title: 4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents--a phantom study.
abstract: OBJECTIVE
  4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents.
  
  
  METHODS
  17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements.
  
  
  RESULTS
  In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n=14) than by 2D phase contrast flow imaging (n=10).
  
  
  CONCLUSIONS
  4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type.
authors: Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster, Germany. alexander.bunck@uk-koeln.de
authors: Alexander C
authors: AC
authors: Bunck
authors: Alena
authors: A
authors: Jüttner
authors: Jan Robert
authors: JR
authors: Kröger
authors: Matthias C
authors: MC
authors: Burg
authors: Harald
authors: H
authors: Kugel
authors: Thomas
authors: T
authors: Niederstadt
authors: Klaus
authors: K
authors: Tiemann
authors: Bernhard
authors: B
authors: Schnackenburg
authors: Gerard R
authors: GR
authors: Crelier
authors: Walter
authors: W
authors: Heindel
authors: David
authors: D
authors: Maintz
mesh_terms: D001783:Blood Flow Velocity; D001807:Blood Vessel Prosthesis; D019544:Equipment Failure Analysis / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000295:instrumentation*; D058729:Peripheral Arterial Disease / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D019047:Phantoms, Imaging; D011474:Prosthesis Design; D015607:Stents