title: Variability of splanchnic blood flow measurements using MR velocity mapping under fasting and post-prandial conditions--comparison with echo-Doppler.
abstract: OBJECTIVE
  The aim was to study the reproducibility of magnetic resonance velocity mapping, when measuring portal vein and superior mesenteric artery blood flow, under fasting and post-prandial conditions. Magnetic resonance flow measurements for the portal vein were compared with echo-Doppler measurements in the right portal vein.
  
  
  METHODS
  Eight healthy volunteers were studied on two occasions, separated by 1 week. Blood flow in the portal vein and superior mesenteric artery was measured repeatedly under basal fasting conditions. On one occasion measurements were also made after a meal. Every magnetic resonance measurement was followed by an echo-Doppler measurement in the right portal vein. Correlations between flow values were calculated using Pearson's r. Variability components were assessed using ANOVA.
  
  
  RESULTS
  Intra-individual variability was approximately 7% for portal vein flow measurements using magnetic resonance velocity mapping. This variability did not increase after 1 h, 1 week and after a meal. Values of flow measured in the portal vein and superior mesenteric artery using magnetic resonance velocity mapping correlated well (r = 0.80, p < 0.001). Fasting portal flow as measured with magnetic resonance velocity mapping was 1.2 l/min (range 0.96-1.6 l/min). Variability in echo-Doppler measurements was comparable to the variability of magnetic resonance velocity mapping, and flow measurements obtained with the two techniques correlated well (r = 0.74; p < 0.001).
  
  
  CONCLUSIONS
  Magnetic resonance velocity mapping accurately measures blood flow in the portal vein with low variability and should be preferred when absolute flow values are necessary. Echo-Doppler measurement of the right portal vein has a low variability and can be used to study changes in flow.
authors.affiliation: Department of Radiology, Leiden University Hospital, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lycklama à Nijeholt
authors.forename: K
authors.initials: K
authors.lastname: Burggraaf
authors.forename: M N
authors.initials: MN
authors.lastname: Wasser
authors.forename: L J
authors.initials: LJ
authors.lastname: Schultze Kool
authors.forename: R C
authors.initials: RC
authors.lastname: Schoemaker
authors.forename: A F
authors.initials: AF
authors.lastname: Cohen
authors.forename: A
authors.initials: A
authors.lastname: de Roos
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D005215:Fasting; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D019518:Postprandial Period; D013152:Splanchnic Circulation; D018608:Ultrasonography, Doppler