Impact of Background Parenchymal Enhancement on Diagnostic Performance in Screening Breast MRI

Abstract

Rationale and objectives: To evaluate the impact of background parenchymal enhancement (BPE) on diagnostic performance in screening breast magnetic resonance imaging (MRI).

Materials and methods: Consecutive screening breast MRIs performed at our institution from 2011 to 2014 were reviewed in a HIPAA-compliant manner with institutional review board approval. BPE was extracted from radiology reports and examinations grouped into minimal/mild (lower) or moderate/marked (higher) BPE. Performance measures were compared between the two groups with Pearson's χ2 test and with logistic regression to adjust for possible confounders of age, screening indication, mammographic density, available prior MRI, and examination year, using lower BPE as the reference group.

Results: For 4686 screening MRIs performed in 2446 women, BPE was reported as minimal or mild for 3975 (85%) examinations and moderate or marked for 711(15%). Following logistic regression to adjust for multiple confounders, abnormal interpretation rate (AIR) significantly differed between the two BPE groups. AIR was 13% (89/711) in the higher BPE group versus 7% (295/3975) in the lower BPE group with an adjusted odds ratio of 1.37 (95% confidence interval: 1.03, 1.82). After adjustment, all other performance metrics, including cancer detection rate, positive predictive value, sensitivity, and specificity did not significantly differ between the two BPE groups (P > 0.05).

Conclusion: Higher BPE on screening MRI is associated with higher abnormal interpretation rate, with no impact on cancer detection rate, sensitivity, or specificity.

Keywords: Background parenchymal enhancement; Breast cancer; Magnetic resonance imaging; Screening.