Premium
In vivo estimation of the flow‐driven adiabatic inversion efficiency for continuous arterial spin labeling: A method using phase contrast magnetic resonance angiography
Author(s) -
O'Gorman Ruth L.,
Summers Paul E.,
Zelaya Fernando O.,
Williams Steven C. R.,
Alsop David C.,
Lythgoe David J.
Publication year - 2006
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.20864
Subject(s) - inversion (geology) , bloch equations , nuclear magnetic resonance , amplitude , adiabatic process , perfusion , magnetic resonance angiography , arterial spin labeling , computational physics , magnetic resonance imaging , physics , materials science , optics , radiology , geology , medicine , thermodynamics , paleontology , structural basin
The accurate quantification of perfusion with arterial spin labeling (ASL) requires consideration of a number of factors, including the efficiency of the inversion and control pulses used for spin labeling. In this study the effects of spin velocity on continuous ASL efficiency when using the amplitude modulated control strategy were investigated using simulations of the Bloch equations. The inversion efficiency was determined in vivo by combining the simulations with phase‐contrast velocity mapping data acquired at the level of the tagging plane. Using this novel method, an average inversion efficiency of 69% was calculated for a group of 28 subjects, in good agreement with experimental data reported previously. There was, however, a large range in inversion efficiency measured across the subject group (50–76%), indicating that the velocity dependence of the amplitude modulated control efficiency may introduce additional variability into the perfusion calculations if not properly taken into account. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.