title: High-grade video compression of echocardiographic studies: a multicenter validation study of selected motion pictures expert groups (MPEG)-4 algorithms.
abstract: BACKGROUND
  Large files produced by standard compression algorithms slow down spread of digital and tele-echocardiography. We validated echocardiographic video high-grade compression with the new Motion Pictures Expert Groups (MPEG)-4 algorithms with a multicenter study.
  
  
  METHODS
  Seven expert cardiologists blindly scored (5-point scale) 165 uncompressed and compressed 2-dimensional and color Doppler video clips, based on combined diagnostic content and image quality (uncompressed files as references). One digital video and 3 MPEG-4 algorithms (WM9, MV2, and DivX) were used, the latter at 3 compression levels (0%, 35%, and 60%).
  
  
  RESULTS
  Compressed file sizes decreased from 12 to 83 MB to 0.03 to 2.3 MB (1:1051-1:26 reduction ratios). Mean SD of differences was 0.81 for intraobserver variability (uncompressed and digital video files). Compared with uncompressed files, only the DivX mean score at 35% (P = .04) and 60% (P = .001) compression was significantly reduced. At subcategory analysis, these differences were still significant for gray-scale and fundamental imaging but not for color or second harmonic tissue imaging. Original image quality, session sequence, compression grade, and bitrate were all independent determinants of mean score.
  
  
  CONCLUSIONS
  Our study supports use of MPEG-4 algorithms to greatly reduce echocardiographic file sizes, thus facilitating archiving and transmission. Quality evaluation studies should account for the many independent variables that affect image quality grading.
authors.affiliation: Centro Cardiologico Monzino, IRCCS, Milano, Italy. pbar@iol.it <pbar@iol.it>
authors.forename: Paolo
authors.initials: P
authors.lastname: Barbier
authors.forename: Marina
authors.initials: M
authors.lastname: Alimento
authors.forename: Giovanni
authors.initials: G
authors.lastname: Berna
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Celeste
authors.forename: Francesco
authors.initials: F
authors.lastname: Gentile
authors.forename: Antonio
authors.initials: A
authors.lastname: Mantero
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Montericcio
authors.forename: Manuela
authors.initials: M
authors.lastname: Muratori
mesh_terms: D000465:Algorithms; D015150:Echocardiography, Doppler / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D012984:Software; D016276:Ventricular Function / Q000502:physiology*; D014741:Video Recording