声辐射力
抖动
声学
光学
流离失所(心理学)
剪切(物理)
物理
声辐射
位移场
材料科学
辐射
超声波
有限元法
计算机科学
电信
热力学
心理学
心理治疗师
作者
Mark L. Palmeri,Stephen A. McAleavey,Gregg E. Trahey,Kathryn R. Nightingale
出处
期刊:IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
[Institute of Electrical and Electronics Engineers]
日期:2006-07-01
卷期号:53 (7): 1300-1313
被引量:182
标识
DOI:10.1109/tuffc.2006.1665078
摘要
The use of ultrasonic methods to track the tissue deformation generated by acoustic radiation force is subject to jitter and displacement underestimation errors, with displacement underestimation being primarily caused by lateral and elevation shearing within the point spread function (PSF) of the ultrasonic beam. Models have been developed using finite element methods and Field II, a linear acoustic field simulation package, to study the impact of focal configuration, tracking frequency, and material properties on the accuracy of ultrasonically tracking the tissue deformation generated by acoustic radiation force excitations. These models demonstrate that lateral and elevation shearing underneath the PSF of the tracking beam leads to displacement underestimation in the focal zone. Displacement underestimation can be reduced by using tracking beams that are narrower than the spatial extent of the displacement fields. Displacement underestimation and jitter decrease with time after excitation as shear wave propagation away from the region of excitation reduces shearing in the lateral and elevation dimensions. The use of higher tracking frequencies in broadband transducers, along with 2D focusing in the elevation dimension, will reduce jitter and improve displacement tracking accuracy. Relative displacement underestimation remains constant as a function of applied force, whereas jitter increases with applied force. Underdeveloped speckle (SNR < 1.91) leads to greater levels of jitter and peak displacement underestimation. Axial shearing is minimal over the tracking kernel lengths used in acoustic radiation force impulse imaging and thus does not impact displacement tracking.
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