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Please see the Editorial Comment by Linda M. Sanders discussing this article. Background: There is a paucity of data and consensus guidelines on the utility of preoperative MRI for planned bilatera...

Background Suppression of background parenchymal enhancement (BPE) is commonly observed after neoadjuvant chemotherapy (NAC) at contrast-enhanced breast MRI. It was hypothesized that nonsuppressed BPE may be associated with inferior response to NAC. Purpose To investigate the relationship between lack of BPE suppression and pathologic response. Materials and Methods A retrospective review was performed for women with menopausal status data who were treated for breast cancer by one of 10 drug arms (standard NAC with or without experimental agents) between May 2010 and November 2016 in the Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging and Molecular Analysis 2, or I-SPY 2 TRIAL (NCT01042379). Patients underwent MRI at four points: before treatment (T0), early treatment (T1), interregimen (T2), and before surgery (T3). BPE was quantitatively measured by using automated fibroglandular tissue segmentation. To test the hypothesis effectively, a subset of examinations with BPE with high-quality segmentation was selected. BPE change from T0 was defined as suppressed or nonsuppressed for each point. The Fisher exact test and the Z tests of proportions with Yates continuity correction were used to examine the relationship between BPE suppression and pathologic complete response (pCR) in hormone receptor (HR)-positive and HR-negative cohorts. Results A total of 3528 MRI scans from 882 patients (mean age, 48 years ± 10 [standard deviation]) were reviewed and the subset of patients with high-quality BPE segmentation was determined (T1, 433 patients; T2, 396 patients; T3, 380 patients). In the HR-positive cohort, an association between lack of BPE suppression and lower pCR rate was detected at T2 (nonsuppressed vs suppressed, 11.8% [six of 51] vs 28.9% [50 of 173]; difference, 17.1% [95% CI: 4.7, 29.5]; P = .02) and T3 (nonsuppressed vs suppressed, 5.3% [two of 38] vs 27.4% [48 of 175]; difference, 22.2% [95% CI: 10.9, 33.5]; P = .003). In the HR-negative cohort, patients with nonsuppressed BPE had lower estimated pCR rate at all points, but the P values for the association were all greater than .05. Conclusions In hormone receptor-positive breast cancer, lack of background parenchymal enhancement suppression may indicate inferior treatment response. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Philpotts in this issue.

This study tested the hypothesis that a change in the apparent diffusion coefficient (ADC) measured in diffusion-weighted MRI (DWI) is an independent imaging marker, and ADC performs better than functional tumor volume (FTV) for assessing treatment response in patients with locally advanced breast cancer receiving neoadjuvant immunotherapy. A total of 249 patients were randomized to standard neoadjuvant chemotherapy with pembrolizumab (pembro) or without pembrolizumab (control). DCE-MRI and DWI, performed prior to and 3 weeks after the start of treatment, were analyzed. Percent changes of tumor ADC metrics (mean, 5th to 95th percentiles of ADC histogram) and FTV were evaluated for the prediction of pathologic complete response (pCR) using a logistic regression model. The area under the ROC curve (AUC) estimated for the percent change in mean ADC was higher in the pembro cohort (0.73, 95% confidence interval [CI]: 0.52 to 0.93) than in the control cohort (0.63, 95% CI: 0.43 to 0.83). In the control cohort, the percent change of the 95th percentile ADC achieved the highest AUC, 0.69 (95% CI: 0.52 to 0.85). In the pembro cohort, the percent change of the 25th percentile ADC achieved the highest AUC, 0.75 (95% CI: 0.55 to 0.95). AUCs estimated for percent change of FTV were 0.61 (95% CI: 0.39 to 0.83) and 0.66 (95% CI: 0.47 to 0.85) for the pembro and control cohorts, respectively. Tumor ADC may perform better than FTV to predict pCR at an early treatment time-point during neoadjuvant immunotherapy.

Localization of metastatic axillary lymph nodes in breast cancer patients is an increasingly common procedure performed by radiologists. In 2014, the National Comprehensive Cancer Network guidelines stated that "clinically positive axillary lymph node (s) should be sampled by FNA or core biopsy and clipped with image-detectable marker; clipped lymph nodes must be removed if FNA or core biopsy was positive prior to neoadjuvant therapy". Since then, multiple studies have further supported targeted axillary surgery after neoadjuvant chemotherapy (NAC), with excision of the clipped metastatic axillary node in addition to the sentinel node (s). Requests for image guided localization of clipped axillary nodes will continue to increase and likely become the standard of care. However, when lymph nodes have decreased in size after NAC, or when small deep lymph nodes are sampled, the clipped node can be difficult to identify under ultrasound at the time of localization. When the target node is questionable, we have found it valuable to place an intermediary clip, and use an axillary mammographic view to confirm this intermediary clip co-localizes with the intended target. With this confirmation, safe, accurate localization can then be performed. We describe 3 cases of intermediary clip placement facilitating successful localization of previously clipped axillary lymph nodes.

OBJECTIVE. The purpose of this article was to determine the frequency and outcomes of new suspicious findings on breast MRI after initiation of neoadjuvant therapy. MATERIALS AND METHODS. A retrosp...

Background: The I-SPY 2 TRIAL randomizes patients with breast cancer to neoadjuvant chemotherapy (NAC) with or without experimental agents followed by anthracycline-cyclophosphamide (AC). As part of a de-escalation strategy to avoid overtreatment in good responders, combined information from serial MRI and mid-treatment core biopsy will be used to identify patients who may be candidates to skip AC. Presented are results of a pilot study to assess the location of biopsy clip in relation to tumor enhancement in MRI before and during treatment. Methods: 40 patients enrolled in I-SPY 2 who underwent mid-treatment core biopsy were reviewed. Patients had MRIs at four time points: pre-treatment (T0), early treatment (T1, 3 weeks after the start of first regimen), inter-regimen (T2, 12 weeks after completing the first regimen), and pre-surgery (T3). Clip visibility and location were assessed by a trained researcher on T1 weighted, fat suppressed dynamic contrast enhanced MR images at three time points: T0, T1, and T2. If clip was visible, location was scored 1 (inside), 2 (edge), or 3 (outside) in relation to tumor enhancement seen on a signal enhancement ratio (SER) map. Clips inside (score 1) were fully embedded and surrounded by a clear margin of tumor enhancement. Clips on the edge (score 2) were not fully embedded, with a portion of the clip touching tumor enhancement. Clips outside (score 3) had no portion of clip touching tumor enhancement. For patients with a focal tumor but with multiple clips visible in MRI, the clip most embedded within tumor enhancement was designated as the primary clip for evaluation. In cases of multifocal disease, the clip visualized in the largest area of tumor enhancement was assessed. Clips touching tumor cavity edge and enhancement were scored as 3. Results: Among 40 patients, two patients had no clips visualized in MRI at all three time points. One patient had no clip visualized at T0, but a clip was observed at T1 and T2. In addition, one T1 MRI was rejected due to incomplete exam and one T2 MRI was rejected due to different scanner from baseline. At T0, 51% (19/37) of clips were inside tumor enhancement and no clips were assessed outside tumor enhancement. 59% (22/37) of clips at T1 were on the edge or outside. At T2, 73% (27/37) of clips were on the edge and 19% (7/37) of clips were outside. While no clips were identified outside of tumor at baseline, tumor shrinkage with treatment resulted in clips outside of tumor in approximately 20 percent of cases at inter-regimen, and higher rates of clips identified at tumor edge. Conclusions: Clips were visible and location could be assessed in MRI in a majority of cases. Clip evaluation can be challenging and attention to clip placement is essential for patients with multifocal disease or diffuse tumors. The results of this study may have implications for assisting the mid-treatment core biopsy and selecting candidates for de-escalation of neoadjuvant chemotherapy. Table 1: Clips observed at three MR time pointsT0T12T231 (inside)191532 (edge)1821273 (outside)01171 No clips were seen outside tumor enhancement 2 One T1 MR was rejected due to incomplete exam 3 One T2 MR was rejected due to different scanner from baseline Citation Format: Teffany Joy Bareng, Jessica Gibbs, Wen Li, Natsuko Onishi, Bonnie N Joe, Elissa Price, Barbara LeStage, Coleen Crespo, I-SPY 2 Imaging Working Group, I-SPY 2 Consortium, Nola M Hylton. Assessment of clip locations on breast MRI during NAC to guide tumor bed biopsy at mid-treatment [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-14.

Purpose To assess the use and outcomes of ultrasound for the evaluation of breast signs and symptoms in pediatric females. Methods A retrospective database review identified all patients ≤18-years-old who underwent breast ultrasound at an academic institution over a 20-year period. Each symptomatic site was designated a case and analyses were performed on each case. Imaging findings were obtained from the radiology reports. Clinical and pathology data were obtained from the medical records. Descriptive statistics were performed. Results The final cohort comprised 124 cases in 101 patients. Mean age was 15 years (range 1–18). The most common indication for ultrasound was a palpable lump (71%). Thirty-seven cases (30%) demonstrated no sonographic correlate to the symptom; 36 (29%) had a benign correlate. The most common benign correlates were abscess/phlegmon and cyst. All cases of abscess/phlegmon had infectious symptoms. Fifty-one cases (41%) demonstrated a sonographic mass that was not characteristically benign. Of these indeterminate masses, 27 were recommended for biopsy, 13 for short-interval follow-up, and 6 had no recommendation. Of 27 biopsied masses, 63% were fibroadenomas. No symptoms were due to malignancy. Therefore, the NPV of ultrasound was 100% and the PPV 0%. Conclusion In this cohort of pediatric and adolescent patients, malignancy was never the cause of breast symptoms. Imaging yielded false positives with a biopsy recommendation in 22% of cases. Ultrasound provided value in evaluating infectious symptoms. Given the extreme rarity of breast cancer in this population, surveillance may be a safe alternative for most indeterminate lesions.

