title: Diagnostic imaging costs: are they driving up the costs of hospital care?
abstract: OBJECTIVE
  To retrospectively determine how changes in utilization of computed tomography (CT), magnetic resonance (MR) imaging, and other imaging technologies between 1996 and 2002 influenced costs of inpatient hospital care at one large academic medical center.
  
  
  METHODS
  Institutional review board did not require its approval or patient informed consent for studies with use of billing data. Patient anonymity was protected by removal of potentially identifying information. Data on hospital costs for 17 139 patients admitted to Massachusetts General Hospital, Boston, Mass, between 1996 and 2002 were downloaded from hospital cost-accounting system; sample was restricted to inpatients with diagnoses in diagnosis-related groups 014-015 (Stroke and TIA [transient ischemic attack]), 164-167 (Appendectomy), 082 (Lung Cancer), 182-183 (Upper Gastrointestinal Conditions), 148-149 (Colon Cancer), and 243 (Back Problems). For each patient, data on demographics, all products and services used, and costs associated with each product or service were obtained. By using institutional codes, we calculated costs of CT, MR imaging, and total imaging relative to total hospital costs. Statistical analyses were performed with Student t test and multiple linear regression analysis.
  
  
  RESULTS
  Between 1996 and 2002, number of inpatient CT and MR images obtained at the hospital more than doubled. In 2002, hospital costs were 155% those of 1996 levels; inpatient imaging costs were 151% those of 1996 levels. Total costs increased an average of 7.8% per year; imaging costs increased 8.3% per year. Although highly variable over the study period, as a percentage of total imaging costs, CT and MR imaging costs appeared to remain stable relative to costs of other imaging modalities.
  
  
  CONCLUSIONS
  Despite substantial increases in utilization of inpatient CT, MR imaging, and other imaging technologies, diagnostic imaging costs increased at approximately same rate as did total costs for inpatients with several diagnoses. CT and MR imaging do not appear to be driving the cost increases seen between 1996 and 2002.
authors.affiliation: Institute for Technology Assessment and Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 101 Merrimac St, 10th Floor, Boston, MA 02114-4724, USA.
authors.forename: Molly T
authors.initials: MT
authors.lastname: Beinfeld
authors.forename: G Scott
authors.initials: GS
authors.lastname: Gazelle
mesh_terms: D003365:Costs and Cost Analysis; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000191:economics* / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000191:economics* / Q000706:statistics & numerical data*