Breast MRI BI-RADS assessments and abnormal interpretation rates by clinical indication in US community practices

Diffusion-weighted Imaging Allows for Downgrading MR BI-RADS 4 Lesions in Contrast-enhanced MRI of the Breast to Avoid Unnecessary Biopsy

PURPOSE

Diffusion-weighted imaging with the calculation of an apparent diffusion coefficient (ADC) has been proposed as a quantitative biomarker on contrast-enhanced MRI (CE-MRI) of the breast. There is a need to approve a generalizable ADC cutoff. The purpose of this study was to evaluate whether a predefined ADC cutoff allows downgrading of BI-RADS 4 lesions on CE-MRI, avoiding unnecessary biopsies.

EXPERIMENTAL DESIGN

This was a retrospective, multicentric, cross-sectional study. Data from five centers were pooled on the individual lesion level. Eligible patients had a BI-RADS 4 rating on CE-MRI. For each center, two breast radiologists evaluated the images. Data on lesion morphology (mass, non-mass), size, and ADC were collected. Histology was the standard of reference. A previously suggested ADC cutoff (≥1.5 × 10-3 mm2/second) was applied. A negative likelihood ratio of 0.1 or lower was considered as a rule-out criterion for breast cancer. Diagnostic performance indices were calculated by ROC analysis.

RESULTS

There were 657 female patients (mean age, 42; SD, 14.1) with 696 BI-RADS 4 lesions included. Disease prevalence was 59.5% (414/696). The area under the ROC curve was 0.784. Applying the investigated ADC cutoff, sensitivity was 96.6% (400/414). The potential reduction of unnecessary biopsies was 32.6% (92/282).

CONCLUSIONS

An ADC cutoff of ≥1.5 × 10-3 mm2/second allows downgrading of lesions classified as BI-RADS 4 on breast CE-MRI. One-third of unnecessary biopsies could thus be avoided.

Multispectral Imaging for Metallic Biopsy Marker Detection During MRI-Guided Breast Biopsy: A Feasibility Study for Clinical Translation

Purpose

To assess the feasibility and diagnostic accuracy of multispectral MRI (MSI) in the detection and localization of biopsy markers during MRI-guided breast biopsy.

Methods

This prospective study included 20 patients undergoing MR-guided breast biopsy. In 10 patients (Group 1), MSI was acquired following tissue sampling and biopsy marker deployment. In the other 10 patients (Group 2), MSI was acquired following tissue sampling but before biopsy marker deployment (to simulate deployment failure). All patients received post-procedure mammograms. Group 1 and Group 2 designations, in combination with the post-procedure mammogram, served as the reference standard. The diagnostic performance of MSI for biopsy marker identification was independently evaluated by two readers using two-spectral-bin MR and one-spectral-bin MR. The κ statistic was used to assess inter-rater agreement for biopsy marker identification.

Results

The sensitivity, specificity, and accuracy of biopsy marker detection for readers 1 and 2 using 2-bin MSI were 90.0% (9/10) and 90.0% (9/10), 100.0% (10/10) and 100.0% (10/10), 95.0% (19/20) and 95.0% (19/20); and using 1-bin MSI were 70.0% (7/10) and 80.0% (8/10), 100.0% (8/8) and 100.0% (10/10), 85.0% (17/20) and 90.0% (18/20). Positive predictive value was 100% for both readers for all numbers of bins. Inter-rater agreement was excellent: κ was 1.0 for 2-bin MSI and 0.81 for 1-bin MSI.

Conclusion

MSI is a feasible, diagnostically accurate technique for identifying metallic biopsy markers during MRI-guided breast biopsy and may eliminate the need for a post-procedure mammogram.

Breast Magnetic Resonance Imaging Audit: Pitfalls, Challenges, and Future Considerations

Breast magnetic resonance (MR) imaging is the most sensitive imaging modality for breast cancer detection and guidelines recommend its use, in addition to screening mammography, for high-risk women. The most recent American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS) manual coordinated cross-modality BI-RADS terminology and established an outcome monitoring section that helps guide a medical imaging outcomes audit. This article provides a framework for performing a breast MR imaging audit in clinical practice, incorporating ACR BI-RADS guidance and more recently published data, clarifies common pitfalls, and discusses audit challenges related to evolving clinical practice.

Variation in Technical Quality of Breast MRI

PURPOSE

Breast magnetic resonance imaging (MRI) quality may vary across the United States. Our aim was to investigate the quality of outside breast MRIs presenting for second opinion at a tertiary cancer center following implementation of the American College of Radiology (ACR) Breast MRI Accreditation Program.