Objective To evaluate the MRI artifact rendered by the typical injection of a ferromagnetic tracer now being intermittently used for intraoperative sentinel node (SN) identification at our institution, and to explore its impact on postoperative imaging and management. Methods This study was Institutional Review Board-approved and granted a waiver of consent. A database search tool was used to identify MRI exams performed on patients who had previously undergone breast-conserving surgery with use of a superparamagnetic iron oxide (SPIO) SN tracer between January 1, 2015, and May 1, 2020. MRI reports, images, and relevant demographic, oncologic, and surgical history were collected. The presence or absence of SPIO residue on breast MRI, as well as its impact on image quality, were extracted from the prospective reports. Results A total of 21 MRI exams were identified in 16 patients who had undergone breast-conservation therapy for cancer with use of SPIO SN tracer. Mean time from particle injection to baseline postoperative MRI exam was 10.8 months. All reports (21/21) noted evidence of SPIO residue. Of these, 5/21 were assessed as non-diagnostic; the remainder were assessed as limited. Conclusion Radiologists should be aware of the use of superparamagnetic tracers for SN identification and the impact on the quality of future MRI examinations. Alternative injection approaches are being developed and sequence parameters adjusted to minimize artifact.

OBJECTIVE. The purpose of this study was to assess the performance of diagnostic mammography alone for evaluation of palpable symptoms in women with almost entirely fatty breast composition. MATERIALS AND METHODS. All diagnostic mammograms performed for palpable symptoms in women who had been assigned a breast density of "almost entirely fatty" over an 8-year period (2009-2017) at an academic breast center were retrospectively identified. Each symptomatic breast was considered a separate case and analyses were performed at the case level. Clinical, imaging, and pathologic results were reviewed. Descriptive statistics and 2 × 2 contingency table analyses were performed. RESULTS. The study cohort included 323 cases evaluated with mammography. Of these, 294 (91%) had undergone targeted ultrasound. At mammography, 240 (74%) had no correlate to the palpable lump; 38 (12%), a benign correlate; and 45 (14%), a suspicious correlate. Three cases had incidental suspicious mammographic findings, for a total of 48 positive mammography cases. Twenty-seven (8%) cases were malignant. Mammography alone detected all but one cancer, which was detected by ultrasound. In retrospect, the woman from whom this single false-negative mammogram was obtained did not have almost entirely fatty breast density. Mammography alone yielded a negative predictive value of 99.6%, percentage of diagnostic examinations recommended for biopsy that resulted in a tissue diagnosis of malignancy within 1 year of 54%, sensitivity of 96%, and specificity of 93%. Adjunct ultrasound contributed to 11 false-positives but also identified benign correlates in eight cases with no mammographic finding. CONCLUSION. In patients with almost entirely fatty breast tissue presenting with palpable symptoms, mammography alone had a high sensitivity and specificity. Our results support that mammography alone may be sufficient for evaluation of palpable symptoms in these women as long as density criteria are strictly applied.

Objective To assess the utilization of patient navigators at breast imaging facilities across the United States. Methods An online survey was distributed to physician members of the Society of Breast Imaging. Questions encompassed use of patient navigators in breast imaging including: presence and qualifications, roles in patient care, perceived benefits, and barriers. Data were analyzed to identify the overall prevalence of patient navigators, their responsibilities and qualifications, and the impact on breast imaging centers. Results Three-hundred and eighty-five board-certified radiologists practicing in the United States completed the survey. The most common practice types were private practice (52%; 201/385) and academic (29%; 110/385). The majority (67%; 256/385) employed navigators, and the most common qualification was a registered nurse (78%; 200/256). Navigators were used for a variety of patient communication and care coordination roles, most commonly to provide educational resources (86%; 219/256), assist patients with scheduling appointments (80%; 205/256), explain the biopsy process (76%;195/256), and communicate biopsy results (64%). Nearly all (99%; 254/256) respondents ranked patient navigators as valuable to extremely valuable in improving patient care and indicated they would recommend implementation of a patient navigation program to other breast imaging practices. The most common barrier to employing a navigator was the financial cost. Conclusion Patient navigators have been widely adopted in breast imaging practices across the United States, with two-thirds of respondents reporting use of a navigator. Although navigator roles varied by practice, nearly all radiologists utilizing patient navigators found that they positively impact patient care and would recommend them to other breast imaging practices.

Background: The apparent diffusion coefficient (ADC) presents a biomarker that is sensitive to tumor cellularity. ADC maps can be calculated from non-contrast diffusion-weighted magnetic resonance imaging (DW-MRI) measurements. ACRIN 6698, a sub-study of clinical trial I-SPY 2, investigated mean ADC – averaged over the whole tumor – as a marker to predict pathologic complete response (pCR) [1]. This work compares a group of histogram-based ADC metrics in addition to mean ADC for early prediction of pCR in patients stratified by breast cancer subtype. Methods: We performed a retrospective analysis of DW-MRI, dynamic-contrast enhanced (DCE) MRI, and clinical outcome (i.e., pCR at surgery) in a cohort of 79 female patients who were diagnosed with high-risk, stage II/III breast cancer. Patients underwent neoadjuvant chemotherapy (NAC) with paclitaxel (12 weeks), followed by doxorubicin plus cyclophosphamide (12 weeks). The included population represents a subset of the I-SPY 2 cohort and comprises 48 patients with hormone receptor [HR]+/HER2-, and 31 patients with HR-/HER2-. DW- and DCE-MRI acquisitions were performed according to the I-SPY 2 protocol at pretreatment (T0) and after three weeks (T1) and were analyzed to find early treatment percentage (%) change (T0 to T1) in any metric M; where %-change = 100 × (M(T1) – M(T0))/M(T0). Histogram analysis provided nine region-of-interest (ROI)-based ADC metrics (Table 1). ROIs were manually delineated by expert observers in three-dimensional ADC maps, focusing on diffusion-restricted regions [2]. DCE-MRI was analyzed for the integral I-SPY 2 imaging marker of %-change in functional tumor volume (FTV) between T0 and T1. Statistical analysis compared the predictive power of ADC metrics and FTV, including: the receiver-operating-characteristic (ROC) curve from a logistic regression model to predict pCR as ‘positive’, area-under-the-curve (AUC) assessment, and rank-sum Wilcoxon test (p< 0.05: statistically significant). Results (Table 1): 16 out of 79 (20.3%) patients reached pCR at surgery, with 18.8% pCR among HR+/HER- and 22.6% among HR-/HER2- groups. For all nine computed ADC statistics (listed as median [Q1, Q3], across all patients), %-change was higher in patients who reached pCR than patients with non-pCR (highest value for metric ‘MIN’: 23.9% [-0.9%, 52.5] vs. 16.6% [0.4%, 27.6%], though without statistical significance: p=0.237). Likewise, %-change of FTV was also stronger in pCR patients than non-pCR patients (-58.8% [-80.6%, -22.5%] vs. -28.2% [54.2%, -2.7%], with statistical significance: p=0.036). For all patients combined (n=79), among the various reported ADC metrics, %-change in ‘PCTL_95’ (95th percentile of histogram) yielded the highest AUC (0.7; 95% CI = [0.56, 0.83]; p=0.012). %-change in FTV showed the second highest AUC (0.67; 95% CI = [0.52, 0.82]; p=0.036). By subtype, AUC was highest for %-change of ‘PCTL_95’ (0.69; 95% CI = [0.5, 0.87]; p=0.072) in the HR+/HER2- subgroup; and highest for both %-change of ‘MEAN’ (AUC = 0.73; 95% CI = [0.49, 0.94]; p=0.065) and ‘PCTL_75’ (AUC = 0.73; 95% CI = [0.49, 0.94]; p=0.073) triple negative (HR-/HER2-) subgroup. By comparison, %-change of FTV yielded AUCs of 0.64 (95% CI = [0.41, 0.85]; p=0.191) and 0.71 (95% CI = [0.51, 0.9]; p=0.098) in the HR+/HER2- and triple-negative subgroups, respectively. Conclusion: Various tumor ADC metrics from non-contrast DW-MRI demonstrate potential biomarkers for assessing responsiveness to NAC at an early treatment timepoint. ADC may have predictive performance that is comparable to FTV, depending on the breast cancer subtype. Observations for %-change in ‘MEAN’ ADC at T1 differed from previous reports [1], which may be explained by the small sample size and single (paclitaxel) drug arm. Additional studies are warranted to include patients of experimental arms and of HER2+ subtypes. [1] Partridge et al., Radiology 289(3):618-27 (2018) [2] Nu et al., Tomography 8: 1208-20 (2022) Results of statistical analysis of ADC-based and FTV markers for predicting treatment response at 3 weeks into NAC. Median [Q1, Q3] values represent the median and interquartile range over the respective patient population regarding the %-change of the respective ADC (FTV) metric from T0 to T1. T0: pretreatment, T1: 3-week timepoint, ADC: apparent diffusion coefficient, MRI: magnetic resonance imaging, DW: diffusion-weighted, DCE: dynamic-contrast enhanced, pCR: pathologic complete response, AUC: area under the ROC curve, 95% CI [LL, UL]: confidence interval lower and upper limit, PCTL_x: xth-percentile of tumor ADC histogram, MEAN: mean of ADC within ROI, MIN: minimum of ADC within ROI, MAX: maximum of ADC within ROI, FTV: functional tumor volume, **: statistically significant. Citation Format: Judith Zimmermann, Julia Carmona-Bozo, Nu N. Le, Natsuko Onishi, Lisa J. Wilmes, Jessica E. Gibbs, Jiachao Liang, David C. Newitt, Savannah Partridge, Patrick Bolan, Bonnie N. Joe, Elissa R. Price, Barbara LeStage, Nola M. Hylton, Wen Li. Diffusion-weighted magnetic resonance imaging for subtype-specific prediction of pathologic complete response in neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-33.

