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Multi‐echo segmented k‐space imaging: An optimized hybrid sequence for ultrafast cardiac imaging
Author(s) -
Reeder Scott B.,
Atalar Ergin,
Faranesh Anthony Z.,
McVeigh Elliot R.
Publication year - 1999
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/(sici)1522-2594(199902)41:2<375::aid-mrm23>3.0.co;2-z
Subject(s) - image quality , ghosting , computer science , magnetic resonance imaging , sampling (signal processing) , k space , temporal resolution , echo planar imaging , cardiac magnetic resonance imaging , echo (communications protocol) , heartbeat , biomedical engineering , artificial intelligence , computer vision , physics , medicine , radiology , image (mathematics) , optics , computer network , filter (signal processing) , computer security
Cardiac magnetic resonance imaging requires high temporal resolution to resolve motion and contrast uptake with low total scan times to avoid breathing artifacts. While spoiled gradient echo (SPGR) imaging is robust and reproducible, it is relatively inefficient and requires long breath‐holds to acquire high time resolution movies of the heart. Echo planar imaging (EPI) is highly efficient with excellent signal‐to‐noise ratio (SNR) behavior; however, it is particularly difficult to use in the heart because of its sensitivity to chemical shift, susceptibility, and motion. EPI may also require reference scans, which are used to measure hardware delays and phase offsets that cause ghosting artifacts; these reference scans are more difficult and less reliable in the heart. Consequently, a hybrid EPI/SPGR sequence is proposed for application to rapid cardiac imaging. A detailed optimization of SNR and echo train length for multi‐echo sequences is presented. It is shown that significant reductions in total scan time are possible while maintaining good image quality. This will allow complete motion sampling of the entire heart in one to three breath‐holds, necessary for MR cardiac dobutamine stress testing. Improved speed performance also permits sampling of three to six slices every heartbeat for bolus injection perfusion studies. Magn Reson Med 41:375–385, 1999. © 1999 Wiley‐Liss, Inc.