MR-directed ("Second-Look") ultrasound examination for breast lesions detected initially on MRI: MR and sonographic findings

Second-Look Ultrasound: When Things Are Not Always as They Seem

ABSTRACT

The purpose of this study was to compare size, morphologic features, and degree of suspicion between findings at second-look ultrasound (SL-US) and additional lesions with histological confirmation detected on breast magnetic resonance imaging (MRI). We performed an observational retrospective study including women who underwent SL-US between January 2021 and August 2022. Size, morphology according to Breast Imaging Reporting and Data System (BI-RADS) lexicon, and BI-RADS categories were analyzed for MRI and US findings. Two hundred twenty-four consecutive patients (aged 29-88 years; mean, 59.2 years) underwent SL-US to identify 235 additional lesions detected on MRI. US identified 173 (73.6%) findings. US- guided biopsy was performed in 148 (85.5%) of the detected lesions, proving 56 (37.8%) malignant and 92 (62.2%) benign. Mean size was 15.2 mm on MRI and 9.4 mm on US. Foci and masses showed good correlation, whereas nonmass enhancements tended to appear larger on MRI, and this difference was statistically significant (P = 0.0001). Morphology showed a higher agreement in the case of foci and masses than with nonmass enhancements. BI-RADS categories agreed in 66 cases (44.6%), whereas in 61 cases (41.2%), the degree of suspicion was higher for MRI, and in only 21 cases (14.2%) were lesions more suspicious on US than on MRI. In conclusion, lesions detected at SL-US show a higher agreement in size and morphologic features for foci and masses than with nonmass enhancements and similar or lower degree of suspicion than on MRI; therefore, decision to perform a biopsy should be based primarily on MRI findings.

Characteristics and Pathologic Results of Foci on Breast Magnetic Resonance Imaging: A Systematic Review and Meta-Analysis

BACKGROUND

Although T2-weighted imaging (T2WI) hypointensity, delayed enhancement washout pattern, interval growth, and new appearance of a focus have been associated with malignancy, the results are not consistent.

PURPOSE

To investigate the malignancy rate and identify the clinical and imaging characteristics associated with malignancy among foci in breast MRI.

STUDY TYPE

Meta-analysis.

SUBJECTS

32 articles with 2645 foci.

FIELD STRENGTH/SEQUENCE

1.5 T and 3.0 T. T1WI, T2WI, and DCE-MRI.

ASSESSMENT

PubMed, Embase, Scopus, and Cochrane databases were searched for articles published from January 2013 to December 2023, using the search terms: "focus," "foci," "small mass," "size," "breast magnetic resonance imaging," and "breast MRI." Extracted data included the reference standard, number of benign/malignant foci, size criterion, BI-RADS categories, amount of fibroglandular tissue, background parenchymal enhancement, T2WI signal intensity, delayed enhancement pattern.

STATISTICAL TESTS

Pooled data were analyzed using Revman 5.4 software. Between-study heterogeneity was investigated with I2-statistics. If I2 < 50% (reflecting no substantial heterogeneity), a fixed effects model was used for analysis. If I2 > 50%, random effects model analysis was used. For continuous variables, the standardized mean difference (SMD) and 95% confidence interval (CI) were used to represent the results. Malignancy rate of each study was transformed via the Freeman-Tukey Doublearcsine method. Odds ratios (OR) with 95% CIs were calculated for dichotomous variables. p values ≤ 0.05 were considered significant.

RESULTS

The pooled malignancy rate of 2645 foci was 16% (95% CI: 13%-19%). There was a significant association between malignant foci and older age (OR = 5.82, 95% CI: 2.08-9.56), T2WI hypointensity (OR = 2.28, 95% CI: 1.19-4.35) and delayed enhancement washout pattern (OR = 2.78, 95% CI: 1.87-4.12). Hyperintense foci were significantly more likely to be benign (OR = 0.41, 95% CI: 0.21-0.79).

DATA CONCLUSION

An enhancing focus with T2WI hypointensity and a washout pattern, especially in older patients, is significantly more likely to be malignant. Therefore, careful attention should be paid to it and could justify consideration of biopsy.

EVIDENCE LEVEL

3.

TECHNICAL EFFICACY

Stage 3.

Predictive factors for non-mass enhancement occult in conventional breast imaging: The "PAMAS" study

OBJECTIVES

To identify predictive factors for malignancy in non-mass enhancement occult on conventional imaging (NMEOCI) using MRI, focusing on morphological traits and clinical contexts to refine management strategies.

MATERIALS & METHODS

This retrospective single-center study reviewed all MRI-guided biopsies performed for NMEOCI between January 2015 and October 2021 at a European oncology reference facility. Exclusion criteria were unavailability of the MRI that led to the biopsy, inability to perform control clip MRI or surgery certifying correct targeting, and clustered ring enhancement. Clinical and radiological characteristics were analyzed, and a multivariate logistic regression model assessed associations with malignancy as confirmed by pathological analysis.

RESULTS

One hundred and twenty-eight patients (median age, 58.0 years (Q1-Q3: 45.5-68.0), 128 women) were evaluated. Increased risk of malignancy was associated with older age (p = 0.013), preoperative context (p = 0.050), presence of homolateral neoplasia (p = 0.031), or axillary adenomegaly (p = 0.034). In contrast, MRIs performed without indications (p = 0.044) or as part of screening for high-risk patients (p = 0.033) were protective. NMEOCI features such as larger size (p < 0.001), segmental distribution (p < 0.001), and micronodular character (p < 0.001) were correlated with malignancy risk, whereas homogeneous enhancement suggested benignity (p < 0.001). Five of these characteristics were independently associated with lesions at risk of malignancy: preoperative context, age of patient, micronodular enhancement, axillary adenomegaly, and segmental distribution.

CONCLUSION

Morphological characteristics and clinical contexts of NMEOCIs on MRI are associated with malignancy risk. The mnemonic acronym "PAMAS" ("not a mass" in French) is a useful guide for this type of lesion: Preoperative context, Age, Micronodular enhancement, axillary Adenomegaly, and Segmental distribution, are independently associated with lesions at risk of malignancy.

CLINICAL RELEVANCE STATEMENT

This study enhances the precision of MRI for the analysis of NMEOCI by identifying key morphological and clinical predictors of malignancy, some of which have never been studied before, potentially reducing unnecessary biopsies, and optimizing patient management.

Utility of chest CT in the diagnosis of additional suspicious lesions on MRI in women with breast cancer

BACKGROUND

Dedicated breast computed tomography (CT) is an emerging modality, but no study has compared breast lesions additionally detected on magnetic resonance imaging (MRI) with correlated CT lesions. Although there are differences between chest CT and dedicated breast CT, a preliminary evaluation would be valuable.

PURPOSE

To evaluate the usefulness of contrast-enhanced chest CT in evaluating additional suspicious lesions preoperatively detected on MRI in patients with breast cancer.

MATERIAL AND METHODS

Between January 2020 and December 2021, 245 patients with breast cancer who underwent preoperative breast MRI and contrast-enhanced chest CT were included. Enhancing lesions detected on CT showing correlation with additional suspicious lesions detected on MRI were recorded as CT-correlated enhancements. The pathological findings were confirmed by subsequent percutaneous biopsy or lesion excision. The clinical and MRI features of additional suspicious lesions were compared according to the standard reference or the presence of CT-correlated enhancement.

RESULTS

There were 96 (39.2%) additional suspicious lesions detected on preoperative breast MRI and a malignancy rate of 39.6%. Of 96 lesions, chest CT revealed correlated enhancement in 64 (66.7%) lesions, including 33 malignant lesions. Among the 32 lesions that showed no correlation enhancement on chest CT, 5 (15.6%) were malignant. Malignancy, diffusion-weighted image restriction, and fast/washout kinetics were more frequently observed in lesions with CT-correlated enhancement than in those without correlated enhancement (P < 0.001, P = 0.001, and P = 0.020, respectively).

CONCLUSION

When evaluating MRI-detected additional suspicious lesions in patients with breast cancer, lesions with CT-correlated enhancement were significantly more likely to be malignant than those without CT-correlated enhancement.

Clinical experience on the limited role of ultrasound for breast cancer screening in BRCA1 and BRCA2 mutations carriers aged 30-39 years

PURPOSE

In BRCA germline pathogenic sequence variants (PSV) carriers aged 30-39 years imaging is recommended at six-month intervals. The European society for medical oncology recommendation of the use of 6-monthly MRI six-monthly MRI screening is being considered at our institution, particularly for younger carriers under the age of 35, although it is not mandatory. If 6-monthly MRI is unavailable, annual MRI may be supplemented by ultrasound (with or without mammography). The aim of this study was to evaluate the utility of ultrasound screening added to mammography, as a 6-month supplement to annual MRI in BRCA PSV carriers aged 30-39 years.

