Dependence of shear wave spectral content on acoustic radiation force excitation duration and spatial beamwidth

2014 ◽  
Author(s):  
Mark L. Palmeri ◽  
Yufeng Deng ◽  
Ned C. Rouze ◽  
Kathryn R. Nightingale
Keyword(s):  
Shear Wave ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Spectral Content ◽  
Force Excitation

Quantitative Images of Elastic Modulus Using Tissue Dynamics in the Region of Impulsive Acoustic Radiation Force Excitation

2009 ◽  
Author(s):  
Mark L. Palmeri ◽  
David Xu ◽  
Michael Wang ◽  
Kathryn Nightingale
Keyword(s):  
Shear Modulus ◽  
Shear Wave ◽  
Acoustic Radiation ◽  
Simulated Data ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Excitation Beam ◽  
Shear Wave Speed ◽  
Shear Elasticity ◽  
Force Excitation

Focused, impulsive, acoustic radiation force excitations can generate shear waves with microns of displacement in tissue. The speed of shear wave propagation is directly related to the tissue’s shear modulus, which can be correlated with tissue pathology to diagnose disease and to follow disease progression. Shear wave speed reconstruction has conventionally been measured over spatial domains that are spatially-offset from the region of excitation (ROE). While these methods are very robust in clinical studies characterizing large, homogeneous organs, their spatial resolution can be limited when generating quantitative images of shear elasticity. The ROETTP algorithm measures time-to-peak (TTP) displacements along the axis-of-symmetry in the ROE of an impulsive acoustic radiation force excitation. These TTP displacements are inversely proportional to shear stiffness and are dependent on the excitation-beam geometry. Lookup tables (LUTs) specific to an excitation/displacement tracking transducer configuration were generated from simulated data, and shear stiffnesses were estimated from experimental data as a function of depth using the LUTs. Quantitative ROETTP shear elasticity images of spherical inclusions in a calibrated tissue-mimicking phantom have been generated. Shear wave reflections and interference can lead to an underestimation of the absolute reconstructed shear modulus (20–25%), but the ratio of absolute shear stiffnesses is well-preserved (3.3 vs. 3.5).

scholarly journals Renal shear wave velocity by acoustic radiation force impulse did not reflect advanced renal impairment

Nephrology ◽  
2016 ◽  
Vol 21 (12) ◽  
pp. 1056-1062 ◽  
Author(s):  
Tomoaki Takata ◽  
Masahiko Koda ◽  
Takaaki Sugihara ◽  
Shinobu Sugihara ◽  
Toshiaki Okamoto ◽  
...  
Keyword(s):  
Renal Impairment ◽  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse
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