Imaging and Management of Radial Scars and Complex Sclerosing Lesions.

Radial scars and complex sclerosing lesions, often collectively referred to as radial sclerosing lesions (RSLs), are breast lesions characterized by sclerotic stroma with entrapped epithelial elements. RSLs have imaging features that overlap with those of breast malignancy and often become the target of imaging-guided biopsy given their suspicious imaging appearance. These can be identified in isolation or can also be associated with atypia or other high-risk lesions that have intrinsic malignant potential, increasing the risk of carcinoma and affecting prognosis and management of RSLs. Because of this, management of these lesions remains controversial. Traditional management has been surgical excisional biopsy. However, as more RSLs are identified (because digital breast tomosynthesis allows identification of more architectural distortions), optimal management is evolving. Physicians in some practices are using a multidisciplinary approach to the management of RSLs when deciding on surgical excision of these lesions versus imaging follow-up. These discussions also incorporate individual patient risk factors and greater patient informed medical decision making. Reported upgrade rates of RSLs at core needle biopsy vary and can depend on the sampling method, number of samples, gauge of the needle, target being sampled, and radiologic-pathologic concordance or discordance. A precise sampling technique also allows greater accuracy of diagnosis and lower upgrade rates for these lesions, with radiologic-pathologic correlation as an integral component for further management decisions. The authors review the overall histopathologic, clinical, and imaging features of RSLs and discuss appropriate management based on currently available data regarding upgrade rates. ©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Digital Breast Tomosynthesis and Digital Mammography Recall and False-Positive Rates by Time of Day and Reader Experience.

Background Digital breast tomosynthesis (DBT) image interpretation might be more cognitively demanding than interpretation of digital mammography (DM) images. The time of day of interpretation might affect recall and false-positive (FP) rates, especially for DBT. Purpose To determine whether recall and FP rates vary by time of day of interpretation for screening mammography for breast cancer performed with DM and DBT. Materials and Methods This is a retrospective study examining 97 671 screening mammograms interpreted by 18 radiologists between January 2018 and December 2019 at one of 12 community radiology sites. The association between the time of day of interpretation, the type of image interpreted (DM vs DBT), and radiologist experience (≤5 posttraining years vs >5 posttraining years) and the likelihood of a patient being recalled from screening mammography and the likelihood of whether the interpretation was FP or true positive were analyzed. Analyses were conducted using generalized linear mixed modeling with a binary distribution and sandwich estimation where observations were nested by radiologist. Results Screening mammograms interpreted by 18 radiologists were reviewed (40 220 DBTs, 57 451 DMs). Nine radiologists had 5 or fewer posttraining years of experience, and nine had more than 5 posttraining years of experience. The overall recall rates for DM (10.2%) and DBT (9.0%) were different (P = .006); FP rate also differed (9.8% DM, 8.6% DBT; P = .004). For radiologists with 5 or fewer posttraining years of experience, odds of recall increased 11.5% (odds ratio [OR] = 1.12, P = .01) with every hour when using DBT, but this was not found for DM (OR = 1.09, P = .06); DBT and DM were different (OR = 1.12 vs 1.09, P = .02). For radiologists with more than 5 posttraining years of experience, no evidence of increase in recall was observed for DBT (OR = 1.02, P = .27) or DM (OR = 1.0, P = .80), and there was no evidence that these were different (OR = 1.02 vs 1.0, P = .13). Conclusion Patients were more likely to be recalled when their screening digital breast tomosynthesis images were interpreted later in the day by less-experienced radiologists. © RSNA, 2022 Online supplemental material is available for this article.

Community-Based Breast Cancer Screening Using Digital Breast Tomosynthesis Versus Digital Mammography: Comparison of Screening Performance and Tumor Characteristics.

