Positive Predictive Value of Tomosynthesis-guided Biopsies of Architectural Distortions Seen on Digital Breast Tomosynthesis and without an Ultrasound Correlate

Suspicious Ultrasound-Occult Non-Calcified Mammographic Masses, Asymmetries, and Architectural Distortions Are Moderate Probability for Malignancy

Suspicious non-calcified mammographic findings have not been evaluated with modern mammographic technique, and the purpose of this work is to compare the likelihood of malignancy for those findings. To do this, 5018 consecutive mammographically guided biopsies performed during 2016-2019 at a large metropolitan, community-based hospital system were retrospectively reviewed. In total, 4396 were excluded for targeting calcifications, insufficient follow-up, or missing data. Thirty-seven of 126 masses (29.4%) were malignant, 44 of 194 asymmetries (22.7%) were malignant, and 77 of 302 architectural distortions (AD, 25.5%) were malignant. The combined likelihood of malignancy was 25.4%. Older age was associated with a higher likelihood of malignancy for each imaging finding type (all p ≤ 0.006), and a possible ultrasound correlation was associated with a higher likelihood of malignancy when all findings were considered together (p = 0.012). Two-view asymmetries were more frequently malignant than one-view asymmetries (p = 0.03). There were two false-negative biopsies (98.7% sensitivity and 100% specificity). In conclusion, the 25.4% likelihood of malignancy confirms the recommendation for biopsy of suspicious, ultrasound-occult, mammographic findings. Mammographically guided biopsies were highly sensitive and specific in this study. Older patient age and a possible ultrasound correlation should raise concern given the increased likelihood of malignancy in those scenarios.

Comparison of prone and upright, stereotactic, and tomosynthesis-guided biopsies with secondary analysis of ultrasound-occult architectural distortions

OBJECTIVES

Compare prone and upright, stereotactic, and tomosynthesis-guided vacuum-assisted breast biopsies (prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB) in a community-practice setting and review outcomes of ultrasound-occult architectural distortions (AD).

METHODS

Consecutive biopsies performed at two community-based breast centers from 2016 to 2019 were retrospectively reviewed. Technical details of each procedure and patient outcomes were recorded. Separate analyses were performed for ultrasound-occult ADs. Two sample t-tests and Fisher's exact test facilitated comparisons.

RESULTS

A total of 1133 patients underwent 369 prone DM-VABB, 324 prone DBT-VABB, 437 upright DM-VABB, and 123 upright DBT-VABB with 99.2%, 100%, 99.3%, and 99.2% success, respectively (p-values > 0.25). Mean lesion targeting times were greater for prone biopsy (minutes: 6.94 prone DM-VABB, 8.54 prone DBT-VABB, 5.52 upright DM-VABB, and 5.51 upright DBT-VABB; p-values < 0.001), yielding longer total prone procedure times for prone biopsy (p < 0.001). Compared to DM-VABB, DBT-VABB used fewer exposures (p < 0.001) and more commonly targeted AD, asymmetries, or masses (p < 0.001). Malignancy rates were similar between procedures: prone DM-VABB 22.4%, prone DBT-VABB 21.9%, upright DM-VABB 22.8%, and upright DBT-VABB 17.2% (p-values > 0.19). One hundred forty of the 1133 patients underwent 145 biopsies for ultrasound-occult AD (143 DBT-VABB and 2 DM-VABB). Biopsy yielded 27 malignancies and 47 high-risk lesions (74 of 145, 51%). Malignancy rate was 20.7% after surgical upgrade of one benign-discordant and two high-risk lesions.

CONCLUSIONS

All biopsy procedure types were extremely successful. The 20.7% malignancy rate for ultrasound-occult AD confirms a management recommendation for tissue diagnosis. Upright biopsy was faster than prone biopsy, and DBT-VABB used fewer exposures than DM-VABB.

CLINICAL RELEVANCE

Our results highlight important differences between prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB. Moreover, the high likelihood of malignancy for ultrasound-occult AD will provide confidence in recommending tissue diagnosis in lieu of observation or clinical follow-up.

KEY POINTS

• Upright and prone stereotactic and tomosynthesis-guided breast biopsies were safe and effective in the community-practice setting. • The malignancy rate for ultrasound-occult architectural distortion of 20.7% confirms the management recommendation for biopsy. • Upright procedures were faster than prone procedures, and tomosynthesis-guided biopsy used fewer exposures than stereotactic biopsy.

Tomosynthesis-Detected Architectural Distortions: Correlations between Imaging Characteristics and Histopathologic Outcomes

OBJECTIVE

to determine the positive predictive value (PPV) of tomosynthesis (DBT)-detected architectural distortions (ADs) and evaluate correlations between AD's imaging characteristics and histopathologic outcomes.

METHODS

biopsies performed between 2019 and 2021 on ADs were included. Images were interpreted by dedicated breast imaging radiologists. Pathologic results after DBT-vacuum assisted biopsy (DBT-VAB) and core needle biopsy were compared with AD detected by DBT, synthetic2D (synt2D) and ultrasound (US).

RESULTS

US was performed to assess a correlation for ADs in all 123 cases and a US correlation was identified in 12/123 (9.7%) cases, which underwent US-guided core needle biopsy (CNB). The remaining 111/123 (90.2%) ADs were biopsied under DBT guidance. Among the 123 ADs included, 33/123 (26.8%) yielded malignant results. The overall PPV for malignancy was 30.1% (37/123). The imaging-specific PPV for malignancy was 19.2% (5/26) for DBT-only ADs, 28.2% (24/85) for ADs visible on DBT and synth2D mammography and 66.7% (8/12) for ADs with a US correlation with a statistically significant difference among the three groups (p = 0.01).

CONCLUSIONS

DBT-only ADs demonstrated a lower PPV of malignancy when compared with syntD mammography, and DBT detected ADs but not low enough to avoid biopsy. As the presence of a US correlate was found to be related with malignancy, it should increase the radiologist's level of suspicion, even when CNB returned a B3 result.

Artificial Intelligence in Breast X-Ray Imaging

This topical review is focused on the clinical breast x-ray imaging applications of the rapidly evolving field of artificial intelligence (AI). The range of AI applications is broad. AI can be used for breast cancer risk estimation that could allow for tailoring the screening interval and the protocol that are woman-specific and for triaging the screening exams. It also can serve as a tool to aid in the detection and diagnosis for improved sensitivity and specificity and as a tool to reduce radiologists' reading time. AI can also serve as a potential second 'reader' during screening interpretation. During the last decade, numerous studies have shown the potential of AI-assisted interpretation of mammography and to a lesser extent digital breast tomosynthesis; however, most of these studies are retrospective in nature. There is a need for prospective clinical studies to evaluate these technologies to better understand their real-world efficacy. Further, there are ethical, medicolegal, and liability concerns that need to be considered prior to the routine use of AI in the breast imaging clinic.

Digital tomosynthesis spot view in architectural distortions: outcomes in management and radiation dose

PURPOSE

To evaluate if digital breast tomosynthesis spot compression view (DBT-SCV) could be an additional projection to confirm or deny architectural distortions (ADs) detected by digital breast tomosynthesis (DBT) while assessing the average glandular radiation dose.

METHODS

This is a retrospective cohort study enrolling 8864 DBT exams, of which only cases detecting primary AD and with BI-RADS 2-5 score were considered. Seventy-one AD cases examined with DBT-SCV, US and MRI were evaluated for correlation in terms of BI-RADS score; variables among exams were assessed for inter-relationships.

RESULTS

Of all ADs identified at DBT, biopsy yielded malignancy in only 38%. PPV in identifying malignancy of ADs was higher for DBT-SCV than DBT (p < 0.05); the NPV of DBT-SCV was 94%. The difference between DBT and DBT-SCV in the detection of benign ADs was statistically significant (p < 0.05). AD without US or MRI confirmation was less likely to represent malignancy (p < 0.05). In detecting malignant cases of ADs, both DBT and DBT-SCV were strongly correlated with US and RM (Kappa > 0.90). In identifying benign cases of ADs, DBT-SCV was poorly/moderately correlated with US and RM (Kappa 0.25 and 0.66); DBT was negatively correlated with US and MRI.

CONCLUSION

DBT-SCV could be useful to better characterize AD firstly identified by DBT, keeping dose levels within the reference limits. If AD is detected by DBT without an US or MRI correlate, that is not confirmed by DBT-SCV, a "wait and see" approach can be applied to reduce unnecessary biopsy.

Outcomes of Canceled Tomosynthesis-Guided Biopsy of Architectural Distortion Due to Nonvisualization

Objective

Architectural distortion without a sonographic correlate is an indication for digital breast tomosynthesis–guided vacuum-assisted biopsy (DBT-VAB). However, when the finding is not visualized on the day of biopsy, the procedure is canceled. This study reports the outcomes of canceled DBT-VAB of architectural distortion due to nonvisualization.

