Diffusion Tensor Imaging for Characterizing Changes in Triple-Negative Breast Cancer During Neoadjuvant Systemic Therapy.

BACKGROUND: Assessment of treatment response in triple-negative breast cancer (TNBC) may guide individualized care for improved patient outcomes. Diffusion tensor imaging (DTI) measures tissue anisotropy and could be useful for characterizing changes in the tumors and adjacent fibroglandular tissue (FGT) of TNBC patients undergoing neoadjuvant systemic treatment (NAST). PURPOSE: To evaluate the potential of DTI parameters for prediction of treatment response in TNBC patients undergoing NAST. STUDY TYPE: Prospective. POPULATION: Eighty-six women (average age: 51 ± 11 years) with biopsy-proven clinical stage I-III TNBC who underwent NAST followed by definitive surgery. 47% of patients (40/86) had pathologic complete response (pCR). FIELD STRENGTH/SEQUENCE: 3.0 T/reduced field of view single-shot echo-planar DTI sequence. ASSESSMENT: Three MRI scans were acquired longitudinally (pre-treatment, after 2 cycles of NAST, and after 4 cycles of NAST). Eleven histogram features were extracted from DTI parameter maps of tumors, a peritumoral region (PTR), and FGT in the ipsilateral breast. DTI parameters included apparent diffusion coefficients and relative diffusion anisotropies. pCR status was determined at surgery. STATISTICAL TESTS: Longitudinal changes of DTI features were tested for discrimination of pCR using Mann-Whitney U test and area under the receiver operating characteristic curve (AUC). A P value <0.05 was considered statistically significant. RESULTS: 47% of patients (40/86) had pCR. DTI parameters assessed after 2 and 4 cycles of NAST were significantly different between pCR and non-pCR patients when compared between tumors, PTRs, and FGTs. The median surface/average anisotropy of the PTR, measured after 2 and 4 cycles of NAST, increased in pCR patients and decreased in non-pCR patients (AUC: 0.78; 0.027 ± 0.043 vs. -0.017 ± 0.042 mm2 /s). DATA CONCLUSION: Quantitative DTI features from breast tumors and the peritumoral tissue may be useful for predicting the response to NAST in TNBC. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 4.

Challenging Contrast-Enhanced Mammography-Guided Biopsies: Practical Approach Using Real-Time Multimodality Imaging and a Proposed Procedural Algorithm.

Contrast-enhanced mammography (CEM) is an emerging functional breast imaging technique that entails the acquisition of dual-energy digital mammographic images after IV administration of iodine-based contrast material. CEM-guided biopsy technology was introduced in 2019 and approved by the U.S. FDA in 2020. This technology's availability enables direct sampling of suspicious enhancement seen only on or predominantly on recombined CEM images and addresses a major obstacle to the clinical implementation of CEM technology. The literature describing clinical indications and procedural techniques of CEM-guided biopsy is scarce. This article describes our initial experience in performing challenging CEM-guided biopsies and proposes a step-by-step procedural algorithm designed to proactively address anticipated technical difficulties and thereby increase the likelihood of achieving successful targeting.

Triple-Negative Breast Cancer: Histopathologic Features, Genomics, and Treatment.

Triple-negative breast cancer (TNBC) is a heterogeneous and aggressive group of tumors that are defined by the absence of estrogen and progesterone receptors and lack of ERBB2 (formerly HER2 or HER2/neu) overexpression. TNBC accounts for 8%-13% of breast cancers. In addition, it accounts for a higher proportion of breast cancers in younger women compared with those in older women, and it disproportionately affects non-Hispanic Black women. TNBC has high metastatic potential, and the risk of recurrence is highest during the 5 years after it is diagnosed. TNBC exhibits benign morphologic imaging features more frequently than do other breast cancer subtypes. Mammography can be suboptimal for early detection of TNBC owing to factors that include the fast growth of this cancer, increased mammographic density in young women, and lack of the typical features of malignancy at imaging. US is superior to mammography for TNBC detection, but benign-appearing features can lead to misdiagnosis. Breast MRI is the most sensitive modality for TNBC detection. Most cases of TNBC are treated with neoadjuvant chemotherapy, followed by surgery and radiation. MRI is the modality of choice for evaluating the response to neoadjuvant chemotherapy. Survival rates for individuals with TNBC are lower than those for persons with hormone receptor-positive and human epidermal growth factor receptor 2-positive cancers. The 5-year survival rates for patients with localized, regional, and distant disease at diagnosis are 91.3%, 65.8%, and 12.0%, respectively. The early success of immunotherapy has raised hope regarding the development of personalized strategies to treat TNBC. Imaging and tumor biomarkers are likely to play a crucial role in the prediction of TNBC treatment response and TNBC patient survival in the future. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Clinical Outcomes Using Magnetic Seeds as a Non-wire, Non-radioactive Alternative for Localization of Non-palpable Breast Lesions.

