Crossed electrode arrays address some of the challenges associated with 3-D ultrasound imaging because of the significant reduction in the number of elements ( $2{N}$ versus ${N}^{{2}}$ ). However, creating a two-way focused 3-D image in real time is difficult with these arrays because azimuth and elevation dimensions cannot be beamformed at the same time. This work describes a new 3-D imaging technique that uses the flexibility of bias-sensitive substrates to create a high-quality elevation focus on a crossed electrode array. The principle behind this technique is to perform conventional compound imaging with an azimuth set of electrodes while implementing a bias controllable elevation lens with an elevation set of electrodes. On transmit, the biases are chosen to mimic a Fresnel lens. Then, on receive, the Hadamard coding is implemented along the elevation dimension. After decoding, we gain the RF data for each element across the elevation aperture even though there is effectively only one channel in that dimension. A 30-MHz, 128-element crossed electrode relaxor array was fabricated on a 1–3 electrostrictive composite substrate and was used to demonstrate the performance of the imaging technique. The on-axis −6-dB beamwidths were simulated to be 175 and $150~\mu \text{m}$ in the azimuth and elevation directions, respectively, and the focus remained isotropic in the furthest elevation slice. Images were generated of a wire phantom to confirm the performance of the azimuth and elevational radiation patterns with good agreement between simulation and experiment. High-resolution 3-D volumetric images were generated of an ex vivo rat brain. Images of the cerebellum showed that the white and gray matter tracts could clearly be visualized with isometric resolution in both the azimuth and elevation dimensions.

中文翻译：

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一种新的3-D成像技术，集成了超快复合，哈达玛编码和可重构菲涅尔透镜

交叉电极阵列解决了与3-D超声成像相关的一些挑战，因为元素数量大大减少了（ $ 2 {N} $ 相对 $ {N} ^ {{2}} $ ）。但是，使用这些阵列很难实时创建双向聚焦的3D图像，因为不能同时对方位角和高程尺寸进行波束成形。这项工作描述了一种新的3-D成像技术，该技术利用了偏置敏感基板的灵活性在交叉电极阵列上创建了高质量的仰角焦点。该技术背后的原理是使用电极的方位角集执行常规的复合成像，同时实现带有电极的仰角集的偏置可控仰角透镜。在发射时，选择偏压来模仿菲涅耳透镜。然后，在接收时，沿高程维度实施Hadamard编码。解码后，即使在该维度上实际上只有一个通道，我们仍可以在仰角孔径上获得每个元素的RF数据。30 MHz 在1–3电致伸缩复合基板上制造了128个元素的交叉电极弛豫器阵列，并用于证明成像技术的性能。轴上-6 dB的波束宽度模拟为175和 $ 150〜\ mu \ text {m} $ 分别在方位角和仰角方向，并且在最远的仰角切片中焦点保持各向同性。生成了导线幻像的图像，以确认方位角和仰角辐射图的性能，并且在仿真和实验之间具有良好的一致性。生成高分辨率的3D体积图像离体老鼠的大脑。小脑的图像显示，在方位角和仰角方向上，等轴测分辨率都能清楚地显示白色和灰色物质区域。