BACKGROUND. Prior studies comparing cancer screening by digital breast tomosynthesis (DBT) and digital mammography (DM) have largely entailed prospective trials and investigations at tertiary academic centers, which may encounter high-risk patient populations and lack heterogeneity among interpreting radiologists. Thus, results may not generalize across real-world community settings in the United States. OBJECTIVE. The purpose of this study was to compare DBT and DM in terms of screening performance and tumor characteristics of screen-detected cancers in a community practice setting. METHODS. Data were retrospectively retrieved for all screening mammography examinations performed by DBT or DM at four outpatient private practice facilities from January 1, 2012, to July 10, 2019. Examinations were interpreted by one of 26 radiologists (21 breast radiologists, five general radiologists). Further detailed information was recorded from radiology and pathology reports for all screen-detected cancers. Statistical comparisons were performed between DBT and DM in terms of screening performance and tumor characteristics of screen-detected cancers. RESULTS. A total of 310 cancers were detected in 47,096 screening DBT examinations and 83,200 screening DM examinations. Cancer detection rate was higher (p < .001) for DBT (3.4 per 1000 women) than for DM (1.8 per 1000 women). PPV1 was higher (p < .001) for DBT (3.5% [161/4641]) than for DM (2.1% [149/7116]). Patients with DBT-detected cancer were younger than those with DM-detected cancer (mean age [range], 61 years [40-87 years] vs 64 years [37-88 years]; p = .02). A greater percentage of DBT-detected than DM-detected cancers were invasive (85.1% [137/161] vs 72.5% [108/149]; p = .006), grade 1 when invasive (27.9% [38/136] vs 17.8% [19/107]; p = .04), and node negative (92.2% [71/77] vs 78.4% [58/74]; p = .02). Cancers detected by DBT and DM were not significantly different in histologic subtype, molecular subtype, or mean size (all p > .05). CONCLUSION. DBT showed a higher cancer detection rate and PPV1 than DM, and patients were younger at cancer diagnosis with DBT. Cancers detected on DBT were more often invasive, grade 1, and node negative. CLINICAL IMPACT. The findings support the generalizability of insights into DBT-based screening, which previously have been investigated primarily in academic settings.

Imaging Surveillance Options for Individuals With a Personal History of Breast Cancer: AJR Expert Panel Narrative Review.

Annual surveillance mammography is recommended for breast cancer survivors on the basis of observational studies and meta-analyses showing reduced breast cancer mortality and improved quality of life. However, breast cancer survivors are at higher risk of subsequent breast cancer and have a fourfold increased risk of interval breast cancers compared with individuals without a personal history of breast cancer. Supplemental surveillance modalities offer increased cancer detection compared with mammography alone, but utilization is variable, and benefits must be balanced with possible harms of false-positive findings. In this review, we describe the current state of mammographic surveillance, summarize evidence for supplemental surveillance in breast cancer survivors, and explore a risk-based approach to selecting surveillance imaging strategies. Further research identifying predictors associated with increased risk of interval second breast cancers and development of validated risk prediction tools may help physicians and patients weigh the benefits and harms of surveillance breast imaging and decide on a personalized approach to surveillance for improved breast cancer outcomes.

Digital Mammography Stereotactic Biopsy versus Digital Breast Tomosynthesis-guided Biopsy: Differences in Biopsy Targets, Pathologic Results, and Discordance Rates.

Background Digital breast tomosynthesis (DBT)-guided biopsy is increasingly used in practice. It is important to know expected changes in biopsy targets, pathologic results, and discordance rates. Purpose To compare biopsy target types, pathologic results, and discordance rates for 2 years preceding and 2 years following implementation of DBT-guided biopsy. Materials and Methods All 9-gauge vacuum-assisted core biopsies from a single tertiary breast center that used digital mammography (DM) stereotactic guidance from 2013 to 2015 and DBT-guided biopsy from 2015 to 2017 were retrospectively reviewed. All mammographic examinations were performed with DBT. Patient demographics, biopsy target type, pathologic reports, surgical excision specimens when available, breast density, and imaging follow-up results were recorded. Biopsy targets and discordance rates between radiologic and pathologic examinations were compared between the two biopsy groups. Generalized mixed modeling was used to examine results before and after DBT-guided biopsy. Results A total of 1313 women underwent 1405 breast biopsies: 643 by using DM (August 2013 to July 2015) (median age, 56 years; interquartile range, 49-66 years) and 762 by using DBT (August 2015 to July 2017) (median age, 58 years; interquartile range, 50-67 years), (P = .58). Calcifications were the most common biopsy target for both groups, constituting 89.9% (578 of 643) of DM-guided biopsies and 71.1% (542 of 762) of DBT-guided biopsies (P = .03). The rate of architectural distortion biopsies was 2.0% (13 of 643) with DM-guided biopsy and 17.7% (135 of 762) with DBT-guided biopsy (P = .01). Although overall malignancy rate was similar for DM-guided biopsy (27.8% [179 of 643]) and DBT-guided biopsy (24.8% [191 of 762], P = .54), DBT-guided biopsy helped identify a similar percentage of invasive malignancies (37.4% [72 of 191] vs 29.0% [52 of 179] at DM P = .35), but more radial sclerosing lesions (8.3% [95% confidence interval {CI}: 6.0, 10.0] vs 1.7% [95% CI: 1.0, 3.1]) (P = .01). The discordance rate was 1.4% (95% CI: 1.0, 2.7) with DM-guided biopsy and 4.5% (95% CI: 3.2, 6.3) with DBT-guided biopsy (P = .01). Of the 34 discordant DBT-guided biopsies, 30 were architectural distortions. Conclusion With the transition to digital breast tomosynthesis-guided biopsy, more architectural distortions were biopsied, more radial sclerosing lesions were identified, and more discordance existed in radiologic and pathologic examinations, with a similar percentage of carcinomas diagnosed. © RSNA, 2020 Online supplemental material is available for this article.

