title: Modified Doppler flowmetry in the splanchnic circulation.
abstract: BACKGROUND
  Absolute measurements of blood flow by Doppler ultrasonography are subject to substantial error. A simplified method of Doppler flowmetry using conventional duplex Doppler equipment was studied to establish its validity in determining short-term changes in flow in the splanchnic circulation in portal hypertension.
  
  
  METHODS
  Two simple indices were measured: peak velocity averaged over two cardiac cycles and vessel diameter. The relationship between peak and mean velocity was studied using a Doppler phantom. The feasibility of studying relevant vessels and the constancy of regional flow was determined by performing Doppler flowmetry in a basal state twice within 2 hours.
  
  
  RESULTS
  Constancy of relationship between peak and mean velocities was confirmed (r > 0.98). Examination was successful in the majority of 28 consecutive patients with portal hypertension for superior mesenteric, main portal, right portal, and paraumbilical (when patent) veins, but was successful in only 54% for the hepatic artery. Constancy of basal flow was found in 11 selected patients when group data were considered, but in individuals, substantial and unpredictable variance was found.
  
  
  CONCLUSIONS
  Modified Doppler flowmetry appears valid in the assessment of short-term changes in splanchnic blood flow of patients with portal hypertension. Individual variance in baseline flow is identified as a potential problem and is further reason for caution in the interpretation of measurements of Doppler flow.
authors.affiliation: Department of Radiology, Royal Melbourne Hospital, University of Melbourne, Victoria, Australia.
authors.forename: R N
authors.initials: RN
authors.lastname: Gibson
authors.forename: P R
authors.initials: PR
authors.lastname: Gibson
authors.forename: J D
authors.initials: JD
authors.lastname: Donlan
authors.forename: R
authors.initials: R
authors.lastname: Padmanabhan
mesh_terms: D006499:Hepatic Artery / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D006975:Hypertension, Portal / Q000503:physiopathology*; D016014:Linear Models; D017538:Mesenteric Artery, Superior / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000503:physiopathology; D011168:Portal System / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000503:physiopathology; D015203:Reproducibility of Results; D013152:Splanchnic Circulation; D013997:Time Factors; D014463:Ultrasonography