Methods

In this IRB-approved retrospective study, chart review was performed to identify DBT-VABs of architectural distortion at our institution between June 1, 2017, and November 1, 2020, that were canceled because of nonvisualization at the time of biopsy. Cases without follow-up imaging were excluded. Statistical analysis, including the frequency of cases yielding malignancy by the end of the study period, was performed.

Results

In total, 7.2% (39/544) of architectural distortions recommended for biopsy during the study period were canceled because of nonvisualization, 30 of which had follow-up imaging and were included in the study. Mean patient age was 56 years (standard deviation [SD], 9.6 years) and mean follow-up time was 26.7 months (SD, 11.2 months; range, 8.4–50.9 months). During the follow-up period, 16.7% (5/30) underwent repeat biopsy attempt, with one malignant result (1/30, 3.3%; SD, 18%; 95% confidence interval: 0.6%–16.7%). In total, 86.7% (26/30) of cases were declared benign during the follow-up period and 10% (3/30) remained stable with a BI-RADS 3 assessment category.

Conclusion

During available follow-up, there was a low likelihood that distortions not visualized at the time of DBT-VAB represented malignancy (3.3%, 1/30). While this low malignancy rate is reassuring, imaging follow-up is warranted.

Management of Architectural Distortion on Digital Breast Tomosynthesis With Nonmalignant Pathology at Biopsy

Background: Digital breast tomosynthesis (DBT) has led to increased detection and biopsy of architectural distortion, which may yield malignancy, radial scar, or other benign pathologies. Management of nonmalignant architectural distortion on DBT remains controversial. Objective: To determine upgrade rates of architectural distortion on DBT from nonmalignant pathology at biopsy to malignancy at surgery. Methods: This retrospective study included cases of mammographically detected architectural distortion from July 1, 2016, to June 30, 2019, that were nonmalignant at image-guided needle biopsy and underwent surgical excision. Mammographic examinations included digital 2D mammography and DBT. Imaging data were extracted from radiology reports. Upgrade rates were summarized using descriptive statistics. Features of upgraded and non-upgraded cases were compared using Pearson's chi-squared test and Wilcoxon signed-rank test. Results: The study included 129 cases of architectural distortion with nonmalignant pathology at biopsy that underwent excision in 125 women (mean age, 54 years; range, 23-90 years). At biopsy, 92 (71.3%) were radial scars and 37 (28.7%) were other nonmalignant pathologies. Of 66 radial scars without atypia at biopsy, one (1.5%) was upgraded to ductal carcinoma in situ (DCIS) at surgery and none to invasive cancer. Of 24 benign pathologies without atypia at biopsy, one was considered discordant. Of the 23 remaining concordant cases, one (4.3%) was upgraded to DCIS at surgery and none to invasive cancer. The overall upgrade rate to cancer of architectural distortion with concordant nonmalignant pathology at biopsy was 10.2% (13/128). The upgrade rate to cancer of architectural distortion without atypia was 2.2% (2/89) and with atypia was 28.2% (11/39). Explored features (age, personal or family breast cancer history, presentation by screening vs diagnostic mammography, breast density, associated mammographic findings, presence and size of ultrasound correlate, biopsy modality) showed no significant associations with upgrade risk (p>.05). Conclusion: Architectural distortion on DBT with concordant nonmalignant pathology at biopsy has an overall upgrade rate to malignancy at surgery of 10.2%. Architectural distortion without atypia has a low upgrade rate of 2.2%. Clinical Impact: Imaging surveillance can be considered for architectural distortion on DBT yielding radial scar without atypia or other concordant benign pathologies without atypia at biopsy.

Value of BI-RADS 3 Audits

Objectives

BI-RADS 3 is an established assessment category in which the probability of malignancy is equal to or less than 2%. However, monitoring adherence to imaging criteria can be challenging and there are few established benchmarks for auditing BI-RADS 3 assignments. In this study, we explore some parameters that could serve as useful tools for quality control and clinical practice management.

Materials and Methods

This retrospective study covered a 4-year period (Jan 2014-Dec 2017) and included all women over 40 years who were recalled from a screening exam and had an initial assignment of BI-RADS 3 (probably benign) category after diagnostic workup. A follow-up period of 2 years following the assignment of BI-RADS 3 was used for quantitative quality control metrics.