Detection of emergent large vessel occlusion stroke with CT angiography is high across all levels of radiology training and grayscale viewing methods.

OBJECTIVES: CT angiography (CTA) is essential in acute stroke to detect emergent large vessel occlusions (ELVO) and must be interpreted by radiologists with and without subspecialized training. Additionally, grayscale inversion has been suggested to improve diagnostic accuracy in other radiology applications. This study examines diagnostic performance in ELVO detection between neuroradiologists, non-neuroradiologists, and radiology residents using standard and grayscale inversion viewing methods. METHODS: A random, counterbalanced experimental design was used, where 18 radiologists with varying experiences interpreted the same patient images with and without grayscale inversion. Confirmed positive and negative ELVO cases were randomly ordered using a balanced design. Sensitivity, specificity, positive and negative predictive values as well as confidence, subjective assessment of image quality, time to ELVO detection, and overall interpretation time were examined between grayscale inversion (on/off) by experience level using generalized mixed modeling assuming a binary, negative binomial, and binomial distributions, respectively. RESULTS: All groups of radiologists had high sensitivity and specificity for ELVO detection (all > .94). Neuroradiologists were faster than non-neuroradiologists and residents in interpretation time, with a mean of 47 s to detect ELVO, as compared with 59 and 74 s, respectively. Residents were subjectively less confident than attending physicians. With respect to grayscale inversion, no differences were observed between groups with grayscale inversion vs. standard viewing for diagnostic performance (p = 0.30), detection time (p = .45), overall interpretation time (p = .97), and confidence (p = .20). CONCLUSIONS: Diagnostic performance in ELVO detection with CTA was high across all levels of radiologist training level. Grayscale inversion offered no significant detection advantage. KEY POINTS: • Stroke is an acute vascular syndrome that requires acute vascular imaging. • Proximal large vessel occlusions can be identified quickly and accurately by radiologists across all training levels. • Grayscale inversion demonstrated minimal detectable benefit in the detection of proximal large vessel occlusions.

Ultrasound-Guided Breast Cancer Cryoablation.

OBJECTIVE. Percutaneous ultrasound-guided breast cryoablation is a minimally invasive technique that kills targeted tissue with extreme cold, requires only local anesthesia, and takes less than 45 minutes to complete. CONCLUSION. We discuss the indications for breast cryoablation, the mechanism of cell death, and types of commercially available devices; illustrate procedural technique; and review expected follow-up imaging findings in treated primary breast cancer.

Dense Breast Ultrasound Screening After Digital Mammography Versus After Digital Breast Tomosynthesis.

OBJECTIVE. The objective of this study was to compare the yield of dense breast ultrasound (US) screening after digital mammography (DM) versus after digital breast tomosyn-thesis (DBT). MATERIALS AND METHODS. For this institutional review board-approved, HIPAA-compliant study, we retrospectively searched databases at two tertiary breast imaging centers and an office practice staffed by the same fellowship-trained breast radiologists for screening US examinations from October 1, 2014, to September 30, 2016. Prior DM versus DBT and screening US and pathology results were recorded. Mammographically occult cancers detected with US and additional benign lesions requiring biopsy were calculated. Differences between DM and DBT were compared using the two-sample proportions z test. RESULTS. A total of 3183 screening breast US examinations were performed, 1434 (45.1%) after DM and 1668 (52.4%) after DBT. Of the 3183 examinations, 81 (2.5%) had no prior mammogram available. Of the 122 DM and DBT patients for whom biopsy or cyst aspiration was recommended (all BI-RADS assessment category 4 or BI-RADS assessment category 5 studies), 118 (96.7%) had biopsy or cyst aspiration results available. Of the 36 biopsies or aspirations after DM, 6 (16.7%) were malignant and 30 (83.3%) were benign; of the 82 biopsies or aspirations after DBT, 11 (13.4%) were malignant and 71 (86.6%) were benign (p = 0.8583). The additional cancer detection rate by US after DM was 5/1434 or 3.5 per 1000 women screened and after DBT was 5/1668 or 3.0 per 1000 women screened (p = 0.9999). CONCLUSION. No significant difference in additional cancer detection rate was found with screening US after DM versus after DBT.