OBJECTIVE. The objective of this study was to evaluate the feasibility of using a magnetic seed system for preoperative localization of axillary lymph nodes in patients with breast cancer. MATERIALS AND METHODS. We performed a retrospective analysis that included patients with breast cancer who underwent preoperative magnetic seed localization of axillary lymph nodes at our institution between January 1, 2017, and January 1, 2019. Magseed (Endomag) is a nonradioactive inducible magnetic seed that is induced to become a magnet when under the influence of its detector in the operating room. Clinical history, prior axillary sampling and clip placement, and procedure details and surgical outcomes were determined from a search of our PACS and electronic medical records. RESULTS. Thirty-five patients (34 women and one man) composed our study cohort. The mean patient age was 56 years (range, 32-78 years). One patient underwent two separate consecutive localizations for two separate operations, and another patient had bilateral lesions, for a total of 37 axillary lymph node localizations. One case of seed misplacement occurred during the ultrasound-guided localization procedure, resulting in immediate placement of a second seed, for a total of 38 Magseeds placed. All seeds were placed under ultrasound guidance. The mean number of days from seed placement to surgery was 5 days (range, 0-31 days). Thirty-seven of 38 Magseeds (97%) were documented to be successfully retrieved in the operating room. CONCLUSION. Magseed localization appears to be a safe, nonradioactive way to accurately localize axillary lymph nodes preoperatively.

Objective There are currently various conflicting recommendations for breast cancer screening with mammography in women between ages 40-49. There are no specific guidelines for breast cancer screening in women of this age group prior to assisted reproductive technology (ART) for the treatment of infertility. The purpose of our study was to evaluate outcomes of screening mammography, specifically ordered for the purpose of pre-fertility treatment clearance in women aged 40-49 years old. Materials and methods This was an IRB approved retrospective study of women aged 40-49 presenting for screening mammography prior to ART between January 2010 and October 2018. Clinical history, imaging, and pathology results were gathered from the electronic medical record. Descriptive statistics were performed. Results Our study cohort consisted of 118 women with a mean age of 42 years (range 40-49). Sixteen of 118 (14%) women were recalled from screening for additional diagnostic work-up. Five of the 16 (31%) were recommended for biopsy (BI-RADS 4 or 5). One of 5 biopsies yielded a malignant result (PPV 20%). Overall cancer detection rate was 0.85% or 8.5 women per 1000 women screened. The single cancer in this cohort was an ER+ PR+ HER2- invasive ductal carcinoma. Conclusion Screening mammography in women 40-49 performed prior to initiation of ART may identify asymptomatic breast malignancy. In accordance with ACR and SBI guidelines to screen women of this age group, women of this age group should undergo screening mammography prior to ART.

Dynamic contrast-enhanced (DCE) MRI provides both morphological and functional information regarding breast tumor response to neoadjuvant chemotherapy (NAC). The purpose of this retrospective study is to test if prediction models combining multiple MRI features outperform models with single features. Four features were quantitatively calculated in each MRI exam: functional tumor volume, longest diameter, sphericity, and contralateral background parenchymal enhancement. Logistic regression analysis was used to study the relationship between MRI variables and pathologic complete response (pCR). Predictive performance was estimated using the area under the receiver operating characteristic curve (AUC). The full cohort was stratified by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status (positive or negative). A total of 384 patients (median age: 49 y/o) were included. Results showed analysis with combined features achieved higher AUCs than analysis with any feature alone. AUCs estimated for the combined versus highest AUCs among single features were 0.81 (95% confidence interval [CI]: 0.76, 0.86) versus 0.79 (95% CI: 0.73, 0.85) in the full cohort, 0.83 (95% CI: 0.77, 0.92) versus 0.73 (95% CI: 0.61, 0.84) in HR-positive/HER2-negative, 0.88 (95% CI: 0.79, 0.97) versus 0.78 (95% CI: 0.63, 0.89) in HR-positive/HER2-positive, 0.83 (95% CI not available) versus 0.75 (95% CI: 0.46, 0.81) in HR-negative/HER2-positive, and 0.82 (95% CI: 0.74, 0.91) versus 0.75 (95% CI: 0.64, 0.83) in triple negatives. Multi-feature MRI analysis improved pCR prediction over analysis of any individual feature that we examined. Additionally, the improvements in prediction were more notable when analysis was conducted according to cancer subtype.

Objective The objective of our study was to determine whether, in the digital era, imaging features of a primary breast tumor can be used to influence the decision to biopsy ipsilateral breast calcifications that occur following surgery in women treated with breast conservation surgery (BCS). Materials and methods We retrospectively identified women treated with BCS who subsequently developed suspicious calcifications in the treated breast (BI-RADS 4 or 5) from January 2012 – December 2018. Only cases with histopathological diagnosis by stereotactic or surgical biopsy were included. Pathology reports were reviewed, and biopsy results were considered malignant if invasive carcinoma or ductal carcinoma in situ (DCIS) was found. All other results were considered benign. Fisher's exact test was done comparing frequencies of malignancy between those patients whose original tumor had calcifications versus those whose original tumors were not calcified. Results Of 90 women with suspicious calcifications on a post-BCS mammogram, 65 (72.2%) were biopsy proven benign and 25 (27.8%) were malignant. The original tumor presented without calcifications in 39 patients (43%), and 51 (57%) had calcifications with or without associated mass, focal asymmetry, or architectural distortion. New calcifications were less likely to be malignant if the original tumor presented without calcifications (5/39; 12.8%) as compared to original tumors with calcifications (20/51; 38.5%) [p-value Conclusion New calcifications after BCS are significantly less likely to be malignant if the original tumor presented without calcifications. However, with a PPV of 12.8%, even calcifications in a patient with a non-calcified primary tumor require biopsy.

PURPOSE Primary endocrine therapy for ductal carcinoma in situ (DCIS) as a potential alternative to surgery has been understudied. This trial explored the feasibility of a short-term course of letrozole and sought to determine whether treatment results in measurable radiographic and biologic changes in estrogen receptor (ER)–positive DCIS. PATIENTS AND METHODS A phase II single-arm multicenter cooperative-group trial was conducted in postmenopausal patients diagnosed with ER-positive DCIS without invasion. Patients were treated with letrozole 2.5 mg per day for 6 months before surgery. Breast magnetic resonance imaging (MRI) was obtained at baseline, 3 months, and 6 months. The primary end point was change in 6-month MRI enhancement volume compared with baseline. RESULTS Overall, 79 patients were enrolled and 70 completed 6 months of letrozole. Of these, 67 patients had MRI data available for each timepoint. Baseline MRI volumes ranged from 0.004 to 26.3 cm3. Median reductions from baseline MRI volume (1.4 cm3) were 0.6 cm3 (61.0%) at 3 months ( P < .001) and 0.8 cm3 (71.7%) at 6 months ( P < .001). Consistent reductions were seen in median baseline ER H-score (228; median reduction, 15.0; P = .005), progesterone receptor H-score (15; median reduction, 85.0; P < .001), and Ki67 score (12%; median reduction, 6.3%; P = .007). Of the 59 patients who underwent surgery per study protocol, persistent DCIS remained in 50 patients (85%), invasive cancer was detected in six patients (10%), and no residual DCIS or invasive cancer was seen in nine patients (15%). CONCLUSIONS In a cohort of postmenopausal women with ER-positive DCIS, preoperative letrozole resulted in significant imaging and biomarker changes. These findings support future trials of extended endocrine therapy as primary nonoperative treatment of some DCIS.

To compare the characteristics, outcomes, and performance metrics in women undergoing initial breast MRI screening versus subsequent screening.A retrospective database search identified screening MRIs performed at an academic practice from 2013 to 2015. MRIs were divided into two groups: (1) initial screens and (2) subsequent screens (interpreted with at least one prior MRI for comparison). Benignity was confirmed with pathology or1-year follow-up. Malignancy was confirmed by pathology. Performance metrics were calculated. Comparisons were made using Binomial and Fisher's exact tests.We observed a higher rate of abnormal interpretations (52% vs. 19%; p 0.001) and rate of biopsy (49% vs. 15%; p 0.001) in the initial versus subsequent screen group. The positive predictive value of biopsy was slightly lower at initial versus subsequent screen (17% vs. 19%, p = 0.99). However, the cancer detection rate was higher at initial than at subsequent screen (85 vs. 29/1000, p = 0.08). Sensitivity was higher at initial (100%) versus subsequent (88%) screen. However, the specificity at initial screen was low (55%) compared to subsequent screen (83%).The higher rate of abnormal interpretations in the initial versus subsequent screen group in part reflects a prevalence screening. Although we observed more abnormal interpretations in the initial screen, this was likely justified by the significantly higher cancer detection. This evidence may be used to counsel patients and referring providers on the expected higher likelihood of recall from an initial screening MRI balanced with higher detection of malignancies. Findings also highlight the importance of having comparison MRIs to decrease false positives.

Purpose. Hormonal status significantly affects background normal parenchymal enhancement (BPE) degree on breast MRI. A previous study reported the association between lack of BPE suppression and non pathologic complete response (pCR) after neoadjuvant chemotherapy for HR+ invasive cancer1. For DCIS, local control is the treatment goal2,3. Surgical outcomes which might be related to local control include presence of invasive components at surgery, re-excision after breast conserving surgery (BCS), and residual DCIS extent. We hypothesized that imaging outcomes (pre-surgery MRI volume and volume reduction from baseline) might also be related to local control. We investigated the association between BPE degree/suppression and 5 surgical/imaging outcomes after neoadjuvant endocrine therapy (NET) for DCIS. Methods. CALGB 40903 was a single arm trial of NET for ER+ DCIS without invasion4. Clinical and image data from a subset of 59 post-menopausal patients from this trial was available for analysis. Patients took letrozole 2.5 mg/day for 6 months before surgery (BCS, 53; mastectomy, 6). Dynamic contrast-enhanced MRIs were obtained at baseline, 3 months, and 6 months (pre-surgery). MRI volume was measured by summing all voxels with pre-defined level of enhancement within a 3D bounding box. MRI volume reduction was measured by percent change from baseline. BPE degree was calculated as the mean early percent enhancement of the central 50% axial slices on a contralateral breast. BPE suppression was dichotomized as suppressed or non-suppressed relative to baseline. For analyses on re-excision, only BCS patients were included. For analyses on residual DCIS extent, patients who achieved pCR or had invasive components were excluded. Mann-Whitney, Spearman’s rho, and Fisher’s exact tests were used for analyses, with P Table 1.Association of BPE Degree with Surgical and Imaging OutcomesOutcomeTime pointOutcome statusNo. of patientsMedian [1st, 3rd quartiles]P-valuePresence of invasive componentBaselineAbsent47 (92)25.0 [19.6, 30.0]0.282Present4 (8)17.2 [15.3, 25.5]3 monthsAbsent48 (91)23.5 [17.8, 31.0]0.668Present5 (9)16.6 [16.3, 34.7]6 monthsAbsent45 (90)24.6 [18.1, 33.0]0.343Present5 (10)17.2 [12.8, 31.2]OutcomeTime pointOutcome statusNo. of patientsMedian [1st, 3rd quartiles]P-valueRe-excision after BCSBaselineNot performed40 (87)22.6 [19.0, 27.1]0.019*Performed6 (13)43.0 [29.3, 53.9]3 monthsNot performed40 (85)22.1 [16.5, 29.5]0.018*Performed7 (15)36.7 [29.2, 40.3]6 monthsNot performed37 (84)19.8 [16.5, 31.4]0.009*Performed7 (16)38.3 [31.4, 41.0]OutcomeTime pointOutcome statusNo. of patientsSpearman’s rhoP-valueResidual DCIS extentBaselineNA3800.9973 monthsNA38-0.270.1016 monthsNA37-0.230.164MRI volumeBaselineNA510.130.3733 monthsNA530.170.2326 monthsNA500.420.003*MRI volume reductionBaselineNA510.070.6093 monthsNA530.290.0336 monthsNA500.50< 0.001** P Table 2.Association of BPE suppression with Surgical and Imaging OutcomesOutcomeTime pointBPE suppression groupNo. of patientsNo. of patients w/o invasive componentNo. of patients w/invasive componentP-valuePresence of invasive component3 monthssuppressed26 (53)24 (53)2 (50)1.000non-suppressed23 (47)21 (47)2 (50)6 monthssuppressed25 (53)22 (51)3 (75)0.611non-suppressed22 (47)21 (49)1 (25)OutcomeTime pointBPE suppression groupNo. of patientsNo. of patients w/o re-excisionNo. of patients w/re-excisionP-valueRe-excision after BCS3 monthssuppressed26 (53)22 (51)4 (67)0.671non-suppressed23 (47)21 (49)2 (33)6 monthssuppressed25 (53)21 (51)4 (67)0.670non-suppressed22 (47)20 (49)2 (33)OutcomeTime pointBPE suppression groupNo. of patientsMedian[1st, 3rd quartiles]P-valueResidual DCIS extent3 monthssuppressed19 (53)23mm[7, 36]0.172non-suppressed17 (47)11mm[4, 22]6 monthssuppressed18 (51)20mm[6.5, 34]0.487non-suppressed17 (49)18mm[4, 24]MRI volume3 monthssuppressed26 (53)0.4cc[0.2, 1.9]0.613non-suppressed23 (47)0.6cc[0.1, 1.6]6 monthssuppressed25 (53)0.3cc[0.1, 0.8]0.015*non-suppressed22 (47)1.1cc[0.4, 2.8]MRI volume reduction3 monthssuppressed26 (53)-73.0%[-91.4, -45.0]0.684non-suppressed23 (47)-71.1%[-92.1, -46.7]6 monthssuppressed25 (53)-84.8%[-96.2, -66.5]0.001*non-suppressed22 (47)-48.6%[-75.0, 57.3]* P Citation Format: Natsuko Onishi, David C Newitt, Jessica E Gibbs, Alex A Nguyen, Rita Freimanis, Elissa R Price, Shelly Hwang, Nola M Hylton. Background parenchymal enhancement as an imaging biomarker in neoadjuvant endocrine therapy for DCIS [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-03-08.

Purpose To evaluate the association between Breast Imaging Reporting and Data System (BI-RADS) mammographic and magnetic resonance (MR) imaging features and breast cancer recurrence risk in patients with estrogen receptor-positive breast cancer who underwent the Oncotype DX assay. Materials and Methods In this institutional review board-approved and HIPAA-compliant protocol, 408 patients diagnosed with invasive breast cancer between 2004 and 2013 who underwent the Oncotype DX assay were identified. Mammographic and MR imaging features were retrospectively collected according to the BI-RADS lexicon. Linear regression assessed the association between imaging features and Oncotype DX test recurrence score (ODxRS), and post hoc pairwise comparisons assessed ODxRS means by using imaging features. Results Mammographic breast density was inversely associated with ODxRS (P ≤ .05). Average ODxRS for density category A was 24.4 and that for density category D was 16.5 (P.02). Both indistinct mass margins and fine linear branching calcifications at mammography were significantly associated with higher ODxRS (P.01 and P.03, respectively). Masses with indistinct margins had an average ODxRS of 31.3, which significantly differed from the ODxRS of 18.5 for all other mass margins (P.01). The average ODxRS for fine linear branching calcifications was 29.6, whereas the ODxRS for all other suspicious calcification morphologies was 19.4 (P.03). Average ODxRS was significantly higher for irregular mass margins at MR imaging compared with spiculated mass margins (24.0 vs 17.6; P.02). The presence of nonmass enhancement at MR imaging was associated with lower ODxRS than was its absence (16.4 vs 19.9; P.05). Conclusion The BI-RADS features of mammographic breast density, calcification morphology, mass margins at mammography and MR imaging, and nonmass enhancement at MR imaging have the potential to serve as imaging biomarkers of breast cancer recurrence risk. Further prospective studies involving larger patient cohorts are needed to validate these preliminary findings.

Purpose To evaluate outcomes of lymph node sampling in patients with suspicious axillary nodes without a diagnosis of breast cancer. Materials and methods We retrospectively identified all axillary ultrasound-guided sampling performed at our institution from 2003 to 2016 in patients. without malignancy. Results Seventy-eight lymph nodes met inclusion criteria. Two of the 78 sampled nodes (2.6%) were malignant. Conclusion Sampling of suspicious nodes in patients without a history of breast cancer rarely yields malignancy. The malignancy rate approaches the 2% BIRADS 3 threshold. Further data may demonstrate that short-interval imaging follow-up is a safe alternative to sampling in this cohort.

To determine the accuracy of post-operative MR in predicting residual disease in women with positive margins, emphasizing the size thresholds at which residual disease can be confidently identified. This IRB-approved HIPAA-compliant retrospective study included 175 patients with MR after positive margins following initial surgery for breast cancer. Two expert readers independently re-evaluated MR images for evidence of residual disease at the surgical cavity and multifocal/multicentric disease. All patients underwent definitive surgery and MR findings were correlated to histopathology. 139/175 (79.4%) patients had residual disease at surgery. Average overall sensitivity, specificity, PPV and NPV for residual disease at the surgical cavity were 73%, 72%, 91% and 45%, respectively. The readers identified 42/45 (93%, reader 1) and 43/45 (95%, reader 2) patients with residual invasive disease at the cavity of ≥5 mm and 22/22 (100%, both readers) patients with disease ≥10 mm. Average sensitivity, specificity, PPV and NPV for unknown multifocal/multicentric disease were 90%, 96%, 93% and 86%, respectively. Post-operative breast MR can accurately depict ≥5-mm residual disease at the surgical cavity and unsuspected multifocal/multicentric disease. These findings have the potential to lead to more appropriate selection of second surgical procedures in women with positive margins. • Post-operative breast MRI accurately defines residual disease of ≥5 mm. • Surgical cavity sensitivities were high for both invasive carcinoma and DCIS. • Post-surgical changes and very small residual disease (

Magnetic resonance imaging (MRI)-guided interventions, including biopsies and wire localizations, are fundamental to any breast imaging practice due to the high sensitivity but limited specificity of breast MRI. The basic steps of MRI-guided biopsies are similar regardless of the vendor or platform, and technical considerations include approach planning, patient preparation and positioning, lesion targeting, and directional sampling using a vacuum-assisted biopsy technique. Unique challenges related to MRI-guided biopsies include vanishing lesions due to contrast washout, obscuration of the biopsy site due to susceptibility artifacts, and limited access to posteromedial lesions. A careful approach to planning, patient positioning, and lesion targeting will maximize the chances for a successful biopsy. Due to overlapping imaging features between benign and malignant lesions, radiologic-pathologic concordance is difficult and essential for further patient management. Level of Evidence: 5 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:631–645

