title: In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension.
abstract: OBJECTIVE
  To implement and validate in vivo radial 4D flow MRI for quantification of blood flow in the hepatic arterial, portal venous, and splanchnic vasculature of healthy volunteers and patients with portal hypertension.
  
  
  METHODS
  Seventeen patients with portal hypertension and seven subjects with no liver disease were included in this Health Insurance Portability and Accountability Act (HIPAA)-compliant and Institutional Review Board (IRB)-approved study. Exams were conducted at 3T using a 32-channel body coil with large volumetric coverage and 1.4 mm isotropic true spatial resolution. Using postprocessing software, cut-planes orthogonal to vessels were used to quantify flow (L/min) in the hepatic and splanchnic vasculature.
  
  
  RESULTS
  Flow quantification was successful in all cases. Portal vein and supraceliac aorta flow demonstrated high variability among patients. Measurements were validated indirectly using internal consistency at three different locations within the portal vein (error = 4.2 ± 3.9%) and conservation of mass at the portal confluence (error = 5.9 ± 2.5%) and portal bifurcation (error = 5.8 ± 3.1%).
  
  
  CONCLUSIONS
  This work demonstrates the feasibility of radial 4D flow MRI to quantify flow in the hepatic and splanchnic vasculature. Flow results agreed well with data reported in the literature, and conservation of mass provided indirect validation of flow quantification. Flow in patients with portal hypertensions demonstrated high variability, with patterns and magnitude consistent with the hyperdynamic state that commonly occurs in portal hypertension.
authors.affiliation: Department of Radiology, University of Wisconsin, Madison, WI 53705, USA. roldan@wisc.edu
authors.forename: Alejandro
authors.initials: A
authors.lastname: Roldán-Alzate
authors.forename: Alex
authors.initials: A
authors.lastname: Frydrychowicz
authors.forename: Eric
authors.initials: E
authors.lastname: Niespodzany
authors.forename: Ben R
authors.initials: BR
authors.lastname: Landgraf
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Johnson
authors.forename: Oliver
authors.initials: O
authors.lastname: Wieben
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
mesh_terms: D000369:Aged, 80 and over; D000465:Algorithms; D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D006975:Hypertension, Portal / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008102:Liver Circulation; D008103:Liver Cirrhosis / Q000150:complications / Q000473:pathology / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity