title: Peak systolic velocity, resistance index and pulsatility index. Variations in measuring a pre-recorded videotape.
abstract: OBJECTIVE
  To study variation in the process of measuring Doppler ultrasound (US) wave forms.
  
  
  METHODS
  Eleven radiologists measured peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI) from a pre-recorded videotape. The wave forms were taken from the carotid, brachial, celiac, and renal interlobar arteries in a healthy volunteer. Each radiologist obtained measurements 10 times from a freely chosen wave form of 10 wave forms (10-beat series) and then a further set of measurements also 10 times from a specific wave form (1-beat series).
  
  
  RESULTS
  There was a significant variation in all the PSV, RI and PI values measured, both in the 1-beat series and in the 10-beat series. The greatest variation was seen in the PI values: up to 5.1-fold. Both intraobserver and interobserver reproducibilities were poor.
  
  
  CONCLUSIONS
  The process of obtaining measurements from an identified wave form is a major source of error in Doppler US studies. Special attention should be paid to this final phase of an examination. We recommend that measurements be obtained from more than one heart beat.
authors.affiliation: Department of Radiology, University Central Hospital, Helsinki, Finland.
authors.forename: R H
authors.initials: RH
authors.lastname: Mikkonen
authors.forename: J M
authors.initials: JM
authors.lastname: Kreula
authors.forename: P J
authors.initials: PJ
authors.lastname: Virkkunen
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D001916:Brachial Artery / Q000000981:diagnostic imaging; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging; D002445:Celiac Artery / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D015588:Observer Variation; D011673:Pulsatile Flow / Q000502:physiology*; D012077:Renal Artery / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D013599:Systole / Q000502:physiology; D018608:Ultrasonography, Doppler / Q000592:standards; D014655:Vascular Resistance / Q000502:physiology*; D014743:Videotape Recording