Detection of mammographically occult architectural distortion on digital breast tomosynthesis screening: initial clinical experience

Abstract

Objective: Digital breast tomosynthesis (DBT) has been shown to improve the sensitivity of screening mammography. DBT may have the most potential impact in cases of subtle mammographic findings such as architectural distortion (AD). The objective of our study was to determine whether DBT provides better visualization of AD than digital mammography (DM) and whether sensitivity for cancer detection is increased by the addition of DBT as it relates to cases of mammographically occult AD.

Materials and methods: Retrospective review of BI-RADS category 0 reports from 9982 screening DM examinations with adjunct DBT were searched for the term "architectural distortion" and were reviewed in consensus by three radiologists. ADs were classified by whether they were seen better on DM or DBT, were seen equally well on both, or were occult on either modality. The electronic medical record was reviewed to identify additional imaging studies, biopsy results, and surgical excision pathology results.

Results: Review identified 26 cases of AD, 19 (73%) of which were seen only on the DBT images. Of the remaining seven ADs, six were seen better on DBT than DM. On diagnostic workup, nine lesions were assigned to BI-RADS category 4 or 5. Surgical pathology revealed two invasive carcinomas, two ductal carcinoma in situ lesions, three radial scars, and two lesions showing atypia. The cancer detection rate of DBT in mammographically occult AD was 21% (4/19). The positive predictive value of biopsy was 44%.

Conclusion: DBT provides better visualization of AD than DM and identifies a subset of ADs that are occult on DM. Identification of additional ADs on DBT increases the cancer detection rate.

Keywords: architectural distortion; mammography screening; tomosynthesis.