title: Normal mammograms and the practice of obtaining previous mammograms: usefulness and costs.
abstract: OBJECTIVE
  To determine the usefulness and cost of acquiring and comparing mammograms previously obtained at a different facility with normal mammograms.
  
  
  METHODS
  Comparison mammographic reports obtained within 52 months in 1,297 consecutive women (aged 33-82 years; mean age, 53 years) were retrospectively reviewed. Mammograms in which a normal interpretation was altered after comparison were reviewed. The clinical importance and the cost of obtaining previous mammograms were determined.
  
  
  RESULTS
  Initially, interpretation was normal in 756 (58%) comparison mammograms and abnormal in 541 (42%). Of the 756 normal mammograms, 197 (26%) were not compared with previous mammograms. Of the remaining 559, 551 (98%) had no change. In eight of the 559 (1%), the original interpretation was altered. Seven of these eight mammograms were available for review: In one, a developing density was detected; in three, differences were attributable to technique; and in three, radiologists had different interpretations. No malignancies were detected. The average labor and postage cost was $21.49.
  
  
  CONCLUSIONS
  Considering the cost and low diagnostic yield, obtaining previous mammograms is of limited usefulness.
authors.affiliation: Department of Radiology, University of Michigan Medical Center, Ann Arbor 48109-0326, USA.
authors.forename: T E
authors.initials: TE
authors.lastname: Wilson
authors.forename: V K
authors.initials: VK
authors.lastname: Nijhawan
authors.forename: M A
authors.initials: MA
authors.lastname: Helvie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D005260:Female; D006801:Humans; D008327:Mammography / Q000191:economics*; D008875:Middle Aged; D012189:Retrospective Studies