title: Interobserver and intraobserver variation in determining intrarenal parameters by Doppler sonography.
abstract: OBJECTIVE
  This study identified the extent of inter- and intraobserver variation in assessing intrarenal Doppler waveform parameters.
  
  
  METHODS
  Optimized Doppler waveforms from the interlobar arteries of five healthy volunteers were recorded. The waveforms were digitized for off-line evaluation by six observers. Using the same set of waveforms, the observers initially selected three of six waveforms for each subject on the basis of their preference for clinical usefulness. The observers then were directed to evaluate three previously picked waveforms. The systolic acceleration time (SAT) and the resistive index were calculated from each waveform. The observers also characterized the shape of each waveform according to four categories.
  
  
  RESULTS
  Significant interobserver (p < .01) but not intraobserver variation occurred when measuring the SAT. Differences were caused by the observers' perceptions of waveform shapes (kappa = .12, p < .01) as well as the observers choosing different systolic starting points. No significant inter- or intraobserver variation occurred in measuring the resistive index.
  
  
  CONCLUSIONS
  Much variability among and within laboratories can be expected when observers of Doppler waveforms use SAT to evaluate patients for renal artery stenosis.
authors.affiliation: Department of Radiology, University of Rochester School of Medicine and Dentistry, NY 14642-8648, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Gottlieb
authors.forename: E L
authors.initials: EL
authors.lastname: Snitzer
authors.forename: D F
authors.initials: DF
authors.lastname: Hartley
authors.forename: P J
authors.initials: PJ
authors.lastname: Fultz
authors.forename: D J
authors.initials: DJ
authors.lastname: Rubens
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D015588:Observer Variation; D012077:Renal Artery / Q000000981:diagnostic imaging*; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000453:epidemiology; D018608:Ultrasonography, Doppler / Q000706:statistics & numerical data*