Premium
Investigating exchange and multicomponent relaxation in fully‐balanced steady‐state free precession imaging
Author(s) -
Deoni Sean C.L.,
Rutt Brian K.,
Jones Derek K.
Publication year - 2008
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21079
Subject(s) - steady state free precession imaging , relaxation (psychology) , precession , nuclear magnetic resonance , signal (programming language) , t2 relaxation , pulse (music) , magnetization , relaxometry , chemistry , physics , computational physics , statistical physics , magnetic resonance imaging , optics , spin echo , condensed matter physics , computer science , magnetic field , quantum mechanics , radiology , medicine , detector , psychology , social psychology , programming language
Purpose To investigate the effect of chemical exchange and multicomponent relaxation on the rapid T 2 mapping method, DESPOT2 (driven equilibrium single pulse observation of T 2 ) and the steady‐state free precession (SSFP) sequence upon which it is based. Although capable of rapid T 2 determination, an assumption implicit of the method is single‐component relaxation. In many biological tissues (such as white and gray matter), it is well established that the T 2 decay curve is more accurately described by the summation of more than one relaxation species. Materials and Methods The effects of exchange were first incorporated into the general SSFP magnetization expressions and its effect on the measured SSFP signal investigated using Bloch‐McConnell simulations. Corresponding imaging experiments were performed to support the presented theory. Results Simulations show the measured multicomponent SSFP signal may be expressed as a linear summation of signal from each species under usual imaging conditions where the repetition time is much less than T 2 . Imaging experiments performed using dairy cream demonstrate strong agreement with the presented theory. Finally, using a dairy cream model, we demonstrate quantification of multicomponent relaxation from multiangle SSFP data for the first time, showing good agreement with reference spin‐echo values. Conclusion SSFP and DESPOT2 may provide a new method for investigating multicomponent systems, such as human brain, and disease processes, such as multiple sclerosis. J. Magn. Reson. Imaging 2008;27:1421–1429. © 2008 Wiley‐Liss, Inc.