Premium
Enhancement of respiratory navigator‐gated three‐dimensional spoiled gradient‐recalled echo sequence with variable flip angle scheme
Author(s) -
Iwadate Yuji,
Brau Anja C. S.,
Vasanawala Shreyas S.,
Kabasawa Hiroyuki
Publication year - 2014
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.24902
Subject(s) - flip angle , imaging phantom , gradient echo , homogeneity (statistics) , fast spin echo , attenuation , computer science , echo (communications protocol) , nuclear medicine , magnetic resonance imaging , physics , medicine , optics , radiology , computer network , machine learning
Purpose To develop and demonstrate the feasibility of a new technique for respiratory‐gated, fat‐suppressed, three‐dimensional spoiled gradient‐recalled echo (3D‐SPGR) with navigator gating for more accurate and robust motion detection. Methods A navigator‐gated 3D‐SPGR technique was modified to include a wait period immediately prior to the navigator sequence for magnetization recovery. Furthermore, a variable flip angle scheme was realized by a combination of ramp‐up, ramp‐down, and attenuation strategies for optimizing point spread functions. Phantom and human experiments were conducted with our technique on 1.5T scanners. Results Using the method, T1‐weighted 3D images with improved signal homogeneity were acquired with a maximum flip angle of 30° in phantom and human tests. Also, compared with the conventional navigator‐gated 3D‐SPGR, accurate respiratory motion detection of free‐breathing subjects was provided, leading to reduced motion artifacts. Conclusion The combination of wait insertion and the variable flip angle method improved both motion detection accuracy and image homogeneity in a navigator‐gated 3D‐SPGR study. Magn Reson Med 72:172–177, 2014. © 2013 Wiley Periodicals, Inc.