Spatially selective implementation of the adiabatic T2prep sequence for magnetic resonance angiography of the coronary arteries

Authors

  • Sahar Soleimanifard,

    1. Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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  • Michael Schär,

    1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, Maryland, USA
    2. Philips Healthcare, Cleveland, Ohio, USA
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  • Allison G. Hays,

    1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, Maryland, USA
    2. Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland, USA
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  • Jerry L. Prince,

    1. Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
    2. Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, Maryland, USA
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  • Robert G. Weiss,

    1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, Maryland, USA
    2. Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, Maryland, USA
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  • Matthias Stuber

    Corresponding author
    1. Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
    2. Russell H. Morgan Department of Radiology and Radiological Science, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, Maryland, USA
    3. Department of Radiology, Centre Hospitalier Universitaire Vaudois, Center for Biomedical Imaging (CBIM) and University of Lausanne, Lausanne, Switzerland
    • Rue de Bugnon 46, BH 8.80 10 11, Lausanne, Switzerland
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Abstract

In coronary magnetic resonance angiography, a magnetization-preparation scheme for T2-weighting (T2Prep) 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 T2Prep would leave the magnetization of blood outside the T2Prep volume unaffected and thereby lower the signal-to-noise ratio penalty. To test this hypothesis, a spatially selective T2Prep was implemented where the user could freely adjust angulation and position of the T2Prep 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 T2Prep and other prepulses to allow for in-flow of a larger volume of unsaturated spins. Consistent with numerical simulation, the spatially selective T2Prep 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 T2Prep. Additionally, a segmental analysis demonstrated that the spatially selective T2Prep 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.

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