Objective There are currently no evidence-based guidelines regarding breast cancer screening in women under 40 prior to initiating assisted reproductive technology (ART). The prevalence of abnormal findings on screening mammography in this population is unknown. The purpose of this study was to describe screening mammography outcomes in women less than 40 years old, referred for the indication of pre-ART. Materials, methods, procedures This is a retrospective review of women less than 40 years old presenting for screening mammography prior to ART between January 2010 and March 2017. Clinical history, breast cancer risk factors, imaging and pathology results were gathered from the electronic medical record. Results The study included 80 women. Mean patient age was 37 years (range 34–39 years). Sixty-seven (84%) had negative or benign screening (BI-RADS 1 or 2) and 13 (16%) were recalled for diagnostic imaging (BI-RADS 0). Four of 13 (31%) recalled women were given BI-RADS 1 or 2 at diagnostic work-up, 4 (31%) were given a BI-RADS 3, and 5 (38%) were recommended for biopsy (BI-RADS 4). At patient request, 2 of 4 (50%) BI-RADS 3 cases underwent biopsy, for 7 total biopsies. Six (86%) biopsies yielded benign results and 1 (14%) yielded DCIS. Overall cancer yield was 1.3%. Conclusion In women under 40 who plan to undergo ART, screening mammography may identify breast malignancies. This may be of particular importance given many breast cancers are hormone sensitive, and thus fertility treatments may affect tumor growth. Future, larger studies are needed.

Background: MRI measured functional tumor volume (FTV) can predict pathologic complete response (pCR) to neoadjuvant chemotherapy (NAC) as early as 3 weeks after treatment initiation (1), indicating the potential of using MRI to guide treatment de-escalation. We developed MRI based, subtype-specific models for predicting pCR, to be used as part of a de-escalation strategy combining MRI and inter-regimen core biopsy pathology in I-SPY 2. Methods: I-SPY 2 patients underwent MRI exams at pre-treatment, early treatment (3 wks), inter-regimen (12 wks), and pre-surgery. pCR was assessed at surgery. FTV was calculated semi-automatically for every MRI (2). Subtype-specific FTV-based MRI prediction models were trained using FTV measurements at baseline, early treatment and inter-regimen timepoints for patients enrolled in I-SPY 2 between May 2010 and November 2016. Breast cancer subtype was defined by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. The MRI prediction model was then used to predict probability of achieving pCR for each patient at inter-regimen, based on their subtype. The therapy de-escalation strategy focuses on achieving high positive predictive value (PPV, correct identification of patients with pCR) while maximizing sensitivity (proportion of patients with pCR identified by the test). Predicted probability above a specified threshold was considered a positive test for pCR. This study investigated the tradeoff between PPV and sensitivity within subtype groups defined by HR and HER2, and held to constraints set by probability thresholds at the 1st, 2nd (median) and 3rd quartile. Results: A total of 814 patients were included in the analysis. Median age was 49 (range: 24 - 77) years. The pCR rate was 36% (289/814). Table 1 shows patient number and pCR rate by HR/HER2 subtype. The subtype-specific MRI models consist of the predictors: change of FTV (dFTV) at inter-regimen for HR+/HER2- and HR-/HER2+; dFTV at early treatment for HR+/HER2+; pre-treatment FTV and dFTV at inter-regimen for triple negatives. The highest probability varied by subtype: 0.24 for HR+/HER2-, 0.61 for HR+/HER2+, 0.73 for HR-/HER2+, 0.68 for triple negatives. The maximum PPV was 67% for HR+/HER2- and 100% for all other subtypes. Table 1 shows the tradeoff between PPV and sensitivity by subtype using the 1st, median, and 3rd quartile thresholds. Conclusions: Our data demonstrate that PPV and sensitivity vary by breast cancer subtype when the probability threshold generated by MRI model increases from low to high quartile. Results from this study suggest that the probability threshold for recommending treatment de-escalation should be selected carefully based on breast cancer subtype. Imaging results will be combined with core biopsy information obtained at the 12-week timepoint to further improve overall accuracy. Table 1 Tradeoff between positive predictive value (PPV) and sensitivity at different levels of PPVCohortNpCR rateProbability thresholdPPV (%)Sensitivity (%)HR+/HER2-32820% (64/328)1st quartile0.1824912nd quartile0.2128773rd quartile0.233552HR+/HER2+13239% (51/132)1st quartile0.2744862nd quartile0.4053693rd quartile0.515837HR-/HER2+7166% (47/71)1st quartile0.6775852nd quartile0.7181623rd quartile0.728934Triple negative(HR-/HER2-)28345% (127/283)1st quartile0.3454912nd quartile0.5262703rd quartile0.607341 Citation Format: Wen Li, David C Newitt, Jessica Gibbs, Lisa J Wilmes, Ella F Jones, Natsuko Onishi, Bonnie N Joe, Elissa Price, John Kornak, Christina Yau, Denise M Wolf, Barbara LeStage, Susan Samson, the I-SPY 2 Imaging Working Group, the I-SPY 2 Consortium, Laura J Esserman, Nola M Hylton. Subtype-specific MRI models to guide selection of candidates for de-escalation of neoadjuvant therapy [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD6-05.

PurposeIn the on-going I-SPY2 TRIAL, participants receive 12 cycles of weekly paclitaxel with or without addition of experimental agents for 12 weeks (first regimen), followed by 4 cycles of anthracycline-cyclophosphamide (AC, second regimen) prior to surgery. A de-escalation strategy currently being introduced in I-SPY2 will give patients the option to skip AC if it is highly likely that they have achieved early pathologic complete response (pCR) at the inter-regimen time point (12 weeks). To guide selection of candidates for this option, a prediction model combining subtype-specific MRI predictive probabilities with mid-treatment percutaneous core biopsy pathology has been developed. The combined model predicts a patient as early pCR if the MRI model based on a quantitative measure of functional tumor volume predicts a high likelihood of pCR, and pathology determines that there are no invasive cancer cells detected in the mid-treatment core biopsy. This study was performed to develop radiologic criteria for post-selection review to further reduce the possibility for incorrect de-escalation recommendation. MethodsA review of 87 I-SPY2 patients with serial MRI and inter-regimen core biopsy identified 25 patients where both the subtype specific MRI model and at least 2 of 11 I-SPY2 pathologists predicted early pCR. One radiologist retrospectively reviewed MRIs at pre-treatment and inter-regimen for the 25 patients in a blinded fashion, and labeled the presence of residual disease on MRI at inter-regimen as follows: rank 0, no residual disease; rank 1, possible residual disease; rank 2, obvious residual disease.To evaluate the accuracy of selecting candidates for de-escalation of neoadjuvant therapy (i.e. predicting patients with early pCR at inter-regimen), surgical pathology of pCR after the completion of NAC (both first and second regimens) was defined as a surrogate “truth” in this study. Positive predictive value (PPV) and sensitivity for the combined MRI-pathology model were computed for all pathologist pairs. After adding qualitative radiologic review, patients labeled as rank 2 were excluded from the candidates with predicted early pCR by the combined MRI-pathology model. PPV and sensitivity before and after radiologic review were compared. ResultsThe 25 patients included 21 patients that ultimately achieved pCR, and 4 patients that did not. Radiologic review of the inter-regimen MRI for these patients classified their MRIs as 20% (5/25) rank 0 (no residual disease), 36% (9/25) rank 1 (possible residual disease), and 44% (11/25) rank 2 (obvious residual disease). Most (3/4) non-pCR patients were classified rank 2, however one (1/4) was assessed rank 0. Eight of the 21 pCR patients (38%) were classified as having obvious residual disease on inter-regimen MRI. Without radiologic review, the combined MRI-pathology model predicted pCR with a mean PPV of 92% (range 83-100%) and a mean sensitivity of 91% (range 76-100%). When patients labeled as rank 2 by radiologic review were excluded from candidates with predicted early pCR, PPV increased to 99% (range 93-100%) at the expense of lower sensitivity of 59% (range 52-62%). Conclusion In this study, elimination of rank 2 lesions resulted in substantial improvement in PPV (92% to 99%) with a consequent reduction in sensitivity from 91% to 59%. Notably, none of the rank 1 lesions, where diagnostic interpretation was less certain, were found to be non-pCR at surgery. High PPV is essential to ensure high accuracy and safety in directing early pCR patients to therapy de-escalation. These findings will be further validated in continuing studies and radiologic re-review will be included in the de-escalation strategy for omission of AC in the I-SPY2 TRIAL. Citation Format: Natsuko Onishi, Wen Li, Sara J Venters, Denise M Wolf, David C Newitt, Elissa R Price, Jessica Gibbs, Barbara LeStage, the I-SPY 2 Pathology Working Group, the I-SPY 2 Imaging Working Group, the I-SPY 2 Consortium, William F Symmans, Nola M Hylton. Radiologic review to refine selection of candidates for de-escalation of neoadjuvant therapy [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS3-02.

