had higher total spending for mammary events ($564 more per woman; 95% CI, $532-$596), extramammary events ($42 more per woman; 95% CI, $16-$69), and overall ($1404 more per woman; 95% CI, $1172-$1636). They also had higher overall out-of-pocket spending ($31 more per woman; 95% CI, $6-$55). Conclusions and Relevance: In this cohort study of commercially insured women, breast MRI was associated with more mammary and extramammary cascade events and spending relative to mammography. These findings can inform cost-benefit assessments and coverage policies to ensure breast MRI is reserved for patients for whom benefits outweigh harms.

Persistent inter-observer variability of breast density assessment using BI-RADS® 5th edition guidelines.

OBJECTIVES: Due to most states' legislation, mammographic density categorization has potentially far-reaching implications, but remains subjective based on BIRADS® guidelines. We aimed to determine 1) effect of BI-RADS® 5th edition (5th-ed) vs 4th-edition (4th-ed) guidelines on reader agreement regarding density assessment; 2) 5th-ed vs 4th-ed density distribution, and visual vs quantitative assessment agreement; 3) agreement between experienced vs less experienced readers. METHODS: In a retrospective review, six breast imaging radiologists (BIR) (23-30 years' experience) visually assessed density of 200 screening mammograms performed September 2012-January 2013 using 5th-ed guidelines. Results were compared to 2016 data of the same readers evaluating the same mammograms using 4th-ed guidelines after a training module. 5th-ed density categorization by seven junior BIR (1-5 years' experience) was compared to eight experienced BIR. Nelson et al.'s kappas (κm, κw), Fleiss' κF, and Cohen's κ were calculated. Quantitative density using Volpara was compared with reader assessments. RESULTS: Inter-reader weighted agreement using 5th-ed is moderately strong, 0.73 (κw, s.e. = 0.01), similar to 4th-ed, 0.71 (κw, s.e. = 0.03). Intra-reader Cohen's κ is 0.23-0.34, similar to 4th-ed. Binary not-dense vs dense categorization, using 5th-ed results in higher dense categorization vs 4th-ed (p < 0.001). 5th-ed density distribution results in higher numbers in categories B/C vs 4th-ed (p < 0.001). Distribution for 5th-ed does not differ based on reader experience (p = 0.09). Reader vs quantitative weighted agreement is similar (5th-ed, Cohen's κ = 0.76-0.85; 4th-ed, Cohen's κ = 0.68-0.83). CONCLUSION: There is persistent subjectivity of visually assessed mammographic density using 5th-ed guidelines; experience does not correlate with better inter-reader agreement.

Clinical Diagnoses and Outcomes After Diagnostic Breast Ultrasound by Nurses and General Practitioner Physicians in Rural Rwanda.

PURPOSE: To scale up early detection of breast cancer in low- and middle-income countries, research is needed to inform the role of diagnostic breast ultrasound performed by nonradiologists in resource-constrained settings. The authors examined 2-year clinical follow-up and outcomes among women who underwent diagnostic breast ultrasound performed by nonradiologist clinicians participating in a breast ultrasound training and mentorship program at a rural Rwandan hospital. METHODS: Imaging findings, management plans, and pathologic results were prospectively collected during the training using a standardized form. Data on follow-up and outcomes for patients receiving breast ultrasound between January 2016 and March 2017 were retrospectively collected through medical record review. RESULTS: Two hundred twenty-nine breast palpable findings (199 patients) met the study's eligibility criteria. Of 104 lesions initially biopsied, 38 were malignant on initial biopsy; 3 lesions were identified as malignant on repeat biopsy. All 34 patients ultimately diagnosed with cancer received initial recommendations for either biopsy or aspiration by trainees. The positive predictive value of trainee biopsy recommendation was 34.8% (95% confidence interval, 24.8%-45.0%). The sensitivity of trainees' biopsy recommendation for identifying malignant lesions was 92.7% (95% confidence interval, 84.2%-100%). Of 46 patients who did not receive biopsy and were told to return for clinical or imaging follow-up, 37.0% did not return. CONCLUSIONS: Trained nonradiologist clinicians in Rwanda successfully identified suspicious breast lesions on diagnostic breast ultrasound. Loss to follow-up was common among patients instructed to return for surveillance, so lower biopsy thresholds, decentralized surveillance, or patient navigation should be considered for patients with low- or intermediate-suspicion lesions.

Distinguishing breast skin lesions from superficial breast parenchymal lesions: diagnostic criteria, imaging characteristics, and pitfalls.

Superficial lesions are commonly encountered in the breast and may be located in the dermis, hypodermis (subcutaneous fat), or parenchyma. The differential diagnosis varies for each anatomic layer. Dermal lesions that are seen by breast imagers are usually benign skin cysts. Hypodermal lesions, although usually benign, may include lesions that arise from anterior terminal duct lobular units and include papilloma, adenosis, fibroadenoma, and breast cancer. To avoid misclassifying a small superficial breast cancer as a benign dermal lesion, it is necessary to understand superficial breast and skin anatomy and the mammographic, ultrasonographic (U.S.), and magnetic resonance (MR) imaging signs that indicate that a lesion is dermal. Mammography is the optimal modality for localizing calcifications to the dermis or hypodermis. However, U.S. typically has higher resolution for localizing masses than mammography and MR imaging. At US, a lesion may be categorized as dermal (a) if it is contained entirely within the dermis, (b) if a tract that extends from the lesion to the skin is seen, or (c) if a claw of tissue surrounding the margin of the lesion is present. As with other breast lesions, suspicious imaging features should be sought in addition to determining the anatomic origin. If histologic analysis is necessary to characterize lesions with an unknown cause or origin, precautions must be taken to decrease patient morbidity.