BACKGROUND: Nonpalpable breast lesions require precise preoperative localization to facilitate negative margins with breast-conserving therapy. The traditional use of wires has several challenges including patient discomfort, wire migration, and coordination of schedules between radiology and the operating room. Radioactive seed localization overcomes some of these challenges, but radiation safety requirements have limited adoption of this technology. The authors examined their institutional experience with Magseed as an alternative technology for localization and compared outcomes with those of wire and radioactive seed localization. METHODS: An institutional review board (IRB)-approved retrospective study was performed to evaluate patients who underwent excisional biopsy or segmental mastectomy after wire-guided localization (WGL), radioactive seed localization (RSL), or Magseed localization (ML). The clinical and pathologic factors of the three groups were assessed with a negative margin rate as the primary outcome measure. RESULTS: Of the 1835 patients in the study, 825 underwent WGL, 449 underwent RSL, and 561 underwent ML. For the patients with either multiple lesions or a large lesion that required bracketing, multiple localization devices were placed in 31% of the WGL patients, 28% of the RSL patients, and 23% of the ML patients (p = 0.006). Negative margins were achieved in 91% of the WGL patients, 89% of the RSL patients, and 89% of the ML patients (p = 0.4). CONCLUSION: Localization of non-palpable breast lesions using Magseed is a safe and effective alternative to WGL and RSL that overcomes radiation safety limitations and increases radiology and surgery scheduling efficiency.

Quantitative Apparent Diffusion Coefficients From Peritumoral Regions as Early Predictors of Response to Neoadjuvant Systemic Therapy in Triple-Negative Breast Cancer.

BACKGROUND: Pathologic complete response (pCR) to neoadjuvant systemic therapy (NAST) in triple-negative breast cancer (TNBC) is a strong predictor of patient survival. Edema in the peritumoral region (PTR) has been reported to be a negative prognostic factor in TNBC. PURPOSE: To determine whether quantitative apparent diffusion coefficient (ADC) features from PTRs on reduced field-of-view (rFOV) diffusion-weighted imaging (DWI) predict the response to NAST in TNBC. STUDY TYPE: Prospective. POPULATION/SUBJECTS: A total of 108 patients with biopsy-proven TNBC who underwent NAST and definitive surgery during 2015-2020. FIELD STRENGTH/SEQUENCE: A 3.0 T/rFOV single-shot diffusion-weighted echo-planar imaging sequence (DWI). ASSESSMENT: Three scans were acquired longitudinally (pretreatment, after two cycles of NAST, and after four cycles of NAST). For each scan, 11 ADC histogram features (minimum, maximum, mean, median, standard deviation, kurtosis, skewness and 10th, 25th, 75th, and 90th percentiles) were extracted from tumors and from PTRs of 5 mm, 10 mm, 15 mm, and 20 mm in thickness with inclusion and exclusion of fat-dominant pixels. STATISTICAL TESTS: ADC features were tested for prediction of pCR, both individually using Mann-Whitney U test and area under the receiver operating characteristic curve (AUC), and in combination in multivariable models with k-fold cross-validation. A P value < 0.05 was considered statistically significant. RESULTS: Fifty-one patients (47%) had pCR. Maximum ADC from PTR, measured after two and four cycles of NAST, was significantly higher in pCR patients (2.8 ± 0.69 vs 3.5 ± 0.94 mm2 /sec). The top-performing feature for prediction of pCR was the maximum ADC from the 5-mm fat-inclusive PTR after cycle 4 of NAST (AUC: 0.74; 95% confidence interval: 0.64, 0.84). Multivariable models of ADC features performed similarly for fat-inclusive and fat-exclusive PTRs, with AUCs ranging from 0.68 to 0.72 for the cycle 2 and cycle 4 scans. DATA CONCLUSION: Quantitative ADC features from PTRs may serve as early predictors of the response to NAST in TNBC. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 4.