Cholesteroloma of the breast: A 10 year retrospective review of 79 cases with radiology correlation.

A cholesteroloma or cholesterol granuloma of the breast is an uncommon lesion representing an inflammatory/reactive process with unclear etiology. In this study, we reviewed our 10-year experience with cholesteroloma of the breast with clinical, radiologic, and histopathological correlation. Seventy-nine cases were selected. The mean patient age was 57.7 (range 25-90) years old. Patients had hypercholesterolemia with mean blood cholesterol level of 201 mg/dL (P < 0.001). The mean body mass index (BMI) was 26.7 kg/m2 (P = 0.1976). The indications for the breast biopsies were mass lesion on radiology (85.5%, n = 65) and microcalcifications (10.5%, n = 8). Of the 65 cases of the mass lesions, 52 presented as solid masses and 13 were cystic. On the diagnostic mammogram or ultrasound, 81.9% were BI-RADS 4% and 6.9% were BI-RADS 5. Macrocysts were the most common pathological finding associated with cholesteroloma suggesting the etiology of cholesteroloma may be the result of repair process from obstruction and rupture of the macrocysts. Six cases (9.2%) of cholesterolomas had persistent masses during follow-up. The recognition of this lesion and radio-pathological correlation can help us better understand this entity and distinguish it from its mimickers.

Screening Digital Mammography Recall Rate: Does It Change with Digital Breast Tomosynthesis Experience?

Purpose To compare screening mammography recall rate, cancer detection rate (CDR), and positive predictive values (PPVs) for digital mammography before and after radiologist experience with digital breast tomosynthesis (DBT). Materials and Methods This retrospective study was approved by the institutional review board and compliant with HIPAA. The authors reviewed screening mammography audit data obtained from 2009 to 2014, during which 108 276 digital mammographic examinations were performed (50 062 before and 58 214 after experience with DBT). Recall rate, CDR, PPV of positive screening result (PPV1), PPV of biopsy recommendation (PPV2), and PPV of biopsies performed (PPV3) of digital mammography for six radiologists were compared before (2009-2011) and after (2012-2014) experience with DBT. Radiologists worked in both a community setting, in which only digital mammography was available, and in two tertiary breast imaging centers, where they interpreted DBT images starting in 2012. Data were examined by using generalized linear mixed modeling wherein observations were nested for each radiologist over time. P < .05 was considered indicative of a statistically significant difference; 95% confidence intervals (CIs) were calculated. Results The average recall rate was 6.8% (range, 3.6%-9.7%) before experience with DBT and 7.9% (range, 5.5%-9.5%) after (P = .0316). Before experience with DBT, the recall rate increased only 0.01% for each year from 2009 to 2011 (P = .9727). After experience with DBT, the recall rate increased 0.65% for each year from 2012 to 2014 (P < .0127). CDR increased from 2.5 per 1000 examinations (95% CI: 2.2, 2.9) to 3.5 per 1000 examinations (95% CI: 3.0, 4.0; P = .0203). PPV2 and PPV3 increased significantly after experience with DBT, from 26.9% (95% CI: 19.9%, 35.3%) to 36.1% (95% CI: 31.7%, 40.7%; P = .0212) for PPV2 and from 31.2% (95% CI: 24.0%, 39.3%) to 40.0% (95% CI: 35.5%, 44.6%; P = .0290) for PPV3. Conclusion Recall rate, CDR, PPV2, and PPV3 of digital mammography increased after radiologist experience with DBT. © RSNA, 2017.

Comparison of digital mammography and digital breast tomosynthesis in the detection of architectural distortion.

