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Combined analysis of spatial and velocity displacement artifacts in phase contrast measurements of complex flows
Author(s) -
Steinman David A.,
Ethier C. Ross,
Rutt Brian K.
Publication year - 1997
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.1880070214
Subject(s) - acceleration , physics , displacement (psychology) , flow velocity , phase (matter) , spins , flow (mathematics) , oblique case , image resolution , pulse (music) , contrast (vision) , tracking (education) , temporal resolution , mechanics , optics , classical mechanics , psychology , linguistics , philosophy , quantum mechanics , detector , psychotherapist , condensed matter physics , pedagogy
MR phase contrast (PC) velocity imaging is a promising tool for quantifying blood flow velocity in vivo. PC velocity imaging is, however, susceptible to artifacts that result from the displacement of spins during the finite duration pulse sequences. Such displacement artifacts can lead to errors in velocity measurements, especially in the presence of oblique and accelerating flows, which are common throughout the cardiovascular system. By tracking particles (representing spins) through a computed velocity field, and assuming that spatial and velocity encodings occur at discrete times during the pulse sequence, we simulate the separate and combined effects of oblique and acceleration artifacts on PC velocity images. We demonstrate, both by simulation and MR measurement, the errors associated with such artifacts in PC velocity measurements in a representative flow geometry. Using example particle trajectories, we provide a fluid dynamic basis for characteristic phase‐velocity image distortions that can arise when imaging complex, physiologically relevant flows.