Imaging feedback of histotripsy treatments using ultrasound shear wave elastography.
Imaging feedback of histotripsy treatments using ultrasound shear wave elastography.
复制标题
使用超声剪切波弹性成像进行组织解剖治疗的成像反馈。
DOI：
10.1109/tuffc.2012.2307
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Cain,CharlesA
中科院分区：
文献类型：
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作者：
Wang,Tzu-Yin;Hall,TimothyL;Xu,Zhen;Fowlkes,JBrian;Cain,CharlesA
组织粉碎术是一种基于空化的超声治疗，其将软固体组织机械分离成流体状匀浆。本文研究了在组织摧毁过程中对组织弹性变化进行成像的可行性，作为为治疗提供反馈的工具。使用由750-kHz治疗阵列在17/108 MPa的峰值负/正压和50 Hz的重复率下递送的3周期超声脉冲对琼脂组织模型和离体肾脏进行治疗。随着每个治疗位置的治疗脉冲数量从0增加到2000个脉冲，产生具有不同程度损伤的病变。用超声剪切波弹性成像测量病变的弹性，其中准平面剪切波由治疗阵列产生的声辐射力引起，并用超声成像以每秒3000帧跟踪。基于从连续捕获的帧计算的剪切波速度，杨氏模量被重建。结果表明，剪切波速度图像比B型图像更容易识别病变。随着治疗脉冲数量从0增加到2000个脉冲/位置，组织体模中的杨氏模量从22.1 ± 2.7呈指数下降至2.1 ± 1.1 kPa（R2 = 0.99，每个N = 9），离体肾脏中的杨氏模量从33.0 ± 7.1降至4.0 ± 2.5 kPa（R2 = 0.99，每个N = 8）。相应地，通过组织学检查，组织从完全完整转变为完全分离。病变的杨氏模量和组织分级程度之间存在良好的相关性，如用剩余结构完整的细胞核的百分比所检查的（R2 = 0.91，N = 8）。这些结果表明，组织破坏产生的病变可以检测到高灵敏度使用剪切波弹性成像。由于组织弹性的下降与形态学和组织学的变化相一致，因此本研究为从组织弹性变化预测局部治疗结果提供了依据。
Histotripsy is a cavitation-based ultrasound therapy that mechanically fractionates soft solid tissues into fluid-like homogenates. This paper investigates the feasibility of imaging the tissue elasticity change during the histotripsy process as a tool to provide feedback for the treatments. The treatments were performed on agar tissue phantoms and ex vivo kidneys using 3-cycle ultrasound pulses delivered by a 750-kHz therapeutic array at peak negative/positive pressure of 17/108 MPa and a repetition rate of 50 Hz. Lesions with different degrees of damage were created with increasing numbers of therapy pulses from 0 to 2000 pulses per treatment location. The elasticity of the lesions was measured with ultrasound shear wave elastography, in which a quasi-planar shear wave was induced by acoustic radiation force generated by the therapeutic array, and tracked with ultrasound imaging at 3000 frames per second. Based on the shear wave velocity calculated from the sequentially captured frames, the Young’s modulus was reconstructed. Results showed that the lesions were more easily identified on the shear wave velocity images than on B-mode images. As the number of therapy pulses increased from 0 to 2000 pulses/location, the Young’s modulus decreased exponentially from 22.1 ± 2.7 to 2.1 ± 1.1 kPa in the tissue phantoms (R2 = 0.99, N = 9 each), and from 33.0 ± 7.1 to 4.0 ± 2.5 kPa in the ex vivo kidneys (R2 = 0.99, N = 8 each). Correspondingly, the tissues transformed from completely intact to completely fractionated as examined via histology. A good correlation existed between the lesions' Young's modulus and the degree of tissue fractionation as examined with the percentage of remaining structurally intact cell nuclei (R2 = 0.91, N = 8 each). These results indicate that lesions produced by histotripsy can be detected with high sensitivity using shear wave elastography. Because the decrease in the tissue elasticity corresponded well with the morphological and histological change, this study provides a basis for predicting the local treatment outcomes from tissue elasticity change.