title: Development of a noninvasive method to measure intravascular and intracardiac pressure differences using magnetic resonance imaging.
abstract: OBJECTIVE
  We developed a noninvasive method using magnetic resonance (MR) imaging to measure differences in intravascular and intracardiac pressure, and we investigated the feasibility of the method's use in a pulsatile flow phantom and human studies.
  
  
  METHODS
  We measured 3 velocity components using phase contrast MR imaging on a 1.5T MR scanner, used velocity data in Navier-Stokes equations to obtain pressure gradients, and directly integrated the in-plane pressure gradients to calculate pressure differences. To validate our method, we compared the pressure differences obtained by our method with the theoretical values obtained from an axisymmetric model of arterial stenosis. We also estimated the pressure differences in glass-tube phantoms simulating various vascular pathologies and in the left ventricle and aortic arch of a normal volunteer as clinical application.
  
  
  RESULTS
  The pressure differences obtained by our method agreed well with theoretical values obtained using the straight-tube phantom with stenosis of 45%, but we observed some differences when stenosis was 65%. We clearly observed variations in pressure differences at specific locations at various phases of a cardiac cycle in both phantom and human studies.
  
  
  CONCLUSIONS
  This method appears useful for measuring intravascular and intracardiac pressure differences.
authors.affiliation: Department of Medical Physics and Engineering, Division of Medical Technology and Science, Course of Health Science, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Nagao
authors.forename: Keita
authors.initials: K
authors.lastname: Yoshida
authors.forename: Koji
authors.initials: K
authors.lastname: Okada
authors.forename: Shohei
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueguchi
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
mesh_terms: D000328:Adult; D000465:Algorithms; D001011:Aorta / Q000033:anatomy & histology* / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity