title: Reliability of Doppler ultrasound in follow-up studies.
abstract: OBJECTIVE
  To evaluate the reliability of repeat Doppler US measurements.
  
  
  METHODS
  Nine radiologists conducted two sets of Doppler US measurements on a healthy volunteer, with a time interval of 9 months. Peak systolic velocity (PSV), resistance index (RI), and pulsatility index (PI) were measured 10 times in 4 arteries.
  
  
  RESULTS
  There was considerable intra- and inter-observer variation both at baseline and 9 months later. The PSV values from the carotid artery varied from 0.27 m/s to 1.95 m/s in February and from 0.22 m/s to 1.38 m/s in November. The RI values from the renal artery ranged from 0.44 to 0.71 in February and from 0.41 to 0.67 in November. The results of the 9-month follow-up varied markedly too. Best reproducibility was achieved by highly experienced radiologists both at baseline and 9 months later.
  
  
  CONCLUSIONS
  The short-term and long-term reliability of Doppler US was poor when the measurements were performed by a heterogeneous group of radiologists. The RI and PI measurements were somewhat more reliable than the PSV measurements and are recommended for use in follow-up studies.
authors.affiliation: Department of Radiology, Helsinki University Central Hospital, 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; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging / Q000502:physiology; D002445:Celiac Artery / Q000000981:diagnostic imaging / Q000502:physiology; D005260:Female; D006801:Humans; D015588:Observer Variation; D011673:Pulsatile Flow; D012016:Reference Values; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000502:physiology; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance