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Mechanical transient‐based magnetic resonance elastography
Author(s) -
McCracken Paul J.,
Manduca Armando,
Felmlee Joel,
Ehman Richard L.
Publication year - 2005
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.20388
Subject(s) - magnetic resonance elastography , transient (computer programming) , acoustics , excitation , transient elastography , transient response , impulse (physics) , nuclear magnetic resonance , stiffness , elastography , harmonic , physics , materials science , mechanics , computer science , ultrasound , classical mechanics , medicine , composite material , quantum mechanics , electrical engineering , engineering , operating system , virus , virology , chronic hepatitis
Magnetic resonance elastography (MRE) is a technique for quantifying material properties by measuring cyclic displacements of propagating shear waves. As an alternative to dynamic harmonic wave MRE or quasi‐steady‐state methods, the idea of using a transient impulse for mechanical excitation is introduced. Two processing methods to calculate shear stiffness from transient data were developed. The techniques were tested in phantom studies, and the transient results were found to be comparable to the harmonic wave results. Transient wave based analysis was applied to the brains of six healthy volunteers in order to assess the method in areas of complex wave patterns and geometry. The results demonstrated the feasibility of measuring brain stiffness in vivo using a transient mechanical excitation. Transient and harmonic methods both measure white matter (∼12 kPa) to be stiffer than gray matter (∼8 kPa). There were some anatomic differences between harmonic and transient MRE, specifically where the transient results better depicted the deeper structures of the brain. Magn Reson Med 53:628–639, 2005. © 2005 Wiley‐Liss, Inc.