Breast density notification laws, passed in 19 states as of October 2014, mandate that patients be informed of their breast density. The purpose of this study is to assess the impact of this legislation on radiology practices, including performance of breast cancer risk assessment and supplemental screening studies. A 20-question anonymous web-based survey was emailed to radiologists in the Society of Breast Imaging between August 2013 and March 2014. Statistical analysis was performed using Fisher's exact test. Around 121 radiologists from 110 facilities in 34 USA states and 1 Canadian site responded. About 50% (55/110) of facilities had breast density legislation, 36% of facilities (39/109) performed breast cancer risk assessment (one facility did not respond). Risk assessment was performed as a new task in response to density legislation in 40% (6/15) of facilities in states with notification laws. However, there was no significant difference in performing risk assessment between facilities in states with a law and those without (p

Background: In an adaptive randomized trial, when new treatment combinations are being tested, it is important to be able to identify patients who are progressing on treatment so that they can be changed to a different therapeutic regimen. We know that even within the molecularly high risk patients in I-SPY 2, there is considerable variation in biology. In this study, we will present results of using MRI-calculated functional tumor volume (FTV) to identify tumor progression for each breast cancer subtype. Methods: Patients (n=990) enrolled in the I-SPY 2 TRIAL who were randomized to the graduated experimental drug arms or controls from 2010 to 2016 were analyzed. Four MRI exams were performed for each patient: pre-NAC (T0), after 3 weeks of NAC (T1), between regimens (T2), and post-NAC (T3). Functional tumor volume (FTV) was calculated at each exam by summing voxels meeting enhancement thresholds. Tumor progression at T1, T2 or T3 was identified by a positive FTV change relative to T0. Visual inspection was used to exclude false progression due to strong background parenchymal enhancement post-contrast, prominent vessels, motion, or insufficient image quality. pCR was defined as no invasive disease in the breast and lymph nodes. Negative predictive value for pCR was defined as:NPV=number of true non-pCRs / number of patients with MRI assessed tumor progressions, where “true non-pCRs” referred to patients who were non-pCRs at surgery and were assessed as progressors by MRI. The analysis was performed in the full cohort and in sub-cohorts defined by HR and HER2 statuses. Results: Out of 990 patients, 878 had pCR outcome data (pCR or non-pCR, pCR rate = 35%). Total and non-pCR numbers for each subtype, number of patients with tumor progression assessed by MRI at T1, T2, and T3, and NPVs, are shown in Table 1. In the full cohort, the NPV increased consistently over treatment, from T1 (NPV=83%) to T2 (93%), and to T3 (100%). The HER2+ cancer subtypes showed fewer MRI-assessed tumor progressions than HER2- subtypes: e.g. 10/209 (5%) vs. 108/669 (16%) at T1. NPV was 100% for HER2+ subtypes at T1 and T2 except for a single misclassification of a HR- tumor at T1. Only 6 tumor progressors, all HER2- were identified at T3, and all were confirmed at surgery as non-pCRs (NPV=100%). For HR+/HER2-, the NPV increased slightly from 89% at T1 to 91% at T2, while triple negative subtype had a more substantial increase, from 78% to 92%. Conclusions: Our study showed strong association between tumor progressors assessed by MRI with true non-pCRs after NAC. For HER2+ tumors, although MRI progressors are rare, they strongly indicate non-pCR at all treatment time points, while HER2- subtypes show more accurate results later in treatment. We are evaluating MRI change at 6 weeks to determine if that time point is sufficient to predict progressors. Table 1 MRI assessed tumor progression at different treatment time pointN/non-pCRs/%non-pCRMRI assessed tumor progressionT1 (after 3 weeks)T2 (inter-regimen)T3 (post-NAC)NNPV (%)NNPV (%)NNPV (%)Full cohort878/572/65%11883.14192.76100%HR+/HER2-344/280/81%4588.91190.93100%HR+/HER2+134/85/63%610021000N/AHR-/HER2+75/23/31%47521000N/Atriple negative325/184/57%6377.82692.33100% Citation Format: Wen Li, Natsuko Onishi, David C Newitt, Jessica Gibbs, Lisa J Wilmes, Ella F Jones, Bonnie N Joe, Laura S Sit, Christina Yau, A. Jo Chien, Elissa Price, Kathy S Albain, Theresa Kuritza, Kevin Morley, Judy C Boughey, Kathy Brandt, Sadia Choudhery, Amy S Clark, Mark Rosen, Elizabeth S McDonald, Anthony D Elias, Dulcy Wolverton, Kelly Fountain, David M Euhus, Heather S Han, Bethany Niell, Jennifer Drukteinis, Julie E Lang, Janice Lu, Jane L Meisel, Zaha Mitri, Rita Nanda, Donald W Northfelt, Tara Sanft, Erica Stringer-Reasor, Rebecca K Viscusi, Anne M Wallace, Douglas Yee, Rachel Yung, Smita M Asare, Michelle E Melisko, Jane Perlmutter, Hope S Rugo, Richard Schwab, W. Fraser Symmans, Laura J van't Veer, Donald A Berry, Angela DeMichele, Hiroyuki Abe, Deepa Sheth, Kirsten K Edmiston, Erin D Ellis, Richard Ha, Ralph Wynn, Erin P Crane, Charlotte Dillis, Michael Nelson, An Church, Claudine Isaacs, Qamar J Khan, Karen Y Oh, Neda Jafarian, Dae Hee Bang, Christiane Mullins, Stefanie Woodard, Kathryn W Zamora, Haydee Ojeda-Fornier, Pulin Sheth, Linda Hovanessian-Larsen, Mohammad Eghtedari, Michael Spektor, Marina Giurescu, Mary S Newell, Michael A Cohen, Elise Berman, Constance Lehman, William Smith, Kim Fitzpatrick, Marisa H Borders, Wei Yang, Basak Dogan, Sally Goudreau, Thelma Brown, Laura J Esserman, Nola M Hylton. Breast cancer subtype specific association of pCR with MRI assessed tumor volume progression during NAC in the I-SPY 2 trial [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD9-04.

Background: Strong background parenchymal enhancement (BPE) may cause overestimation in tumor volume measured from dynamic contrast-enhanced (DCE) MRI, which may adversely affect the ability of MR tumor volume to predict treatment outcome for patients undergoing neoadjuvant chemotherapy (NAC). Specifically, an overestimation of tumor volume can result in misclassification of patients with complete pathologic response (pCR) as non-responders, leading to less confidence in MRI prediction. As well, overestimation of extent of disease might lead to more aggressive surgical therapy than necessary. This study investigated whether high BPE in the contralateral breast influences the predictive performance of MRI-measured functional tumor volume (FTV) for patients with locally advanced breast cancer undergoing NAC. Methods: patients (n=990) enrolled in the I-SPY 2 TRIAL who were randomized to the graduated experimental drug arms or controls from 2010 to 2016 were analyzed. Each patient had 4 MRI exams: pre-NAC (T0), after 3 weeks of NAC (T1), between NAC regimens (T2), and post-NAC (T3). FTV was calculated at each MRI exam by summing voxels meeting enhancement thresholds. Background parenchymal enhancement (BPE) in the contralateral breast was calculated automatically as mean percentage enhancement on the early (nominal 150sec post-contrast) image in the fibroglandular tissue segmented from 5 continuous axial slices centered in the inferior-to-superior stack. For each treatment time point, patients having both FTV and BPE measurements were included in the analysis. The area under the ROC curve (AUC) was estimated as the association between FTV and pCR at T1, T2, and T3. The analysis was conducted in the full patient cohort and in sub-cohorts defined by hormone receptor (HR) and HER2 status. In each patient cohort, a cut-off BPE value was selected to classify patients with high vs. low BPE by testing AUCs estimated with low-BPE patients reached maximum when the cut-off value varied from median to maximum in steps of 10%. Results: Out of 990 patients, 878 had pCR outcome data (pCR or non-pCR, pCR rate = 35%). Table 1 shows the number of patients, pCR rate, and AUC of FTV for predicting pCR using all patients available vs. a subset patients with low BPE (< BPE cut-off). In the full cohort, AUC increased slightly across all time points after patients with high BPE were removed. In the HR+/HER2- subtype, AUC increased at T1 after removal of cases with high BPE (0.65 vs. 0.71). For HR-/HER2+, AUC increased substantially after removal of high BPE cases (0.65 to 0.86 at T1, 0.71 to 0.87 at T2, and 0.71 to 0.89 at T3), with greater improvement at the early time point (T1) compared to later time points (T2 and T3). Only a slight improvement in the AUC was observed in the HR+/HER2+ and HR-/HER2- subtypes across all time points. Conclusions: High background parenchymal enhancement adversely affected the predictive performance of functional tumor volume measured by DCE-MRI, at early treatment time point for HR+/HER2- and across all time points for HR-/HER2+ cancer subtype. The adverse effect might be offset using subtype-optimized enhancement threshold in calculating functional tumor volume. Table 1 Effect of BPE on the prediction of pCR using FTV at various treatment time pointsT1T2T3npCR rateAUCBPE cut-offnpCR rateAUCBPE cut-offnpCR rateAUCBPE cut-offFullAll64734%0.662762334%0.701761134%0.6925Subset45334%0.6831133%0.7230534%0.72HR+/HER2-All26218%0.651924918%0.718225518%0.7519Subset13118%0.7124818%0.7120419%0.76HR+/HER2+All10636%0.642110538%0.62269634%0.7120Subset5332%0.668438%0.665740%0.73HR-/HER2+All5175%0.65204774%0.71204973%0.7116Subset3073%0.862871%0.872475%0.89HR-/HER2-All22842%0.682822243%0.751821143%0.6916Subset15940%0.7111137%0.7810540%0.75 Citation Format: Wen Li, Natsuko Onishi, David C Newitt, Roy Harnish, Ella F Jones, Lisa J Wilmes, Jessica Gibbs, Elissa Price, Bonnie N Joe, A. Jo Chien, Donald A Berry, Judy C Boughey, Kathy S Albain, Amy S Clark, Kirsten K Edmiston, Anthony D Elias, Erin D Ellis, David M Euhus, Heather S Han, Claudine Isaacs, Qamar J Khan, Julie E Lang, Janice Lu, Jane L Meisel, Zaha Mitri, Rita Nanda, Donald W Northfelt, Tara Sanft, Erica Stringer-Reasor, Rebecca K Viscusi, Anne M Wallace, Douglas Yee, Rachel Yung, Michelle E Melisko, Jane Perlmutter, Hope S Rugo, Richard Schwab, W. Fraser Symmans, Laura J van't Veer, Christina Yau, Smita M Asare, Angela DeMichele, Sally Goudreau, Hiroyuki Abe, Deepa Sheth, Dulcy Wolverton, Kelly Fountain, Richard Ha, Ralph Wynn, Erin P Crane, Charlotte Dillis, Theresa Kuritza, Kevin Morley, Michael Nelson, An Church, Bethany Niell, Jennifer Drukteinis, Karen Y Oh, Neda Jafarian, Kathy Brandt, Sadia Choudhery, Dae Hee Bang, Christiane Mullins, Stefanie Woodard, Kathryn W Zamora, Haydee Ojeda-Fornier, Mohammad Eghedari, Pulin Sheth, Linda Hovanessian-Larsen, Mark Rosen, Elizabeth S McDonald, Michael Spektor, Marina Giurescu, Mary S Newell, Michael A Cohen, Elise Berman, Constance Lehman, William Smith, Kim Fitzpatrick, Marisa H Borders, Wei Yang, Basak Dogan, Laura J Esserman, Nola M Hylton. The effect of background parenchymal enhancement on the predictive performance of functional tumor volume measured in MRI [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-02-01.

