title: Spatial factors for quantifying constant flow velocity in a small tube phantom: comparison of phase-contrast cine-magnetic resonance imaging and the intraluminal Doppler guidewire method.
abstract: OBJECTIVE
  We examined the spatial factors influencing magnetic resonance (MR) flow velocity measurements in a small tube phantom and used the same measurements obtained with an intraluminal Doppler guidewire as reference.
  
  
  METHODS
  We generated constant flow velocities from approximately 40 to 370 cm/s in a tube 4 mm in diameter. We then performed segmented k-space, phase-contrast cine-MR imaging to quantify spatial peak flow velocities of one pixel and of five adjacent pixels as well as spatial mean velocities within regions of interest in a cross section of the phantom. Pixel dimensions ranged from 1.00 x 1.00 mm to 2.50 x 2.50 mm. We compared the MR measurements with the temporally averaged Doppler spectral peak velocities.
  
  
  RESULTS
  For one pixel (r > 0.99: MR flow velocity for pixel dimension 1.00 x 1.00 mm = 1.03x + 9.8 cm/s), the linear correlation was excellent between flow velocities by MR and Doppler guidewire methods. However, for the five adjacent pixels, MR measurements were significantly underestimated using pixels 1.25 x 1.25 mm to 2.50 x 2.50 mm and for mean velocities for all pixel dimensions.
  
  
  CONCLUSIONS
  Relatively high spatial resolution allows accurate MR measurement of constant flow velocity in a small tube at spatial peak velocities for one pixel.
authors: Department of Radiology, Tokyo Women's Medical University Medical Center East, 2-1-10 Nishiogu, Arakawa-ku, Tokyo, 116-8567, Japan. machira@dnh.twmu.ac.jp
authors: Haruhiko
authors: H
authors: Machida
authors: Yoshiaki
authors: Y
authors: Komori
authors: Eiko
authors: E
authors: Ueno
authors: Yun
authors: Y
authors: Shen
authors: Masami
authors: M
authors: Hirata
authors: Shinya
authors: S
authors: Kojima
authors: Satoru
authors: S
authors: Morita
authors: Munekuni
authors: M
authors: Sato
authors: Takeshi
authors: T
authors: Okazaki
mesh_terms: D001783:Blood Flow Velocity; D003331:Coronary Vessels; D004562:Electrocardiography; D007091:Image Processing, Computer-Assisted / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000379:methods*