title: Hepatic vascular flow measurements by phase contrast MRI and doppler echography: a comparative and reproducibility study.
abstract: OBJECTIVE
  To directly compare and study the variability of parameters related to hepatic blood flow measurements using 3 T phase-contrast magnetic resonance imaging (PC-MRI) and Doppler ultrasound (US).
  
  
  METHODS
  Nine healthy subjects were studied. Blood velocities and flow rate measurements were performed in the portal vein and the proper hepatic artery. MR studies were performed using a 3 T imager. Gradient-echo fast phase contrast sequences were used with both cardiac and respiratory gating. MR and Doppler flow parameters were extracted and compared. Two methods of calculation were used for Doppler flow rate analysis.
  
  
  RESULTS
  Compared to Doppler US, PC-MRI largely underestimated hepatic flow data with lower variability and higher reproducibility. This reproducibility was more pronounced in the portal vein than in the proper hepatic artery associated with poorer velocity correlations. Total hepatic flow values were 1239 +/- 223 mL/min and 1595 +/- 521 mL/min for PC-MRI and Doppler US, respectively.
  
  
  CONCLUSIONS
  Free-breathing PC-MRI can provide reliable noninvasive measurement of hepatic flow parameters compared to Doppler US. The MR technique could help to improve Doppler flow calculations, thereby allowing standardization of protocols, particularly for applications in disease.
authors.affiliation: Department of Imaging and Biophysics, University Hospital, Jules Verne University of Picardie, Amiens, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Yzet
authors.forename: Roger
authors.initials: R
authors.lastname: Bouzerar
authors.forename: Jean-Dominique
authors.initials: JD
authors.lastname: Allart
authors.forename: Fabien
authors.initials: F
authors.lastname: Demuynck
authors.forename: Cécile
authors.initials: C
authors.lastname: Legallais
authors.forename: Brice
authors.initials: B
authors.lastname: Robert
authors.forename: Hervé
authors.initials: H
authors.lastname: Deramond
authors.forename: Marc-Etienne
authors.initials: ME
authors.lastname: Meyer
authors.forename: Olivier
authors.initials: O
authors.lastname: Balédent
mesh_terms: D000328:Adult; D000792:Angiography / Q000379:methods*; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D006499:Hepatic Artery / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D008102:Liver Circulation / Q000502:physiology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D055420:Perfusion Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler / Q000379:methods*