OBJECTIVES: To compare interobserver variability (IOV), reader confidence, and sensitivity/specificity in detecting architectural distortion (AD) on digital mammography (DM) versus digital breast tomosynthesis (DBT). METHODS: This IRB-approved, HIPAA-compliant reader study used a counterbalanced experimental design. We searched radiology reports for AD on screening mammograms from 5 March 2012-27 November 2013. Cases were consensus-reviewed. Controls were selected from demographically matched non-AD examinations. Two radiologists and two fellows blinded to outcomes independently reviewed images from two patient groups in two sessions. Readers recorded presence/absence of AD and confidence level. Agreement and differences in confidence and sensitivity/specificity between DBT versus DM and attendings versus fellows were examined using weighted Kappa and generalised mixed modeling, respectively. RESULTS: There were 59 AD patients and 59 controls for 1,888 observations (59 × 2 (cases and controls) × 2 breasts × 2 imaging techniques × 4 readers). For all readers, agreement improved with DBT versus DM (0.61 vs. 0.37). Confidence was higher with DBT, p = .001. DBT achieved higher sensitivity (.59 vs. .32), p < .001; specificity remained high (>.90). DBT achieved higher positive likelihood ratio values, smaller negative likelihood ratio values, and larger ROC values. CONCLUSIONS: DBT decreases IOV, increases confidence, and improves sensitivity while maintaining high specificity in detecting AD. KEY POINTS: • Digital breast tomosynthesis decreases interobserver variability in the detection of architectural distortion. • Digital breast tomosynthesis increases reader confidence in the detection of architectural distortion. • Digital breast tomosynthesis improves sensitivity in the detection of architectural distortion.

Cancer Yield of Incidental Breast Lesions Detected on Chest Computed Tomography.

OBJECTIVE: This study aimed to determine the cancer yield for abnormal breast findings initially identified on chest computed tomography (CT). MATERIALS AND METHODS: This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study retrospectively reviewed reports of 41,217 consecutive chest CT examinations done from January 1, 2006, to December 31, 2011, to identify those with breast findings noted in the impression of the report. Examinations done for staging of newly diagnosed breast cancer were excluded. The electronic medical record was searched for any subsequent breast imaging and any corresponding pathology results. Cancer yield was calculated. RESULTS: A total of 258 chest CT examinations with abnormal breast findings were identified in 218 unique patients. Average patient age was 65.6 years (range, 30-100 years). There were 207 women and 11 men. Of these, 75 patients had follow-up breast imaging in our system. One hundred forty-three patients did not have follow-up in our system and were excluded for purposes of cancer detection rate calculation. Thirteen of 75 patients were found to have lesions that were malignant: infiltrating ductal carcinoma (8), invasive lobular carcinoma (2), lymphoma (2), and intracystic papillary cancer with atypical features (1). Four of 75 patients underwent further workup and were found to have lesions that were benign: fibroadenoma (3) and benign fibrocystic change (1). The remainder of the 58 of 75 patients had dedicated breast imaging that was classified as either Breast Imaging Reporting and Data System score 1 or 2, and no further workup was performed. Cancer yield from CT findings was 17.3%. CONCLUSIONS: Abnormal CT findings in the breast warrant additional evaluation with dedicated breast imaging to evaluate for a possible underlying malignancy. Cancer yield from CT findings in this study was 17.3%.

Diffuse dermal angiomatosis mimicking inflammatory breast carcinoma.

Diffuse dermal angiomatosis (DDA) is a rare pathologically distinct subtype of reactive angioendotheliomatosis. In the literature, few biopsy-proven cases involving breast skin have been reported. We present a case of a 49-year-old female who presented with an indurated, erythematous, weeping, puckered and tender lesion with focal ulceration. Mammography demonstrated diffuse cutaneous and trabecular thickening concerning for inflammatory breast carcinoma. A punch biopsy demonstrated findings consistent with DDA. To our knowledge, this is the first reported case of DDA mimicking inflammatory carcinoma of the breast by clinical and radiologic examination.

Imaging Unusual Pregnancy Implantations: Rare Ectopic Pregnancies and More.

OBJECTIVE: The purpose of this article is to review key clinical issues and imaging features of unusual pregnancy implantations. Examples from different imaging modalities are provided to increase interpreting physicians' familiarity with the appearance and potential complications of unusual ectopic, cesarean scar, heterotopic, and rudimentary horn pregnancies. CONCLUSION: Abnormal pregnancy implantations are life-threatening. Interpreting physicians' familiarity with the appearance of unusual pregnancy implantations is critical for early identification and initiation of appropriate therapy.