OBJECTIVE. The purpose of this study is to evaluate a nonradioactive inducible magnetic seed system (Magseed, Endomag) for preoperative localization of nonpalpable breast lesions. CONCLUSION. All of the 73 seeds placed in the first 4 months of clinical use were successfully placed and all were successfully retrieved intraoperatively. The mean time from seed placement to surgery was 3 days. Early clinical experience suggests that Magseed is an effective and accurate means of preoperative breast lesion localization.

Radiomics is an emerging technology for imaging biomarker discovery and disease-specific personalized treatment management. This paper aims to determine the benefit of using multi-modality radiomics data from PET and MR images in the characterization breast cancer phenotype and prognosis. Eighty-four features were extracted from PET and MR images of 113 breast cancer patients. Unsupervised clustering based on PET and MRI radiomic features created three subgroups. These derived subgroups were statistically significantly associated with tumor grade (p = 2.0 × 10−6), tumor overall stage (p = 0.037), breast cancer subtypes (p = 0.0085), and disease recurrence status (p = 0.0053). The PET-derived first-order statistics and gray level co-occurrence matrix (GLCM) textural features were discriminative of breast cancer tumor grade, which was confirmed by the results of L2-regularization logistic regression (with repeated nested cross-validation) with an estimated area under the receiver operating characteristic curve (AUC) of 0.76 (95% confidence interval (CI) = [0.62, 0.83]). The results of ElasticNet logistic regression indicated that PET and MR radiomics distinguished recurrence-free survival, with a mean AUC of 0.75 (95% CI = [0.62, 0.88]) and 0.68 (95% CI = [0.58, 0.81]) for 1 and 2 years, respectively. The MRI-derived GLCM inverse difference moment normalized (IDMN) and the PET-derived GLCM cluster prominence were among the key features in the predictive models for recurrence-free survival. In conclusion, radiomic features from PET and MR images could be helpful in deciphering breast cancer phenotypes and may have potential as imaging biomarkers for prediction of breast cancer recurrence-free survival., Radiomics: algorithms decipher tumor grade, stage, subtype, and more Automated analyses of breast scans taken with two types of medical imaging technologies can help oncologists decode clinically relevant features, a finding that could help personalize cancer diagnosis and treatment. Youngho Seo from the University of California, San Francisco, USA, and coworkers extracted 84 quantitative features from positron emission tomography and magnetic resonance imaging scans performed on 113 women with breast cancer. The researchers then applied data-characterization and pattern-recognition algorithms—which included machine-learning methods and engineered features coded by experts—to create classification models that helped uncover disease characteristics that were not obvious to the naked eye. These models successfully subdivided patients according to tumor grade, overall stage, cancer subtype and disease recurrence risk, providing proof of principle that radiomic analyses of this kind could provide valuable information for personalized management of breast cancer.

The purpose of this study was to determine the prevalence of very strong family history and extremely dense tissue in women 40-49 years old with breast cancer detected on screening mammography.All cancers detected by screening mammography at our institution between January 1997 and November 2012 in 40- to 49-year-old women were retrospectively identified. Those with a personal history of breast cancer were excluded. Family history, breast density, type of malignancy, hormone receptor status, and lymph node status were recorded.One hundred thirty-six cases of breast cancer were identified on screening mammography in 40- to 49-year-old women; 50% were invasive cancers, and 50%, ductal carcinoma in situ. Very strong family history was absent in 88%, and extremely dense breast tissue was absent in 86%. Seventy-six percent of patients had neither very strong family history nor extremely dense breasts, including 79% of the cases of invasive cancers, of which 25% had axillary nodal involvement and 89% were estrogen receptor positive.Very strong family history and extremely dense breast tissue were absent in most 40- to 49-year-old women with breast cancer detected at screening mammography. These cancers were frequently invasive (often with nodal metastases) and treatable (hormone receptor positive). Reducing the number of women to be screened in this age group by using this risk-based approach would reduce the number of screen-detected cancers by more than 75%, thereby precluding the benefit of mortality reduction. Even using a risk-based strategy with an expanded definition of high risk that included any first-degree family history, extremely dense tissue, or both, 66% of malignancies would still be missed.

Reconstruction of lumpectomy defects with reduction mammoplasty techniques can improve aesthetic outcomes and patient satisfaction. However, one concern with the substantial tissue rearrangement required is the possible difficulty with mammographic follow up and/or increased recommendations for future biopsies. We performed a retrospective review of 49 patients who underwent oncoplastic reduction mammoplasty between 2001 and 2009 who were age-matched to patients who underwent lumpectomy without reconstruction. Mammography reports at 6 months, 1, 2, and 5 years postoperatively were reviewed for predominant findings, Breast Imaging Reporting and Data System final assessments, and recommendations for biopsy. There was no significant difference in abnormal mammographic findings prompting biopsy between the two cohorts at 6 months, 2 years, and 5 years postoperatively (p > 0.05). Biopsy rates over the 5-year period did not differ significantly between the two cohorts [9 (18 %) lumpectomy cohort, 12 (24 %) oncoplastic cohort, p = 0.46]. Overall cancer-to-biopsy ratio was 33 % in the lumpectomy cohort and 42 % in the oncoplastic cohort (p = 1.00). Although substantial tissue rearrangement is performed at the time of oncoplastic reduction mammoplasty, our results reveal no increased incidence of postoperative mammographic abnormalities or unnecessary biopsies compared to lumpectomy alone. This demonstrates that fear of increasing mammographic abnormalities and biopsies after reduction mammoplasty is unfounded and should not prevent utilization of this technique if it can optimize cosmetic outcomes and extend the option of breast conservation.

OBJECTIVE. The purpose of this article is describe the origins and provisions of breast density legislation and to evaluate these mandates with regard to the balance between the potential benefit of supplementary screening and the substantial risk of false-positive findings and the adjunctive tests they necessitate. CONCLUSION. Many states have passed breast density notification legislation, and federal legislation is pending. These mandates present a number of challenges for patients and physicians. There is no consensus regarding the need for supplementary testing solely because a woman has dense breasts. The failure of density legislation to require insurance coverage in many states further complicates implementation of the mandates.

A large body of evidence demonstrates a 30% to 50% mortality benefit of screening mammography for women aged 40 to 49. Because of more rapid cancer growth rates in younger women, annual screening is more effective than biennial. Studies indicate that selective screening of women aged 40 to 49 would miss the majority of breast cancers. If implemented, recent US Preventive Services Task Force breast cancer screening guidelines, which recommend against routine screening of women in their 40s, could result in thousands of preventable breast cancer deaths per year. Vigilance is needed to safeguard younger women's access to screening mammography.

The objective of this study was to evaluate the effect of bilateral salpingo-oophorectomy (BSO) on background parenchymal enhancement (BPE) and the amount of fibroglandular tissue (FGT) seen on breast MRI. Retrospective review identified 21 BRCA mutation carriers who underwent breast MRI before and after elective BSO. After exclusion of patients placed on postoperative hormone replacement therapy, there were 18 eligible patients. Blinded to surgical status, three independent readers used categorical scales to rate BPE (minimal, mild, moderate, marked) and the amount of FGT (fatty, scattered, heterogeneously dense, dense) on pre- and post-BSO MRI examinations. The sign test was used to assess for changes in the categorical ratings of BPE and FGT. Significant proportions of women demonstrated decreases in BPE and in the amount of FGT following oophorectomy (P = 0.004 and 0.02, respectively.) BPE decreases were larger and seen earlier than FGT changes. There was no significant relationship between age/body mass index and changes in BPE and FGT. BPE and the amount of FGT seen on breast MRI are significantly decreased by oophorectomy; BPE decreases to a greater extent and earlier than FGT. • Background parenchymal enhancement significantly decreases at breast MRI following oophorectomy. • Fibroglandular tissue significantly decreases on breast MRI following oophorectomy. • Decrease in background parenchymal enhancement is greater than in fibroglandular tissue. • Decrease in background parenchymal enhancement occurs earlier than in fibroglandular tissue.

