Positive predictive value of axillary lymph node cortical thickness and nodal, clinical, and tumor characteristics in newly diagnosed breast cancer patients.

PURPOSE: Axillary lymph nodes (LNs) with cortical thickness > 3 mm have a higher likelihood of malignancy. To examine the positive predictive value (PPV) of axillary LN cortical thickness in newly diagnosed breast cancer patients, and nodal, clinical, and tumor characteristics associated with axillary LN metastasis. METHODS: Retrospective review of axillary LN fine needle aspirations (FNAs) performed 1/1/2018-12/31/2019 included 135 axillary FNAs in 134 patients who underwent axillary surgery. Patient demographics, clinical characteristics, histopathology, and imaging features were obtained from medical records. Hypothesis testing was performed to identify predictors of axillary LN metastasis. RESULTS: Cytology was positive in 72/135 (53.3%), negative in 61/135 (45.2%), and non-diagnostic in 2/135 (1.5%). At surgery, histopathology was positive in 84 (62.2%) and negative in 51 (37.8%). LN cortices were thicker in metastatic compared to negative nodes (p < 0.0001). PPV of axillary LNs with cortical thickness ≥ 3 mm, ≥ 3.5 mm, ≥ 4 mm and, ≥ 4.25 mm was 0.62 [95% CI 0.53, 0.70], 0.63 [0.54, 0.72], 0.67 [0.57, 0.76] , and 0.74 [0.64, 0.83], respectively. At multivariable analysis, abnormal hilum (OR = 3.44, p = 0.016) and diffuse cortical thickening (OR = 2.86, p = 0.038) were associated with nodal metastasis. CONCLUSION: In newly diagnosed breast cancer patients, increasing axillary LN cortical thickness, abnormal fatty hilum, and diffuse cortical thickening are associated with nodal metastasis. PPV of axillary LN cortical thickness ≥ 3 mm and ≥ 3.5 mm is similar but increases for cortical thickness ≥ 4 mm. FNA of axillary LNs with cortex < 4 mm may be unnecessary for some patients undergoing sentinel LN biopsy.

Discriminative Factors of Malignancy of Ipsilateral Nonmass Enhancement in Women With Newly Diagnosed Breast Cancer on Initial Staging Breast MRI.

BACKGROUND: Nonmass enhancement (NME) on breast MRI impacts surgical planning. PURPOSE: To evaluate positive predictive values (PPVs) and identify malignancy discriminators of NME ipsilateral to breast cancer on initial staging MRI. STUDY TYPE: Retrospective. SUBJECTS: Eighty-six women (median age, 48 years; range, 26-75 years) with 101 NME lesions (BI-RADS 4 and 5) ipsilateral to known cancers and confirmed histopathology. FIELD STRENGTH/SEQUENCE: 1.5 T and 3.0 T dynamic contrast-enhanced fat-suppressed T1-weighted fast spoiled gradient-echo. ASSESSMENT: Three radiologists blinded to pathology independently reviewed MRI features (distribution, internal enhancement pattern, and enhancement kinetics) of NME, locations relative to index cancers (contiguous, non-contiguous, and different quadrants), associated mammographic calcifications, lymphovascular invasion (LVI), axillary node metastasis, and radiology-pathology correlations. Clinical factors, NME features, and cancer characteristics were analyzed for associations with NME malignancy. STATISTICAL TESTS: Fisher's exact, Chi-square, Wilcoxon rank sum tests, and mixed-effect multivariable logistic regression were used. Significance threshold was set at P < 0.05. RESULTS: Overall NME malignancy rate was 48.5% (49/101). Contiguous NME had a significantly higher malignancy rate (86.7%) than non-contiguous NME (25.0%) and NME in different quadrants (10.7%), but no significant difference was observed by distance from cancer for non-contiguous NME, P = 0.68. All calcified NME lesions contiguous to the calcified index cancer were malignant. NME was significantly more likely malignant when index cancers were masses compared to NME (52.9% vs. 21.4%), had mammographic calcifications (63.2% vs. 39.7%), LVI (81.8% vs. 44.4%), and axillary node metastasis (70.8% vs. 41.6%). NME features with highest PPVs were segmental distribution (85.7%), clumped enhancement (66.7%), and nonpersistent kinetics (77.1%). On multivariable analysis, contiguous NME, segmental distribution, and nonpersistent kinetics were associated with malignancy. DATA CONCLUSION: Malignancy discriminators of ipsilateral NME on staging MRI included contiguous location to index cancers, segmental distribution, and nonpersistent kinetics. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

High Peritumoral and Intratumoral T2 Signal Intensity in HER2-Positive Breast Cancers on Preneoadjuvant Breast MRI: Assessment of Associations With Histopathologic Characteristics.

