Noninvasive Carotid Strain Imaging Using Angular Compounding at Large Beam Steered Angles: Validation in Vessel Phantoms
Noninvasive Carotid Strain Imaging Using Angular Compounding at Large Beam Steered Angles: Validation in Vessel Phantoms
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DOI：
10.1109/tmi.2008.2011510
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发表时间：
2009-06-01
影响因子：
10.6
通讯作者：
de Korte, Chris L.
中科院分区：
文献类型：
--
作者：
Hansen, Hendrik H. G.;Lopata, Richard G. P.;de Korte, Chris L.
中风和心肌梗死是由易损动脉粥样硬化斑块破裂引发的。无创超声弹性成像，这些斑块可能会发现在颈动脉。然而，由于超声波束通常不与动脉脉动的径向方向对准，因此需要从轴向和侧向数据导出径向和周向应变。进行这种转换的传统技术具有需要横向应变的缺点。由于横向应变具有相对较差的精度，因此径向和周向应变的质量降低。在这项研究中，通过结合在多个声穿透角度下获取的轴向应变数据来改进径向和周向应变估计。介绍了自适应技术，以纠正光栅波瓣干扰和其他工件时，发生在大角度进行波束转向。在多个角度的采集与波束转向线性阵列执行。对于每个波束转向角，存在圆形血管横截面的两个空间受限区域，其中轴向应变与径向应变紧密对准，以及两个空间受限区域（不同于径向应变区域），其中轴向应变与周向应变紧密对准。这些具有高质量应变估计的片段被复合以形成径向或周向应变图像。复合径向和周向应变图像构建了一个均匀的血管体模与同心腔受到不同的腔内压力。弹性成像信噪比（SNRe）和对比度噪声比（CNRe）的比较显示，与仅来自0度信息的图像相比，复合显著提高了图像质量。SNRe和CNRe分别增加到2.7和6.6 dB。最高的图像质量是通过投影轴向数据，完成与一个小的部分确定的主成分分析或通过应用旋转矩阵。
Stroke and myocardial infarction are initiated by rupturing vulnerable atherosclerotic plaques. With noninvasive ultrasound elastography, these plaques might be detected in carotid arteries. However, since the ultrasound beam is generally not aligned with the radial direction in which the artery pulsates, radial and circumferential strains need to be derived from axial and lateral data. Conventional techniques to perform this conversion have the disadvantage that lateral strain is required. Since the lateral strain has relatively poor accuracy, the quality of the radial and circumferential strains is reduced. In this study, the radial and circumferential strain estimates are improved by combining axial strain data acquired at multiple insonitication angles. Adaptive techniques to correct for grating lobe interference and other artifacts that occur when performing beam steering at large angles are introduced. Acquisitions at multiple angles are performed with a beam steered linear array. For each beam steered angle, there are two spatially restricted regions of the circular vessel cross section where the axial strain is closely aligned with the radial strain and two spatially restricted regions (different from the radial strain regions) where the axial strain is closely aligned with the circumferential strain. These segments with high quality strain estimates are compounded to form radial or circumferential strain images. Compound radial and circumferential strain images were constructed for a homogeneous vessel phantom with a concentric lumen subjected to different intraluminal pressures. Comparison of the elastographic signal-to-noise ratio (SNRe) and contrast-to-noise ratio (CNRe) revealed that compounding increases the image quality considerably compared to images from 0 degrees information only. SNRe and CNRe increase up to 2.7 and 6.6 dB, respectively. The highest image quality was achieved by projecting axial data, completed with a small segment determined by either principal component analysis or by application of a rotation matrix.