MATERIALS AND METHODS

We retrospectively reviewed the technical quality of the MRI studies of 100 consecutive cases submitted for second opinion in 2013. The image quality was blindly reviewed per ACR Breast MRI Accreditation Program by three fellowship-trained breast radiologists and one breast imaging fellow.

RESULTS

In total, 88 of the 100 cases were referred from facilities in the United States. Sixty (68%) of the 88 cases had at least one technical deficiency. In 10 cases (11%), more than five different technical deficiencies occurred. The most frequently encountered deficiencies were related to artifacts (74%), with shimming (N = 17) and motion (N = 16) being the most common. In total, 38% of cases (N = 33) had a deficient T2-weighted sequence, mostly due to low signal to noise ratio (N = 25). A total of 27% cases (N = 24) had deficiencies in the delayed phase postcontrast T1-weighted sequence, mainly due to low signal to noise ratio (N = 21) and 23% had deficiencies in the early phase postcontrast T1-weighted sequence, predominantly due to low signal to noise ratio as well. (N = 19).

CONCLUSION

Our study demonstrates variability of breast MRI quality across the United States. Radiologists should become familiar with the requirements of the ACR breast MRI accreditation program and strive to meet the expected standards in order to enhance patient quality and safety.

American College of Radiology Accreditation, Performance Metrics, Reimbursement, and Economic Considerations in Breast MR Imaging

Accreditation through the American College of Radiology (ACR) Breast Magnetic Resonance Imaging Accreditation Program is necessary to qualify for reimbursement from Medicare and many private insurers and provides facilities with peer review on image acquisition and clinical quality. Adherence to ACR quality control and technical practice parameter guidelines for breast MR imaging and performance of a medical outcomes audit program will maintain high-quality imaging and facilitate accreditation. Economic factors likely to influence the practice of breast MR imaging include cost-effectiveness, competition with lower-cost breast-imaging modalities, and price transparency, all of which may lower the cost of MR imaging and allow for greater utilization.

Prevalence and Predictive Value of BI-RADS 3, 4, and 5 Lesions Detected on Breast MRI: Correlation with Study Indication

RATIONALE AND OBJECTIVES

This study aims to determine the prevalence and predictive value of Breast Imaging Reporting and Data System (BI-RADS) 3, 4, and 5 findings on breast magnetic resonance imaging (MRI) and to evaluate the impact of study indication on the predictive value of BI-RADS categories.

MATERIALS AND METHODS

This institutional review board approved, Health Insurance Portability and Accountability Act (HIPAA) compliant retrospective review of our breast MRI database from 2009 to 2011, of 5778 contrast-enhanced studies in 3360 patients was performed. At our institution, each breast receives an individual BI-RADS assessment. Breast MRI reports and electronic medical records were reviewed to obtain BI-RADS assessment, patient demographics, and outcomes. Univariate analysis was performed with Fisher exact and chi-square tests.

RESULTS

A total of 9216 BI-RADS assessments were assigned during the study period: 7879 (85.5%) BI-RADS 1 and 2, 567 (6.2%) BI-RADS 3, 715 (7.8%) BI-RADS 4, and 55 (0.6%) BI-RADS 5 assessments. The frequency of BI-RADS 3, 4, and 5 assessments was higher in studies performed for diagnostic (7.8%, 14.6%, 1.6%, respectively) than screening (5.2%, 4.0%, 0.1%) indications (P < 0.01). A total of 663 BI-RADS 4 and 5 lesions were biopsied with 209 (31.5%) malignant and 454 (68.5%) benign outcomes. The overall cancer rate for BI-RADS 3 findings was 1.9% (11 of 567) with no difference observed by study indication (diagnostic, 1.6%; screening, 2.3%; P = 0.76). The positive predictive value (PPV2) of BI-RADS 4 and 5 was higher for diagnostic (29.1%, 154 of 530) than for screening (22.9%, 55 of 240) indications.

CONCLUSIONS

Abnormal interpretation rates and PPV2 for MRIs performed for diagnostic indications are higher than for screening indications. Similar to mammography, breast MRI audits should be separated by study indication.

Screening Breast MRI Outcomes in Routine Clinical Practice: Comparison to BI-RADS Benchmarks

RATIONALE AND OBJECTIVES

The BI-RADS Atlas 5th Edition includes screening breast magnetic resonance imaging (MRI) outcome benchmarks. However, the metrics are from expert practices and clinical trials of women with hereditary breast cancer predispositions, and it is unknown if they are appropriate for routine practice. We evaluated screening breast MRI audit outcomes in routine practice across a spectrum of elevated risk patients.

