title: Non-contrast-enhanced MR portography with balanced steady-state free-precession sequence and time-spatial labeling inversion pulses: comparison of imaging with flow-in and flow-out methods.
abstract: OBJECTIVE
  To compare and evaluate images of non-contrast-enhanced MR portography acquired with two different methods, the flow-in and flow-out methods.
  
  
  METHODS
  Twenty-five healthy volunteers were examined using respiratory-triggered three-dimensional balanced steady-state free-precession (SSFP) with two selective inversion recovery pulses (flow-in method) and one tagging pulse and one nonselective inversion recovery pulse (flow-out method). For quantitative analysis, vessel-to-liver contrast (Cv-l) ratios of the main portal vein (MPV), right portal vein (RPV), and left portal vein (LPV) were measured. The quality of portal vein visualization was scored using a four-point scale.
  
  
  RESULTS
  The Cv-ls of the MPV, RPV, and LPV were all significantly higher with the flow-out than flow-in method (MPV = 0.834 ± 0.06 versus 0.711 ± 0.10; RPV = 0.861 ± 0.04 versus 0.729 ± 0.11; LPV = 0.786 ± 0.08 versus 0.545 ± 0.22; P < 0.0001). In all analyses of vessel visibility, non-contrast-enhanced MR portography with the flow-out method showed higher scores than with the flow-in method. With the flow-out method, visual scores of the MPV, RPV, portal vein branches of segments 4 (P4), and 8 (P8) were significantly better than with the flow-in method (MPV = 3.4 ± 0.7 versus 2.6 ± 0.9; RPV = 4.0 ± 0.0 versus 3.5 ± 0.9; P4 = 2.8 ± 1.3 versus 1.6 ± 1.0; P8 = 4.0 ± 0.0 versus 2.9 ± 1.1; P < 0.05).
  
  
  CONCLUSIONS
  Non-contrast-enhanced MR portography with the flow-out method improves the visualization of the intrahepatic portal vein in comparison with the flow-in method. J. Magn. Reson. Imaging 2014;40:583-587. © 2013 Wiley Periodicals, Inc.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Furuta
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Isoda
authors.forename: Rikiya
authors.initials: R
authors.lastname: Yamashita
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ohno
authors.forename: Seiya
authors.initials: S
authors.lastname: Kawahara
authors.forename: Hironori
authors.initials: H
authors.lastname: Shimizu
authors.forename: Koji
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kusahara
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D011169:Portal Vein / Q000033:anatomy & histology*
keywords: MR angiography; balanced SSFP; flow-out method; non-contrast-enhanced; portal vein; time-spatial labeling pulses