title: Hepatic vein Doppler studies: variability of flow pattern in normal children.
abstract: BACKGROUND
  Loss of triphasicity of hepatic venous flow on Doppler US has been correlated with hepatic parenchymal disease such as cirrhosis and graft rejection in adults.
  
  
  OBJECTIVE
  To document physiological variations of hepatic vein (HV) flow patterns in normal children of different age groups, the influence of age, sex, body position, site of measurements within a given vein, exercise and food intake. Also, to document the reproducibility of the Doppler US findings in the three major HVs, in order to establish the limits of normal flow against which to assess liver pathology giving rise to abnormal flow pattern.
  
  
  METHODS
  Thirty-two children, divided into four age groups: less than 1 year, 1-5 years, 5-12 years and 12-16 years, with four boys and four girls in each group, underwent repeated US examinations of their HVs. The HV flow pattern was recorded as triphasic = 4, diphasic = 3, monophasic = 2 or uninterpretable = 1 at three sites in each vein: peripheral, middle and proximal in the supine position in the fasting state. One recording was then obtained in the midportion of each vein in the sitting position, another one after exercise, then after a meal and lastly one by a second radiologist. Statistical analysis of variance was done of each variable alone, in combination two by two and three by three.
  
  
  RESULTS
  HV flow pattern was different from one vein to another in the majority of the children, the right HV having the least triphasic flow. Age was highly significant, the HV flow being less triphasic in young children. Sex and position were significant for the right HV only, which was the most difficult to examine. Exercise and food intake did not change the triphasicity of flow.
  
  
  CONCLUSIONS
  HV flow pattern differs with age and can differ from one HV to another within an apparently normal liver. Interpretation is generally reproducible from one radiologist to another. A difference of sex, seen mostly for the right HV, may be due to unfavourable Doppler angle and difficulty of interpretation. The site of measurements within a given vein, body position, exercise and food intake do not influence the triphasicity of HV flow.
authors.affiliation: Department of Paediatric Radiology, University Hospital of Geneva, Children's Hospital, 6 rue Willy Donzé, 1112 Geneva 14, Switzerland. sigrid.jequier@hcuge.ch
authors.forename: Sigrid
authors.initials: S
authors.lastname: Jequier
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Jequier
authors.forename: Sylviane
authors.initials: S
authors.lastname: Hanquinet
authors.forename: Claude
authors.initials: C
authors.lastname: Le Coultre
authors.forename: Dominique C
authors.initials: DC
authors.lastname: Belli
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D004435:Eating / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005260:Female; D006503:Hepatic Veins / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D007223:Infant; D008102:Liver Circulation / Q000502:physiology*; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D012737:Sex Factors; D016683:Supine Position / Q000502:physiology; D018608:Ultrasonography, Doppler