BACKGROUND. Intratumoral necrosis and peritumoral edema are features of aggressive breast cancer that may present as high T2 signal intensity (T2 SI). Implications of high T2 SI in HER2-positive cancers are unclear. OBJECTIVE. The purpose of this study was to assess associations with histopathologic characteristics of high peritumoral T2 SI and intratumoral T2 SI of HER2-positive breast cancer on MRI performed before initiation of neoadjuvant therapy. METHODS. This retrospective study included 210 patients (age, 24-82 years) with 211 HER2 breast cancers who, from January 1, 2015, to July 30, 2022, underwent breast MRI before receiving neoadjuvant therapy. Two radiologists independently assessed cancers for high peritumoral T2 SI and high intratumoral T2 SI on fat-suppressed T2-weighted imaging and classified patterns of high peritumoral T2 SI (adjacent to tumor vs prepectoral extension). A third radiologist resolved discrepancies. Multivariable logistic regression analyses were performed to identify associations of high peritumoral and intratumoral T2 SI with histopathologic characteristics (associated ductal carcinoma in situ, hormone receptor status, histologic grade, lymphovascular invasion, and axillary lymph node metastasis). RESULTS. Of 211 HER2-positive cancers, 81 (38.4%) had high peritumoral T2 SI, and 95 (45.0%) had high intratumoral T2 SI. A histologic grade of 3 was independently associated with high peritumoral T2 SI (OR = 1.90; p = .04). Otherwise, none of the five assessed histopathologic characteristics were independently associated with high intratumoral T2 SI or high peritumoral T2 SI (p > .05). Cancers with high T2 SI adjacent to the tumor (n = 29) and cancers with high T2 SI with prepectoral extension (n = 52) showed no significant difference in frequency for any of the histopathologic characteristics (p > .05). Sensitivities and specificities for predicting the histopathologic characteristics ranged from 35.6% to 43.7% and from 59.7% to 70.7%, respectively, for high peritumoral T2 SI, and from 37.3% to 49.6% and from 49.3% to 62.7%, respectively, for high intratumoral T2 SI. Interreader agreement was almost perfect for high peritumoral T2 SI (Gwet agreement coefficient [AC] = 0.93), high intratumoral T2 SI (Gwet AC = 0.89), and a pattern of high peritumoral T2 SI (Gwet AC = 0.95). CONCLUSION. The only independent association between histopathologic characteristics and high T2 SI of HER2-positive breast cancer was observed between a histologic grade of 3 and high peritumoral T2 SI. CLINICAL IMPACT. In contrast with previously reported findings in broader breast cancer subtypes, peritumoral and intratumoral T2 SI had overall limited utility as prognostic markers of HER2-positive breast cancer.

Peri-surgical imaging of intersex and gender diverse youths.

This publication provides an overview of current imaging indications and practices for patients undergoing gender-affirming surgery, with an emphasis on the importance of tailored, patient-specific care. Gender-affirming surgeries are performed with personalized approaches at various stages of life for those with intersex traits or differences in sex development (I/DSD) and transgender and gender diverse (TGD) individuals. For I/DSD patients, ultrasound, genitography, or MRI occurs during infancy and puberty to evaluate genital and gonadal anatomy. Facial harmonization involves bony and soft tissue modifications, guided by maxillofacial computerized tomography (CT) with three-dimensional reconstruction. Ultrasound is the main modality in assessing hormone-related and post-surgical changes in the chest. Imaging for genital reconstruction uses cross-sectional images and fluoroscopy to assess neoanatomy and complications.