The Challenging Image-Guided Preoperative Breast Localization: A Modality-Based Approach.

Breast conservation surgery (BCS) is the standard of care for treating patients with early-stage breast cancer and those with locally advanced breast cancer who achieve an excellent response to neoadjuvant chemotherapy. The radiologist is responsible for accurately localizing nonpalpable lesions to facilitate successful BCS. In this article, we present a practical modality-based guide on approaching challenging pre-operative localizations and incorporate examples of challenging localizations performed under sonographic, mammographic, and MRI guidance, as well as under multiple modalities. Aspects of preprocedure planning, modality selection, patient communication, and procedural and positional techniques are highlighted. Clip and device migration is also considered. Further, an overview is provided of the most widely used wire and nonwire localization devices in the United States. Accurate pre-operative localization of breast lesions is essential to achieve successful surgical outcomes. Certain modality-based techniques can be adopted to successfully complete challenging cases.

Early ultrasound evaluation identifies excellent responders to neoadjuvant systemic therapy among patients with triple-negative breast cancer.

BACKGROUND: Heterogeneity exists in the response of triple-negative breast cancer (TNBC) to standard anthracycline (AC)/taxane-based neoadjuvant systemic therapy (NAST), with 40% to 50% of patients having a pathologic complete response (pCR) to therapy. Early assessment of the imaging response during NAST may identify a subset of TNBCs that are likely to have a pCR upon completion of treatment. The authors aimed to evaluate the performance of early ultrasound (US) after 2 cycles of neoadjuvant NAST in identifying excellent responders to NAST among patients with TNBC. METHODS: Two hundred fifteen patients with TNBC were enrolled in the ongoing ARTEMIS (A Robust TNBC Evaluation Framework to Improve Survival) clinical trial. The patients were divided into a discovery cohort (n = 107) and a validation cohort (n = 108). A receiver operating characteristic analysis with 95% confidence intervals (CIs) and a multivariate logistic regression analysis were performed to model the probability of a pCR on the basis of the tumor volume reduction (TVR) percentage by US from the baseline to after 2 cycles of AC. RESULTS: Overall, 39.3% of the patients (42 of 107) achieved a pCR. A positive predictive value (PPV) analysis identified a cutoff point of 80% TVR after 2 cycles; the pCR rate was 77% (17 of 22) in patients with a TVR ≥ 80%, and the area under the curve (AUC) was 0.84 (95% CI, 0.77-0.92; P < .0001). In the validation cohort, the pCR rate was 44%. The PPV for pCR with a TVR ≥ 80% after 2 cycles was 76% (95% CI, 55%-91%), and the AUC was 0.79 (95% CI, 0.70-0.87; P < .0001). CONCLUSIONS: The TVR percentage by US evaluation after 2 cycles of NAST may be a cost-effective early imaging biomarker for a pCR to AC/taxane-based NAST.

Tumor necrosis by pretreatment breast MRI: association with neoadjuvant systemic therapy (NAST) response in triple-negative breast cancer (TNBC).

PURPOSE: To determine if tumor necrosis by pretreatment breast MRI and its quantitative imaging characteristics are associated with response to NAST in TNBC. METHODS: This retrospective study included 85 TNBC patients (mean age 51.8 ± 13 years) with MRI before NAST and definitive surgery during 2010-2018. Each MRI included T2-weighted, diffusion-weighted (DWI), and dynamic contrast-enhanced (DCE) imaging. For each index carcinoma, total tumor volume including necrosis (TTV), excluding necrosis (TV), and the necrosis-only volume (NV) were segmented on early-phase DCE subtractions and DWI images. NV and %NV were calculated. Percent enhancement on early and late phases of DCE and apparent diffusion coefficient were extracted from TTV, TV, and NV. Association between necrosis with pathological complete response (pCR) was assessed using odds ratio (OR). Multivariable analysis was used to evaluate the prognostic value of necrosis with T stage and nodal status at staging. Mann-Whitney U tests and area under the curve (AUC) were used to assess performance of imaging metrics for discriminating pCR vs non-pCR. RESULTS: Of 39 patients (46%) with necrosis, 17 had pCR and 22 did not. Necrosis was not associated with pCR (OR, 0.995; 95% confidence interval [CI] 0.4-2.3) and was not an independent prognostic factor when combined with T stage and nodal status at staging (P = 0.46). None of the imaging metrics differed significantly between pCR and non-pCR in patients with necrosis (AUC < 0.6 and P > 0.40). CONCLUSION: No significant association was found between necrosis by pretreatment MRI or the quantitative imaging characteristics of tumor necrosis and response to NAST in TNBC.