Magnetic resonance (MR) imaging is now an accepted component of standard breast-imaging practice. This article reviews the fundamentals of performing an MR imaging-guided biopsy using a grid localization system, and discusses many of the finer points and nuances of the procedure. Tips and tricks found useful at the authors' institution are included, although multiple variations also exist. Performing effective and efficient MR imaging-guided biopsy depends both on deliberate preparation (of the proceduralist, the patient, and the equipment) and on deliberate positioning (of the patient and the sampling device).

The purpose of this study was to identify potential BI-RADS 3 mass descriptors on breast magnetic resonance imaging by systematically defining positive predictive values (PPV). In a blinded retrospective review of BI-RADS 4 masses, reader 1 identified 132 masses and reader 2 identified 76 masses. PPV for mass descriptors and for descriptor combinations was determined. No mass descriptor resulted in a PPV ≤2% (BI-RADS 3 threshold). Descriptors with the lowest PPVs were circumscribed margin (8%), rim internal enhancement and persistent kinetics (13% each), and oval shape (15%). The results demonstrate the difficulty in transferring the theoretical concept of lesion surveillance to systematic clinical use.

Magnetic resonance imaging (MRI)-guided interventions, including biopsies and wire localizations, are fundamental to any breast imaging practice due to the high sensitivity but limited specificity of breast MRI. The basic steps of MRI-guided biopsies are similar regardless of the vendor or platform, and technical considerations include approach planning, patient preparation and positioning, lesion targeting, and directional sampling using a vacuum-assisted biopsy technique. Unique challenges related to MRI-guided biopsies include vanishing lesions due to contrast washout, obscuration of the biopsy site due to susceptibility artifacts, and limited access to posteromedial lesions. A careful approach to planning, patient positioning, and lesion targeting will maximize the chances for a successful biopsy. Due to overlapping imaging features between benign and malignant lesions, radiologic-pathologic concordance is difficult and essential for further patient management.5 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2017;46:631-645.

The proliferation of legislation on breast density, requiring direct notification of a patient if she has dense tissue on mammography, has resulted in a highly charged debate. Early legislation stemmed from a grassroots patient advocacy group (AreYouDense, Inc.) led by Nancy Cappello, PhD. Dr. Cappello is a breast cancer patient who believes her delayed diagnosis resulted from the masking effect of her dense breast tissue. The thrust of the advocacy group is summarized in an article that Dr. Cappello wrote in the Journal of the American College of Radiology titled, “Decade of ‘normal’ mammography reportsdthe happygram.” In this article, Dr. Cappello discussed the blissful ignorance of being told she had a normal mammogram year after year without being aware of the reduced sensitivity of the examination due to her dense tissue. She has a valid point. Patients should be more aware of the reality of reading mammograms. Mammography is not a perfect test. The ability to identify some cancers in dense breasts is a difficult and sometimes impossible task. Dr. Cappello went on to say, “My radiologist knew I had dense breasts. My doctor knew I had dense breasts. The only person who didn’t know was me: the woman with the dense breasts.” Advocating for patient education and awareness became her mission. As a consequence of the massive lobbying efforts of such advocacy groups, legislation was passed in Connecticut in 2009 and has been passed in 14 subsequent states. Although only 15 states have these laws in effect, most of them are heavily populated states, accounting for over half of the female population of the United States. Based on nationwide data, women with breasts considered dense under the law account for approximately 50% of women undergoing screening mammography. Thus, density notification legislation is already affecting many millions of American women. This issue has been divisive in the medical community: some physicians perceive the legislation to be beneficial, others see it as reasonable, and still others perceive it to be frankly harmful.

Magnetic resonance imaging (MRI) is highly sensitive in identifying residual breast cancer following neoadjuvant chemotherapy (NAC), and consequently is a commonly used imaging modality in locally advanced breast cancer patients. In these patients, tumor response is an important prognostic indicator. However, discrepancies between MRI findings and surgical pathology are well documented. Overestimation of residual disease by MRI may result in greater surgery than is actually required while underestimation may result in insufficient surgery. Thus, it is important to understand when MRI findings are reliable and when they are less accurate. MRI most accurately predicts pathology in triple negative, Her2 positive and hormone receptor negative tumors, especially if they are of a solid imaging phenotype. In these cases, post-NAC MRI is highly reliable for surgical planning. Hormone receptor positive cancers and those demonstrating non mass enhancement show lower concordance with surgical pathology, making surgical guidance more nebulous in these cases. Radiologists and surgeons must assess MRI response to NAC in the context of tumor subtype. Indiscriminate interpretations will prevent MRI from achieving its maximum potential in the pre-operative setting.

Developing asymmetry is a subtype of asymmetry that has changed in appearance over time. This change implies a higher level of suspicion than other types of asymmetry. This article aims to clarify and review (a) the defining features of a developing asymmetry, (b) tools to facilitate its appropriate identification and evaluation at mammography and sonography, (c) relevant percutaneous biopsy considerations, and (d) benign and malignant pathologies that may present as developing asymmetries.

Reconstruction of partial lumpectomy defects with reduction mammoplasty techniques can improve aesthetic outcomes. However, the impact of the significant tissue rearrangement on postoperative mammographic findings and subsequent recommendations for biopsy has not been well studied. A retrospective review of 64 patients who underwent partial mastectomy with immediate oncoplastic reduction mammoplasty reconstruction from 2001 to 2008 was performed. Mammography reports at 6 months, 1 year, and 2 years postoperatively were reviewed for Breast Imaging Reporting and Data System (BI-RADS) scores, predominant findings, and recommendations for subsequent imaging or biopsy. At 6 months postoperatively, 38 patients had benign findings of postsurgical changes, whereas 5 patients had benign calcifications on mammography. At 1 year, 41 patients continued to have benign mammograms, whereas 8 patients had calcifications. Five patients underwent biopsy; 4 patients revealed benign findings, and one patient revealed recurrent carcinoma. At 2 years, 50 patients had postsurgical changes, 2 patients developed fat necrosis, and 6 patients had calcifications. Two patients required biopsies, both of which demonstrated benign findings. Overall, 89% of the patients required no additional intervention in the 2-year period after oncoplastic reduction mammoplasty. Malignancy was discovered in one patient at 1 year postoperatively, for an overall recurrence rate of 2% at 2 years. Although substantial tissue rearrangement is performed at the time of oncoplastic reduction mammoplasty, our results demonstrate low rates of abnormal postoperative mammograms and subsequent biopsies over the first 2 years after the procedure, supporting this technique as a safe approach to reconstructing defects after partial mastectomy.

Suspicious lesions on breast MRI are often initially evaluated using targeted ultrasound. However, workup varies. Data on the rate of correlate detection by morphology [mass, non-mass enhancement (NME), or focus] would be useful for developing practice guidelines. Breast MRI examinations from 1 January 2008 to 31 December 2010 were reviewed. BI-RADS 4 or 5 lesions on MRI evaluated with targeted ultrasound where definitive diagnosis was obtained were included. Statistical analysis was performed on aggregate data and at the lesion level. A total of 204 lesions were included in the study. A statistically significant difference in ultrasound correlate identification by morphology was found; a correlate was found in 49.3 % of masses, 15 % of NME, and 42.3 % of foci (p = 0.0006). Additional analysis within each morphology demonstrated significantly greater rate of malignancy in masses with an ultrasound correlate than masses without a correlate (p = 0.0062), while the rate of malignancy in NME and foci did not differ with ultrasound correlation. Morphology of a suspicious lesion on breast MRI affects the probability of identifying an ultrasound correlate. As sonographic correlates are found in nearly half of masses and foci, targeted ultrasound should be the initial step in their workup. • Lesion morphology on breast MRI affects the probability of ultrasound correlate identification. • An ultrasound correlate is significantly more likely for masses and foci. • Mass or focus should undergo targeted ultrasound before MRI-guided biopsy.

Recent improvements in breast coil performance have made detection of extra-mammary findings increasingly common. Some of these findings have important clinical implications. The radiologist should be aware of the spectrum of extra-mammary pathologies found on breast magnetic resonance imaging (MRI) and be able to distinguish clinically significant findings from those that are inconsequential. The purpose of this essay is to demonstrate various common and uncommon extra-mammary findings encountered while interpreting breast MRI and to detail appropriate management recommendations.

In anticipation of breast density notification legislation in the state of California, which would require notification of women with heterogeneously and extremely dense breast tissue, a working group of breast imagers and breast cancer risk specialists was formed to provide a common response framework. The California Breast Density Information Group identified key elements and implications of the law, researching scientific evidence needed to develop a robust response. In particular, issues of risk associated with dense breast tissue, masking of cancers by dense tissue on mammograms, and the efficacy, benefits, and harms of supplementary screening tests were studied and consensus reached. National guidelines and peer-reviewed published literature were used to recommend that women with dense breast tissue at screening mammography follow supplemental screening guidelines based on breast cancer risk assessment. The goal of developing educational materials for referring clinicians and patients was reached with the construction of an easily accessible Web site that contains information about breast density, breast cancer risk assessment, and supplementary imaging. This multi-institutional, multidisciplinary approach may be useful for organizations to frame responses as similar legislation is passed across the United States. Online supplemental material is available for this article.

OBJECTIVE. This article will discuss routine 1.5 and 3 T MRI of the breast as well as illustrate several examples of patient-related and technical artifacts one might encounter. Suggestions to help eliminate these artifacts and optimize images will be provided. CONCLUSION. Artifacts seen on breast MR images can degrade image quality and obscure important findings. Recognizing artifacts and understanding how to address and troubleshoot them is essential for any radiologist interpreting breast MRI.