title: Utilization trends for advanced imaging procedures: evidence from individuals with private insurance coverage in California.
abstract: BACKGROUND
  Recent reports by the Medicare Payment Advisory Commission have highlighted sharp increases in the use of advanced diagnostic imaging procedures among the Medicare fee-for-service population. Little research has examined whether such trends also exist among persons with generous private insurance coverage. Moreover, research documenting changes in the share of utilization linked to self-referral is nonexistent.
  
  
  METHODS
  Using data from a large private insurer in California, we document trends in utilization for magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) scans over the time period 2000-2004. We collected data that enable us to calculate relative changes in use rates by provider type (self-referral physicians, radiologists, hospitals, and independent diagnostic testing facilities). Examining trends in the share of utilization performed by provider type can offer insights as to the effects of self-referral on rates of use.
  
  
  RESULTS
  Rates of use for the 3 advanced imaging modalities examined-MRI, CT, and PET-increased rapidly between 2000 and 2004. PET utilization increased by almost 400%, whereas the corresponding increases for MRI and CT exceeded 50%. Findings suggest that physician self-referral arrangements and independent diagnostic testing facilities seem to be contributing to this greater use of advanced imaging, especially for MRI and PET. In contrast, relative changes in use of advanced imaging performed at hospitals were small. Use rates for all 3 modalities were much higher in southern California compared with the northern region of the state.
  
  
  CONCLUSIONS
  Use of highly reimbursed advanced imaging, a major driver of higher health care costs, should be based on clear clinical practice guidelines to ensure appropriate use.
authors.affiliation: Georgetown University, Georgetown Public Policy Institute, 3520 Prospect St., NW Room 423, Washington, DC 20007, USA. mitchejm@georgetown.edu
authors.forename: Jean M
authors.initials: JM
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002140:California; D002648:Child; D002675:Child, Preschool; D003952:Diagnostic Imaging / Q000706:statistics & numerical data* / Q000639:trends; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D019458:Insurance Coverage; D007348:Insurance, Health / Q000191:economics; D008297:Male; D008875:Middle Aged; D018584:Physician Self-Referral; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011243:Preferred Provider Organizations; D017149:Private Sector; D011871:Radiology / Q000706:statistics & numerical data; D017678:Sex Distribution; D014600:Utilization Review