Enhancing foci on breast MRI: Identifying criteria that increase levels of suspicion.

OBJECTIVE: Prior studies evaluating features of foci associated with malignancy have not been conclusive. This study evaluates foci that were deemed suspicious and assesses multiple imaging and clinical findings with the goal of identifying criteria that can increase diagnostic confidence when evaluating foci on breast MRI. METHODS: After Institutional Review Board approval, a retrospective chart review was performed to identify patients who underwent an image-guided biopsy of an enhancing focus. To be included in the study, a breast MRI performed between 2012 and 2019 must have been classified as suspicious for an enhancing focus or foci, and a biopsy using imaging guidance must have been subsequently performed. Patient and imaging characteristics as well as the corresponding biopsy results were recorded and statistically analyzed. RESULTS: There were 74 patients with 85 foci of enhancement who underwent biopsy within the study period. Thirteen of the 85 foci yielded malignant results for an overall positive predictive value of 15.3% (95% confidence interval: 7.7-22.9%). Additionally, twenty-six of the 85 cases (30.6%) yielded high risk lesions. There was a statistically significant negative correlation between screening breast MRIs and biopsies that yielded cancer or atypia (p = 0.04). There was also a significant association between foci and malignant results if the focus was in the same quadrant of a known malignancy (p = 0.001). CONCLUSION: Clinical information, such as the indication for a breast MRI or the location of a focus relative to a known cancer, can play an important role in evaluating foci of enhancement. Diagnostic confidence in identifying suspicious foci can be aided by incorporating clinical context with imaging findings deemed suspicious by prior research studies.

Architectural Distortion on Screening Digital Breast Tomosynthesis: Pathologic Outcomes and Indicators of Malignancy.

OBJECTIVE: Digital breast tomosynthesis (DBT) has significantly improved cancer detection capabilities through its identification of subtle findings often imperceptible on 2D digital mammography, particularly architectural distortion (AD). The purpose of this study was to analyze of suspicious AD detected on screening DBT to evaluate the incidence of malignancy and to determine other patient or imaging characteristics in these cases as possible predictors of malignancy. METHODS: This was an IRB approved retrospective analysis of subjects with AD detected on DBT screening mammography who were given a biopsy recommendation between January 1, 2016, and June 30, 2018. Univariate analysis of various imaging characteristics and patient high-risk factors was performed for statistical correlation with diagnosis of malignancy. RESULTS: In the 218 DBT-detected AD findings with a final BI-RADS assessment of 4 or 5 on diagnostic workup, 94 (43.1%) yielded malignancy, 57 (26.2%) were classified as high-risk, and 67 (30.7%) were benign. There was a strong statistically significant association with malignancy in the cases with an US correlate (P < 0.0001). There was a statistically significant inverse correlation between malignancy and one-view findings (P = 0.0002). The presence of AD on 2D (P = 0.005) or synthetic 2D views (P = 0.002) showed statistically significant correlations with malignancy, whereas breast density or high-risk factors (P = 0.316) did not. CONCLUSION: AD detected on DBT that persists on further workup and has no explainable cause should be considered suspicious for malignancy. Identification of the AD on both standard mammographic views and the presence of an US correlate significantly increase the probability of malignancy.