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Spatially selective implementation of the adiabatic T 2 prep sequence for magnetic resonance angiography of the coronary arteries
Author(s) -
Soleimanifard Sahar,
Schär Michael,
Hays Allison G.,
Prince Jerry L.,
Weiss Robert G.,
Stuber Matthias
Publication year - 2013
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.24437
Subject(s) - blood flow , nuclear magnetic resonance , magnetic resonance imaging , magnetization , spins , coronary arteries , signal to noise ratio (imaging) , signal (programming language) , physics , artery , nuclear medicine , medicine , radiology , computer science , optics , condensed matter physics , magnetic field , quantum mechanics , programming language
In coronary magnetic resonance angiography, a magnetization‐preparation scheme for T 2 ‐weighting (T 2 Prep) is widely used to enhance contrast between the coronary blood‐pool and the myocardium. This prepulse is commonly applied without spatial selection to minimize flow sensitivity, but the nonselective implementation results in a reduced magnetization of the in‐flowing blood and a related penalty in signal‐to‐noise ratio. It is hypothesized that a spatially selective T 2 Prep would leave the magnetization of blood outside the T 2 Prep volume unaffected and thereby lower the signal‐to‐noise ratio penalty. To test this hypothesis, a spatially selective T 2 Prep was implemented where the user could freely adjust angulation and position of the T 2 Prep slab to avoid covering the ventricular blood‐pool and saturating the in‐flowing spins. A time gap of 150 ms was further added between the T 2 Prep and other prepulses to allow for in‐flow of a larger volume of unsaturated spins. Consistent with numerical simulation, the spatially selective T 2 Prep increased in vivo human coronary artery signal‐to‐noise ratio (42.3 ± 2.9 vs. 31.4 ± 2.2, n = 22, P < 0.0001) and contrast‐to‐noise‐ratio (18.6 ± 1.5 vs. 13.9 ± 1.2, P = 0.009) as compared to those of the nonselective T 2 Prep. Additionally, a segmental analysis demonstrated that the spatially selective T 2 Prep was most beneficial in proximal and mid segments where the in‐flowing blood volume was largest compared to the distal segments. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.