MATERIALS AND METHODS

This Institutional Review Board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included all consecutive screening breast MRI examinations from July 1, 2010 to June 30, 2013. Examination indications were categorized as gene mutation carrier (GMC), personal history (PH) breast cancer, family history (FH) breast cancer, chest radiation, and atypia/lobular carcinoma in situ (LCIS). Outcomes were determined by pathology and/or ≥12 months clinical and/or imaging follow-up. We calculated abnormal interpretation rate (AIR), cancer detection rate (CDR), positive predictive value of recommendation for tissue diagnosis (PPV2) and biopsy performed (PPV3), and median size and percentage of node-negative invasive cancers.

RESULTS

Eight hundred and sixty examinations were performed in 566 patients with a mean age of 47 years. Indications were 367 of 860 (42.7%) FH, 365 of 860 (42.4%) PH, 106 of 860 (12.3%) GMC, 14 of 860 (1.6%) chest radiation, and 8 of 22 (0.9%) atypia/LCIS. The AIR was 134 of 860 (15.6%). Nineteen cancers were identified (13 invasive, 4 DCIS, two lymph nodes), resulting in CDR of 19 of 860 (22.1 per 1000), PPV2 of 19 of 88 (21.6%), and PPV3 of 19 of 80 (23.8%). Of 13 invasive breast cancers, median size was 10 mm, and 8 of 13 were node negative (61.5%).

CONCLUSIONS

Performance outcomes of screening breast MRI in routine clinical practice across a spectrum of elevated risk patients met the American College of Radiology Breast Imaging Reporting and Data System benchmarks, supporting broad application of these metrics. The indication of a personal history of treated breast cancer accounted for a large proportion (42%) of our screening examinations, with breast MRI performance in this population at least comparable to that of other screening indications.

Challenges With Identifying Indication for Examination in Breast Imaging as a Key Clinical Attribute in Practice, Research, and Policy

PURPOSE

To assess indication for examination for four breast imaging modalities and describe the complexity and heterogeneity of data sources and ascertainment methods.

METHODS

Indication was evaluated among the Population-based Research Optimizing Screening through Personalized Regimens (PROSPR) breast cancer research centers (PRCs). Indication data were reported overall and separately for four breast imaging modalities: digital mammography (DM), digital breast tomosynthesis (DBT), ultrasound (US), and magnetic resonance imaging (MRI).

RESULTS

The breast PRCs contributed 236,262 women with 607,735 breast imaging records from 31 radiology facilities. We found a high degree of heterogeneity for indication within and across six data sources. Structured codes within a data source were used most often to identify indication for mammography (59% DM, 85% DBT) and text analytics for US (45%) and MRI (44%). Indication could not be identified for 17% of US and 26% of MRI compared with 2% of mammography examinations (1% DM, 3% DBT).

CONCLUSIONS

Multiple and diverse data sources, heterogeneity of ascertainment methods, and nonstandardization of codes within and across data systems for determining indication were found. Consideration of data sources and standardized methodology for determining indication is needed to assure accurate measurement of cancer screening rates and performance in clinical practice and research.

Diagnostic Performance of Breast Magnetic Resonance Imaging in Non-Calcified Equivocal Breast Findings: Results from a Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the performance of MRI for diagnosis of breast cancer in non-calcified equivocal breast findings.

MATERIALS AND METHODS

We performed a systematic review and meta-analysis of peer-reviewed studies in PubMed from 01/01/1986 until 06/15/2015. Eligible were studies applying dynamic contrast-enhanced breast MRI as an adjunct to conventional imaging (mammography, ultrasound) to clarify equivocal findings without microcalcifications. Reference standard for MRI findings had to be established by histopathological sampling or imaging follow-up of at least 12 months. Number of true or false positives and negatives and other characteristics were extracted, and possible bias was determined using the QUADAS-2 applet. Statistical analyses included data pooling and heterogeneity testing.

RESULTS

Fourteen out of 514 studies comprising 2,316 lesions met our inclusion criteria. Pooled diagnostic parameters were: sensitivity (99%, 95%-CI: 93-100%), specificity (89%, 95%-CI: 85-92%), PPV (56%, 95%-CI: 42-70%) and NPV (100%, 95%-CI: 99-100%). These estimates displayed significant heterogeneity (P<0.001).

CONCLUSIONS

Breast MRI demonstrates an excellent diagnostic performance in case of non-calcified equivocal breast findings detected in conventional imaging. However, considering the substantial heterogeneity with regard to prevalence of malignancy, problem solving criteria need to be better defined.