title: Effect of CT digital image compression on detection of coronary artery calcification.
abstract: OBJECTIVE
  To test the effect of digital compression of CT images on the detection of small linear or spotted high attenuation lesions such as coronary artery calcification (CAC).
  
  
  METHODS
  Fifty cases with and 50 without CAC were randomly selected from a population that had undergone spiral CT of the thorax for screening lung cancer. CT image data were compressed using JPEG (Joint Photographic Experts Group) or wavelet algorithms at ratios of 10:1, 20:1 or 40:1. Five radiologists reviewed the uncompressed and compressed images on a cathode-ray-tube. Observer performance was evaluated with receiver operating characteristic analysis.
  
  
  RESULTS
  CT images compressed at a ratio as high as 20:1 were acceptable for primary diagnosis of CAC. There was no significant difference in the detection accuracy for CAC between JPEG and wavelet algorithms at the compression ratios up to 20:1. CT images were more vulnerable to image blurring on the wavelet compression at relatively lower ratios, and "blocking" artifacts occurred on the JPEG compression at relatively higher ratios.
  
  
  CONCLUSIONS
  JPEG and wavelet algorithms allow compression of CT images without compromising their diagnostic value at ratios up to 20:1 in detecting small linear or spotted high attenuation lesions such as CAC, and there was no difference between the two algorithms in diagnostic accuracy.
authors.affiliation: Department of Radiology, Second Hospital of Hebei Medical University, Shijazhuang, China.
authors.forename: L M
authors.initials: LM
authors.lastname: Zheng
authors.forename: S
authors.initials: S
authors.lastname: Sone
authors.forename: Y
authors.initials: Y
authors.lastname: Itani
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Hanamura
authors.forename: K
authors.initials: K
authors.lastname: Asakura
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.forename: Z G
authors.initials: ZG
authors.lastname: Yang
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.forename: T
authors.initials: T
authors.lastname: Funasaka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002114:Calcinosis / Q000000981:diagnostic imaging*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D012680:Sensitivity and Specificity; D019112:Teleradiology; D014057:Tomography, X-Ray Computed