Prospective Registry Trial Assessing the Use of Magnetic Seeds to Locate Clipped Nodes After Neoadjuvant Chemotherapy for Breast Cancer Patients.

BACKGROUND: Targeted axillary dissection (TAD) involves locating and removing both clipped nodes and sentinel nodes for assessment of the axillary response to neoadjuvant chemotherapy (NAC) by clinically node-positive breast cancer patients. Initial reports described radioactive seeds used for localization, which makes the technique difficult to implement in some settings. This trial was performed to determine whether magnetic seeds can be used to locate clipped axillary lymph nodes for removal. METHODS: This prospective registry trial enrolled patients who had biopsy-proven node-positive disease with a clip placed in the node and treatment with NAC. A magnetic seed was placed under ultrasound guidance in the clipped node after NAC. All the patients underwent TAD. RESULTS: Magnetic seeds were placed in 50 patients by 17 breast radiologists. All the patients had successful seed placement at the first attempt (mean time for localization was 6.1 min; range 1-30 min). The final position of the magnetic seed was within the node (n = 44, 88%), in the cortex (n = 3, 6%), less than 3 mm from the node (n = 2, 4%), or by the clip when the node could not be adequately visualized (n = 1, 2%). The magnetic seed was retrieved at surgery from all the patients. In 49 (98%) of the 50 cases, the clip and magnetic seed were retrieved from the same node. Surgeons rated the transcutaneous and intraoperative localization as easy for 43 (86%) of the 50 cases. No device-related adverse events occurred. CONCLUSIONS: Localization and selective removal of clipped nodes can be accomplished safely and effectively using magnetic seeds.

Male Mammary Paget Disease: A Tale of 2 Contrasting Cases.

Mammary Paget disease (MPD) comprises 1.45% all male breast cancers, compared with only 0.68% of all female breast cancers. Patients usually present in the fifth and sixth decades of life with ulceration, eczematous changes, discharge, bleeding, itching, and induration of the nipple and areola. Typically, there is a delay in definitive diagnosis and treatment from the onset of symptoms because most patients are initially treated for a rash. At the time of diagnosis, about half of the patients may have palpable breast mass, positive lymph nodes, or both. In this article, we present 2 cases of male MPD representing the extremes of clinical, radiologic, and histopathologic spectrum of the disease. One patient presented with a rash of the nipple of several months duration without an underlying lesion, whereas the other presented with sensitivity and pain of the nipple for 1 year and an underlying mass. Biopsies were diagnostic of MPD in both cases, and definitive surgery revealed an underlying ductal carcinoma in situ in the first case and an invasive ductal carcinoma in the second, highlighting the importance of early biopsy to initiate appropriate management.

American College of Radiology-Compliant Short Protocol Breast MRI for High-Risk Breast Cancer Screening: A Prospective Feasibility Study.

