Dual-arrays brain imaging prototype: experimental in vitro results
Dual-arrays brain imaging prototype: experimental in vitro results
复制标题
双阵列脑成像原型：体外实验结果
DOI：
10.1109/ultsym.2005.1602901
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
J. Lecoeur
中科院分区：
文献类型：
--
作者：
F. Vignon;J. Aubry;M. Tanter;A. Margoum;M. Fink;J. Lecoeur
大脑的经颅成像目前受到颅骨散焦效应（超声的吸收、扩散和折射）的限制。提出了一种考虑颅骨散焦效应的非侵入性脑成像装置。该装置由位于头部两侧的两个相同的“孪生”线性阵列组成。它示出了如何区分两个骨窗口的超声波从一个阵列到另一个的路径上的各自的影响，以及如何估计在每个频率的衰减和相移本地引起的每个骨窗口。然后，该信息用于执行通过颅骨的非侵入性自适应聚焦。与商业扫描仪波束形成过程中使用的未校正波前相比，消除了焦点的空间偏移，减小了焦斑的宽度，并且旁瓣水平降低了15dB。该技术已被用于获取在体外的组织幻影背后的颅骨壁的图像，表现出相对于圆柱形聚焦获得的图像的图像质量增强。进一步的改进应导致图像对比度的改善大于20 dB相比，conventionnal扫描仪。
Transcranial imaging of the brain is currently limited by the defocusing effect of the skull bone (absorption, diffusion and refraction of ultrasound. A noninvasive brain imaging device is presented that takes into account the defocusing effect of the skull. This device is made of two identical "twin" linear arrays located on each side of the head. It is shown how to differentiate the respective influence of the two bone windows on the path of an ultrasonic wave going from one array to the other, and how to estimate at each frequency the attenuation and phase shifts locally induced by each of the bone windows. This information is then used to perform non invasive adaptive focusing through the skull. Compared to non corrected wavefronts used in the beamforming process of commercial scanners, the spatial shift of the focal point is cancelled, the width of the focal spot is reduced, and the sidelobes level is decreased up to 15dB. The technique has been used to acquire in vitro images of tissue phantoms behind a skull wall, exhibiting the image quality enhancement with respect to images obtained with cylindrical focusing. Further refinement should lead to an improvement of the image contrast greater than 20 dB compared to conventionnal scanners.