MATERIALS AND METHODS

This IRB approved retrospective study included BRCA PSV carriers aged 30-39 years, who underwent breast cancer screening at our institution between January 2015 and March 2023. Participants were divided into two groups, those who had supplemental whole-breast US and mammography at six months and underwent screening before March 2019, and those who had only mammography without supplemental US and enrolled in screening after March 2019. Patient characteristics, cancer detection rates and cancer characteristics were compared between the two groups.

RESULTS

Overall, 200 asymptomatic BRCA1/2 PSV carriers undergoing screening in our institution were included in the study. Mean age was 35.7 ± 3.5 years, and mean follow-up time was 37.4 ± 38.0 months. There were 118 (59 %) women screened with supplemental US, and 82 (41 %) women without. Eight cancers were diagnosed during the study period, four in women with supplemental US and four in women without. The sensitivity of whole-breast screening US was 25 % (1/4), specificity 85.7 % (222/259), PPV 2.6 % (1/38), and NPV 98.7 % (222/225). Of the four cancers detected in women screened with supplemental US, one was diagnosed by whole-breast US, two by MRI, and one by mammography. Of eight cancers included in this study, two were not detectable by targeted second-look US. All eight cancers were detectable by MRI.

CONCLUSION

The addition of whole-breast ultrasound to mammography and MRI screening in BRCA PSV carriers aged 30-39 years offered limited incremental benefit. MRI with 6 months supplemental mammography without US detected all cancer cases.

Third-look contrast-enhanced ultrasonography plus needle biopsy for differential diagnosis of magnetic resonance imaging-only detected breast lesions

Research has shown that in approximately 20-30% of cases, breast lesions that were not detected on mammography (MG) or ultrasonography (US) were incidentally found during preoperative magnetic resonance imaging (MRI) examination for breast cancer. MRI-guided needle biopsy is recommended or considered for such MRI-only detected breast lesions invisible on second-look US, but many facilities in Japan cannot perform this biopsy procedure because it is expensive and time consuming. Thus, a simpler and more accessible diagnostic method is needed. Two studies to date have shown that third-look contrast-enhanced US (CEUS) plus needle biopsy for MRI-only detected breast lesions (i.e., MRI + /MG-/US-) that were not detected on second-look US showed moderate/high sensitivity (57.1 and 90.9%) and high specificity (100.0% in both studies) with no severe complications. In addition, the identification rate was higher for MRI-only lesions with a higher MRI BI-RADS category (i.e., category 4/5) than for those with a lower category (i.e., category 3). Despite the fact that there are limitations in our literature review, CEUS plus needle biopsy is a feasible and convenient diagnostic tool for MRI-only lesions invisible on second-look US and is expected to reduce the frequency of MRI-guided needle biopsy. When third-look CEUS does not reveal MRI-only lesions, a further indication for MRI-guided needle biopsy should be considered according to the BI-RADS category.

Women in Radiology: Challenges and Opportunities

Improving the status of women in radiology is crucial to better work environments. There is strong evidence in the business world that women leaders improve the workplace by making it more financially viable and by increasing collaboration, job satisfaction, and engagement. Diverse leadership fosters innovation, and women approach problem-solving with unique insights and collaborative styles. Gender diversity in leadership correlates with improved patient outcomes because women leaders prioritize patient-centered care and communication. Women create sustainable, productive work and improve radiology. Women serve as powerful role models, inspiring the next generation of women in radiology and addressing gender disparities. Increasing women leaders in radiology is essential to increase the number of women in radiology. This article summarizes many challenges women face when taking leadership roles: organizational biases prioritizing male viewpoints and marginalizing women's voices and contributions, a lack of role models, a lack of time ("second shift"), a lack of confidence, a lack of interest or perceived benefit, a lack of support, burnout, and previous poor experiences. While systemic issues are difficult to overcome, this article assists in the training and development of women radiologists by offering strategies to enhance job satisfaction and bring new and valuable perspectives to leadership.

Evaluation of the intramammary distribution of breast lesions detected by MRI but not conventional second-look B-mode ultrasound using an MRI/ultrasound fusion technique

The objective of this study was to evaluate the intramammary distribution of MRI-detected mass and focus lesions that were difficult to identify with conventional B-mode ultrasound (US) alone. Consecutive patients with lesions detected with MRI but not second-look conventional B-mode US were enrolled between May 2015 and June 2023. Following an additional supine MRI examination, we performed third-look US using real-time virtual sonography (RVS), an MRI/US image fusion technique. We divided the distribution of MRI-detected mammary gland lesions as follows: center of the mammary gland versus other (superficial fascia, deep fascia, and atrophic mammary gland). We were able to detect 27 (84%) of 32 MRI-detected lesions using third-look US with RVS. Of these 27 lesions, 5 (19%) were in the center of the mammary gland and 22 (81%) were located in other areas. We were able to biopsy all 27 lesions; 8 (30%) were malignant and 19 (70%) were benign. Histopathologically, three malignant lesions were invasive ductal carcinoma (IDC; luminal A), one was IDC (luminal B), and four were ductal carcinoma in situ (low-grade). Malignant lesions were found in all areas. During this study period, 132 MRI-detected lesions were identified and 43 (33%) were located in the center of the mammary gland and 87 (64%) were in other areas. Also, we were able to detect 105 of 137 MRI-detected lesions by second-look conventional-B mode US and 38 (36%) were located in the center of the mammary gland and 67 (64%) were in other areas. In this study, 81% of the lesions identified using third-look US with RVS and 64% lesions detected by second-look conventional-B mode US were located outside the center of the mammary gland. We consider that adequate attention should be paid to the whole mammary gland when we perform third-look US using MRI/US fusion technique.

Yield of MR-directed US for MRI-detected breast findings: how often can we avoid MR biopsy?

PURPOSE

To evaluate the yield of MR-directed ultrasound for MRI detected breast findings.

METHODS

This retrospective study included 857 consecutive patients who had a breast MRI between January 2017-December 2020 and received a BI-RADS 4 assessment. Only exams recommended for MR-directed ultrasound were included in the study, yielding 765 patients. Findings were characterized by presence or absence of a sonographic correlate. Utilizing the electronic medical record, for those with a sonographic correlate, the size, location, and morphology were noted. Imaging guided (Ultrasound and MRI) pathology results as well as excisional pathology results were recorded. A multivariable logistical regression analysis was used to investigate the clinical utility of MR-directed ultrasound.

RESULTS

There were 1262 MRI-detected BI-RADS category 4 findings in 765 patients. Of the 1262 findings, MR-directed ultrasound was performed on 852 (68 %). Of these, 291/852 (34 %) had an ultrasound correlate, including 143/291 (49 %) benign lesions, 81/291 (28 %) malignant lesions, 16/291 (5 %) with high-risk pathology and 51/291 (18 %) unknown due to lost to follow-up. Of those findings with ultrasound correlates, 173/291 (59 %) represented masses, 69/291 (24 %) were regions of non-mass enhancement, 22/291 (7.6 %) were foci and 27/291 (9.3 %) fell into the category of other which included lymph node, cysts, and scar tissue. Masses were significantly more likely to be identified on MR-directed ultrasound (p < 0.0001) compared to foci.

CONCLUSION

The yield of MR-directed ultrasound is significantly higher for masses, than foci and non-mass enhancement, which should be taken into consideration when recommending an MR-directed ultrasound.

Nonmass Lesions on Breast US: An International Perspective on Clinical Use and Outcomes

Nonmass lesions (NMLs) on breast US are defined as discrete areas of altered echotexture compared to surrounding breast tissue and lack the 3-dimensionality of a mass. They are not a component of American College of Radiology BI-RADS, but they are a finding type included in the Japan Association of Breast and Thyroid Sonology lexicon. Use of the NML finding is routine in many Asian practices, including the Samsung Medical Center and Seoul National University Hospital, and their features and outcomes have been investigated in multiple studies. Nonmass lesions are most often observed when US is used to evaluate mammographic asymmetries, suspicious calcifications, and nonmass enhancement on MRI and contrast-enhanced mammography. Nonmass lesions can be described by their echogenicity, distribution, presence or absence of associated calcifications, abnormal duct changes, architectural distortion, posterior shadowing, small cysts, and hypervascularity. Malignant lesions, especially ductal carcinoma in situ, can manifest as NMLs on US. There is considerable overlap between the US features of benign and malignant NMLs, and they also must be distinguished from normal variants. The literature indicates that NMLs with linear or segmental distribution, associated calcifications, abnormal duct changes, posterior shadowing, and hypervascularity are suggestive of malignancy, whereas NMLs with only interspersed small cysts are usually benign fibrocystic changes. In this article, we introduce the concepts of NMLs, illustrate US features suggestive of benign and malignant etiologies, and discuss our institutional approach for evaluating NMLs and an algorithm that we use to guide interpretation in clinical practice.

Practical Challenges of DBT-Guided VABB: Harms and Benefits, from Literature to Clinical Experience

Vacuum-assisted breast biopsy (VABB) guided by digital breast tomosynthesis (DBT) represents one of the best instruments to obtain a histological diagnosis of suspicious lesions with no ultrasound correlation or those which are visible only on DBT. After a review of the literature, we retrospectively analyzed the DBT-guided VABBs performed from 2019 to 2022 at our department. Descriptive statistics, Pearson's correlation and χ2 test were used to compare distributions of age, breast density (BD) and early performance measures including histopathology. We used kappa statistics to evaluate the agreement between histological assessment and diagnosis. Finally, we compared our experience to the literature to provide indications for clinical practice. We included 85 women aged 41-84 years old. We identified 37 breast cancers (BC), 26 stage 0 and 11 stage IA. 67.5% of BC was diagnosed in women with high BD. The agreement between VABB and surgery was 0.92 (k value, 95% CI: 0.76-1.08). We found a statistically significant inverse correlation between age and BD. The post-procedural clip was correctly positioned in 88.2%. The post-procedural hematoma rate was 14.1%. No infection or hemorrhage were recorded. When executed correctly, DBT-guided VABB represents a safe and minimally invasive technique with high histopathological concordance, for detecting nonpalpable lesions without ultrasound correlation.

Pathology of MRI and second-look ultrasound detected multifocal breast cancer

INTRODUCTION

Targeted second-look ultrasound (US) is often performed following MRI of the breast to determine if an MRI-detected lesion is visible on US and thus amenable to US-guided biopsy. This study aimed to assess the pathology of lesions detected and biopsied on the second-look US. In particular, for multifocal cancers, whether the pathology of additional lesions detected by second-look US is different to the index lesion.

METHODS

Multicentre single-institution retrospective study of 300 consecutive cases of second-look US biopsies from August 2017 to April 2022 was performed, with their histopathology and imaging characteristics recorded. For multifocal cancers, Wilcoxon Signed Ranks Tests were used to compare differences between the index and additional lesions in the histopathology category (i.e., high-risk benign, precursor or malignant) and BRE grade.

RESULTS

69 multifocal cancers were detected. For the purposes of this study, additional lesions were considered more invasive if they were of a higher histopathological category or BRE grade, or demonstrated lymphovascular invasion when the primary lesion did not. 15/69 additional lesions were not seen on the initial mammogram/tomography or ultrasound, seen on subsequent MRI and second look US, and were less invasive than the index lesion. 3/69 additional lesions were more invasive than their index lesions. Wilcoxon Signed Ranks test showed additional lesions were of either similar or lesser invasiveness compared to index lesions (z= -3.207, p = 0.001) in the histopathological category, and the same or lower BRE grade (z= -2.972, p = 0.003).

CONCLUSION

In multifocal breast cancers, additional lesions detected on MRI and second-look US have the same or less invasive histopathology compared to the index lesion.

Comparison of the diagnostic value of contrast-enhanced ultrasound combined with conventional ultrasound versus magnetic resonance imaging in malignant non-mass breast lesions

OBJECTIVE

To compare the diagnostic value of contrast-enhanced ultrasound (CEUS)+conventional ultrasound vs MRI for malignant non-mass breast lesions (NMLs).

METHODS

A total of 109 NMLs detected by conventional ultrasound and examined by both CEUS and MRI were retrospectively analysed. The characteristics of NMLs in CEUS and MRI were noted, and agreement between the two modalities was analysed. Sensitivity, specificity, positive-predictive value (PPV), negative-predictive value (NPV), and area under the curve (AUC) of the two methods for diagnosing malignant NMLs were calculated in the overall sample and subgroups of different sizes(<10 mm, 10-20 mm, >20 mm).

RESULTS

A total of 66 NMLs detected by conventional ultrasound showed non-mass enhancement in MRI. Agreement between ultrasound and MRI was 60.6%. Probability of malignancy was higher when there was agreement between the two modalities. In the overall group, the sensitivity, specificity, PPV, and NPV of the two methods were 91.3%, 71.4%, 60%, 93.4% and 100%, 50.4%, 59.7%, 100%, respectively. The diagnostic performance of CEUS+conventional ultrasound was better than that of MRI (AUC: 0.825 vs 0.762, p = 0.043). The specificity of both methods decreased as lesion size increased, but sensitivity did not change. There was no significant difference between the AUCs of the two methods in the size subgroups (p > 0.05).

CONCLUSION

The diagnostic performance of CEUS+conventional ultrasound may be better than that of MRI for NMLs detected by conventional ultrasound. However, the specificity of both methods decrease significantly as lesion size increases.

ADVANCES IN KNOWLEDGE

This is the first study to compare the diagnostic performance of CEUS+conventional ultrasound vs that of MRI for malignant NMLs detected by conventional ultrasound. While CEUS+conventional ultrasound appears to be superior to MRI, subgroup analysis suggests that diagnostic performance is poorer for larger NMLs.

A new scoring system for differentiating malignant from benign "second-look" breast lesions detected by MRI in patients with known breast cancer

AIM

To propose a scoring system made of reproducible and objective criteria to aid in differentiating malignant from benign "second-look" breast lesions detected at magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Data were collected retrospectively for "second-look" lesions identified on breast MRI studies performed at the University Hospitals of Leicester NHS Trust breast unit over a 2-year period (from January 2020 to January 2022). Ninety-five "second look" MRI-detected lesions were included in this retrospective study. Lesions were assessed according to margins, T2 signal, internal enhancement patterns, contrast kinetics, and diffusion-weighted imaging (DWI) patterns.

RESULTS

Fifty-two per cent of the included lesions were confirmed at histopathology to be malignant. The most common contrast kinetics identified in malignant lesions was the plateau pattern followed by the washout pattern while the most common pattern in benign lesions was the progressive pattern. The apparent diffusion coefficient (ADC) cut-off value for separating benign and malignant lesions at the unit was found to be 1.1 × 10-3 mm2/s. Based on the MRI features described above, a scoring system is suggested to help differentiate benign from malignant "second-look" lesions. According to the present results, setting a score of 2 or more points as an indication for biopsy was 100% reliable in identifying malignant lesions and avoiding biopsies in >30% of lesions.

CONCLUSION

The suggested scoring system could avoid biopsy of >30% of the "second-look" lesions detected by MRI without missing any malignant lesions.

Ultrasound diagnosis of non-mass MRI-detected lesions

Magnetic resonance imaging (MRI)-detected lesions are often category 2 or 3 lesions on initial ultrasound examination. In addition, in the case of new non-mass lesions detected on MRI, one would expect to find lesions with ductal dilatation with minimal secretory accumulation, single short lesions with ductal dilatation, cyst-like lesions less than 5 mm in size, mammary gland-like lesions less than 8 mm in size, and very indistinct lesions. Detection is expected to be even more difficult. Currently, there are no clear uniform criteria for the indication of second-look ultrasonography (US) for MRI-detected lesions, so it is not possible to make a general comparison, but recent studies have indicated that the ratio of mass to non-mass MRI-detected lesions is 7:3. And it has been pointed out that the percentage of malignancy is about 30% for each. Before about 2012, the US detection rate was about 70%, and MRI-guided biopsies of undetected lesions showed a small percentage of malignant lesions. Therefore, some observers believe that lesions not detected on US should be followed up, while others believe that MRI-guided biopsy should be performed. Recently, however, the use of surrounding anatomical structures as landmarks for second-look US has increased the detection rate to as high as 87-99%, and the percentage of malignancy remains the same. In addition, recent surveillance of high-risk breast cancer requires careful management of MRI-detected lesions. In this review, we will discuss the literature on MRI-detected lesions and describe ultrasound techniques to accurately detect small lesions and reliably reveal pale lesions based on their structural differences from their surroundings.

MRI Features of Synchronous Masses in Known Breast Cancer Patients in Predicting Benign Versus Malignant Lesions: A Case Based Review at Tertiary Care Cancer Hospital

Sara RehmanObjectives  The purpose of this study was to determine the diagnostic accuracy of breast magnetic resonance imaging (MRI) in classifying incidental satellite masses in biopsy-proven breast cancer patients as benign or malignant masses and assessing its impact on surgical management of these patients. We also analyzed the incidence of MRI-detected lesions, which were thereafter assessed with second look ultrasound (US). Materials and Methods  A retrospective study was performed on breast cancer patients presenting from August 01, 2016 to July 31, 2019, with satellite masses seen on base line MRI. Satellite masses were classified as benign and malignant based on MRI features of shape, margin, T2-weighted imaging signals, internal enhancement pattern, enhancement kinetic curves, and diffusion restriction. This was compared with results of histopathological examination. The number of MRI-detected lesions, location of the satellite mass, and type of surgery were also documented. Results  Out of 400 breast cancer patients undergoing MRI breast, 115 patients had multiple masses. Histopathological diagnosis was available for 73 patients; and a total of 93 satellite masses were evaluated. There was evidence of additional masses on second look ultrasound in 21 patients. Of 72 masses classified as malignant on MRI, 58 showed malignant pathological outcome; while out of 21 masses characterized as benign on MRI, 18 turned out to be benign on histopathology. A statistically significant association was found between MRI features and pathological outcome of satellite masses ( p  = 0.001). The sensitivity, specificity, positive and negative predictive values, and accuracy were 95%, 56%, 80.56%, 85.7% and 81.7%, respectively. Based on these findings, modified radical mastectomy (MRM)/mastectomy was done for 42 patients, 5 patients underwent lumpectomy limited to a single tumor, extended resection done for 14 patients, 5 underwent bilateral breast conservation surgery (BCS), BCS for contralateral breast done for 4 patients undergoing ipsilateral MRM/mastectomy, and bilateral MRM/mastectomies were performed for 2 patients. One patient was lost to follow up. Conclusion  Breast MRI is the most sensitive modality for the assessment of breast cancer and plays an essential role in the detection of additional tumor foci. These findings can modify the surgical approach in these patients. However, considering the low specificity, biopsy of satellite masses is imperative to determine the most appropriate surgical plan.

BI-RADS 3 Assessment on MRI: A Lesion-Based Review for Breast Radiologists

Unlike mammography and US, limited data exist to establish well-defined criteria for MRI findings that have a ≤2% likelihood of malignancy. Therefore, determining which findings are appropriate for a BI-RADS 3 assessment on MRI remains challenging and variable among breast radiologists. Emerging data suggest that BI-RADS 3 should be limited to baseline MRI examinations (or examinations with less than two years of prior comparisons) performed for high-risk screening and only used for masses with all of the typical morphological and kinetic features suggestive of a fibroadenoma or dominant enhancing T2 hypointense foci that is distinct from background parenchymal enhancement and without suspicious kinetics. This article presents an updated discussion of BI-RADS 3 assessment (probably benign) for breast MRI using current evidence.

Dynamic contrast-enhanced breast magnetic resonance imaging findings that affect the magnetic resonance-directed ultrasound correlation of non-mass enhancement lesions: a single-center retrospective study

OBJECTIVE

Our single-center retrospective study aimed to evaluate the relationship between magnetic resonance (MR)-directed ultrasound (MDUS) detectability and MRI findings of non-mass enhancement (NME) lesions, regarding the morphologic and enhancement features, the distance from the skin and nipple, and the presence of concomitant landmarks.

METHODS

A total of 350 MRI-detected NME lesions that were determined between January 2015 and May 2019 and subsequently underwent MDUS were analyzed. The MRI findings, biopsy results, and follow-up outcomes of lesions were recorded. The correlation between the MRI findings of the lesions and MDUS detectability was analyzed.

RESULTS

114 (32.6%) of the 350 lesions had a counterpart in the MDUS. Respectively, 66 (37.9%), 38 (43.2%) and 59 (38.3%) of the lesions detected in MDUS were larger than 20 mm in size, with a distance of less than 20 mm to the nipple and 15 mm to the skin. The lesion size and lesion distance to the nipple and skin were significantly associated with a ultrasound correlate (p < 0.05). The MDUS detection rate was significantly higher in NME lesions with MR findings including diffuse distribution (p < 0.001), clustered-ring enhancement pattern (p < 0.001), washout kinetic curve (p = 0.006), and MR-BIRADS category 5 (p < 0.001). Multivariate logistic regression showed that only the clustered-ring enhancement pattern was significantly associated with an MDUS correlation (p < 0.001).

CONCLUSION

Statistically significant correlations were found between the size, distance to the nipple and skin, distribution pattern, enhancement pattern and kinetic curve of the NME lesions on MRI and ultrasound detectability.

ADVANCES IN KNOWLEDGE

We found that clustered-ring enhancement patterns were significantly more frequent in MR-directed ultrasound detectable lesions.

Additional Workups Recommended During Preoperative Breast MRI: Methods to Gain Efficiency and Limit Confusion

BACKGROUND

Preoperative breast MRI is indicated for staging but can lead to complex imaging workups. This study reviewed imaging recommendations made on preoperative MRI exams, to simplify management approaches for patients with newly diagnosed breast cancer.

METHODS

This retrospective single-institution review was restricted to women with breast cancer who underwent staging MRI. Additional breast lesions, separate from index tumors, recommended for additional workup or surveillance were assessed to see which were detected and which characteristics predicted success in detection. Univariate mixed-effects logistic modeling predicted the likelihood of finding lesions using MRI-directed ultrasound (US), with odds ratios reported. Tests were two-sided, with a p value lower than 0.05 considered significant.

RESULTS

In this study, 534 (39.6%) patients had recommendations for additional workup after preoperative MRI. MRI detected additional malignancy in 178 patients (33.3%). Half of the 66 patients who refused an additional workup and opted for mastectomy had additional malignancies at mastectomy. MRI-directed US was 14 times more likely to detect masses than nonmass enhancement (NME) (p < 0.001). NME was detected on US in only 16% of cases, with one third of subsequent biopsy results considered discordant. Probably benign assessments were given to 35 patients, with 23% not returning for follow-up evaluation and 7% returning at least 6 months later than recommended.

CONCLUSION

Use of preoperative breast MRI has increased. Although it can add value, institutions should establish indications and expectations to prevent unnecessary workups. Limiting MRI-directed US to masses, avoiding probably benign assessments, and consulting with patients after MRI but prior to workups can prevent unnecessary exams and confusion.

Evaluation of an MRI/US fusion technique for the detection of non-mass enhancement of breast lesions detected by MRI yet occult on conventional B-mode second-look US

PURPOSE

The aim of this study was to verify the utility of second-look ultrasound (US) using real-time virtual sonography (RVS), a magnetic resonance imaging (MRI)/US fusion technique, in identifying MRI-detected breast lesions with non-mass enhancement (NME).

METHODS

Consecutive patients who had one or more NME lesions detected by MRI yet occult on the subsequent second-look US in conventional B (cB)-mode imaging were enrolled in the study between June 2015 and April 2020. Supine MRI of the lesions was performed and, using its data, second-look US using RVS was performed.

RESULTS

Twenty patients with 21 NME lesions were included. The overall median lesion size on prone MRI was 23 mm (range, 5-63 mm). Supine MRI identified all the 21 NME lesions, and second-look US using RVS successfully detected 18 (86%) of them. RVS-guided biopsy was performed for histopathological evaluation, showing that nine of the 18 lesions were benign and the other nine malignant. Of the nine malignant lesions, two (22%) were invasive cancer and seven (78%) were ductal carcinoma in situ. In four of five patients who underwent prone MRI for preoperative evaluation, the diagnosis was benign and surgery was conducted as originally planned. In the other patient, the diagnosis was malignant and contralateral breast-conserving surgery was added. Three (14%) of the 21 NME lesions had no RVS correlates and were judged to be benign after 24-month follow-up.

CONCLUSION

The results suggest that second-look US using RVS helps identify MRI-detected NME lesions that are occult on cB-mode second-look US.

Advantages and Challenges of Using Breast Biopsy Markers

Percutaneous image-guided biopsy procedures are the standard of care for histologic assessment of suspicious breast lesions. Post-biopsy tissue markers (clips) optimize patient management by allowing for assessment on follow-up imaging and precise lesion localization. Markers are used to ensure accurate correlation between imaging modalities, guide preoperative localization for malignant and high-risk lesions, and facilitate accurate identification of benign lesions at follow-up. Local practices differ widely, and there are no data detailing the exact frequency of use of clips for different breast biopsies. There are many indications for biopsy marker deployment, and some difficulties may be encountered after placement. The placement of biopsy markers has many advantages and few disadvantages, such that deployment should be routinely used after percutaneous biopsy procedures with rare exception.

Classification of MR-Detected Additional Lesions in Patients With Breast Cancer Using a Combination of Radiomics Analysis and Machine Learning

Objective

This study was conducted in order to investigate the feasibility of using radiomics analysis (RA) with machine learning algorithms based on breast magnetic resonance (MR) images for discriminating malignant from benign MR-detected additional lesions in patients with primary breast cancer.

Materials and Methods

One hundred seventy-four MR-detected additional lesions (benign, n = 86; malignancy, n = 88) from 158 patients with ipsilateral primary breast cancer from a tertiary medical center were included in this retrospective study. The entire data were randomly split to training (80%) and independent test sets (20%). In addition, 25 patients (benign, n = 21; malignancy, n = 15) from another tertiary medical center were included for the external test. Radiomics features that were extracted from three regions-of-interest (ROIs; intratumor, peritumor, combined) using fat-saturated T1-weighted images obtained by subtracting pre- from postcontrast images (SUB) and T2-weighted image (T2) were utilized to train the support vector machine for the binary classification. A decision tree method was utilized to build a classifier model using clinical imaging interpretation (CII) features assessed by radiologists. Area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and specificity were used to compare the diagnostic performance.

Results

The RA models trained using radiomics features from the intratumor-ROI showed comparable performance to the CII model (accuracy, AUROC: 73.3%, 69.6% for the SUB RA model; 70.0%, 75.1% for the T2 RA model; 73.3%, 72.0% for the CII model). The diagnostic performance increased when the radiomics and CII features were combined to build a fusion model. The fusion model that combines the CII features and radiomics features from multiparametric MRI data demonstrated the highest performance with an accuracy of 86.7% and an AUROC of 91.1%. The external test showed a similar pattern where the fusion models demonstrated higher levels of performance compared with the RA- or CII-only models. The accuracy and AUROC of the SUB+T2 RA+CII model in the external test were 80.6% and 91.4%, respectively.

Conclusion

Our study demonstrated the feasibility of using RA with machine learning approach based on multiparametric MRI for quantitatively characterizing MR-detected additional lesions. The fusion model demonstrated an improved diagnostic performance over the models trained with either RA or CII alone.

Assessment of MRI-Detected Breast Lesions: A Benign Correlate on Second-Look Ultrasound Can Safely Exclude Malignancy

Introduction

Due to the increasing use of dynamic breast MRI and the limited availability of MR-guided interventions, MRI-detected lesions usually undergo a second-look ultrasound (SLUS). We investigated the safety of a negative SLUS and a benign SLUS correlate in excluding malignant and high-risk lesions (B3) and evaluated criteria for the rate of detection on SLUS.

Methods

In the retrospective analysis, all breast MRIs performed between 2011 and 2013 were screened for newly detected lesions. We analyzed the SLUS detection rate dependent on breast density, mass character, lesion size, and histology. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a negative and benign SLUS for malignant lesions (B5) and lesions requiring surgical excision (including high-risk and B5 lesions).

Results

We successfully correlated 110 of 397 lesions. The detection rate was significantly higher for mass than for non-mass lesions and correlated with lesion size for mass lesions only. Lesions without/with a benign SLUS correlate were more frequently benign (including B3) or required no further procedure (B2). The sensitivity of SLUS in the detection of B3 and B5 lesions was 58%, and 73% in the detection of B5 lesions. The NPV of a negative or benign SLUS for B3 and B5 lesions was 89%, and 96% for B5 lesions.

Discussion

SLUS is a safe diagnostic tool for the management of MRI-detected lesions and can spare patients from undergoing invasive procedures.

Recalibrating the decision for MRI-directed breast ultrasound in patients with newly diagnosed breast cancer, factors predicting sonographic success

OBJECTIVE

Evaluate utilization of MRI-directed breast ultrasound (US) in patients with newly diagnosed breast cancer and refine practices to increase success of sonographic lesion detection.

METHODS

This retrospective single-institution review was restricted to women with breast cancer who underwent MRI from November 2006 to January 2017. Enhancing breast lesions, separate from the index tumor, recommended for MRI-directed US were assessed to see which were detected and which characteristics predicted success in detection. Univariate mixed-effects logistic modeling predicted likelihood of finding breast lesions with US, with odds ratios reported. All tests were two-sided with p < 0.05 considered significant.

RESULTS

A total of 275 patients underwent MRI-directed US for 361 breast lesions, of which 187 (51.8%) were found on US. Of those detected, 171 (91.4%) were masses and 16 (8.6%) were nonmass enhancement (NME), with masses 14 times more likely to be seen (p < 0.001). Size alone was not a significant predictor but achieved significance when associated with lesion type (mass size, p < 0.001). Masses with irregular shapes or margins and invasive carcinomas were more frequently detected. Patient age, internal enhancement pattern, and distribution of NME were not significant predictors in sonographic detection. A presumed sonographic correlate for NME was found for 16 (16.2%) of 99 attempted lesions.

CONCLUSION

As MRI access expands, utilization of MRI-directed US should be scrutinized to avoid downstream practice inefficiencies. Sonographic detection rates for NME remain low for women undergoing MRI for disease extent, with NME often better suited for MRI-guided biopsy.

Analysis of false-negative findings of breast cancer on previous magnetic resonance imaging

BACKGROUND

Despite the excellent contribution of contrast-enhanced breast magnetic resonance imaging (MRI), there are variable false-negative cases on MRI.

PURPOSE

To evaluate the false-negative findings of breast cancer on previous MRI.

MATERIAL AND METHODS

Between 2012 and 2016, we collected 132 patients who underwent surgery for a second primary cancer and had both current and previous MRI at an interval of <3 years. We included 45 patients; we excluded 38 patients who could not find a second cancer in the previous MRI and 49 patients who had a second cancer near to the original cancer and within within the same quadrant. Compared with current MRI, we retrospectively assessed the second primary cancer on previous MRI according to BI-RADS and analyzed the reasons of misinterpretation.

RESULTS

Analysis of previous MRI revealed 26 (57.8%) masses (mean size 7.7 ± 2.25 mm), 12 (26.7%) non-mass enhancements (mean size 14.7 ± 4.76 mm), and 7 (15.5%) foci. At first reading, 24 (53.3%) were missed, 17 (37.8%) were assessed as BI-RADS category 2 or 3, and 4 (8.9%) were assessed as category 4. On current MRI, 39 (86.7%) lesions showed an increase in size and 22 (48.9%) showed a change in kinetics to wash-out pattern.

CONCLUSION

On previous MRI, missed or misinterpreted cancers show variable findings of mass and non-mass enhancements with any types of kinetics. Careful application of BI-RADS is necessary as well as an appropriate biopsy. Any lesion that increases in size and changes in kinetics should not be underestimated.

Unveiling the histopathologic spectrum of MRI-guided breast biopsies: an institutional pathological-radiological correlation

PURPOSE

Breast magnetic resonance imaging (MRI) has high sensitivity but suffers from low specificity, resulting in many benign breast biopsies for MRI-detected lesions. We sought to compare histologic findings between patients who underwent MRI-guided breast biopsy versus biopsy via other imaging modalities as well as to examine features associated with malignancy in the MRI cohort to help inform MRI-biopsy practice.

METHODS

A 2-year (2018-2019) retrospective review of breast biopsies at our enterprise was conducted. Biopsies were categorized as stereotactic, ultrasound, MRI, or palpation guided. Pathology was categorized as benign (further divided into nine categories), atypical, or malignant (subdivided into in situ and invasive carcinoma). Pathology was compared between biopsy groups. Clinical, pathologic, and imaging features were compared between pathology groups within the MRI cohort.

RESULTS

5828 biopsies from 4154 patients were reviewed, including 548 MRI-guided biopsies with stratification of MRI-biopsy pathology as follows: 69% benign, 13.8% atypical, and 17.2% malignant. Among benign MRI biopsies, there was higher frequency of "clustered cysts with papillary apocrine metaplasia" (56/548; 10.2%) and lower rate of fibroadenoma/fibroadenomatous change (55/548; 10%) compared to other modalities (158 or 3% and 1144 or 21.7% of 5280 biopsies, respectively). Multivariate analysis revealed indication of breast cancer (p < .0001), ipsilateral cancer (p < .0001) and rapid initial phase kinetics (p = .017) to remain significantly associated with malignant MRI-biopsy pathology.

CONCLUSIONS

A concurrent or recent breast cancer diagnosis was most predictive of malignancy on MRI-guided breast biopsy. Combined MRI feature evaluation and radiologic-pathologic concordance activities may allow for prognostic refinement and improved risk stratification.

Synchronous BI-RADS category 3 lesions detected by preoperative breast MRI in patients with breast cancer: may follow-up be adequate?

OBJECTIVE

The purpose of this study was to analyze the rate of malignancy of synchronous Breast Imaging Reporting and Data System (BI-RADS) category 3 lesions identified by preoperative magnetic resonance imaging (MRI) in patients with breast cancer that were followed up rather than biopsied.

METHODS

From electronic medical records, we identified 99 patients treated in our institution for whom preoperative breast MRI identified synchronous BI-RADS 3 lesions. Lesion characteristics, rate of second-look ultrasonography (US), rate of collegial decision-making, and rate of biopsies performed during the period of monitoring were analyzed.

RESULTS

Second-look US was performed in 96 of 99 patients and did not reveal any lesion. Collegial decision-making for follow-up validation was asked in 32%. The median time to last MRI was 24.4 months (interquartile range [IQR] [19.3; 36.3]). The median follow-up was 39 months (IQR [28; 52]). Two cancers were diagnosed, one at 5 months and one at 26 months of follow-up. The incidence of malignancy of followed up synchronous BI-RADS category 3 lesions was 1.0% (95% CI [0.1%; 7.1%]) at 6 months and 2.2% (95% CI [0.6%; 8.6%]) at 30 months.

CONCLUSION

Monitoring could be proposed for synchronous BI-RADS category 3 lesions detected in preoperative breast cancer patients. A continued follow-up beyond 2 years could be of benefit.

KEY POINTS

• Follow-up can be proposed for MRI BI-RADS category 3 lesions not detected at second-look ultrasound, possibly after a collegial decision. • Follow-up should be continued annually since cancer may occur beyond 2 years.

Magnetic resonance imaging in the evaluation of pathologic nipple discharge: indications and imaging findings

Pathologic nipple discharge (PND) is typically unilateral, spontaneous, involves a single duct, and is serous or bloody in appearance. In patients with PND, breast MRI can be helpful as an additional diagnostic tool when conventional imaging with mammogram and ultrasound are negative. MRI is able to detect the etiology of nipple discharge in 56-61% of cases when initial imaging with mammogram and ultrasound are negative. Advantages to using MRI in evaluation of PND include good visualization of the retroareolar breast and better evaluation of posterior lesions which may not be well evaluated on mammograms and galactograms. It is also less invasive compared to central duct excision. Papillomas and nipple adenomas are benign breast masses that can cause PND and are well visualized on MRI. Ductal ectasia, and infectious etiologies such as mastitis, abscess, and fistulas are additional benign causes of PND that are well evaluated with MRI. MRI is also excellent for evaluation of malignant causes of PND including Paget's disease, ductal carcinoma in-situ and invasive carcinoma. MRI's high negative predictive value of 87-98.2% is helpful in excluding malignant etiologies of PND.

Second Look Ultrasonography-Guided Breast Biopsy with Magnetic Resonance Imaging Confirmation by Intralesional Contrast Injection

Objective

This study aimed to introduce an alternative pre-biopsy confirmation technique that combines sonography-guided intra-lesional contrast injections and single non-enhanced magnetic resonance imaging (MRI) pulse sequence in order to identify sonographic correlates of incidentally detected breast MRI lesions which were occult on primary ultrasonography (USG) and mammography examination.

Materials and Methods

From May 2014 through May 2015, a total of 37 incidental breast lesions of 37 patients, which were detected by breast MRI, were evaluated with targeted second look ultrasound (SLUS). The suspected lesion on USG was marked with a gadolinium-based contrast agent under USG guidance. After a single non-enhanced T1 weighted control MR sequence, positively correlated lesions with initial MRI were sampled by USG guided core biopsy.

Results

Of the 37 lesions evaluated, 32 (86%) lesions showed a correlation between MRI and SLUS findings. On SLUS core biopsy, there were eight (25%) malignant and 11 (34.4%) high-risk lesions among these 32 cases with correlated MRI findings; while the remaining 13 (40.6%) cases had benign histopathology. Eleven (34.4%) of the SLUS-discovered lesions were focus, 11 (34.4%) were non-mass enhancements, and the remaining 10 (31.2%) were mass lesions. Of the five lesions (13.5%) that showed no correlations on MRI and SLUS examinations, four were non-mass enhancements and one was focus.

Conclusion

SLUS represents a method for identifying MRI-detected lesions and provides a bridge to ultrasound-guided biopsy for histopathological diagnosis. There is a need for confirmation of biopsies to avoid false negative results. We describe a cheap, safe, and easy-to-apply USG-guided pre-biopsy lesions marking method in order to ensure definite correlation.

MRI-guided breast biopsy based on diffusion-weighted imaging: a feasibility study

Objectives

This study evaluated the feasibility of DWI for lesion targeting in MRI-guided breast biopsies. Furthermore, it assessed device positioning on DWI during biopsy procedures.

Methods

A total of 87 biopsy procedures (5/87 bilateral) consecutively performed between March 2019 and June 2020 were retrospectively reviewed: in these procedures, a preliminary DWI sequence (b = 1300 s/mm²) was acquired to assess lesion detectability. We included 64/87 procedures on lesions detectable at DWI; DWI sequences were added to the standard protocol to localize lesion and biopsy device and to assess the site marker correct positioning.

Results

Mass lesions ranged from 5 to 48 mm, with a mean size of 10.7 mm and a median size of 8 mm. Non-mass lesions ranged from 7 to 90 mm, with a mean size of 33.9 mm and a median size of 31 mm. Positioning of the coaxial system was confirmed on both T1-weighted and DWI sequences. At DWI, the biopsy needle was detectable in 62/64 (96.9%) cases; it was not visible in 2/64 (3.1%) cases. The site marker was always identified using T1-weighted imaging; a final DWI sequence was acquired in 44/64 cases (68.8%). In 42/44 cases (95.5%), the marker was recognizable at DWI.

Conclusions

DWI can be used as a cost-effective, highly reliable technique for targeting both mass and non-mass lesions, with a minimum size of 5 mm, detectable at pre-procedural DWI. DWI is also a feasible technique to localize the biopsy device and to confirm the deployment of the site marker.

Key Points

• MRI-guided breast biopsy is performed in referral centers by an expert dedicated staff, based on prior MR imaging; contrast agent administration is usually needed for lesion targeting.

• DWI represents a feasible, highly reliable technique for lesion targeting, avoiding contrast agent administration.

• DWI allows a precise localization of both biopsy needle device and site marker.

Utility of Targeted Ultrasound to Predict Malignancy Among Lesions Detected on Contrast-Enhanced Digital Mammography

BACKGROUND. Targeted ultrasound (US) can be performed to characterize and potentially biopsy areas of enhancement detected on contrast-enhanced mammography (CEM). OBJECTIVE. The purpose of this study was to assess the utility of targeted US in predicting malignancy of lesions with indeterminate or suspicious enhancement on CEM. METHODS. One thousand consecutive CEM examinations with same-day targeted breast US at one institution between October 2013 and May 2018 were retrospectively reviewed. All patients with indeterminate or suspicious enhancement detected on CEM that underwent US evaluation were included. Patients with palpable or symptomatic lesions, those with suspicious findings on low-energy mammograms or images obtained with another modality, and those with less than 1 year of follow-up were excluded. Medical records, imaging, and pathology data were reviewed. Histopathologic analysis was used as the reference standard for biopsied lesions, and follow-up imaging was used for unbiopsied lesions. Associations between pathologic diagnosis, presence of a US correlate, and lesion characteristics were assessed by Fisher exact, chi-square, and Wilcox-on rank sum tests. RESULTS. Among 153 enhancing lesions detected on CEM in 144 patients, 47 (31%) had a US correlate. The frequency of a correlate between CEM and US was significantly higher among enhancing masses (28/43 [65%]) than among lesions exhibiting nonmass enhancement (19/110 [17%]) (p < .001). The likelihood of malignancy was significantly greater among lesions with a US correlate (12/47 [26%]) than among those without a US correlate (11/106 [10%]) (p = .03), and among mass lesions (11/43 [26%]) than among nonmass lesions (12/110 [11%]) (p = .04). The PPV of US-guided biopsy after CEM-directed US was 32%. CONCLUSION. Enhancing CEM-detected lesions that have a US correlate are more likely to be malignant and can be evaluated with US-guided biopsy to obviate additional breast MRI. CLINICAL IMPACT. CEM-directed US of enhancing lesions is useful given that lesions with a US correlate are more likely to be malignant and can be used as targets for US-guided biopsy until a CEM biopsy system becomes commercially available.

Imaging of Breast Cancers With Predilection for Nonmass Pattern of Growth: Invasive Lobular Carcinoma and DCIS-Does Imaging Capture It All?

OBJECTIVE. Invasive lobular carcinoma (ILC) and ductal carcinoma in situ (DCIS) are distinct histopathologic entities with several commonalities: both have subtle clinical and imaging presentation, have been linked with controversy regarding optimal imaging techniques and management, and exemplify the codependence of adequate imaging evaluation and optimal treatment strategies in breast care. CONCLUSION. We review molecular mechanisms and histopathologic patterns that define the biologic behavior of both ILC and DCIS and discuss how these mechanisms translate into distinct clinical and imaging presentations that affect the staging workup and patient management algorithm.

Utility and Diagnostic Performance of Automated Breast Ultrasound System in Evaluating Pure Non-Mass Enhancement on Breast Magnetic Resonance Imaging

Objective

To compare the utility and diagnostic performance of automated breast ultrasound system (ABUS) with that of hand-held ultrasound (HHUS) in evaluating pure non-mass enhancement (NME) lesions on breast magnetic resonance imaging (MRI).

Materials and Methods

One hundred twenty-six consecutive MRI-visible pure NME lesions of 122 patients with breast cancer were assessed from April 2016 to March 2017. Two radiologists reviewed the preoperative breast MRI, ABUS, and HHUS images along with mammography (MG) findings. The NME correlation rate and diagnostic performance of ABUS were compared with that of HHUS, and the imaging features associated with ABUS visibility were analyzed.

Results

Among 126 pure NME lesions, 100 (79.4%) were malignant and 26 (20.6%) were benign. The overall correlation rate was 87.3% (110/126) in ABUS and 92.9% (117/126) in HHUS. The sensitivity and specificity were 87% and 50% for ABUS and 92% and 42.3% for HHUS, respectively, with no significant differences (p = 0.180 and 0.727, respectively). Malignant NME was more frequently visualized than benign NME lesions on ABUS (93% vs. 65.4%, p = 0.001). Significant factors associated with the visibility of ABUS were the size of NME lesions on MRI (p < 0.001), their distribution pattern (p < 0.001), and microcalcifications on MG (p = 0.027).

Conclusion

ABUS evaluation of pure NME lesions on MRI in patients with breast cancer is a useful technique with high visibility, especially in malignant lesions. The diagnostic performance of ABUS was comparable with that of conventional HHUS in evaluating NME lesions.

MR imaging-guided vacuum assisted breast biopsy: Radiological-pathological correlation and underestimation rate in pre-surgical assessment

BACKGROUND

Magnetic Resonance(MR) guided percutaneous procedures(MRgVABB) have been developed and largely employed to reduce the need of surgical biopsies for suspicious lesions which can be detected only by MR(MR-only lesion). The present study aims to investigate correlation between imaging, histological features of MRgVABB and surgical specimens of MR-only lesions.

METHODS

We retrospectively enrolled 56 patients with a total of 61 lesions. Each finding was defined as Mass-Enhancement(ME) or Non-ME(NME) and classified according to BI-RADS. MRgVABB and surgical data were collected. Concordance between MR, MRgVABB and open biopsy was calculated. Underestimation Rate(UR) of MRgVABB with surgery was obtained.

RESULTS

B2 and B5b lesions were statistically associated with NME and ME, respectively. No statistical association was found to B3 nor to B5a with radiological features. UR was 10 %; underestimated lesions were strongly associated with the presence of a ME on MR imaging. Moreover, B3 lesions are associated with higher UR.

CONCLUSION

Radiological features should influence patient management aiming to construct a correct diagnostic and therapeutic plan. When MR is prescribed for breast cancer staging for ME-MR-only lesions, we suggest surgical open biopsy instead of MRgVABB when upfront surgery is the treatment of choice.

Can second-look ultrasound downgrade MRI-detected lesions? A retrospective study

PURPOSE

To determine whether MRI-detected suspicious (BIRADS 4 & 5) breast lesions can be downgraded using second-look ultrasound (SLU) and thus reduce unnecessarily performed breast biopsies.

MATERIALS METHODS

A retrospective single-center review of consecutive patients, who underwent breast MRI studies during a 12-month time period was performed. 94 patients with 103 lesions undergoing SLU of incidentally detected MRI BI-RADS 4&5 lesions which were not identified on previous ultrasound were included in the study. The SLU detection rate and SLU features of the lesions were assessed. Histology (91/103) or two year follow up (n = 12) were defined as the reference standard for lesion diagnosis.

RESULTS

57 (55.3 %) of the 103 lesions were identified on SLU. 17 of the identified lesions were malignant (29.8 %). Lesions detected on ultrasound presented on MRI as masses in 66.7 % (38/57) and non-mass in 33.3 % (19/57). Our findings showed that it is possible to distinguish between malignant and benign lesions with SLU. The results were significant (p < 0.05) for the following morphological features: shape, orientation, margins, architectural distortion, hyperechoic rim/ edema. All lesions classified as SLU BI-RADS 2 in our study were benign and thus, 30 % of all unnecessary biopsies could potentially have been avoided. Including SLU BI-RADS 3 lesions, this rate increased to 60 %, while yielding one (of 17, 5.8 %) false negative result. All three BI-RADS 5 lesions detected by SLU presented as malignant on ultrasound.

CONCLUSION

SLU can potentially downgrade incidental MRI BIRADS 4 lesions. This may reduce the number of unnecessarily performed biopsies by 30-60 %, thus simplifying patient management.

MRI-guided vacuum-assisted breast biopsy: experience of a single tertiary referral cancer centre and prospects for the future

MRI-guided vacuum-assisted breast biopsy (VABB) is used for suspicious breast cancer (BC) lesions which are detectable only with MRI: because the high sensitivity but limited specificity of breast MRI it is a fundamental tool in breast imaging divisions. We analyse our experience of MRI-guided VABB and critically discuss the potentialities of diffusion-weighted imaging (DWI) and artificial intelligence (AI) in this matter. We retrospectively analysed a population of consecutive women underwent VABB at our tertiary referral BC centre from 01/2011 to 01/2019. Reference standard was histological diagnosis or at least 1-year negative follow-up. McNemar, Mann-Whitney and χ² tests at 95% level of significance were used as statistical exams. 217 women (mean age = 52, 18-72 years) underwent MRI-guided VABB; 11 were excluded and 208 MRI-guided VABB lesions were performed: 34/208 invasive carcinomas, 32/208 DCIS, 8/208 LCIS, 3/208 high-risk lesions and 131/208 benign lesions were reported. Accuracy of MRI-guided VABB was 97%. The predictive features for malignancy were mass with irregular shape (OR 8.4; 95% CI 0.59-31.6), size of the lesion (OR 4.4; 95% CI 1.69-9.7) and mass with irregular/spiculated margins (OR 5.4; 95% CI 6.8-31.1). Six-month follow-up showed 4 false-negative cases (1.9%). Invasive BC showed a statistically significant higher hyperintense signal at DWI compared to benign lesions (p = 0.03). No major complications occurred. MR-guided VABB showed high accuracy. Benign-concordant lesions should be followed up with breast MRI in 6-12 months due to the risk of false-negative results. DWI and AI applications showed potential benefit as support tools for radiologists.

The role of magnetic resonance imaging in patients with palpable breast abnormalities and negative mammographic and sonographic findings

OBJECTIVE OR PURPOSE OF STUDY

The objective of this retrospective study was to determine the frequency of positive findings on breast magnetic resonance imaging (MRI) in patients with palpable breast abnormalities in the setting of negative mammographic and sonographic evaluations.

MATERIALS, METHODS, AND PROCEDURES

Consecutive patients undergoing breast MRI for palpable abnormalities from January 1, 2005 to December 31, 2015 were identified for this retrospective study. Those with preceding imaging (mammograms or ultrasounds) demonstrating positive findings related to the palpable abnormalities were excluded. The location and the duration of the symptoms, the type and the location of the abnormal MRI findings, and their relationships to the symptoms were recorded. Clinical and imaging follow-up as well as the type and the resultant biopsies were recorded. Patients with less than two years of imaging or clinical follow-up were excluded from the study.

RESULTS

22 004 women presented with palpable abnormalities at one breast imaging center between January 1, 2005 and December 31, 2015. Nine thousand and three hundred and thirty-four patients had negative or benign findings on mammography, ultrasound, or mammography plus ultrasound. Thirty-one patients underwent MRI with the complaint of palpable abnormalities despite negative or benign mammographic and/or sonographic findings. Their age range was between 32 and 74 years, and their mean age was 49 years. Of those who had MRI, twenty-one patients had negative MRI findings. Six patients had negative concordant results for the palpable abnormalities and benign incidental findings. Three patients had benign concordant results for the palpable abnormalities, and one patient had incidental atypia. Twenty-eight patients had negative MRI results in the area of the palpable abnormality, and none of these patients underwent biopsy. Of the 31 cases, four patients (13%) underwent additional examinations (three second-look ultrasounds and one bone scan) after MRI. Five patients (16%) underwent MRI-guided biopsies, two patients (6%) underwent ultrasound-guided biopsies, and one patient (3%) had an excision. All biopsies showed benign results. The Gail risk score was calculated for 22 of them and the mean 5-year risk was 1.64 and the mean lifetime risk was 12.51.

CONCLUSION

Breast MRI to evaluate palpable abnormalities after negative mammography and ultrasound results in a low yield for malignancy. The majority of patients (67.7%) had negative MRI examinations, and there were no malignancies detected. Our findings lead us to believe that there are no data to encourage the use of MRI in patients with palpable abnormalities and negative mammographic and/or ultrasound studies.