Frequency and Outcomes of BI-RADS Category 3 Assessments in Patients With a Personal History of Breast Cancer: Full-Field Digital Mammography Versus Digital Breast Tomosynthesis.

BACKGROUND. Studies establishing the validity of BI-RADS category 3 excluded patients with personal history of breast cancer (PHBC). Use of category 3 in patients with PHBC may be impacted not only by this population's increased breast cancer risk, but also by adoption of digital breast tomosynthesis (DBT) over full-field digital mammography (FFDM). OBJECTIVE. The purpose of this article was to compare the frequency, outcomes, and additional characteristics of BI-RADS category 3 assessments between FFDM and DBT in patients with PHBC. METHODS. This retrospective study included 14,845 mammograms in 10,118 patients (mean age, 63 years) with PHBC who had undergone mastectomy and/or lumpectomy. Of these, 8422 examinations were performed by FFDM from October 2014 to September 2016, and 6423 examinations by FFDM with DBT from February 2017 to December 2018, after interval conversion of the center's mammography units. Information was extracted from the EHR and radiology reports. FFDM and DBT groups were compared in the entire sample and among index category 3 lesions (i.e., earliest category 3 assessment per lesion). RESULTS. The frequency of category 3 assessment was lower for DBT than FFDM (5.6% vs 6.4%; p = .05). DBT, compared with FFDM, showed a lower malignancy rate for category 3 lesions (1.8% vs 5.0%; p = .04), higher malignancy rate for category 4 lesions (32.0% vs 23.2%; p = .03), and no difference in malignancy rate for category 5 lesions (100.0% vs 75.0%; p = .24). Analysis of index category 3 lesions included 438 and 274 lesions for FFDM and DBT, respectively. For category 3 lesions, DBT, compared with FFDM, showed lower PPV3 (13.9% vs 36.1%; p = .02) and a more frequent mammographic finding of mass (33.2% vs 23.1%; p = .003). CONCLUSION. The malignancy rate for category 3 lesions in patients with PHBC was less than the accepted limit (2%) for DBT (1.8%), but not FFDM (5.0%). A lower malignancy rate for category 3 lesions but higher malignancy rate for category 4 lesions for DBT supports more appropriate application of category 3 assessment in patients with PHBC through use of DBT. CLINICAL IMPACT. These insights may help establish whether category 3 assessments in patients with PHBC are within benchmarks for early detection of second cancers and reduction of benign biopsies.

Synthetic Mammography: Benefits, Drawbacks, and Pitfalls.

Digital breast tomosynthesis (DBT) allows three-dimensional assessment of breast tissue; however, DBT requires a two-dimensional (2D) image for comparison with prior mammograms and accurate interpretation of calcifications. Traditionally, full-field digital mammography (FFDM) has been performed after the DBT image acquisition. Synthetic mammography (SM), the 2D reconstruction of the tomosynthesis slice dataset, has been designed to replace FFDM. Advantages of SM include decreased image acquisition time and decreased radiation exposure, with maintained or improved screening performance metrics. Because SM algorithms give extra weight to lesion-like characteristics (eg, calcifications and architectural distortions), they may enable increased visibility of these characteristics relative to that at FFDM. Although SM algorithms were designed to improve lesion identification, they have led to varied outcomes in studies reported in the literature. Compared with FFDM, SM has been reported to be associated with a higher false-positive rate for calcifications, decreased conspicuity of asymmetries, lower breast density assessments, and imaging artifacts (eg, metallic artifact, bright-band artifact, blurring of the axilla, and truncation artifact). The authors review the literature on SM, including its implementation, benefits, and artifacts. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Multimodality Imaging Review of HER2-positive Breast Cancer and Response to Neoadjuvant Chemotherapy.