Clinical and Radiologic Follow-up Study for Biopsy Diagnosis of Radial Scar/Radial Sclerosing Lesion without Other Atypia.

To determine the incidence of malignancy for radial scars (RS)/radial sclerosing lesions (RSL) without associated atypia or malignancy identified at needle biopsy. Retrospective review of the pathology data base from January 2004 to July 2013 yielded 100 needle biopsies diagnosed as RS/RSL without associated atypia/malignancy. The RS/RSL was considered "incidental" if the target was calcifications and "targeted" if imaging revealed a mass, architectural distortion, or suspicious magnetic resonance imaging enhancement. The electronic medical record was used to identify surgical pathology, follow-up imaging, and clinical course; all pathology slides and imaging were reviewed by a board-certified pathologist and radiologist, respectively. Patient age, laterality, RS/RSL size, microcalcifications, and associated benign lesions were recorded. Among 100 cases, 54 were "incidental" and 46 were "targeted." In the incidental group, 14 underwent excision, 30 had imaging follow-up, and 10 were lost to follow-up. In the targeted group, 27 underwent excision, 11 had imaging follow-up, and 8 were lost to follow-up. Atypia was identified in four excisions: three from the incidental group and one from the targeted group. Among these, three had negative imaging follow-up (mean 45 months; range 15-60 months); the fourth patient (one of the incidental group) underwent excision alone. One of the 27 "targeted" patients who underwent excision developed ductal carcinoma in situ of the contralateral breast at 96 months. There have been no ipsilateral malignancies. We found no evidence of associated malignancy at excision for either incidental or targeted biopsies of RS/RSL without atypia. Our study suggests that close imaging follow-up is adequate for patients with RS/RSL without associated atypia/malignancy on needle biopsy.

Changes in recall type and patient treatment following implementation of screening digital breast tomosynthesis.

PURPOSE: To compare recall rate, types of abnormalities recalled, additional imaging required, biopsy positive predictive value (PPV), and cancer detection rate before and after implementation of screening digital breast tomosynthesis (DBT). MATERIALS AND METHODS: This retrospective analysis was approved by the institutional review board and complied with HIPAA. The requirement to obtain informed consent was waived. Results from all screening digital mammography (DM) examinations performed without tomosynthesis from March 1, 2011, through February 29, 2012, and DBT examinations performed from March 1, 2012, through February 28, 2013, were reviewed to identify all Breast Imaging Reporting and Data System (BI-RADS) category 0 examinations (needs additional imaging). Radiology and pathology reports were reviewed. The recall rate, biopsy PPV, and cancer detection rate were calculated. Statistical analysis was performed by using a two-proportions z test. RESULTS: The recall rate was 9.3% (1175 of 12 577 examinations; 95% confidence interval [CI]: 8.8%, 9.9%) for DM and 6.4% (827 of 12 921 examinations; 95% CI: 6.0%, 6.8%) for DBT, an overall reduction of 31% (P < .00001). The recall rate was lower with DM than with DBT for masses (8.9% vs 26.8%, respectively), distortions (0.6% vs 5.3%), and calcifications (13.4% vs 20.3%) (P < .0001 for all). The recall rate was lower with DBT than with DM for asymmetries (13.3% vs 32.2%, respectively) and focal asymmetries (18.2% vs 32.2%) (P < .0001 for both). Diagnostic evaluation with ultrasonography (US) increased with DBT at the time of additional imaging (2.6% for DM vs 28.3% for DBT, P < .0001). There was no significant difference between DM and DBT with regard to biopsy PPV (30.2% vs 23.8%, P = .21) or cancer detection rate per 1000 patients (5.4 vs 4.6, P = .44). CONCLUSION: With DBT, the recall rate decreased and the biopsy PPV and cancer detection rate did not decrease. The distribution of recalled abnormalities changed, and more patients were evaluated with US only.

Improving outcomes of screening breast MRI with practice evolution: initial clinical experience with 3T compared to 1.5T.