Results

Among 135,765 screening exams, 13,453 were recalled and 1,037 BI-RADS 3 cases met inclusion criteria. The follow-up rate at 24 months was 86.7%. The upgrade rate was 7.4% (77/1,037) [CI: 5.9-9.2%] and the PPV3 was 33.8% (26/77) [CI: 23.4-45.5%]. The cancer yield was 2.51% (26/1,037) [CI: 1.64-3.65%] and did not differ (p=0. 243) from the 2% probability of malignancy. The initial BI-RADS3 per screening exam and per recall from screening were 0.76% (1,037/135,765) [CI: 0.72-0.81%] and 7.7% (1,037/13,453) [CI: 7.26-8.17%], respectively.

Conclusion

Regular audit of BIRADS 3 metrics has the potential to provide additional insights for clinical practice management. Data from varied clinical settings with input from an expert committee could help establish benchmarks for these metrics.

Developing Asymmetries without Sonographic Correlate at Digital Breast Tomosynthesis

Background Digital breast tomosynthesis (DBT) has improved the accuracy of mammography, including resolving many breast asymmetries as overlapping breast tissue. The pathologic outcomes of persistent developing asymmetries visualized at DBT are not well established. Purpose To characterize the outcomes and the predictors of malignancy for developing asymmetries visualized at DBT without a sonographic correlate. Materials and Methods This retrospective study included all tomosynthesis-guided biopsies of developing asymmetries performed at a single institution from May 2017 through January 2020. A reader study including three breast imaging radiologists determined interrater agreement and inclusion into the study. Electronic medical records were used to extract patient characteristics, imaging characteristics, and pathologic diagnoses. The Wilcoxon rank sum test, Fisher exact test, and χ² test were used to analyze correlations of patient and imaging characteristics with likelihood of malignancy. Results The reader study included 95 DBT examinations with moderate interrater reliability (Fleiss κ = 0.45). There was majority reader agreement in 85 of the 95 DBT examinations (89%) of 83 women (median age, 56 years; interquartile range, 47-69 years), and this finalized the study data set. At pathologic examination, most asymmetries (68 of 85, 80%) were benign, with common diagnoses being fibrocystic change (n = 20), stromal fibrosis (n = 10), and fat necrosis (n = 10). The overall malignancy rate was 20% (17 of 85 asymmetries; 95% CI: 12, 29); 15 of the 17 malignancies (88%) were invasive cancers. Malignancies were more common in women with a personal history of breast cancer (35% vs 10%, P = .02). Conclusion In 85 developing asymmetries visualized at digital breast tomosynthesis without a sonographic correlate, there was a 20% (95% CI: 12, 29) malignancy rate, which was higher than the rates of malignancy for a developing asymmetry detected at digital mammography. © RSNA, 2021 See also the editorial by Skaane in this issue.

Tomosynthesis-Guided Vacuum-Assisted Breast Biopsy of Architectural Distortion Without a Sonographic Correlate: A Retrospective Review

BACKGROUND. Digital breast tomosynthesis-guided vacuum-assisted breast biopsy (DBT VAB) allows biopsy of findings seen better or exclusively on digital breast tomosynthesis (DBT), including architectural distortion. Although architectural distortion with an associated sonographic mass correlate has a high risk of malignancy, limited data describe the radiologic-pathologic correlation of tomosynthesis-detected architectural distortion without a sonographic correlate. OBJECTIVE. This study evaluates the malignancy rate of architectural distortions without a sonographic correlate that undergo DBT VAB and provides radiologic-pathologic correlation for benign, high-risk, and malignant entities that are associated with architectural distortion. METHODS. We retrospectively reviewed imaging, as well as pathology slides and/or reports, for DBT VABs performed for architectural distortion without a sonographic correlate at a single institution between June 1, 2017, and January 15, 2020. According to the correlative histopathology, cases were categorized as benign, high risk, or malignant, and specific histopathologic diagnoses were summarized. RESULTS. During the study period, 142 patients (mean age, 59 years) underwent DBT VAB for 151 unique architectural distortions without a sonographic correlate. DBT VAB revealed a malignant diagnosis in 27 (18%), a high-risk lesion in 50 (33%), and a benign diagnosis in 74 (49%). Two cases of atypical ductal hyperplasia were upgraded to malignancy, resulting in a final malignancy rate of 19% (n = 29/151). Most malignant lesions were invasive carcinomas (83%, n = 24/29); most invasive carcinomas were of lobular subtype (54%, n = 13/24). Most high-risk lesions were radial scars/complex sclerosing lesions (62%, n = 31/50). Most benign results represented fibrocystic change (66%, n = 49/74). A subset (11%, n = 8/74) of benign results were considered discordant and subsequently excised, with none representing malignancy. CONCLUSION. The final malignancy rate of 19% in architectural distortion without a sonographic correlate justifies a recommendation for biopsy using DBT VAB. CLINICAL IMPACT. Our results highlight the utility of DBT VAB in the era of DBT. The detailed radiologic-pathologic correlations will assist radiologists in assessing concordance when performing DBT VAB for architectural distortions and provide a reference for future patient management.

