Outcome of Architectural Distortion Detected Only at Breast Tomosynthesis versus 2D Mammography

Purpose: To compare the outcome of architectural distortion (AD) without associated mass only on digital breast tomosynthesis (DBT) with AD seen at two-dimensional (2D) mammography and to evaluate if the incidence of malignancy is influenced by the presence of a correlate at ultrasonography (US). Materials and Methods: This retrospective study had institutional review board approval and was HIPAA compliant. All consecutive cases in which patients with AD were ultimately assigned Breast Imaging Reporting and Data System (BI-RADS) 4 or 5 categories from 2009 to 2016 were reviewed by three readers for visibility (2D vs DBT). The level of suspicion was assigned using a Likert scale. Pathologic results were compared between 2D-detected and DBT-detected AD. Frequencies were compared by using the McNemar and Pearson chi(2) exact tests. Results: One hundred eighty-one AD lesions were included; 122 (67.4%) were 2D visible while 59 (32.6%) were DBT detected. Forty-two women (with 43 lesions) underwent 2D mammography prior to initiation of DBT. In 117 women with 121 AD lesions who underwent 2D mammography plus DBT, 59 lesions (48.8%) were detected only with DBT. The malignancy rate based on final pathology was significantly higher for 2D-detected AD (53 [43.4%] of 122) compared with DBT (six [10.2%] of 59) (P < .001). A US correlate was more frequent with 2D-detected AD (103 [84.4%] of 122) than DBT (33 [55.9%] of 59) (P < .001). Malignancy rate was not different for DBT-detected AD with (four [12.1%] of 33; 95% confidence interval [CI]: 3.4%, 28.2%]) or without (two [7.7%] of 26; 95% CI: 0.9%, 25.1%]) a US correlate. NPV based on radiologists' level of suspicion was high (91.8%-98.0%) but not sufficient enough to forgo biopsy. Conclusion: DBT-detected suspicious AD has a lower malignancy outcome compared with 2D mammography-detected suspicious AD, although still high enough to warrant biopsy. (C) RSNA, 2018