OBJECTIVE: The purpose of this study was to assess the feasibility of a short protocol for screening breast MRI that is noninferior to standard-of-care (SOC) MRI in image quality that complies with American College of Radiology accreditation requirements. SUBJECTS AND METHODS: In a prospective feasibility trial, 23 women at high risk underwent both an initial SOC MRI examination that included axial iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) and T1-weighted volume imaging for breast assessment (VIBRANT) dynamic contrast-enhanced sequences and a separate short breast MRI protocol comprising a fast spin-echo (FSE) triple-echo Dixon T2 sequence for T2-weighted imaging and a 3D dual-echo fast spoiled gradient-echo two-point Dixon sequence for dynamic contrast-enhanced imaging from October 1, 2015, through May 2, 2016. Image quality assessment was performed by three radiologists, who scored the images for fat saturation, artifact severity, and quality of normal anatomic structures. Enhancing lesions were evaluated according to BI-RADS MRI features. Quantitative analysis was performed by measuring the signal intensity of anatomic areas in each patient. RESULTS: The mean acquisition time for short-protocol breast MRI was 9.42 minutes and for SOC MRI was 22.09 minutes (p < 0.0001). The mean table times were 13.92 and 35.87 minutes (p < 0.0001). Compared with the FSE triple-echo Dixon T2 short-protocol breast MRI sequence, the IDEAL SOC MRI sequence had significantly worse motion artifact (p < 0.01) and fat saturation (p = 0.04). The other parameters did not differ significantly. Quantitative analysis showed that the FSE triple-echo Dixon T2 sequence had more effective fat saturation and higher tissue contrast. All five lesions were given the same assessments by the readers, and at BI-RADS lesion morphologic ranking, identical high image quality scores were assigned to both the VIBRANT and 3D dual-echo fast spoiled gradient-echo 2-point Dixon sequences. CONCLUSION: Short-protocol breast MRI comprising a T2-weighted sequence and a fast dynamic sequence with less than 10-minute acquisition time is feasible and has image quality at least equivalent to that of an SOC MRI protocol with a > 20-minute mean acquisition time. Larger studies comparing the cancer detection rate, sensitivity, and specificity of each imaging protocol are needed to determine whether short-protocol breast MRI can replace SOC MRI to screen patients at high breast cancer risk.

Microcalcifications in 1657 Patients with Pure Ductal Carcinoma in Situ of the Breast: Correlation with Clinical, Histopathologic, Biologic Features, and Local Recurrence.

PURPOSE: This study was designed to determine the relationship of microcalcification morphology and distribution with clinical, histopathologic, biologic features, and local recurrence (LR) in patients with pure ductal carcinoma in situ (DCIS) of the breast. METHODS: All patients with pure DCIS who underwent preoperative mammography at our institution from 1996 through 2009 were identified. Mammographic findings were classified according to the ACR BI-RADS lexicon. Associations between mammographic findings and clinical, histopathologic, biologic characteristics, and LR were analyzed. Statistical inference used multiple logistic regression and Cox proportional hazards regression adjusted for age and confounding due to bias from nonrandomized selection of radiation therapy. RESULTS: We identified 1657 patients with microcalcifications visualized on mammography. The mean age at diagnosis was 55 years (SD, 11). The mean follow-up was 7 years (range 1-16). Ipsilateral LR was 4 % in segmentectomy (987) and 1.5 % in mastectomy (670) patients. Increased LR risk was seen in patients with dense breast tissue (p < 0.05) and larger DCIS size (p < 0.01). Radiation therapy was associated with a 2.8-fold decrease in the LR risk. Fine linear (branching) microcalcifications were associated with 5.2-fold increase in LR. Extremely dense breast tissue was associated with positive/close margins (p = 0.04) and multicentricity (p < 0.01). Younger women were more likely to have extremely dense breast tissue (p < 0.0001), multicentric disease (p < 0.0004), and undergo mastectomy (p < 0.0001). CONCLUSIONS: Dense breast tissue, large DCIS size, and fine linear (branching) microcalcifications were associated with increased LR, yet overall LR rates remained low. Extremely dense breast tissue was a risk factor for multicentricity and positive margins in DCIS.

Correlation between sonographic findings and clinicopathologic and biologic features of pure ductal carcinoma in situ in 691 patients.

OBJECTIVE: The objective of our study was to compare the sonographic features of pure ductal carcinoma in situ (DCIS) lesions with the initial clinical presentation and histopathologic findings. MATERIALS AND METHODS: The images and records of 691 patients with pure DCIS who underwent preoperative mammography and whole-breast sonography as part of staging workup in a single institution from January 1, 1996, through July 31, 2009, were reviewed. The BI-RADS sonography lexicon was used when reviewing the sonographic studies. Histopathologic features recorded included estrogen receptor (ER) status, nuclear grade, and presence or absence of comedonecrosis. Statistical comparisons were made using the Student t test, chi-square test, Fisher exact test, Kruskal-Wallis or Wilcoxon rank sum test, multiple logistic regression analysis, and Pearson correlation coefficient. RESULTS: A total of 304 (44%) tumors were visible on mammography and sonography; 315 (46%), on mammography only; 58 (8%), on sonography only; and 14 (2%), on neither mammography nor sonography. The most common sonographic appearance of DCIS was an irregular hypoechoic mass with indistinct margins and normal posterior features that was indistinguishable from invasive carcinoma. Patients with symptomatic high-nuclear-grade DCIS, dense breasts, and comedonecrosis were younger and had larger tumors on sonography than asymptomatic women with nondense breasts and low-nuclear-grade and noncomedo DCIS. Women with ER-negative DCIS were older and had larger tumors on sonography than women with ER-positive DCIS. ER-negative tumors were more frequently visible on sonography than ER-positive tumors (p=0.007). High-grade DCIS (p<0.0001) and comedo DCIS (p<0.0001) presented more frequently as microcalcifications, architectural distortion, and ductal changes on sonography than low-grade DCIS or noncomedo DCIS. CONCLUSION: Of the 691 pure DCIS lesions, 362 (52%) were visible on sonography and presented most commonly as a mass. Lesion visibility of DCIS on sonography was not related to nuclear grade or the presence of comedonecrosis.