Human epidermal growth factor receptor 2 (HER2/neu or ErbB2)-positive breast cancers comprise 15%-20% of all breast cancers. The most common manifestation of HER2-positive breast cancer at mammography or US is an irregular mass with spiculated margins that often contains calcifications; at MRI, HER2-positive breast cancer may appear as a mass or as nonmass enhancement. HER2-positive breast cancers are often of intermediate to high nuclear grade at histopathologic analysis, with increased risk of local recurrence and metastases and poorer overall prognosis. However, treatment with targeted monoclonal antibody therapies such as trastuzumab and pertuzumab provides better local-regional control and leads to improved survival outcome. With neoadjuvant treatments, including monoclonal antibodies, taxanes, and anthracyclines, women are now potentially able to undergo breast conservation therapy and sentinel lymph node biopsy versus mastectomy and axillary lymph node dissection. Thus, the radiologist's role in assessing the extent of local-regional disease and response to neoadjuvant treatment at imaging is important to inform surgical planning and adjuvant treatment. However, assessment of treatment response remains difficult, with the potential for different imaging modalities to result in underestimation or overestimation of disease to varying degrees when compared with surgical pathologic analysis. In particular, the presence of calcifications at mammography is especially difficult to correlate with the results of pathologic analysis after chemotherapy. Breast MRI findings remain the best predictor of pathologic response. The authors review the initial manifestations of HER2-positive tumors, the varied responses to neoadjuvant chemotherapy, and the challenges in assessing residual cancer burden through a multimodality imaging review with pathologic correlation. © RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Atypical Lobular Hyperplasia and Classic Lobular Carcinoma In Situ Can Be Safely Managed Without Surgical Excision.

BACKGROUND: Based on modern series demonstrating low upgrade rates for pure lobular neoplasia (LN) diagnosed on core needle biopsy (CNB), our institution no longer recommends routine excision, provided imaging is concordant. This study describes outcomes in patients managed without surgical excision. METHODS: From an institutional database, we identified all patients with a diagnosis of pure atypical lobular hyperplasia and/or classic lobular carcinoma in situ on CNB managed without surgical excision (i.e., conservative management) from 2015 to 2019. The primary outcome of interest was failure of conservative management, defined as development of ipsilateral same-quadrant ductal carcinoma in situ or invasive breast cancer within 2 years of CNB, or need for ipsilateral same-quadrant excisional biopsy. We also evaluated rates of ipsilateral same-quadrant CNB during follow-up. RESULTS: Among 96 pure LN lesions on CNB since 2015, 80 (83%) were managed without surgical excision. Median follow-up was 27 months (IQR: 16-28), with only 2 (2%) patients lost to follow-up. No patients developed an ipsilateral, same-quadrant breast cancer. The 3-year risk of conservative management failure was 6.2% (95% CI 2.3-15.7%). All failures were a result of need for excisional biopsy due to progressive imaging abnormalities at the initial CNB site, with benign final pathology. The 3-year risk of ipsilateral same-quadrant CNB was 9.2% (95% CI 3.8-21.5%). CONCLUSION: Non-surgical management of pure LN is safe, and the likelihood of requiring subsequent surgical excision or repeat CNB during follow-up is low. These data provide reassurance that routine excision of pure LN in the setting of radiologic-pathologic concordance is not required.

Multidisciplinary Recommendations Regarding Post-Vaccine Adenopathy and Radiologic Imaging: Radiology Scientific Expert Panel.

Vaccination-associated adenopathy is a frequent imaging finding after administration of COVID-19 vaccines that may lead to a diagnostic conundrum in patients with manifest or suspected cancer, in whom it may be indistinguishable from malignant nodal involvement. To help the medical community address this concern in the absence of studies and evidence-based guidelines, this special report offers recommendations developed by a multidisciplinary panel of experts from three of the leading tertiary care cancer centers in the United States. According to these recommendations, some routine imaging examinations, such as those for screening, should be scheduled before or at least 6 weeks after the final vaccination dose to allow for any reactive adenopathy to resolve. However, there should be no delay of other clinically indicated imaging (eg, for acute symptoms, short-interval treatment monitoring, urgent treatment planning or complications) due to prior vaccination. The vaccine should be administered on the side contralateral to the primary or suspected cancer, and both doses should be administered in the same arm. Vaccination information-date(s) administered, injection site(s), laterality, and type of vaccine-should be included in every preimaging patient questionnaire, and this information should be made readily available to interpreting radiologists. Clear and effective communication between patients, radiologists, referring physician teams, and the general public should be considered of the highest priority when managing adenopathy in the setting of COVID-19 vaccination.

