Song Pengfei, Song Chengjin, Zhang Yubao, Han Xiao, Tang Peijun, Duvvuri Chaitanya, Xu Jingjiang, Huang Yanping, Qin Jia, An Lin, Twa Michael D, Lan Gongpu
Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China.
Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang 330063, China.
Biomed Opt Express. 2025 Mar 11;16(4):1371-1391. doi: 10.1364/BOE.557984. eCollection 2025 Apr 1.
We evaluate the effect of excitation angles on the observation and characterization of surface wave propagations used to derive tissue's mechanical properties in optical coherence tomography (OCT)-based elastography (OCE). Air-pulse stimulation was performed at the center of the sample with excitation angles ranging from oblique (e.g., 70° or 45°) to perpendicular (0°). OCT scanning was conducted radially to record mechanical wave propagations in 360°, and the wave features (amplitude, attenuation, group and phase velocities) were calculated in the spatiotemporal or wavenumber-frequency domains. We conducted measurements on isotropic, homogeneous samples (1-1.6% agar phantoms), anisotropic samples (chicken breast), and samples with complex boundaries, coupling media, and stress conditions ( porcine cornea, intraocular pressure (IOP): 5-20 mmHg). Our findings indicate that mechanical wave velocities are less affected by excitation angles compared to displacement features, demonstrating the robustness of using mechanical waves for elasticity estimations. Agar and chicken breast sample measurements showed that all these metrics (particularly wave velocities) are relatively consistent when excitation angles are smaller than 45°. However, significant disparities were observed in the porcine cornea measurements across different excitation angles (even between 15° and 0°), particularly at high IOP levels (e.g., 20 mmHg). Our findings provide valuable insights for enhancing the accuracy of biomechanical assessments using air-pulse-based or other dynamic OCE approaches. This facilitates the refinement and clinical translation of the OCE technique and could ultimately improve diagnostic and therapeutic applications across various biomedical fields.
我们评估了激发角度对用于在基于光学相干断层扫描（OCT）的弹性成像（OCE）中推导组织力学特性的表面波传播的观察和表征的影响。在样品中心进行空气脉冲刺激，激发角度范围从倾斜（例如70°或45°）到垂直（0°）。进行径向OCT扫描以记录360°范围内的机械波传播，并在时空或波数 - 频率域中计算波特征（振幅、衰减、群速度和相速度）。我们对各向同性、均匀的样品（1 - 1.6%琼脂模型）、各向异性样品（鸡胸肉）以及具有复杂边界、耦合介质和应力条件的样品（猪角膜，眼内压（IOP）：5 - 20 mmHg）进行了测量。我们的研究结果表明，与位移特征相比，机械波速度受激发角度的影响较小，这表明使用机械波进行弹性估计具有稳健性。琼脂和鸡胸肉样品的测量表明，当激发角度小于45°时，所有这些指标（特别是波速度）相对一致。然而，在猪角膜测量中，不同激发角度（甚至在15°和0°之间）观察到显著差异，特别是在高眼压水平（例如20 mmHg）时。我们的研究结果为提高使用基于空气脉冲或其他动态OCE方法的生物力学评估的准确性提供了有价值的见解。这有助于OCE技术的改进和临床转化，并最终改善各个生物医学领域的诊断和治疗应用。