Clinicopathologic, mammographic, and sonographic features in 1,187 patients with pure ductal carcinoma in situ of the breast by estrogen receptor status.

The clinicopathologic, mammographic, and sonographic findings in patients with pure ductal carcinoma in situ (DCIS) were assessed by estrogen receptor (ER) expression. After institutional review board approval, patients with pure DCIS evaluated from January 1996 to July 2009 with known ER status and available imaging were identified. Images were reviewed as per the ACR BI-RADS(®) lexicon (4th edition). Clinical, pathologic, and imaging characteristics were analyzed by ER status using t test, Chi square test, and Fisher's exact test. Of 1,219 patients with pure DCIS and known ER status identified, 1,187 with complete data were included. Mammography was performed in all 1,187 patients and sonography in 519 (44 %). There were 972 (82 %) patients with ER-positive and 215 (18 %) with ER-negative disease. ER-negative DCIS was more likely to be high grade (93 vs 44 %, p < 0.0001), associated with comedonecrosis (64 vs 29 %, p < 0.0001), and multifocal (23 vs 15 %, p = 0.009). On sonography, ER-negative DCIS was more likely to be visible (61 vs 46 %, p = 0.004), larger (mean size, 2.3 vs 1.6 cm, p = 0.006), and show posterior shadowing (53 vs 28 %, p = 0.006). Mastectomy was more frequently performed for ER-negative DCIS (47 vs 37 %, p = 0.008). Palpable DCIS was visible on sonography in 55 % of cases and mammography in 81 %. Compared with ER-positive palpable DCIS, ER-negative palpable DCIS was larger and more likely to be visible on sonography. Compared with ER-positive noncalcified DCIS, ER-negative noncalcified DCIS was less likely to be visible on mammography. ER-positive and ER-negative pure DCIS have different clinicopathologic and imaging characteristics. ER-negative DCIS is associated with worse prognostic factors than ER-positive DCIS. On sonography, ER-negative DCIS is more frequently visible than ER-positive DCIS, tends to be larger, and more frequently demonstrates posterior shadowing.

Assessment, Complications, and Surveillance of Breast Implants: Making Sense of 2022 FDA Breast Implant Guidance.

As more information about the potential risks and complications related to breast implants has become available, the United States Food and Drug Administration (FDA) has responded by implementing changes to improve patient education, recalling certain devices and updating the recommendations for screening for silicone implant rupture. In addition to staying up-to-date with FDA actions and guidance, radiologists need to maintain awareness about the types of implants they may see, breast reconstruction techniques including the use of acellular dermal matrix, and the multimodality imaging of implants and their complications. Radiologists should also be familiar with some key differences between the updated FDA guidelines for implant screening and the imaging recommendations from the American College of Radiology Appropriateness Criteria. The addition of US as an acceptable screening exam for silicone implant rupture by the FDA is one of the most notable changes that has potentially significant implications.

Performance Benchmark Metrics and Clinicopathologic Outcomes of MRI-Guided Breast Biopsies: A Systematic Review and Meta-Analysis.