Screening Mammography Performance Metrics of 2D Digital Mammography Versus Digital Breast Tomosynthesis in Women With a Personal History of Breast Cancer.

BACKGROUND. Patients with a history of breast cancer are at higher risk of subsequent breast cancers and need close clinical and imaging follow-up. Limited data are available on screening of these patients with digital breast tomosynthesis (DBT) versus full-field digital mammography (FFDM). OBJECTIVE. The purpose of this study was to evaluate the screening mammography performance of DBT compared with FFDM among patients with a history of breast cancer undergoing imaging at a large academic oncology center. METHODS. This retrospective study included consecutively registered patients with a personal history of breast cancer treated with mastectomy or lumpectomy who underwent screening FFDM from October 2014 through September 2016 (5706 examinations of 4091 patients) or screening DBT from February 2017 through December 2018 (4440 examinations of 3647 patients). An institutional mammographic database was queried to obtain imaging type, breast density, history of mastectomy or lumpectomy, and BI-RADS category. An institutional breast cancer registry identified cancer diagnoses. Screening performance metrics were compared between FFDM and DBT groups. RESULTS. Recall rate was significantly lower with DBT than with FFDM (7.9% vs 10.1%; p < .001). DBT and FFDM did not differ in PPV1 (7.7% vs 6.1%; p = .36) or cancer detection rate (CDR) (6.1/1000 vs 6.0/1000; p = .97). Sensitivity was 96.4% for DBT and 71.4% for FFDM (p = .008). Specificity was 92.3% for DBT and 90.0% for FFDM (p < .001). With stratification by breast density, patients with nondense breast tissue had a lower recall rate with DBT than with FFDM (5.9% vs 8.8%; p < .001) and a nonsignificant increase in PPV1 (12.0% vs 6.4%; p = .05). The metrics were not otherwise different between DBT and FFDM among patients with nondense and those with dense breast tissue. Recall rates were lower with DBT than with FFDM among both patients who underwent mastectomy (7.8% vs 9.1%; p = .09) and those who underwent lumpectomy (7.9% vs 11.0%; p = .002). PPV1 and CDR were not different between DBT and FFDM among patients who underwent mastectomy and those who underwent lumpectomy. CONCLUSION. For patients with a personal history of breast cancer who have nondense breasts, the use of DBT as opposed to FFDM reduces recall rate and improves sensitivity and specificity. CDR and PPV1 remain unchanged. CLINICAL IMPACT. For women with a personal history of breast cancer and nondense breasts, DBT offers the potential to maintain the benefits of early cancer detection while reducing the potential harms of false-positive findings.

Nonmass Findings at Breast US: Definition, Classifications, and Differential Diagnosis.

A nonmass finding at US has been described as a discrete identifiable area of altered echotexture compared with that of the surrounding breast tissue that does not conform to a mass shape. Recognizing nonmass findings is important because breast cancer can manifest as such lesions, and US correlate findings for mammographic and breast MRI abnormalities may manifest as nonmass findings. The term nonmass finding is not part of the current Breast Imaging Reporting and Data System US terminology, and no standardized approach to classify and evaluate nonmass findings at US currently exists, despite the various classification systems proposed in the literature. There is also considerable overlap between the sonographic features of benign and malignant causes of nonmass findings. These limitations cause diagnostic difficulty in evaluating clinical significance and recommending appropriate management. The authors review the definitions and classification systems of US nonmass findings proposed in the literature and illustrate the sonographic features of nonmass findings to help radiologists identify them at US. A range of benign and malignant causes of nonmass findings are reviewed, and sonographic-histopathologic correlations of nonmass findings are discussed. Cases of breast MRI and mammographic findings that may manifest as US nonmass findings are presented. Radiologists can improve detection and interpretative accuracy, as well as correlation of mammographic and MRI breast lesions, by increasing their recognition and understanding of nonmass findings at US.©RSNA, 2020.

Impact of an Information Technology-Enabled Quality Improvement Initiative on Timeliness of Patient Contact and Scheduling of Screening Mammography Recall.

