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Referenceless interleaved echo‐planar 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(199901)41:1<87::aid-mrm13>3.0.co;2-x
Subject(s) - ghosting , echo planar imaging , artifact (error) , orientation (vector space) , imaging phantom , computer science , echo (communications protocol) , computer vision , physics , anisotropy , artificial intelligence , optics , algorithm , magnetic resonance imaging , mathematics , medicine , geometry , radiology , computer network
Interleaved echo‐planar imaging (EPI) is an ultrafast imaging technique important for applications that require high time resolution or short total acquisition times. Unfortunately, EPI is prone to significant ghosting artifacts, resulting primarily from system time delays that cause data matrix misregistration. In this work, it is shown mathematically and experimentally that system time delays are orientation dependent, resulting from anisotropic physical gradient delays. This analysis characterizes the behavior of time delays in oblique coordinates, and a new ghosting artifact caused by anisotropic delays is described. “Compensation blips” are proposed for time delay correction. These blips are shown to remove the effects of anisotropic gradient delays, eliminating the need for repeated reference scans and postprocessing corrections. Examples of phantom and in vivo images are shown. Magn Reson Med 41:87‐94, 1999. © 1999 Wiley‐Liss, Inc.