Mammography is the primary method for breast cancer imaging. Its introduction in the 1960s and 1970s revolutionized breast cancer screening, leading to reduced mortality from breast cancer with use of relatively inexpensive imaging tool. However, breast magnetic resonance imaging (MRI), introduced in the 1990s, has been shown to be highly sensitive (nearly 100%) and accurate due to its ability to determine the contrast enhancement properties of tumors, nevertheless it has lower specificity than standard mammography owing to the false-positive results associated with contrast enhancement of benign breast parenchyma.

Although the use of iodinated contrast material increases the conspicuity of hypervascular tumors at digital mammography, overlapping high-density breast tissue can still mask small enhancing tumors. This challenge has led to the development of subtraction contrast-enhanced mammography (CEM) techniques that utilizes a dual-energy technique that combines low energy imaging with recombined imaging by imaging the breast energies just above and just below the k edge of iodine. Also CEM is less expensive, faster and easier to perform than MRI, and is preferred by patients.

Since the initial feasibility study, additional studies have demonstrated that CEM, alone or in combination with standard mammography, is as accurate as MRI for lesion detection. Compared with MRI, CEM has demonstrated lower sensibility but higher specificity, particularly in patients with dense breast tissue. Furthermore,the information acquired from CEM images has been found to be specially useful in addressing inconclusive screening studies, shows promise for possible improvement in high risk screening populations, and enables assessment of neoadjuvant systemic therapy responses.

There are various reasons for false positives and false negatives at CEM. False positives at CEM can be caused by benign lesions with vascularity, including benign tumors, infection or inflammation, benign lesions in the skin, and imaging artifacts. False negatives at CEM can be attributed to incomplete or inadequate visualization of lesions, marked background parenchymal enhancement (BPE) obscuring cancer, lack of lesion contrast enhancement due to technical issues or less-vascular cancers, artifacts, and errors of lesion perception or characterization. When possible, real-time interpretation of CEM studies is ideal. If additional views are necessary, they may be obtained while contrast material is still in the breast parenchyma.