A Forward Model Incorporating Elevation-Focused Transducer Properties for 3-D Full-Waveform Inversion in Ultrasound Computed Tomography.
A Forward Model Incorporating Elevation-Focused Transducer Properties for 3-D Full-Waveform Inversion in Ultrasound Computed Tomography.
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DOI：
10.1109/tuffc.2023.3313549
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发表时间：
2023-10
影响因子：
3.6
通讯作者：
Anastasio, Mark A
中科院分区：
文献类型：
--
作者：
Li, Fu;Villa, Umberto;Duric, Nebojsa;Anastasio, Mark A
超声计算机断层扫描（USCT）是一种新兴的医学成像方式，对改善人类健康有很大的希望。基于全波形反演（FWI）的图像重建方法考虑了相关的波物理学，以产生乳腺组织声学特性的高空间分辨率图像。实际的USCT设计采用由仰角聚焦超声换能器组成的圆形环形阵列，并且通过将环形阵列正交于成像平面平移来实现体积成像。在通常部署的逐切片（SBS）重建方法中，通过将针对环阵列的每个位置重建的2-D图像堆叠在一起来重建3-D体积。SBS重建方法的局限性在于它不考虑换能器的3-D波传播物理和聚焦特性，这可能导致显著的图像伪影和不准确性。当采用仰角聚焦换能器时，为了进行3-D图像重建，应在正演模型中包括换能器的聚焦特性的数值描述。为了解决这一问题，开发了仰角聚焦换能器的3-D计算模型，以使基于3-D FWI的重建方法能够部署在基于环形阵列的USCT中。聚焦通过对超声脉冲（发射器模式）和记录信号（接收器模式）施加空间变化的时间延迟来实现。建议的数值换能器模型进行了定量验证，并在计算机模拟研究，证明其用于图像重建的环阵列USCT。
Ultrasound computed tomography (USCT) is an emerging medical imaging modality that holds great promise for improving human health. Full-waveform inversion (FWI)-based image reconstruction methods account for the relevant wave physics to produce high spatial resolution images of the acoustic properties of the breast tissues. A practical USCT design employs a circular ring-array comprised of elevation-focused ultrasonic transducers, and volumetric imaging is achieved by translating the ring-array orthogonally to the imaging plane. In commonly deployed slice-by-slice (SBS) reconstruction approaches, the 3-D volume is reconstructed by stacking together 2-D images reconstructed for each position of the ring-array. A limitation of the SBS reconstruction approach is that it does not account for 3-D wave propagation physics and the focusing properties of the transducers, which can result in significant image artifacts and inaccuracies. To perform 3-D image reconstruction when elevation-focused transducers are employed, a numerical description of the focusing properties of the transducers should be included in the forward model. To address this, a 3-D computational model of an elevation-focused transducer is developed to enable 3-D FWI-based reconstruction methods to be deployed in ring-array-based USCT. The focusing is achieved by applying a spatially varying temporal delay to the ultrasound pulse (emitter mode) and recorded signal (receiver mode). The proposed numerical transducer model is quantitatively validated and employed in computer simulation studies that demonstrate its use in image reconstruction for ring-array USCT.