Xu Lexiu, Li Yifang, Liu Yuan, Shi Qinzhen, Xing Wenyu, Jiang Tao, Zhang Gaobo, Li Ying, Ta Dean
IEEE Trans Biomed Eng. 2025 Mar;72(3):878-890. doi: 10.1109/TBME.2024.3477708. Epub 2025 Feb 20.
Classic ultrasound bone imaging modalities usually demand either a prior knowledge or an advanced estimation on speed of sound (SoS), which not only renders to a burdensome imaging process but also supplies a limited resolution. To overcome these drawbacks, this article proposed a frequency-domain full-waveform inversion (FDFWI) modality using phased array tomography for high-accuracy cortical bone imaging. A transmission scenario of ultrasound wave in 2-D space was presented in the frequency domain to simulate the forward wavefield propagation. Iterations in the inversion process were performed by matching the simulation wavefield to the experimental one from low to high discrete frequency points. Moreover, the association between the maximum initial frequency and the initial SoS model was explored to prevent the occurrence of cycle-skipping phenomenon, which could lead to the outcomes being trapped in local minima. The feasibility and effectiveness of the proposed imaging scheme were testified by simulation, phantom, and ex-vivo studies, with mean relative errors of cortical part being 3.18%, 8.71%, and 9.36%, respectively. It is verified that the proposed FDFWI method is an effective way for parametric imaging of cortical bone without any prior knowledge of sound speed.
经典的超声骨成像模式通常需要对声速（SoS）有先验知识或进行高级估计，这不仅使成像过程繁琐，而且分辨率有限。为克服这些缺点，本文提出了一种使用相控阵层析成像的频域全波形反演（FDFWI）模式，用于高精度皮质骨成像。在频域中给出了二维空间中超声波的传播场景，以模拟前向波场传播。反演过程中的迭代通过将模拟波场与从低到高离散频率点的实验波场进行匹配来执行。此外，还探索了最大初始频率与初始SoS模型之间的关联，以防止出现跳周现象，这种现象可能导致结果陷入局部最小值。通过模拟、体模和离体研究验证了所提出成像方案的可行性和有效性，皮质部分的平均相对误差分别为3.18%、8.71%和9.36%。验证了所提出的FDFWI方法是一种无需任何声速先验知识即可进行皮质骨参数成像的有效方法。
