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A quantitative method for fast diffusion imaging using magnetization‐prepared turboFLASH
Author(s) -
Thomas David L.,
Pell Gaby S.,
Lythgoe Mark F.,
Gadian David G.,
Ordidge Roger J.
Publication year - 1998
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.1910390613
Subject(s) - diffusion , pulse sequence , imaging phantom , fourier transform , nuclear magnetic resonance , materials science , in vivo , phase (matter) , pulse (music) , chemistry , analytical chemistry (journal) , physics , optics , chromatography , thermodynamics , organic chemistry , detector , microbiology and biotechnology , quantum mechanics , biology
For the in vivo measurement of the apparent diffusion coefficient (ADC), it is desirable for the total imaging time to be as short as possible. One technique is based on a TurboFLASH acquisition in which the diffusion gradients are inserted into a driven equilibrium Fourier transform (DEFT) combination of hard pulses. However, this sequence has the disadvantage that eddy current‐induced inhomogeneities lead to incomplete refocusing of the magnetization during the diffusion preparation and to incorrect ADC values. A modification to the sequence is suggested that eliminates this error by phase‐cycling the second 90° pulse of the preparation. This study also investigates the effect of a reduced delay time between acquisitions on the accuracy of the measurement. The quality of the TurboFLASH sequence is demonstrated by experimental validation on an agar phantom and in vivo on the rat brain using a high‐field (8.5 T) system. Reduction of the interexperiment delay time is shown to be achievable to a certain degree without compromising the measurement accuracy.