OBJECTIVE. The purpose of this study was to evaluate the impact of an information technology-enabled quality improvement initiative on timeliness of patient contact and scheduling of screening mammography recall. MATERIALS AND METHODS. The study was conducted in a screening practice (two ambulatory centers, A and B; two hospitals, C and D) that uses offline batch results (A, B, C) and same-day results (D) with on-site (A, C, D) or off-site (B) coordinators scheduling recalls. Before the intervention, radiologists at sites A, B, and C conveyed recalls via paper lists to coordinators after batch interpretation. At site D, coordinators received recall lists several times a day. In March 2017 an electronic alert system was implemented to notify coordinators of recall at report signing with required closed-loop acknowledgment once recall was scheduled. Mean time (hours, excluding weekends) to schedule diagnostic evaluation was compared for 4-month periods before and after intervention by two-tailed t test and statistical process control analyses. RESULTS. Recall rates were 9.5% (1356/14,315) before and 8.9% (1432/16,034) after the intervention (p = 0.10). Mean time to schedule screening decreased after the intervention as follows: site A from 86 to 65 hours (-24.4%, p = 0.01); site B, 116 to 70 hours (-39.7%, p < 0.0001); site C, 98 to 65 hours (-33.7%, p = 0.002); and site D, 49 to 42 hours (-14.3%, p = 0.21). Statistical process control analysis showed significant sustained improvements at sites A, B, and C in mean time to patient contact and scheduling of diagnostic evaluation. CONCLUSION. An information technology-enabled quality improvement initiative to notify coordinators of screening recalls in real time with required patient contact and scheduling acknowledgment reduced time to diagnostic scheduling in a multisite practice. The greatest impact was found at the site with off-site coordinators, the least at the site performing same-day interpretation.

Screening breast MRI in patients with history of atypia or lobular neoplasia.

Our goal was to determine outcomes of screening breast MRI in patients with prior history of atypia or lobular neoplasia (LN). Review of the MRI data base revealed 264/7482 (3.5%) screening MRIs in 145 patients with history of atypia or LN. Overall, 39/264 (14.7%) received an abnormal interpretation, with 7.2% BI-RADS 4 and 5 (19/264) and 7.6% BI-RADS 3 (20/264). PPV1 was 38.4% (six cancers in 39 BI-RADS 3, 4, 5); PPV3 was 28.5% (six cancers in 21 biopsies). Screening breast MRI use in this population is low (3.5%), although PPVs are comparable to other high-risk groups for which breast MRI is recommended.

Ultrasound Features of Mammographic Developing Asymmetries and Correlation With Histopathologic Findings.

OBJECTIVE: The purpose of this study is to review the ultrasound (US) features of developing asymmetries and correlate them with histopathologic findings. MATERIALS AND METHODS: We searched the mammography database of an academic medical center, affiliated cancer center, and two ambulatory imaging facilities from 2009 to 2012 and identified 201 patients with developing asymmetries, 187 of whom had US at the time of, or within 1 month of, diagnostic mammography evaluation. Seventy-five (40.1%) of these 187 patients had a US correlate, and three additional patients had a positive second-look US after MRI (US results were initially negative), and one patient had a US correlate for a newly palpable developing asymmetry 1 month after receiving a BI-RADS category 3 mammography-only assessment. These 78 developing asymmetries with US correlates comprised the study cases. US features were obtained by consensus image review; patient demographic characteristics and outcomes were obtained from the electronic medical record. RESULTS: Thirty-six of 78 US correlates (46.2%) were masses, the echotexture of which was as follows: 26 (72.2%) were hypoechoic, four (11.1%) were hyperechoic, three (8.3%) were mixed hyperechoic and hypoechoic, and three (8.3%) were anechoic. Forty-two of 78 US correlates (53.8%) were nonmass findings, the echotexture of which was as follows: 24 (57.1%) were mixed hyperechoic and hypoechoic, 13 (31.0%) were hypoechoic, and five (11.9%) were hyperechoic. Twenty-one of 78 lesions (26.9%) were malignant; of these, eight were invasive ductal carcinoma, seven were invasive lobular carcinoma, three were mixed invasive ductal and lobular carcinoma, and three were ductal carcinoma in situ. Malignant findings on US included 17 masses (81.0%) (13 hypoechoic and four mixed hyperechoic and hypoechoic), and four nonmass findings (19.0%) (three mixed hyperechoic and hypoechoic and one hypoechoic). CONCLUSION: When present, US correlates for developing asymmetries are often nonmass findings with mixed echotexture. Most malignant developing asymmetries with US correlates present as a hypoechoic mass, but 19% present as a nonmass finding with either mixed hyperechoic and hypoechoic echotexture or hypoechoic echotexture.

