This work was supported by the National Institutes of Health (R01-EB014496). The authors would like to thank Iason Apostolakis for his contribution to the experiments.

该协议被批准哥伦比亚大学的机构动物护理和使用委员会。所有的数据采集和处理用Matlab环境执行。 1.实验装置<ol><li>在90分钟的脱气离体犬肝脏样本。把肝脏样品中的填充有脱气磷酸盐缓冲溶液（ 图1）罐。固定在一个声吸收用针在肝脏的四肢的肝样品。 </li><li>通过一个圆孔位于93元半球阵列HIFU换能器（治疗）的中心，在4.5 MHz的中心频率的70 mm焦距的深度和插入64元0.32毫米间距，2.5 MHz的中心频率相控阵（成像） 1.7毫米×0毫米焦距的大小11。对齐两个传感器同轴和修复成像传感器到治疗换能器的调整螺丝。 <ol><li>盖上HIFU换能器与AVolume控制聚氨酯膜填充有流动的脱气的水来冷却下来。安装在一个计算机控制的3-D定位的换能器组件。 </li></ol></li><li>的HIFU换能器连接到功能发生器发送具有500毫伏最大振幅为25赫兹的调幅正弦波形。成像传感器连接到使用Matlab软件完全可编程超声系统。 注意：用超声系统相关联的软件和利用Matlab环境必须连接到系统中的计算机上。将50 dB的RF放大器和匹配网络应当放置在HIFU换能器与函数发生器分别放大功率并匹配的阻抗之间。 </li><li>创建一个极性的网格，用Matlab，开始从阵​​列的表面50毫米和40毫米深的在径向方向上具有9.625微米，90°，128线和哪些原点的空间的步骤在方位角方向是FOCUS发散波。限定的发散的波10.24毫米源（孔径大小的一半）的阵列的表面的后面，并集中在横向方向上。 <ol><li>创建一个笛卡尔网格，用Matlab，开始从阵​​列的表面50毫米和40毫米深在与9.625微米，宽20毫米，与64线，为平面波的左右方向的空间的步骤的轴向方向。限定所述阵列的表面上的平面波的来源。对于每一个网格，计算从源的时间的每个点的网格和背面到阵列中的每个元素。 </li></ol></li><li>输入“ReconMat_DW”的发散波成像或“ReconMat_PW”在MATLAB命令窗口平面波成像，然后按“Enter”来创建一个标准的延迟与求和算法，每个网格相关的​​重建矩阵。申请延迟与求和算法的标准基础的每个矢量和检索所述非零点的Elemen所得矩阵 11的TS。分配从所得矩阵获得的稀疏矩阵的相应位置中的非零元素。保存在电脑硬盘上的重建矩阵。 注意：发散和平面波的方法使用两个不同的重建矩阵。 <ol><li>铸造重建矩阵到GPU矩阵。输入“SetUpP4_2Flash_4B_streaming_DW”的发散波成像或“SetUpP4_2Flash_4B_streaming_PW”在Matlab的命令窗口，然后按“Enter”来创建使用相控阵由制造商相关的并脚本超声通道数据采集设置文件平面波成像的超声系统。命名安装文件“P4-2Flash_DivergingWave.mat”的发散波成像和“P4-2Flash_PlaneWave.mat”的平面波成像。 注：商业软件包，必须在电脑•安装Ø投重建稀疏矩阵到GPU矩阵。 </li></ol></li><li>使高帧速率的超声数据采集的肝脏开始同时作为HIFU超声系统使用外部触发函数发生器同步。 </li><li>打开Matlab的。运行安装脚本“SetUpP4_2Flash_4B.m”由超声系统制造商使用B模式成像提供。命名创建的安装文件：“P4-2Flash_4B_Bmode.mat”。使用“VSX”命令，在“.MAT文件要处理的名称：”提示，输入安装文件“P4-2Flash_4B_Bmode.mat”的名称。移动这两个换能器，并使用B模式显示该出现在计算机屏幕上，以它们在肝脏消融的目标区域放置。目标的区域中的肝脏表面下大约1cm，以避免高超声波衰减因吸收。保存在计算机上的肝脏的常规B模式图像。 注意：在这里，我们两个肝标本进行高强度聚焦超声消融在11个不同的位置通过移动换能器与所述3D定位器为每个消融。 </li></ol> 2.超声数据采集<ol><li>打开Matlab的。使用“VSX”命令，在“.MAT文件要处理的名称：”提示，输入安装文件“P4-2Flash_DivergingWave.mat”的名称发散波成像或“P4-2Flash_PlaneWave.mat”的平面波成像。启动HIFU和2分钟的目标区域中应用它。 </li><li>在使用发散波2分钟收购以每秒1000帧的RF信道的数据。另外，在2分钟利用平面波收购以每秒1000帧的RF信道的数据。 </li><li>通过PCI特快电缆将数据传输到主计算机每200帧。或者，对于实时流，使用平面波和TRANSF期间2分钟获取以每秒167帧的RF信道的数据器中的数据到主计算机的每2帧。 注：带套200帧的成像方法提供了每套之间的每个设置，但创造的间隙内高时间分辨率，适用于离线处理。在167 fps的影像处理方法具有较低的时间分辨率，但不创建整个消融时间的任何间隙，并且非常适合实时流。 </li><li>铸造RF信道的数据矩阵与Matlab的单精度GPU矩阵。由重建矩阵相乘RF信道的数据矩阵，以获得重建的RF数据11。 </li></ol> 3.排量成像<ol><li>创建一个6 阶 Butterworth低通于4 MHz的截止频率利用Matlab的DSP系统工具箱过滤器。应用此低通滤波器，以重构RF数据来过滤掉4.5兆赫HIFU组件。 </li><li>估计使用一维归一化互相关的连续帧之间的轴向位移用3.1毫米窗口长度和90％的重叠。 </li><li>创建一个6 阶 Butterworth低通在100赫兹的截止频率利用Matlab的DSP系统工具箱过滤器。用Matlab检索50赫兹振荡频率分量应用此低通滤波器的时间位移的数据。 </li><li>定义感兴趣区域（ROI）的区域作为在-6分贝焦点区域（1.7×0.4毫米，在水中）和位于70毫米背离换能器表面。在提取该ROI的位移数据。消融2分钟作为平均位移和在ROI的位移的标准偏差之间的比率后估计在焦点区域中的位移信噪比（SNR d）所示。 </li><li>提取50赫兹时间位移信号在从位移矩阵数据的焦点。时间位移信号转换的重点放到利用Matlab可听见的声音。 </li></ol>