Objective: To determine key performance metrics of magnetic resonance imaging (MRI)-guided breast biopsies (MRGB) to help identify reference benchmarks. Materials and Methods: We identified studies reporting MRGB results up to 04.01.2021 in the Embase database, Ovid Medline (R) Process, Other Non-Indexed Citations, Ovid Medline (R) and completed a PRISMA checklist and sources of bias (QUADAS-2). The inclusion criteria were English language, available histopathological outcomes, or at least one imaging follow-up after biopsy. A random intercept logistic regression model was used to pool rates. Between-study heterogeneity was quantified by the I2 statistic. Results: A total of 11,215 lesions in 50 articles were analyzed. The technical success rate was 99.10% [95% confidence interval (CI): 97.89-99.62%]. The MRI indications were staging in 1,496 (28.05%, 95% CI: 26.85-29.28%), screening in 1,427 (26.76%, 95% CI: 25.57-27.97%), surveillance in 1,027 (19.26%, 95% CI: 18.21-20.34%), diagnostic in 1,038 (19.46%, 95% CI: 18.41-20.55%), unknown primary in 74 (1.39%, 95% CI: 1.09-1.74%), and other in 271 (5.08%, 95% CI: 4.51-5.71%). Histopathology was benign in 65.06% (95% CI: 59.15-70.54%), malignant in 29.64% (95% CI: 23.58-36.52%) and high risk in 16.69% (95% CI: 9.96-26.64%). Detection of malignancy was significantly lower in those patients who underwent MRI for screening purposes (odds ratio 0.47, 95% CI: 0.25-0.87; p = 0.02), while mass lesions were more likely to yield malignancy compared to non-mass and foci [27.39% vs 11.36% (non-mass),18.03% (foci); p<0.001]. Surgical upgrade to invasive cancer occurred in 12.24% of ductal carcinoma in situ (95% CI: 7.76-18.77%) and malignancy in 15.14% of high-risk lesions (95% CI: 10.69-21.17%). MRI follow-up was performed in 1,651 (20.92%) patients after benign results [median=25 months (range: 0.4-117)]. Radiology-pathology discordance (2.48%, 95% CI: 1.62-3.77%), false negative after a benign-concordant biopsy (0.75%, 95% CI: 0.34-1.62%) and biopsy complications (2.36%, 95% CI: 2.03-2.72%) were rare. Conclusion: MRGB is a highly accurate minimally-invasive diagnostic technique with low false-negative and complication rates. MRI indication and lesion type should be considered when evaluating the performance of institutional MRGB programs.

Imaging Features Following Breast Explant Surgery: A Pictorial Essay.

Breast implants can be removed with breast explantation surgery (BES) for various reasons, including patient dissatisfaction, capsular contracture, implant infection or rupture, breast implant-associated anaplastic large cell lymphoma, and a recently emerging phenomenon called breast implant illness. There is very limited data on the imaging appearance after BES. A retrospective chart review was performed for patients with BES findings on imaging reports for the period between October 2016 and October 2021. When assessing BES techniques, a key element is determining whether the implant's fibrous capsule requires removal. The second important question is if the patient requires an additional aesthetic procedure after BES. BES techniques include capsulotomy, and partial, total, or en bloc capsulectomy. Adjunctive aesthetic or reconstructive procedures after BES include fat grafting, mastopexy, augmentation, and reconstruction with flaps. The majority of post-BES breast imaging findings are related to the surgical scar/bed, thereby confirming that the type of explantation surgery is important. Imaging findings after BES include focal and global asymmetries, architectural distortions, calcifications, calcified and non-calcified fat necrosis, masses, hematomas, seromas, capsular calcifications, and silicone granulomas. Most importantly, since these patients have residual breast tissue, paying attention to imaging features that are suspicious for breast cancer is necessary.

Prediction of pathologic complete response to neoadjuvant systemic therapy in triple negative breast cancer using deep learning on multiparametric MRI.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer. Neoadjuvant systemic therapy (NAST) followed by surgery are currently standard of care for TNBC with 50-60% of patients achieving pathologic complete response (pCR). We investigated ability of deep learning (DL) on dynamic contrast enhanced (DCE) MRI and diffusion weighted imaging acquired early during NAST to predict TNBC patients' pCR status in the breast. During the development phase using the images of 130 TNBC patients, the DL model achieved areas under the receiver operating characteristic curves (AUCs) of 0.97 ± 0.04 and 0.82 ± 0.10 for the training and the validation, respectively. The model achieved an AUC of 0.86 ± 0.03 when evaluated in the independent testing group of 32 patients. In an additional prospective blinded testing group of 48 patients, the model achieved an AUC of 0.83 ± 0.02. These results demonstrated that DL based on multiparametric MRI can potentially differentiate TNBC patients with pCR or non-pCR in the breast early during NAST.