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Analysis of MR phase‐contrast measurements of pulsatile velocity waveforms
Author(s) -
Hangiandreou Nicholas J.,
Rossman Phillip J.,
Riederer Stephen J.
Publication year - 1993
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.1880030214
Subject(s) - pulsatile flow , waveform , sensitivity (control systems) , signal (programming language) , phase (matter) , physics , nuclear magnetic resonance , magnitude (astronomy) , contrast (vision) , phase contrast microscopy , computer science , optics , medicine , cardiology , quantum mechanics , voltage , electronic engineering , astronomy , engineering , programming language
Errors in the measurement of the mean velocity of pulsatile velocity waveforms with ungated phasecontrast techniques were studied theoretically and experimentally. Waveforms consisting of a constant and two sinusoidal components were analyzed. Variations in magnitude and phase of the vascular magnetic resonance (MR) signal resulted in errors, the severity of which increased when either factor increased. Magnitude variations always resulted in overestimation. The general shape of the waveform greatly influenced the error, with certain waveforms producing greater inherent error than others. Experimental measurements were performed, validating the predicted sensitivity of these errors to changes in imaging parameters, including TR and flow‐encoding sensitivity. Errors generally became more severe with increased flow‐encoding sensitivity. The theoretical and experimental results suggest that accurate mean velocity measurements in many vessels of the body‐with acquisition times of less than 15 seconds‐should be attainable with ungated imaging techniques and with careful selection of relevant imaging parameters.