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The authors declare that they have no competing financial interests.

HIFU病变的实时监控是非常重要的，以确保适当和有效的病变交付。作为病变形式中，组织变硬和下激励它的运动幅度减小。施加在HIFU的组织的结果的区域中诱导组织位移的声辐射力。在位移的相对变化是组织硬度相对变化的替代。这种技术提供监测HIFU病变不停止在与其它超声基础的方法治疗的优点。在这项研究中（4.5赫兹）的实时监测的时间分辨率比在MR引导HIFU消融（1赫兹）中获得更高。 ...

High Intensity Focused Ultrasound (HIFU) is a technique that generates temperature elevation at the focal region and can be used to ablate cancerous tissue 1. Temperature elevation at the focus causes thermal lesions in the tissue 2. In order to avoid overtreating a region and to reduce treatment duration, it is imperative to reliably monitor the ablation. Magnetic resonance-guided focused ultrasound (MRgFUS) is the main technique used in clinic to guide and monitor HIFU treatment 3. MRI provides high spatial resolution images of the treated region with tissue displacement or thermal dose but has a frame rate of 0.1-1 Hz and is costly. Several ultrasound-based techniques such as B-mode imaging 4, passive acoustic mapping 5, shear wave imaging 6 and acoustic radiation force impulse 7 have been developed to guide and monitor thermal ablation. However, B-mode imaging and passive acoustic mapping do not provide imaging of mechanical properties of the ablated region which is useful to the operator to improve lesion delivery. 
Shear wave imaging and acoustic radiation force impulse can both characterize the elasticity of the tissue by measuring acoustic radiation force-induced displacements 7,8. However, in both methods, the HIFU treatment is typically interrupted to monitor the ablation. Our group has developed a technique called Harmonic Motion Imaging for Focus Ultrasound (HMIFU) which can monitor the HIFU treatment with ultrasound without stopping the ablation9,10. Briefly, a HIFU transducer sends an amplitude-modulated wave to the region to ablate while simultaneously generating an oscillatory motion in the focal region. A co-axially aligned ultrasound transducer is used to image this oscillation. The magnitude of the induced motion is related to the stiffness of the tissue.
To ensure proper lesion delivery, the temporal resolution of real-time monitoring is of key interest in ablation guidance. Recently, our group has shown real-time streaming of displacement at a frame rate up to 15 Hz, imaged with diverging waves in a narrow field of view and using a fast image reconstruction method 11. Several beamforming techniques can be used to image the displacements. A large field of view can be obtained with diverging wave imaging by changing the delay profile but the axial direction is not aligned with the HIFU beam on the lateral regions and the wave is attenuated due to geometric spreading in the lateral direction, which can affect the quality of the displacement estimation. In contrast, the lateral field of view for plane wave is upper bounded by the active aperture but the axial direction is aligned with the HIFU beam at the focus and there is no geometric spreading in the lateral direction. Depending on the type of application, one or the other imaging method can be selected. The objectives of this protocol are to show how plane wave imaging can provide real-time streaming of displacements images using HMIFU during ablation and to compare the quality of the motion estimation between diverging and plane wave imaging.

<table border="0" cellpadding="0" cellspacing="0">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr>
			<td>P4-2 Phased array</td>
			<td>ATL</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>H-178 HIFU transducer</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3-D positioner</td>
			<td>Velmex Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>AT33522A function generator</td>
			<td>Agilent Technologies</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>V-1 ultrasound system</td>
			<td>Verasonics</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3100L RF amplifier</td>
			<td>ENI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matching network</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Degasing system</td>
			<td>Sonic Concepts</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Programming software</td>
			<td>Matlab</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Jacket software package</td>
			<td>Accelereyes</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

real-time monitoring of high intensity focused ultrasound (hifu) ablation of in vitro canine livers using harmonic motion imaging for focused ultrasound (hmifu)

谐运动成像的聚焦超声（HMIFU）是可以执行和监控高强度聚焦超声（HIFU）消融的技术。的振荡运动在一个93元件和4.5兆赫中心频率的HIFU换能器的焦点通过使用函数发生器施加25赫兹振幅调制的信号生成的。与68kPa峰值压力64元件和2.5兆赫成像换能器被共焦地放置在HIFU换能器获取的射频（RF）信道数据的中心。在这个协议中，使用高强度聚焦超声与对体外犬肝7瓦的声功率热消融的实时监控进行说明。在2分钟HIFU治疗被施加在组织上和烧蚀区域是使用发散或平面波成像高达1000帧/秒成像实时。的RF信道的数据的矩阵乘以一个稀疏矩阵图像重建。视重建场是90°的发散わ已经和20毫米的平面波成像和数据进行采样，在80兆赫。重建是在4.5显示帧速率上的图形处理单元（GPU）执行，以图像在实时的。重构RF数据的一维归一化互相关性被用于估计轴向位移在焦点区域。的峰 - 峰位移的在焦深幅度它表示所述组织的硬化由于病灶的形成热消融过程中降低。位移信噪比（SNR D）在重点领域的平面波是比发散波显示出平面波成像的1.4倍似乎产生更好的置换贴图质量HMIFU比发散波成像。

可以用发散和平面波成像获得HMI排量的实时流期间，高强度聚焦超声消融治疗。 图2是在高强度聚焦超声消融视频截屏显示使用平面波成像技术在体外犬肝脏的声辐射力引起的位移实时显示。的位移以4.5赫兹的显示帧速率流在实时计算机屏幕上。正位移示于红色和负位移为蓝色。病变使用HIFU消融。 图3示出对应于图2的消融后在肝脏中获得的病变被成功?...

Watch this Scientific Journal Video about Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU a

Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU

This article describes real-time monitoring of HIFU ablation in canine liver with high frame rate ultrasound imaging using diverging and plane wave imaging. Harmonic Motion Imaging for Focused Ultrasound is used to image the decrease of acoustic radiation force induced displacement in the ablated region.

高强度的实时监控聚焦超声（HIFU）消融<em&gt;体外</em&gt;使用谐运动成像的聚焦超声犬肝脏（HMIFU）

Harmonic Motion Imaging for Focused Ultrasound (HMIFU) is a technique that can perform and monitor high-intensity focused ultrasound (HIFU) ablation. An ...

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Real-time Monitoring of High Intensity Focused Ultrasound (HIFU) Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound (HMIFU)

9.9K 次观看.  Columbia University. This article describes real-time monitoring of HIFU ablation in canine liver with high frame rate ultrasound imaging using diverging and plane wave imaging. Harmonic Motion Imaging for Focused Ultrasound is used to image the decrease of acoustic radiation force induced displacement in the ablated region.

视频: Real-time Monitoring of High Intensity Focused Ultrasound HIFU Ablation of In Vitro Canine Livers Using Harmonic Motion Imaging for Focused Ultrasound HMIFU