Breast MRI and Background Parenchymal Enhancement: What a Meta-Analysis Reveals

A new meta-analysis shows that the presence of moderate or marked background parenchymal enhancement (BPE) significantly compromises the sensitivity and specificity of breast magnetic resonance imaging (MRI).

For the meta-analysis, recently published in Radiology, researchers reviewed breast MRI data from eight studies and a total of 6,044 women (mean age of 52). Out of 8,182 detected lesions, 6,583 (80.5 percent) were detected on scans with minimal or mild BPE and 1,599 lesions (19.5 percent) were revealed on MRIs with moderate or marked BPE, according to the study.

The study authors found that breast MRI scans with minimal or mild BPE offered a greater AUC and over 10 percent higher sensitivity and specificity in contrast to MRI views with moderate or marked BPE.

Specifically, the researchers noted a 95.3 sensitivity, an 89 percent specificity and a 95 percent AUC in cases with minimal or mild BPE. When breast MRI scans had moderate or marked BPE, the study authors found an 84.1 percent sensitivity, 78.7 percent specificity and a 91 percent AUC.

“ … The degree of background parenchymal enhancement (BPE) has an impact on the diagnostic performance of breast MRI, with minimal or mild BPE being associated with higher sensitivity and specificity and moderate or marked BPE being associated with lower diagnostic performance. The degree of BPE in MRI reports may prompt follow-up strategies and additional imaging to prevent missed diagnoses and unnecessary biopsies,” wrote Sonja Bechyna, M.D., and Pascal A.T. Baltzer, M.D., who are affiliated with the Department of Biomedical Imaging and Image-Guided Treatment at the University of Vienna in Vienna, Austria, and colleagues.

While acknowledging that they did not specifically assess the impact of BPE on abnormal interpretation rate or biopsies, the study authors emphasized key treatment considerations that can be missed in cases involving a higher degree of BPE.

“Moderate or marked BPE may mask multifocal or multicentric lesions, especially non-mass enhancements, compared with monofocal masses,” noted Drs. Bechyna and Baltzer.

In an accompanying editorial, Manisha Bahl, MD, suggested that BPE could be a factor in enhancing personalized risk stratification.

“BPE could be added to risk models to guide imaging surveillance strategies and inform individualized patient counseling. In addition, changes in BPE have been explored as a surrogate marker of response to neoadjuvant chemotherapy. These emerging insights about BPE highlight the need for more standardized and reproducible methods for assessing BPE in addition to a clearer understanding of its biologic underpinnings,” posited Dr. Bahl, an associate professor of radiology at Harvard Medical School.

(Editor’s note: For related content, see “Study Questions Utility of Ultrafast Breast MRI for Challenging Lesions and Moderate/Marked BPE,” “Contrast-Enhanced Mammography Study Reveals 24 Percent Lower Sensitivity with Moderate/Marked BPE” and “Abbreviated MRI and Contrast-Enhanced Mammography Provide Fourfold Higher Cancer Detection than Breast Ultrasound.”)

In regard to study limitations, the meta-analysis authors noted that single-center studies comprised many of the reviewed studies and acknowledged a lack of differentiation between mass and non-mass lesions with different BPE in the majority of the studies. The researchers also conceded wide variability between the studies with respect to screening indications.