The diffusion of technologies such as CT, MRI, PET, and SPECT has often been cited as an important driver of increasing medical expenditures. A number of important questions remain to be answered around whether expanding imaging leads to overall growth in the number of people using the services. Does expanded availability lead patients who would have been fine with one study to now get two? Does expanded availability lead patients who didn’t really need any studies to now get some?

These kinds of questions cannot be addressed with clinical trial or other data on the merits of imaging technologies in specific populations with specific conditions. They are, however, the exact questions that drive policy debates. If expanding imaging at the population level drives up costs, it could attract attempts to restrain it. Regulatory or other actions, however, would be best framed around information about the population-level effects on both costs and benefits of imaging expansion over time.

This project aims to provide evidence about these population-level effects of expanding MRI and CT availability on health care costs, utilization, and, ultimately, outcomes. The project is designed to:

• develop and examine measures of the availability of CT and MRI by geographic area over time;
  
  
• develop evidence about the relationship between the availability of diagnostic imaging services, utilization, and related spending;
  
  
• investigate the relationship between area availability of imaging, utilization patterns, and measures related to quality of care.