Computer-aided heterogeneity analysis in breast MR imaging assessment of ductal carcinoma in situ: Correlating histologic grade and receptor status.

PURPOSE: To identify breast MR imaging biomarkers to predict histologic grade and receptor status of ductal carcinoma in situ (DCIS). MATERIALS AND METHODS: Informed consent was waived in this Health Insurance Portability and Accountability Act-compliant Institutional Review Board-approved study. Case inclusion was conducted from 7332 consecutive breast MR studies from January 1, 2009, to December 31, 2012. Excluding studies with benign diagnoses, studies without visible abnormal enhancement, and pathology containing invasive disease yielded 55 MR-imaged pathology-proven DCIS seen on 54 studies. Twenty-eight studies (52%) were performed at 1.5 Tesla (T); 26 (48%) at 3T. Regions-of-interest representing DCIS were segmented for precontrast, first and fourth postcontrast, and subtracted first and fourth postcontrast images on the open-source three-dimensional (3D) Slicer software. Fifty-seven metrics of each DCIS were obtained, including distribution statistics, shape, morphology, Renyi dimensions, geometrical measure, and texture, using the 3D Slicer HeterogeneityCAD module. Statistical correlation of heterogeneity metrics with DCIS grade and receptor status was performed using univariate Mann-Whitney test. RESULTS: Twenty-four of the 55 DCIS (44%) were high nuclear grade (HNG); 44 (80%) were estrogen receptor (ER) positive. Human epidermal growth factor receptor-2 (HER2) was amplified in 10/55 (18%), nonamplified in 34/55 (62%), unknown/equivocal in 8/55 (15%). Surface area-to-volume ratio showed significant difference (P < 0.05) between HNG and non-HNG DCIS. No metric differentiated ER status (0.113 < p ≤ 1.000). Seventeen metrics showed significant differences between HER2-positive and HER2-negative DCIS (0.016 < P < 0.050). CONCLUSION: Quantitative heterogeneity analysis of DCIS suggests the presence of MR imaging biomarkers in classifying DCIS grade and HER2 status. Validation with larger samples and prospective studies is needed to translate these results into clinical applications. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1748-1759.

Revisiting Nonmass Enhancement in Breast MRI: Analysis of Outcomes and Follow-Up Using the Updated BI-RADS Atlas.

OBJECTIVE: The purpose of this study is to assess the frequency of reclassification of nonmass enhancement (NME) as background parenchymal enhancement (BPE) and to determine positive predictive values (PPVs) of NME descriptors using the revised BI-RADS atlas. MATERIALS AND METHODS: A retrospective review of our institution's MRI database from January 1, 2009, through March 30, 2012, identified 6220 contrast-enhanced breast MRI examinations. All findings prospectively assessed as NME and rated as BI-RADS categories 3, 4, and 5 (n = 386) were rereviewed in consensus by two radiologists who were blinded to pathologic findings with the fifth edition of the BI-RADS lexicon. Findings considered as postsurgical, associated with known cancers, NME given a BI-RADS category 3 assessment before 2009, previously biopsied, and those reclassified as BPE, focus, or mass were excluded (n = 181). Medical records were reviewed for demographics and outcomes. RESULTS: Two hundred five women were included (mean age, 48.8 years; range, 21-84 years). Seventy-seven of 386 findings (20.0%) were reclassified as BPE, and patients with BPE were younger than those with NME (mean age, 43.9 years; range, 31-62 years) (p = 0.003). Pathology results for 144 of 205 (70.2%) patients included 52 malignant, 11 high-risk, and 81 benign lesions. The highest PPVs for distribution patterns were 34.5% (10/29) for segmental and 100.0% (3/3) for diffuse distribution. The highest PPVs for internal enhancement patterns were 36.7% (11/30) for clustered ring enhancement and 27.5% (11/40) for clumped enhancement. No difference for NME malignancy rate was noted according to BPE (10/52 [19.2%] marked or moderate; 42/153 [27.5%] mild or minimal, p = 0.24). Thirty-two percent (17/52) of malignant NMEs had high T2 signal. CONCLUSION: Careful assessment of findings as BPE versus NME can improve PPVs, particularly in younger women. Although clustered ring enhancement had one of the study's highest PPVs, this number falls below previously published rates. Reliance on T2 signal as a benign feature may be misleading, because one-third of malignancies had T2 signal.

