1. Expanding CT and MR Availability, Imaging Utilization in the Medicare Population, and the Challenge of Measuring Value (Health Affairs, 2008) Laurence Baker, PhD* Stanford University Scott Atlas, MD Stanford University Christopher Afendulis, PhD Harvard University *Presenter; contact: laurence.baker@stanford.edu

2. The number of CT and MRI units in the U.S. has grown substantially Procedure use has also grown rapidly, in Medicare and outside

3. Each new MRI scanner is associated with 800 more Medicare MRI procedures Each new CT scanner is associated with 2500 more Medicare CT procedures

4. Substituting newer diagnostic procedures for older Expanding the set of patients receiving any diagnostic procedures Changes in side effect rates Improvements in diagnostic precision & therapy Information More Better Faster Better health outcomes The value of information Information More Better Faster Improvements in diagnostic precision & therapy Better health outcomes The value of information

5. Better Health Outcomes Impacts on Costs The Value of Information What we need Estimates of health impacts on a population basis -accounting for treatment expansion -accounting for shifts in utilization A better understanding of the value of information What we have: Studies of some specific technologies applied to some specific populations vs. If we want to compare… We need evidence

6. -68 for people newly tested -15 for people who switch from catheter based angiography -16 for people who now get both CTA and catheter-based angiography An Example: CTA for Abdominal Aortic Aneurysm 100 Additional CTA Procedures 1.1 additional people who get a therapeutic treatment CT Angiography (CTA) is a newer, less invasive, way to diagnose potential abdominal aortic aneurysms. Can substitute for catheter based angiography.