title: Effects of heart valve prostheses on phase contrast flow measurements in Cardiovascular Magnetic Resonance - a phantom study.
abstract: BACKGROUND
  Cardiovascular Magnetic Resonance is often used to evaluate patients after heart valve replacement. This study systematically analyses the influence of heart valve prostheses on phase contrast measurements in a phantom trial.
  
  
  METHODS
  Two biological and one mechanical aortic valve prostheses were integrated in a flow phantom. B0maps and phase contrast measurements were acquired at a 1.5 T MR scanner using conventional gradient-echo sequences in predefined distances to the prostheses. Results were compared to measurements with a synthetic metal-free aortic valve.
  
  
  RESULTS
  The flow results at the level of the prosthesis differed significantly from the reference flow acquired before the level of the prosthesis. The maximum flow miscalculation was 154 ml/s for one of the biological prostheses and 140 ml/s for the mechanical prosthesis. Measurements with the synthetic aortic valve did not show significant deviations. Flow values measured approximately 20 mm distal to the level of the prosthesis agreed with the reference flow for all tested all prostheses.
  
  
  CONCLUSIONS
  The tested heart valve prostheses lead to a significant deviation of the measured flow rates compared to a reference. A distance of 20 mm was effective in our setting to avoid this influence.
authors.affiliation: Working Group on Cardiovascular Magnetic Resonance Imaging, Experimental and Clinical Research Center, joint cooperation of the Max-Delbrück-Centrum and Charité -Medical University Berlin, Berlin, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Richau
authors.affiliation: Siemens Healthcare GmbH, Erlangen, Germany.
authors.forename: Matthias A
authors.initials: MA
authors.lastname: Dieringer
authors.affiliation: Working Group on Cardiovascular Magnetic Resonance Imaging, Experimental and Clinical Research Center, joint cooperation of the Max-Delbrück-Centrum and Charité -Medical University Berlin, Berlin, Germany.|HELIOS Klinikum Berlin-Buch, Department of Cardiology and Nephrology, Berlin, Germany.
authors.forename: Julius
authors.initials: J
authors.lastname: Traber
authors.affiliation: Working Group on Cardiovascular Magnetic Resonance Imaging, Experimental and Clinical Research Center, joint cooperation of the Max-Delbrück-Centrum and Charité -Medical University Berlin, Berlin, Germany.|HELIOS Klinikum Berlin-Buch, Department of Cardiology and Nephrology, Berlin, Germany.|Department of Cardiology, Clinic Agatharied, Ludwig-Maximilians-University Munich, Hausham, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: von Knobelsdorff-Brenkenhoff
authors.affiliation: Siemens Healthcare GmbH, Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiser
authors.affiliation: SCO:SSiS, Berlin, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Schwenke
authors.affiliation: Working Group on Cardiovascular Magnetic Resonance Imaging, Experimental and Clinical Research Center, joint cooperation of the Max-Delbrück-Centrum and Charité -Medical University Berlin, Berlin, Germany. jeanette.schulz-menger@charite.de.|HELIOS Klinikum Berlin-Buch, Department of Cardiology and Nephrology, Berlin, Germany. jeanette.schulz-menger@charite.de.
authors.forename: Jeanette
authors.initials: J
authors.lastname: Schulz-Menger
mesh_terms: D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D016477:Artifacts; D001783:Blood Flow Velocity; D006350:Heart Valve Prosthesis / Q000009:adverse effects; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006439:Hemodynamics; D008279:Magnetic Resonance Imaging / Q000009:adverse effects / Q000295:instrumentation* / Q000592:standards; D008422:Materials Testing; D008670:Metals / Q000009:adverse effects; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011474:Prosthesis Design; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D008670:Metals
keywords: Artefacts; Cardiovascular magnetic resonance; Flow phantom; Phase contrast; Valve prosthesis