Premium
Static susceptibility effects in balanced SSFP sequences
Author(s) -
Ganter Carl
Publication year - 2006
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.20986
Subject(s) - steady state free precession imaging , nuclear magnetic resonance , precession , steady state (chemistry) , signal (programming language) , physics , phase (matter) , quadratic growth , condensed matter physics , mathematics , chemistry , mathematical analysis , magnetic resonance imaging , quantum mechanics , computer science , programming language , medicine , radiology
Abstract The steady state of balanced steady–state free precession (b–SSFP) sequences in presence of field inhomogeneities can be expressed in terms of a rapidly convergent series, which contains the characteristic function of the susceptibility related phase variations. As long as the intravoxel standard deviation σ of the accumulated phase per repetition time (TR) is of order 1 (radians) or lower, the signal at TE=TR/2 behaves like a spin echo (SE), in accordance with recent observations. The signal decays quadratically around the maximum near TR/2 with a curvature, which solely depends on σ and not on T ′ 2 . For larger σ, a qualitative change toward a gradient echo (GRE) occurs and the signal shows characteristics of an usual FID. With increasing off–resonance the width of the SE regime decreases. Magn Reson Med 56:, 2006. © 2006 Wiley‐Liss, Inc.