Clinical Utility of Breast MRI in the Diagnosis of Malignancy After Inconclusive or Equivocal Mammographic Diagnostic Evaluation.

OBJECTIVE: The purpose of this study was to determine the clinical utility of breast MRI for diagnosing malignancy in women with equivocal mammographic findings but no symptoms. MATERIALS AND METHODS: Retrospective review of an institutional MRI database of 7332 contrast-enhanced breast MRI examinations from January 1, 2009, through December 31, 2012, yielded the records of 296 (4.0%) examinations of 294 women without symptoms who underwent MRI for mammographic findings uncertain at diagnostic evaluation. Imaging findings, histopathologic results, and patient demographics were obtained from the electronic medical record. RESULTS: The mean patient age was 55 years (range, 29-83 years). Mammographic lesion type (n = 294) included 89 focal asymmetries, 76 asymmetries, 64 masses, 44 architectural distortions, 17 surgical scar versus lesion, and four miscellaneous lesions. Diagnostic ultrasound, performed on 286 of 294 (97.3%) lesions at mammographic evaluation, showed an ultrasound correlate in 37 (12.9%) lesions, equivocal correlate in 48 (16.8%), and no ultrasound correlate in 201 (70.3%). MRI examination of 294 index lesions showed a correlate in 133 (45.2%) and no correlate in 161 (54.8%). Forty of 294 (13.6%) index lesions were malignant, 37 (92.5%) with an MRI correlate and three (7.5%) without an MRI correlate. Among 250 patients who underwent biopsy or had 2 or more years of imaging stability, the sensitivity, specificity, negative predictive value, and positive predictive value of breast MRI for malignancy were 92.5%, 62.4%, 97.8%, and 31.9%. Forty-four of 294 (15.0%) patients had lesions incidentally found at MRI; 7 of 41 (17.1%) lesions that were biopsied or were stable for at least 1 year were malignant. CONCLUSION: Problem-solving breast MRI for inconclusive mammographic findings helps identify malignancies with high sensitivity and a high negative predictive value.

Strengths and Weaknesses of Synthetic Mammography in Screening.

Synthetic mammography (SM) consists of two-dimensional images reconstructed from digital breast tomosynthesis (DBT) data. Unlike standard full-field digital mammography (FFDM), SM does not require additional radiation exposure. SM is being introduced in breast imaging centers because early clinical data demonstrate that synthetic images are comparable to FFDM in cancer detection, positive predictive values, and recall rates. SM has completely replaced FFDM in some practices. Thus, an understanding of SM and its strengths and weaknesses compared with those of FFDM is essential. The artifacts of SM include blurring subcutaneous tissue, loss of resolution in the axilla on mediolateral oblique views, pseudocalcifications, and decreased resolution near foreign bodies (eg, biopsy markers). SM's strengths include a reduced radiation dose, shorter acquisition time compared with a combined FFDM/DBT screening examination (with potentially less motion artifact), and increased conspicuity of calcifications, spiculated margins, and architectural distortion. The weaknesses of SM include the potential for false positives due to pseudocalcifications and the difficulty in assessing for motion artifact. This article reviews SM and its role in screening and presents clinical cases to highlight SM's strengths, weaknesses, and artifacts. ©RSNA, 2017.