Contrast Enhanced Mammography versus Breast MRI for pre- operative assessment of pathologically proven breast malignancies: A case series from a large regional tertiary cancer center experience.

Background: Contrast-enhanced mammography (CEM) is a fast-developing imaging technique that combines full-field digital mammography with a dual-energy technique following injection of iodinated contrast injection. CEM has been widely used over the last few decades as an adjunct breast cancer diagnostic tool, but over the past years, it has played a pivotal role in assessing disease extent in the pre-operative setting as an alternative to breast MRI due to different factors, including availability and better tolerability among breast cancer patients.

We are presenting a collection of case reports around pre-operative assessment of pathology-proven breast cancer cases, each with both CEM and breast MRI done at our large regional tertiary cancer centre.

Learning Objectives: 1. Increase familiarity with CEM as a modality.
2. Know how to apply the CEM BI-RADS lexicon vs MRI BI-RADS lexicon.
3. Identifying the similarities and differences in regard to the extent of disease on both CEM and MRI.
4. Identifying potential pitfalls of each modality.
5. Identifying causes of false positives/negatives of each modality.

Abstract Content/Results: Pathology-proven breast cancer cases, each had both CEM and MRI done for pre-operative assessment. Total number of cases = 5
Each case:
-Short introduction of each case, including patient's history and presentation.
-Pathology results (histology + grade+ markers) and patient course.
-Presenting both CEM and MRI images with annotated findings.
-Comparison of each modality in terms of
1. Findings
2. Number of additional lesions
3. Lesion enhancement relative to background
4. Size of lesions
5. NBCC score
-Discussion of additional lesions detected by either modality and/or referring to discrepancies in findings.
-Followed by a brief discussion over the cause of false positives/negatives in each case (difference of background parenchymal enhancement, technical factors, out-of-field/deep lesions..etc.)

Conclusion: This case series underlines the differences and similarities between CEM and breast MRI in the pre-operative assessment setting. Five pathology-proven breast cancer cases from our large regional tertiary cancer centre will be presented. The advantages and pitfalls of each modality will be highlighted in this presentation, backed up with annotated high-quality images.