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High‐frequency mode conversion technique for stiff lesion detection with magnetic resonance elastography (MRE)
Author(s) -
Mariappan Yogesh K.,
Glaser Kevin J.,
Manduca Armando,
Romano Anthony J.,
Venkatesh Sudhakar K.,
Yin Meng,
Ehman Richard L.
Publication year - 2009
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.22091
Subject(s) - magnetic resonance elastography , elastography , soft tissue , shear waves , magnetic resonance imaging , viscoelasticity , materials science , biomedical engineering , nuclear magnetic resonance , shear (geology) , ultrasound , acoustics , pathology , radiology , physics , medicine , composite material
A novel imaging technique is described in which the mode conversion of longitudinal waves is used for the qualitative detection of stiff lesions within soft tissue using magnetic resonance elastography (MRE) methods. Due to the viscoelastic nature of tissue, high‐frequency shear waves attenuate rapidly in soft tissues but much less in stiff tissues. By introducing minimally‐attenuating longitudinal waves at a significantly high frequency into tissue, shear waves produced at interfaces by mode conversion will be detectable in stiff regions, but will be significantly attenuated and thus not detectable in the surrounding soft tissue. This contrast can be used to detect the presence of stiff tissue. The proposed technique is shown to readily depict hard regions (mimicking tumors) present in tissue‐simulating phantoms and ex vivo breast tissue. In vivo feasibility is demonstrated on a patient with liver metastases in whom the tumors are readily distinguished. Preliminary evidence also suggests that quantitative stiffness measurements of stiff regions obtained with this technique are more accurate than those from conventional MRE because of the short shear wavelengths. This rapid, qualitative technique may lend itself to applications in which the localization of stiff, suspicious neoplasms is coupled with more sensitive techniques for thorough characterization. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.