Shen Che-Chou, Li Pai-Chi
Department of Electrical Engineering, National Taiwan University, Taipei, ROC.
IEEE Trans Ultrason Ferroelectr Freq Control. 2002 Sep;49(9):1203-11. doi: 10.1109/tuffc.2002.1041536.
Motion artifacts of the pulse inversion technique were studied for finite amplitude distortion-based harmonic imaging. Motion in both the axial and the lateral directions was considered. Two performance issues were investigated. One is the harmonic signal intensity relative to the fundamental intensity and the other is the potential image quality degradation resulting from spectral leakage. A one-dimensional (1-D) correlation-based correction scheme also was used to compensate for motion artifacts. Results indicated that the tissue harmonic signal is significantly affected by tissue motion. For axial motion, the tissue harmonic intensity decreases much more rapidly than with lateral motion. The fundamental signal increases for both axial and lateral motion. Thus, filtering is still required to remove the fundamental signal, even if the pulse inversion technique is applied. The motion also potentially decreases contrast resolution because of the uncancelled spectral leakage. Also, it was indicated that 1-D motion correction is not adequate if nonaxial motion is present.
针对基于有限振幅失真的谐波成像，研究了脉冲反转技术的运动伪影。考虑了轴向和横向的运动。研究了两个性能问题。一个是谐波信号强度相对于基波强度，另一个是频谱泄漏导致的潜在图像质量下降。还使用了基于一维（1-D）相关性的校正方案来补偿运动伪影。结果表明，组织谐波信号受组织运动的影响很大。对于轴向运动，组织谐波强度的下降比横向运动时快得多。轴向和横向运动时基波信号都会增加。因此，即使应用了脉冲反转技术，仍需要滤波来去除基波信号。由于未消除的频谱泄漏，运动还可能降低对比度分辨率。此外，研究表明，如果存在非轴向运动，一维运动校正并不足够。
