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Combined T 2 ‐preparation and two‐dimensional pencil‐beam inner volume selection
Author(s) -
Coristine Andrew J.,
van Heeswijk Ruud B.,
Stuber Matthias
Publication year - 2015
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.25442
Subject(s) - ghosting , imaging phantom , materials science , pencil (optics) , nuclear magnetic resonance , pulse sequence , optics , nuclear medicine , magnetic resonance imaging , biomedical engineering , physics , medicine , radiology
Purpose To improve coronary magnetic resonance angiography (MRA) by combining a two‐dimensional (2D) spatially selective radiofrequency (RF) pulse with a T 2 ‐preparation module (“2D‐T 2 ‐Prep”). Methods An adiabatic T 2 ‐Prep was modified so that the first and last pulses were of differing spatial selectivity. The first RF pulse was replaced by a 2D pulse, such that a pencil‐beam volume is excited. The last RF pulse remains nonselective, thus restoring the T 2 ‐prepared pencil‐beam, while tipping the (formerly longitudinal) magnetization outside of the pencil‐beam into the transverse plane, where it is then spoiled. Thus, only a cylinder of T 2 ‐prepared tissue remains for imaging. Numerical simulations were followed by phantom validation and in vivo coronary MRA, where the technique was quantitatively evaluated. Reduced field‐of‐view (rFoV) images were similarly studied. Results In vivo, full field‐of‐view 2D‐T 2 ‐Prep significantly improved vessel sharpness as compared to conventional T 2 ‐Prep, without adversely affecting signal‐to‐noise (SNR) or contrast‐to‐noise ratios (CNR). It also reduced respiratory motion artifacts. In rFoV images, the SNR, CNR, and vessel sharpness decreased, although scan time reduction was 60%. Conclusion When compared with conventional T 2 ‐Prep, the 2D‐T 2 ‐Prep improves vessel sharpness and decreases respiratory ghosting while preserving both SNR and CNR. It may also acquire rFoV images for accelerated data acquisition. Magn Reson Med 74:529–536, 2015. © 2014 Wiley Periodicals, Inc.