Coherent Plane Wave Compounding for Very High Frame Rate Ultrasonography of Rapidly Moving Targets
Coherent Plane Wave Compounding for Very High Frame Rate Ultrasonography of Rapidly Moving Targets
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DOI：
10.1109/tmi.2013.2255310
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发表时间：
2013-07-01
影响因子：
10.6
通讯作者：
Lovstakken, Lasse
中科院分区：
文献类型：
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作者：
Denarie, Bastien;Tangen, Thor Andreas;Lovstakken, Lasse
相干平面波复合是一种很有前途的技术，可以在不影响图像质量或穿透力的情况下实现非常高的帧速率成像。然而，这种方法依赖于成像对象在复合扫描序列期间不移动的假设，这在心血管成像中不是这种情况。研究了相干复合平面波成像中组织运动对回溯聚焦的影响。研究了两种基于线性和交替倾斜平面波序列的复合扫描序列，具有不同的时序特性。模拟研究揭示了在回顾性聚焦过程中潜在的严重退化，其中径向和横向分辨率都降低，引入了成像介质的横向偏移，并推断出信噪比（SNR）的损失。对于心肌成像，生理组织位移是半个波长的量级，导致SNR损失高达35 dB，对比度降低40 dB。在不同倾斜序列之间没有观察到显著差异。介绍了一种基于互相关的运动补偿技术，该技术显著地恢复了生理组织速度在信噪比和对比度方面的损失。SNR和对比度的最坏情况损失分别恢复了35 dB和27-35 dB。运动的影响，证明在体内成像大鼠心脏时。使用PWI，在高图像质量下实现了高达463 fps的非常高的帧速率，但随后需要运动校正方案。
Coherent plane wave compounding is a promising technique for achieving very high frame rate imaging without compromising image quality or penetration. However, this approach relies on the hypothesis that the imaged object is not moving during the compounded scan sequence, which is not the case in cardiovascular imaging. This work investigates the effect of tissue motion on retrospective transmit focusing in coherent compounded plane wave imaging (PWI). Two compound scan sequences were studied based on a linear and alternating sequence of tilted plane waves, with different timing characteristics. Simulation studies revealed potentially severe degradations in the retrospective focusing process, where both radial and lateral resolution was reduced, lateral shifts of the imaged medium were introduced, and losses in signal-to-noise ratio (SNR) were inferred. For myocardial imaging, physiological tissue displacements were on the order of half a wavelength, leading to SNR losses up to 35 dB, and reductions of contrast by 40 dB. No significant difference was observed between the different tilt sequences. A motion compensation technique based on cross-correlation was introduced, which significantly recovered the losses in SNR and contrast for physiological tissue velocities. Worst case losses in SNR and contrast were recovered by 35 dB and 27-35 dB, respectively. The effects of motion were demonstrated in vivo when imaging a rat heart. Using PWI, very high frame rates up to 463 fps were achieved at high image quality, but a motion correction scheme was then required.