Digital Breast Tomosynthesis: Update on Technology, Evidence, and Clinical Practice

Digital breast tomosynthesis (DBT) has been widely adopted in breast imaging in both screening and diagnostic settings. The benefits of DBT are well established. Compared with two-dimensional digital mammography (DM), DBT preferentially increases detection of invasive cancers without increased detection of in-situ cancers, maximizing identification of biologically significant disease, while mitigating overdiagnosis. The higher sensitivity of DBT for architectural distortion allows increased diagnosis of invasive cancers overall and particularly improves the visibility of invasive lobular cancers. Implementation of DBT has decreased the number of recalls for false-positive findings at screening, contributing to improved specificity at diagnostic evaluation. Integration of DBT in diagnostic examinations has also resulted in an increased percentage of biopsies with positive results, improving diagnostic confidence. Although individual DBT examinations have a longer interpretation time compared with that for DM, DBT has streamlined the diagnostic workflow and minimized the need for short-term follow-up examinations, redistributing much-needed time resources to screening. Yet DBT has limitations. Although improvements in cancer detection and recall rates are seen for patients in a large spectrum of age groups and breast density categories, these benefits are minimal in women with extremely dense breast tissue, and the extent of these benefits may vary by practice environment and by geographic location. Although DBT allows detection of more invasive cancers than does DM, its incremental yield is lower than that of US and MRI. Current understanding of the biologic profile of DBT-detected cancers is limited. Whether DBT improves breast cancer-specific mortality remains a key question that requires further investigation. ^©RSNA, 2021.

Malignant Outcomes of Architectural Distortion on Tomosynthesis: A Systematic Review and Meta-Analysis

BACKGROUND. The literature has reported varying rates of malignancy for architectural distortion (AD) on digital breast tomosynthesis (DBT). OBJECTIVE. The purpose of this study was to evaluate the PPV for malignancy of AD on DBT without a known cause and to assess the presence of an ultrasound (US) correlate for malignant AD through systematic review and meta-analysis of the literature. EVIDENCE ACQUISITION. This meta-analysis included all studies published in Em-base, MEDLINE, and Evidence-Based Medicine Reviews databases through July 15, 2020, that assessed the rate of malignancy in patients with AD on DBT without a known cause that was deemed BI-RADS category 4 or 5. Rates of benign or high-risk lesions and the presence of a US correlate for malignant AD were assessed. Core needle biopsy or surgical pathology was used as the reference standard for lesion diagnosis. The pooled PPV and 95% CI were estimated using a random-effects model. EVIDENCE SYNTHESIS. Thirteen retrospective, observational studies were included, yielding 857 ADs seen on DBT. Of the 857 ADs, 339 were breast malignancies, yielding a pooled PPV for malignancy of 34.6% (95% CI, 24.5-46.3%). The pooled PPV for invasive malignancy was 34% (95% CI, 25-45%) and for ductal carcinoma in situ was 5% (95% CI, 4-7%). Of the 857 ADs, 235 (27.4%) were benign lesions, 282 (32.9%) were high-risk lesions, and 1 (0.1%) was a nonbreast metastatic lesion. From the studies that assessed for US correlates, 217 of 277 malignant ADs (78.3%) had a US correlate. CONCLUSION. The pooled PPV for malignancy of AD on DBT without a known cause is high at 34.6%, warranting tissue sampling. CLINICAL IMPACT. A needle biopsy should be performed for ADs on DBT without a known cause. Because most malignant distortions have a corresponding finding on US, a US examination should be performed to look for a correlate, but the absence of a correlate does not obviate a biopsy.