Neera Malik MD, Presenter: Nothing to Disclose

Jean M. Seely MD, Abstract Co-Author: Nothing to Disclose

Barbara Deren, Abstract Co-Author: Nothing to Disclose

Jacqueline Christine Lau MD, Abstract Co-Author: Nothing to Disclose

Angel Arnaout MD, MSc, Abstract Co-Author: Nothing to Disclose

To determine the yield of pre-operative breast MRI in patients with fat-density breasts.

Patients who underwent breast MRI in 2009 for pre-operative staging of  breast cancer were recorded. Of these, those with mammography performed at our insitution within 3 years of the breast MRI were identified. Patients for whom mammography had been performed elsewhere and for whom imaging was unavailable were included if mammographic findings were indicated in the breast MRI report. For patients meeting these criteria, mamographic breast density and the presence of additional multifocal, multicentric, and contralateral lesions on breast MRI not identified on mammography were recorded.

570 pre-operative breast MRIs were performed in 2009 in patients with breast cancer, of which mammographic density within 3 years of breast MRI was available in 267 cases. Of these, 33 had fat density breasts with MRI identifying additional lesions in 18% of cases. Additional lesions included multifocal disease (n=1), multicentric disease (n=3), stromal fibrosis and sclerosing adenosis (n=1), and papilloma (n=1). Of the 33 patients with fat density breasts, MRI altered management in the 4 patients with new multifocal and multicentric disease (12%). 100 patients had scattered fibroglandular parenchyma, with MRI identifying 41 additional lesions; 92 patients had heterogeneously dense breasts, with MRI identifying 44 additional lesions; and 37 patients had dense breasts, with MRI identifying 22 additional lesions. Chi-squared analysis showed a statistically significant difference between breast density and number of additional findings on MRI (p<0.005). Patients with fat density breasts were 6.6X less likely to have additional findings on MRI compared to those with dense breasts (95% CI 2.2-19.9, p<0.005).

Although patients with fat density breasts are 6.6X less likely to have additional findings on pre-operative breast MRI in comparison to patients with dense breasts, 12% of patients with fat density breasts had additional MRI findings that altered management. Thus, if selective use of pre-operative MRI is considered, patients with fat density breasts show relatively low benefit.

Identifying a subset of patients in whom pre-operative breast MRI is of low yield and can be obviated will result in more optimal allocation of health care resources and more timely management.

Malik, N, Seely, J, Deren, B, Lau, J, Arnaout, A, The Yield of Pre-operative Breast MRI in Patients with Fat Density Breasts.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13022873.html