NON-INVASIVE SMALL VESSEL IMAGING OF HUMAN THYROID USING MOTION-CORRECTED SPATIOTEMPORAL CLUTTER FILTERING
NON-INVASIVE SMALL VESSEL IMAGING OF HUMAN THYROID USING MOTION-CORRECTED SPATIOTEMPORAL CLUTTER FILTERING
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DOI：
10.1016/j.ultrasmedbio.2018.10.028
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发表时间：
2019-04-01
影响因子：
2.9
通讯作者：
Alizad, Azra
中科院分区：
文献类型：
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作者：
Nayak, Rohit;Kumar, Viksit;Alizad, Azra
在不使用任何造影剂的情况下可靠地评估甲状腺中的小血管血流可能具有挑战性，因为它靠近搏动的颈动脉，导致生理运动增加。在这项研究中，我们假设在基于奇异值分解（SVD）的杂波过滤之前校正组织运动可以提高组织成分的一致性，因此可以更好地杂波抑制和甲状腺小血管的可视化。我们通过使用复合平面波成像的临床超声扫描仪进行体模和体内研究，证实了这一假设。体模研究是使用均匀的模拟组织体模进行的，以研究在没有血液活动的情况下运动对时空多普勒数据协方差的影响。这项非侵入性体内研究是对一名患有疑似恶性肿瘤的甲状腺结节的 74 岁女性进行的。使用从二维归一化基于互相关的散斑跟踪获得的组织位移来执行基于刚体的运动校正。随后，使用基于 SVD 的时空杂波滤波计算功率多普勒图像。模型研究的结果表明，运动可以显着降低时空数据的协方差，从而提高组织成分的等级。当模型在整个整体上在每个方向（轴向和横向）受到 6 个像素的总平移位移时，协方差下降了 25% 以上。非侵入性体内研究的结果表明，通过功率多普勒系综的运动校正，小血管血流的可视化得到了改善。与使用标准 SVD 方法在最佳阈值（0.87 和 4.33 dB）和较低奇异值阈值（1.92 和 3.05 dB）下获得的结果相比，运动校正功率多普勒图像中的血液信号对比度要高得多（8.17 和 8.32 dB）。此外，通过运动校正，体内甲状腺时空数据的协方差增加了约 10%。这些初步结果表明，运动校正可用于改善甲状腺中小血管血流的可视化，而无需使用任何造影剂。这项可行性研究的结果令人鼓舞，并有必要在移动组织和器官中进行进一步的开发和更多的体内验证。 (C) 2018 作者。由爱思唯尔公司代表世界医学与生物学超声联合会出版。
Reliable assessment of small vessel blood flow in the thyroid, without using any contrast agents, can be challenging because of increased physiological motion resulting from its proximity to the pulsating carotid artery. In this study, we hypothesized that correction of tissue motion prior to singular value decomposition (SVD)-based clutter filtering can improve the coherency of the tissue components and, thus, may allow better clutter suppression and visualization of small vessels in the thyroid. We corroborated this hypothesis by conducting phantom and in vivo studies using a clinical ultrasound scanner implemented with compounded plane wave imaging. The phantom studies were conducted using a homogeneous tissue-mimicking phantom to study the impact of motion on the covariance of the spatiotemporal Doppler data, in the absence of blood activity. The non-invasive in vivo study was conducted on a 74-y-old woman with a thyroid nodule suspicious of malignancy. A rigid body-based motion correction was performed using tissue displacements obtained from 2-D normalized cross-correlation-based speckle tracking. Subsequently, the power Doppler images were computed using SVD-based spatio-temporal clutter filtering. The results from the phantom study revealed that motion can considerably reduce the covariance of the spatio-temporal data and, thus, increase the rank of the tissue components. When the phantom was subjected to a total translation displacement of 6 pixels over the entire ensemble, in each direction (axial and lateral), the covariance dropped by more than 25%. The results obtained from the non-invasive in vivo study indicated that visualization of small vessel blood flow improved with motion correction of the power Doppler ensemble. The contrast-to-noise ratio of the blood signal in motion-corrected power Doppler images was considerably higher (8.17 and 8.32 dB), compared with that obtained using the standard SVD approach at an optimal threshold (0.87 and 4.33 dB) and a lower singular value threshold (1.92 and 3.05 dB). Further, the covariance of the in vivo thyroid spatiotemporal data increased by approximately 10% with motion correction. These preliminary results indicate that motion correction can be used to improve the visualization of small vessel blood flow in the thyroid, without using any contrast agents. The results of this feasibility study were encouraging, and warrant further development and more in vivo validation in moving tissues and organs. (C) 2018 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology.