Diagnostic Excellence, Imaging Stewardship, and Re-establishing the Value Proposition in Radiology: A Look Back and a Way Forward.

Historically, imaging was used to test specific clinical hypotheses and reduce diagnostic uncertainty by clarifying, narrowing, and prioritizing differential diagnoses. Advanced imaging, such as CT and MRI, was used judiciously owing to concerns about high costs and, in the case of CT scanning, the need to limit patients' exposure to ionizing radiation. But times have changed: the threshold for ordering imaging tests is now substantially lower, and as a result, a high - and growing - volume of low-value imaging is performed, often without any particular clinical or diagnostic hypothesis in mind. Several factors are contributing to this excess demand. Perhaps chief among them is a psychological discomfort with diagnostic uncertainty and a higher tolerance for low-value imaging. Other factors include perceived medicolegal risk and the widespread expectation that physicians exhaustively investigate all incidental findings. These factors are effectively changing the role of diagnostic imaging in ways that far exceed its original mandate of answering specific clinical questions. In this manuscript, we discuss these factors, review the value proposition of imaging, and attempt to place its use in the context of diagnostic excellence. We also discuss methods to curb increasing overutilization.