title: Use of Public Data to Target Variation in Providers' Use of CT and MR Imaging among Medicare Beneficiaries.
abstract: OBJECTIVE
  To examine geographic variation in providers' use of diagnostic imaging to identify potential targets for quality improvement initiatives after adjusting for imaging referral across hospital referral regions (HRRs).
  
  
  METHODS
  Using two Centers for Medicare and Medicaid Services datasets, the authors included all claims for beneficiaries enrolled in the Medicare fee-for-service program. Diagnostic imaging procedures were selected on the basis of common procedure coding system codes, excluding interventional procedures. The authors assessed providers' use of imaging for each HRR after creating an imaging referral index (IRI) to adjust for imaging referral rates across HRRs. Relative risk statistics were used to assess geographic variation. The authors calculated two imaging measures for computed tomography (CT) and magnetic resonance (MR) imaging: IRI-adjusted utilization intensity (number of examinations per 1000 beneficiaries) and total payments (in dollars, after deducting deductibles and coinsurances) in each HRR. High-impact regions were defined as those in the highest deciles for both imaging intensity and payment.
  
  
  RESULTS
  For 34 million Medicare beneficiaries, 124 million unique diagnostic imaging services (totaling $5.6 billion) were performed in 2012. The average adjusted CT utilization intensity ranged from 330.4 studies per 1000 beneficiaries in the lowest decile to 684.0 in the highest decile (relative risk, 2.1); adjusted MR imaging utilization intensity varied from 105.7 studies per 1000 beneficiaries to 256.3 (relative risk, 2.4). The most common CT and MR imaging procedures were head CT and lumbar spine MR imaging.
  
  
  CONCLUSIONS
  With use of public data, the authors identified a wide variation in imaging use across the United States. Potential targets for future imaging quality improvement initiatives include head CT and lumbar spine MR imaging.
authors: From the Center for Evidence-based Imaging (I.K.I., A.S.R., R.K.), Department of Radiology (I.K.I., A.S.R., S.E.S., R.K.), Department of Medicine (I.K.I., K.E.J.), Department of Surgery (A.A.G.), and Department of Emergency Medicine (A.S.R.), Brigham and Women's Hospital, 20 Kent St, 2nd Floor, Boston, MA 02120; Department of Health Policy and Management, Harvard School of Public Health, Boston, Mass (A.A.G., K.E.J.); and VA Boston Healthcare System, Boston, Mass (K.E.J.).
authors: Ivan K
authors: IK
authors: Ip
authors: Ali S
authors: AS
authors: Raja
authors: Steven E
authors: SE
authors: Seltzer
authors: Atul A
authors: AA
authors: Gawande
authors: Karen E
authors: KE
authors: Joynt
authors: Ramin
authors: R
authors: Khorasani
mesh_terms: D016208:Databases, Factual; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D006278:Medicare; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D058996:Quality Improvement; D012017:Referral and Consultation; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014481:United States