Image-guided breast biopsy and localisation: recommendations for information to women and referring physicians by the European Society of Breast Imaging

We summarise here the information to be provided to women and referring physicians about percutaneous breast biopsy and lesion localisation under imaging guidance. After explaining why a preoperative diagnosis with a percutaneous biopsy is preferred to surgical biopsy, we illustrate the criteria used by radiologists for choosing the most appropriate combination of device type for sampling and imaging technique for guidance. Then, we describe the commonly used devices, from fine-needle sampling to tissue biopsy with larger needles, namely core needle biopsy and vacuum-assisted biopsy, and how mammography, digital breast tomosynthesis, ultrasound, or magnetic resonance imaging work for targeting the lesion for sampling or localisation. The differences among the techniques available for localisation (carbon marking, metallic wire, radiotracer injection, radioactive seed, and magnetic seed localisation) are illustrated. Type and rate of possible complications are described and the issue of concomitant antiplatelet or anticoagulant therapy is also addressed. The importance of pathological-radiological correlation is highlighted: when evaluating the results of any needle sampling, the radiologist must check the concordance between the cytology/pathology report of the sample and the radiological appearance of the biopsied lesion. We recommend that special attention is paid to a proper and tactful approach when communicating to the woman the need for tissue sampling as well as the possibility of cancer diagnosis, repeat tissue sampling, and or even surgery when tissue sampling shows a lesion with uncertain malignant potential (also referred to as "high-risk" or B3 lesions). Finally, seven frequently asked questions are answered.

Minimally Invasive Breast Procedures: Practical Tips and Tricks

OBJECTIVE. The purpose of this article is to review the literature regarding image-guided breast procedures, including helpful tips and tricks to guide the practicing interventional breast radiologist. CONCLUSION. The successful diagnosis and treatment of breast cancer involves coordination of the multidisciplinary breast team. Optimal procedural skills for image-guided biopsy and preoperative lesion localization are paramount to the radiologists' success.

Feasibility of supine MRI (Magnetic Resonance Imaging)-navigated ultrasound in breast cancer patients

OBJECTIVE

The purpose of this study was to evaluate the feasibility of image fusion between US and supine MRI in breast cancer patients, and to evaluate differences in tumor location between prone and supine positions.

METHODS

This prospective study included 88 patients who underwent an additional supine MRI (MRsup) sequence following routine prone MRI (MRpro) for breast cancer between May 2016 and December 2017. The location of the tumor and discrepancies in the distances from nipple to lesion (NLD), skin to lesion (SLD), and chest wall to lesion (CLD) were evaluated between MRpro and MRsup (MRpro-sup), MRpro and MRsup-navigated US (MRpro-USnav), and MRsup and USnav (MRsup-USnav). Associations between breast thickness and measurement discrepancies were analyzed.

RESULTS

Total 91 index lesions were evaluated. The intraclass correlation coefficients (ICCs) for the location of MRpro and MRsup compared with USnav were 0.994 (range: 0.990-0.996) and 0.998 (range: 0.996-0.999), respectively. The mean MRpro-sup and MRpro-USnav measurement discrepancies were greater than those of MRsup-USnav, significantly. Most outer locations showed greater mean measurement discrepancies than inner locations, and each NLD, SLD, and CLD mean measurement discrepancy showed different tendencies according to location (upper or lower) and lesion depth (superficial, middle, or deep). High breast thickness showed significantly greater mean measurement discrepancies than low breast thickness.

CONCLUSION

Image fusion between US and supine MRI is feasible in breast cancer patients, although there is a considerable difference in tumor location measurements between prone and supine positions, especially with thicker breasts.

Association of Retrospective Peer Review and Positive Predictive Value of Magnetic Resonance Imaging-Guided Vacuum-Assisted Needle Biopsies of Breast

Objective

To evaluate the association between retrospective peer review of breast magnetic resonance imaging-guided vacuum-assisted needle biopsies and positive predictive value of subsequent magnetic resonance imaging-guided biopsies.

Materials and Methods

In January, 2015, a weekly conference was initiated in our institution to evaluate all breast magnetic resonance imaging-guided vacuum-assisted needle biopsies performed over January 1, 2014-December 31, 2015. During this weekly conferences, breast dynamic contrast-enhanced magnetic resonance imaging findings of 6 anonymized cases were discussed and then the faculty voted on whether they agree with the biopsy indication, accurate sampling and radiology-pathology correlation. We retrospectively reviewed and compared the magnetic resonance imaging indication, benign or malignant pathology rates, lesion types and the positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsy in the years before and after initiating this group peer review.

Results

The number of dynamic contrast-enhanced magnetic resonance imaging and magnetic resonance imaging-guided vacuum-assisted needle biopsies before and after initiating the review were 1447 vs 1596 (p=0.0002), and 253 (17.5%) vs 203 (12.7%) (p=0.04), respectively. There was a significant decrease in the number of benign biopsies in 2015 (n=104) compared to 2014 (n=154, p=0.04). The positive predictive value of magnetic resonance imaging-guided biopsy significantly increased after group review was implemented (Positive predictive value in 2014=%39.1 and positive predictive value in 2015=%48.8) (p=0.03), although the indications (p=0.49), history of breast cancer (p=0.14), biopsied magnetic resonance imaging lesion types (p=0.53) were not different. Less surgical excision was performed on magnetic resonance imaging-guided vacuum-assisted needle biopsy identified high-risk lesions in 2015 (p=0.25).

Conclusion

Our study showed an association between retrospective peer review of past biopsies and increased positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsies in our institution.

MRI-detected breast lesions: clinical implications and evaluation based on MRI/ultrasonography fusion technology

Magnetic resonance imaging (MRI) is a highly sensitive imaging modality that frequently reveals additional breast lesions that are occult on mammography and ultrasonography (US) and are thus difficult to diagnose. It is important to investigate these MRI-detected suspicious lesions, which are associated with a fairly high rate of malignancy. In this review, we have discussed MRI/US fusion technology, a magnetic position tracking system that synchronizes real-time US and MRI to improve lesion detection and enables comparisons of MRI and US findings of the detected lesions. This combination increases the precision of second-look US. We hope that our review underscores the importance of understanding the US findings and histopathology of MRI-detected breast lesions, as this will enable radiologists to perform appropriate assessments.

Differentiation between subcentimeter carcinomas and benign lesions using kinetic parameters derived from ultrafast dynamic contrast-enhanced breast MRI

OBJECTIVES

This study aims to evaluate ultrafast DCE-MRI-derived kinetic parameters that reflect contrast agent inflow effects in differentiating between subcentimeter BI-RADS 4-5 breast carcinomas and benign lesions.

METHODS

We retrospectively reviewed consecutive 3-T MRI performed from February to October 2017, during which ultrafast DCE-MRI was performed as part of a hybrid clinical protocol with conventional DCE-MRI. In total, 301 female patients with 369 biopsy-proven breast lesions were included. Ultrafast DCE-MRI was acquired continuously over approximately 60 s (temporal resolution, 2.7-7.1 s/phase) starting simultaneously with the start of contrast injection. Four ultrafast DCE-MRI-derived kinetic parameters (maximum slope [MS], contrast enhancement ratio [CER], bolus arrival time [BAT], and initial area under gadolinium contrast agent concentration [IAUGC]) and one conventional DCE-MRI-derived kinetic parameter (signal enhancement ratio [SER]) were calculated for each lesion. Wilcoxon rank sum test or Fisher's exact test was performed to compare kinetic parameters, volume, diameter, age, and BI-RADS morphological descriptors between subcentimeter carcinomas and benign lesions. Univariate/multivariate logistic regression analyses were performed to determine predictive parameters for subcentimeter carcinomas.

RESULTS

In total, 125 lesions (26 carcinomas and 99 benign lesions) were identified as BI-RADS 4-5 subcentimeter lesions. Subcentimeter carcinomas demonstrated significantly larger MS and SER and shorter BAT than benign lesions (p = 0.0117, 0.0046, and 0.0102, respectively). MS, BAT, and age were determined as significantly predictive for subcentimeter carcinoma (p = 0.0208, 0.0023, and < 0.0001, respectively).

CONCLUSIONS

Ultrafast DCE-MRI-derived kinetic parameters may be useful in differentiating subcentimeter BI-RADS 4 and 5 carcinomas from benign lesions.

KEY POINTS

• Ultrafast DCE-MRI can generate kinetic parameters, effectively differentiating breast carcinomas from benign lesions. • Subcentimeter carcinomas demonstrated significantly larger maximum slope and shorter bolus arrival time than benign lesions. • Maximum slope and bolus arrival time contribute to better management of suspicious subcentimeter breast lesions.