PURPOSE: To determine if changing from 1.5T to 3T breast magnetic resonance imaging (MRI) is associated with a change in BI-RADS categories, positive predictive value of biopsy recommendation, or cancer detection rates in high-risk screening breast MRI. MATERIALS AND METHODS: Institutional Review Board (IRB) approval was obtained for this Health Insurance Portability and Accountability Act (HIPAA)-compatible retrospective review. Prior to October 2010, breast MRI was performed at 1.5T and after October 2010 breast MRI was performed at 3T. Reports of 495 consecutive screening 3T breast MRI exams from October 2010 through October 2011 were reviewed. Comparison was made to previously collected data on 650 screening breast MRI exams at 1.5T. Data were analyzed for statistical significance using the two-sample test of proportions. RESULTS: There were 495 screening breast MRI exams. There were 419 (84.6%) BI-RADS 1/2 results, 35 (7.1%) BI-RADS 3 results, and 41 (8.3%) BI-RADS 4/5 results. BI-RADS 4/5 results increased at 3T (P=0.04). The positive predictive value for BI-RADS 4/5 was 29.3% (12/41) at 3T, compared with 17.6% at 1.5T (P<0.001). Cancer detection rate was 2.6% at 3T, compared with 0.9% at 1.5T (P=0.02). CONCLUSION: Transition to 3T breast MRI in a screening population resulted in increased BI-RADS 4/5 interpretations, positive predictive value of biopsy recommendations, and cancer detection rate.

Probably benign breast MRI lesions: frequency, lesion type, and rate of malignancy.

PURPOSE: To determine the frequency, malignancy rate, and imaging characteristics of BI-RADS (Breast Imaging Reporting and Data System) 3 MRI detected lesions. MATERIALS AND METHODS: A total of 4370 consecutive contrast-enhanced breast MRI exams from March 1, 2004, to March 1, 2009, were retrospectively reviewed. The study was HIPAA (Health Insurance Portability Accountability Act) compliant and Institutional Review Board approved. The frequency of BI-RADS 3 MRI interpretations and lesion type, as well as malignancy rate at follow-up were calculated. RESULTS: There were 348/4370 (8%) BI-RADS 3 exams performed on 345 patients. There were 125 foci (35.9%), 52 non-masslike enhancements (14.9%), and 171 masses (49.1%). There were 207 lesions with biopsy or imaging follow-up of at least 24 months (mean, 32 months; range, 6-77 months) of the BI-RADS 3 lesion. Five of these 207 (2.4%) lesions were found to be malignant. CONCLUSION: Rate of malignancy among BI-RADS 3 MRI exams with follow-up was 2.4%. Types of lesions assigned as probably benign were 35.9% foci, 14.9% non-masslike enhancements, and 49.1% masses.

High-risk lesions at MRI-guided breast biopsy: frequency and rate of underestimation.

OBJECTIVE: The purpose of this article is to determine the underestimation rate of high-risk lesions diagnosed at MRI-guided breast biopsy. MATERIALS AND METHODS: This was a retrospective review of 446 MRI-guided breast biopsies from January 2006 through December 2010. Data were collected on examination indication, lesion size and type, and pathology results. Biopsies were performed with a 9-gauge vacuum-assisted device. Biopsy results of atypical ductal hyperplasia (ADH), papillary lesion, radial scar, lobular neoplasia, and atypia were identified and compared with final excisional pathology results. Underestimation rates were calculated and data were compared by patient and lesion characteristics using chi-square analysis. RESULTS: Of the 446 MRI-guided biopsies, 96 (21.5%) were high-risk lesions. Forty-two of 96 lesions (44%) were masses, and 54 (56%) showed nonmass enhancement. Twenty of 96 lesions (20.8%) were ADH, nine (9.4%) were lobular neoplasia, 27 (28.1%) were papillary lesions, 20 (20.8%) were radial scar, and 20 (20.8%) were other atypias. Sixty-nine of 96 lesions (71.9%) had surgical excisional pathology results available. Sixteen of 69 (23.2%) lesions were upgraded to malignancy; 11 of the 16 (68.8%) were upgraded to ductal carcinoma in situ (DCIS) and five (31.2%) were upgraded to invasive carcinoma. The underestimation rate was 31.6% (6/19) for ADH, 5.9% (1/17) for papillary lesions, 23.1% (3/13) for radial scar, 28.6% (2/7) for lobular neoplasia, and 30.8% (4/13) for other atypias (p = 0.43). There was no statistically significant difference in underestimation rate by lesion type, size, or history of newly diagnosed breast cancer. CONCLUSION: MRI-guided breast biopsy yielded high-risk lesions in 21.5% of cases, and the underestimation rate was 23.2%. No patient or lesion characteristics correlated with underestimation rate.