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.
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.
Machida
Haruhiko
H
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
Komori
Yoshiaki
Y
Ueno
Eiko
E
Shen
Yun
Y
Hirata
Masami
M
Kojima
Shinya
S
Morita
Satoru
S
Sato
Munekuni
M
Okazaki
Takeshi
T
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*