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Partial RF echo planar imaging with the FAISE method. I. Experimental and theoretical assessment of artifact
Author(s) -
Melki Philippe S.,
Jolesz Ferenc A.,
Mulkern Robert V.
Publication year - 1992
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.1910260212
Subject(s) - artifact (error) , echo planar imaging , echo (communications protocol) , nuclear magnetic resonance , echo time , planar , fast spin echo , computer science , materials science , magnetic resonance imaging , physics , artificial intelligence , medicine , radiology , computer graphics (images) , computer network
The fast acquisition interleaved spin‐echo (FAISE) method is a partial RF echo‐planar technique which utilizes a specific phase‐encode reordering algorithm to manipulate image contrast (Melki et al., J. Magn. Reson. imaging 1:319, 1991). The technique can generate “spin‐echo” like images up to 16 times faster than conventional spin‐echo methods. However, the presence of T 2 decay throughout the variable k ‐space trajectories used to manipulate T 2 contrast ensures the presence of image artifacts, especially along the phase‐encode direction. In this work, we experimentally and theoretically examine the type and extent of artifacts associated with the FAISE technique. We demonstrate the existence of well‐defined minima of phase‐encode ghost noise for selected k ‐space trajectories, examine the extent of blurring and edge enhancement artifacts, demonstrate the influence of matrix size and number of echoes per train on phase‐encode artifact, and show how proper choice of FAISE sequence parameters can lead to proton density brain images which are practically indistinguishable from conventional spin‐echo proton density images. A comparison of contrast between FAISE and standard spin‐echo methods is presented in a companion article referred to as II.