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Background
Contrast-enhanced mammography (CEM) is an increasingly used modality that may improve breast cancer detection in select patient populations. Dedicated education on the appropriate indications, protocol, advantages, and limitations of CEM is not formally addressed in many academic curricula. As CEM becomes increasingly available, it is important for residents, technicians, and ordering providers to understand the applications of CEM for breast cancer screening.

Educational Goals / Teaching Points
For radiology residents and mammography imaging technicians to become familiar with a typical CEM protocol, review the applications of CEM as it applies to breast cancer screening, and understand the advantages and limitations of CEM.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Two minutes after IV administration of iodinated contrast (1.5 mL/kg at 2-3mL/sec), full-field exposures at high and low energy are obtained in craniocaudal (CC) and mediolateral oblique (MLO) views. Both sets of images are used to create a recombined image demonstrating enhancement. In a screening setting, a minimum of 8 images are generated showing the low energy and recombined CC and MLO views bilaterally. CEM has been used to supplement the evaluation of specific patient populations with improved cancer detection rates, including those with dense breast tissue, family history of breast cancer, high risk of breast cancer, clarification of indeterminate screening exam findings, evaluating the extent of disease, and monitoring treatment response. Currently, CEM has not been approved by the FDA for screening; however, some studies indicate its utility in certain screening populations with increased sensitivity and specificity as compared to conventional screening full-field digital mammography (FFDM). In the newest ACR guidelines, CEM should be considered as a supplemental screening method for women with dense breasts or other elevated risk factors, or for those who are high risk with contraindications for MRI. CEM is more sensitive than FFDM, more sensitive and specific than FFDM + ultrasound, and has similar sensitivity and specificity to breast MRI with fewer false positive results and offers logistical advantages over MRI such as cost, examination time, patient satisfaction, patient eligibility for MRI, and the ease of implementation in standard mammography equipment, thereby increasing accessibility. The radiation dose in CEM is less than FFDM + tomosynthesis, following MQSA guidelines. From a safety standpoint, the concern for studies using contrast is the risk of an allergic reaction, ineligibility due to renal insufficiency, and increased radiation exposure. Technical performance errors, including limited FOV or improper contrast administration, can lead to missed lesions or false negatives.

Conclusion
CEM is an increasingly utilized imaging technique with the potential to improve breast cancer detection rates compared to traditional screening mammography. CEM has been shown to be particularly helpful in detecting breast cancer in patients with dense breast tissue, without a history of iodinated contrast allergy.