Methods of assessing categorical agreement between correlated screening tests in clinical studies.

Advances in breast imaging and other screening tests have prompted studies to evaluate and compare the consistency between experts' ratings of existing with new screening tests. In clinical settings, medical experts make subjective assessments of screening test results such as mammograms. Consistency between experts' ratings is evaluated by measures of inter-rater agreement or association. However, conventional measures, such as Cohen's and Fleiss' kappas, are unable to be applied or may perform poorly when studies consist of many experts, unbalanced data, or dependencies between experts' ratings exist. Here we assess the performance of existing approaches including recently developed summary measures for assessing the agreement between experts' binary and ordinal ratings when patients undergo two screening procedures. Methods to assess consistency between repeated measurements by the same experts are also described. We present applications to three large-scale clinical screening studies. Properties of these agreement measures are illustrated via simulation studies. Generally, a model-based approach provides several advantages over alternative methods including the ability to flexibly incorporate various measurement scales (i.e. binary or ordinal), large numbers of experts and patients, sparse data, and robustness to prevalence of underlying disease.

Lesion conspicuity on synthetic screening mammography compared to full field digital screening mammography.

OBJECTIVE: To compare lesion conspicuity on synthetic screening mammography (SM) plus digital breast tomosynthesis (DBT) versus full field digital mammography (FFDM) plus DBT. MATERIALS AND METHODS: Seven breast imagers each prospectively evaluated 107-228 screening mammograms (FFDM, DBT, and SM; total 1206 examinations) over 12 weeks in sets of 10-50 consecutive examinations. Interpretation sessions alternated as follows: SM + DBT, then FFDM, or FFDM + DBT, then SM. Lesion conspicuity on SM versus FFDM (equal/better versus less) was assessed using proportions with 95% confidence intervals. DBT-only findings were excluded. RESULTS: Overall 1082 of 1206 (89.7%) examinations were assessed BI-RADS 1/2, and 124 of 1206 (10.3%) assessed BI-RADS 0. There were 409 evaluated findings, including 134 masses, 119 calcifications, 72 asymmetries, 49 architectural distortion, and 35 focal asymmetries. SM conspicuity compared to FFDM conspicuity for lesions was rated 1) masses: 77 (57%) equal or more conspicuous, 57 (43%) less conspicuous; 2) asymmetries/focal asymmetries: 61 (57%) equal or more conspicuous, and 46 (43%) less conspicuous; 3) architectural distortion: 46 (94%) equal or more conspicuous, 3 (6%) less conspicuous; 4) calcifications: 115 (97%) equal or more conspicuous, 4 (3%) less conspicuous. SM had better conspicuity than FFDM for calcifications and architectural distortion and similar conspicuity for most masses and asymmetries. CONCLUSION: Compared to FFDM, SM has better conspicuity for calcifications and architectural distortion and similar conspicuity for most masses and asymmetries.

Training Nonradiologist Clinicians in Diagnostic Breast Ultrasound in Rural Rwanda: Impact on Knowledge and Skills.

OBJECTIVE: To assess the effectiveness of diagnostic breast ultrasound training provided for general practitioners and nurses in Rwanda via intensive in-person and subsequent online supervision and mentorship. METHODS: Four breast radiologists from Brigham and Women's Hospital trained two general practitioner physicians and five nurses in Rwanda over 9 total weeks of in-person training and 20 months of remote mentorship using electronic image review with emailed feedback. Independently recorded assessments were compared to calculate the sensitivity and specificity of trainee assessments, with radiologist assessments as the gold standard. We compared performance in the first versus second half of the training. RESULTS: Trainees' performance on written knowledge assessments improved after training (57.7% versus 98.1% correct, P = .03). Mean sensitivity of trainee-performed ultrasound for identifying a solid breast mass was 90.6% (SD 4.2%) in the first half of the training (period 1) and 94.0% (SD 6.7%) in period 2 (P = .32). Mean specificity was 94.7% (SD 5.4%) in period 1 and 100.0% (SD 0) in period 2 (P = .10). Mean sensitivity for identifying a medium- or high-suspicion solid mass increased from 79.2% (SD 11.0%) in period 1 to 96.3% (SD 6.4%) in period 2 (P = .03). Specificity was 84.4% (SD 15.0%) in period 1 and 96.7% (SD 5.8%) in period 2 (P = .31). DISCUSSION: Nonradiologist clinicians (doctors and nurses) in a rural sub-Saharan African hospital built strong skills in diagnostic breast ultrasound over 23 months of combined in-person training and remote mentorship. The sensitivity of trainees' assessments in identifying masses concerning for malignancy improved after sustained mentorship. Assessment of impact on patient care and outcomes is ongoing.