Pigatto A V, Rosa N B, Furuie S S, Mueller J L
School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523 USA.
Escola Politécnica, University of São Paulo, Brazil.
IEEE Sens J. 2024 Apr 1;24(7):11091-11101. doi: 10.1109/jsen.2024.3359634. Epub 2024 Feb 8.
Pulmonary imaging with ultrasound in the conventional MHz range suffers from significant artifacts, as the high frequency acoustic waves primarily reflect off of the lung pleura with little to no penetration through the lung tissue. Furthermore, B-mode ultrasound images are difficult to interpret and require a skilled technician to obtain. Motivated by the finding that acoustic frequencies in the kHz penetrate lung tissue, a low-frequency tomographic ultrasound system is presented. A Verasonics Vantage 64 low-frequency ultrasound system is programmed to work with a novel low-frequency Tonpilz transducers set arranged in a circular array on a belt. After signal processing, a time-of-flight (TOF) tomographic reconstruction algorithm with refraction correction is applied to estimate the sound speed in the plane of the transducer array. Data were collected on experimental phantoms made of ballistic gel containing targets of varying sound speeds, and reconstructions TOF were computed. Results demonstrate that the low-frequency ultrasound tomography system effectively detects targets in an experimental phantom with the ability to resolve multiple targets and distinguish between targets of high and low sound speed compared to the background medium.
传统兆赫兹范围内的肺部超声成像存在显著伪像，因为高频声波主要从肺胸膜反射，几乎无法穿透肺组织。此外，B 模式超声图像难以解读，需要熟练的技术人员来获取。受千赫兹频率声波能穿透肺组织这一发现的启发，提出了一种低频断层超声系统。对 Verasonics Vantage 64 低频超声系统进行编程，使其与一组新型低频Tonpilz 换能器配合工作，这些换能器呈圆形阵列排列在一条皮带上。经过信号处理后，应用一种带有折射校正的飞行时间（TOF）断层重建算法来估计换能器阵列平面内的声速。在由含有不同声速目标的弹道凝胶制成的实验体模上收集数据，并计算 TOF 重建结果。结果表明，与背景介质相比，低频超声断层系统能够在实验体模中有效检测目标，具有分辨多个目标以及区分高声速和低声速目标的能力。
