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Error in MR volumetric flow measurements due to ordered phase encoding in the presence of flow varying with respiration
Author(s) -
Wolf Ronald L.,
Hangiandreou Nicholas J.,
Felmlee Joel P.,
Rossman Phillip J.,
Julsrud Paul R.,
Riederer Stephen J.,
Ehman Richard L.
Publication year - 1995
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910340326
Subject(s) - imaging phantom , respiration , volunteer , venae cavae , flow (mathematics) , biomedical engineering , materials science , flow measurement , medicine , nuclear magnetic resonance , nuclear medicine , physics , cardiology , mechanics , anatomy , biology , agronomy
Respiratory ordered phase encoding is often employed in MRI studies to reduce image artifacts due to breathing motion. The purpose of this work was to evaluate error caused by the use of respiratory ordering of phase encoding in MR cine phase‐contrast (CPC) volumetric flow measurements when the flow rate is sensitive to respiration. It was hypothesized that this effect is due to the systematic biasing of a respiratory‐induced phase modulation function in k ‐space. A theoretical model for the effects of respiration was developed and then tested in flow phantom studies and in normal volunteer studies. In phantom experiments, the use of respiratory ordering induced an error of as much as 13% in CPC volumetric flow measurements. In preliminary volunteer studies, error was as high as 26% in superior vena cava flow measurements versus less than 1% error in the ascending aorta. It is concluded that a potential for error exists in CPC volumetric flow measurements obtained with the use of respiratory ordering schemes. Volunteer studies with larger numbers are warranted. Clinical applications in which this effect may be important include flow measurements in vessels subject to variations in flow due to respiration, such as the venae cavae, pulmonary vasculature, and portal vein.