In spite of significant gains in detection and treatment, breast cancer continues to have a broad impact in the United States, with an estimated 234,580 individuals with new diagnoses in 2013. About 33 percent of individuals with breast cancer diagnosed between 2001 and 2007 had regional metastases, with a 5-year relative survival rate of 84 percent. Approximately 5 percent were diagnosed with distant metastases, most commonly to the bones, lungs, liver, or brain, and had a 5-year relative survival rate of only 23 percent. Several imaging modalities, including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), PET/CT, and bone scintigraphy, are used to evaluate the effects of treatment for metastatic breast cancer. However, as outlined in guidelines from the National Comprehensive Cancer Network and the National Institute for Health and Clinical Excellence, evidence regarding the accuracy and effectiveness of these modalities to evaluate treatment of metastatic breast cancer is lacking, even though the types and results of imaging may strongly affect patient outcomes. Inappropriate use could lead to overtreatment. Although multiple imaging modalities for treatment evaluation for metastatic breast cancer are used clinically, their comparative effectiveness in terms of health outcomes, patient satisfaction, and cost, has not been determined. The purpose of this technical brief is to understand current imaging utilization, emerging technologies, research in progress, patient values, and study design issues, in order to summarize the current state of the science and inform future research in this area. We evaluated whether imaging technologies were utilized differently among subpopulations and whether outcomes varied by subpopulations. We also evaluated the potential role of novel biomarkers in imaging for treatment evaluation of metastatic breast cancer. We combined information we obtained from published literature, gray literature, and Key Informants in order to provide the context for appropriate comparative effectiveness studies on imaging for treatment evaluation for metastatic breast cancer in the near future.