IEEE Trans Biomed Eng. 2024 Nov;71(11):3232-3243. doi: 10.1109/TBME.2024.3414419. Epub 2024 Oct 25.
Wearable ultrasound is emerging as a new paradigm of real-time imaging in freely moving humans and has wide applications from cardiovascular health monitoring to human gesture recognition. However, current wearable ultrasound devices have typically employed pulse-echo imaging which requires high excitation voltages and sampling rates, posing safety risks, and requiring specialized hardware. Our objective was to develop and evaluate a wearable ultrasound system based on time delay spectrometry (TDS) that utilizes low-voltage excitation and significantly simplified instrumentation.
We developed a TDS-based ultrasound system that utilizes continuous, frequency-modulated sweeps at low excitation voltages. By mixing the transmit and receive signals, the system digitizes the ultrasound signal at audio frequency (kHz) sampling rates. Wearable ultrasound transducers were developed, and the system was characterized in terms of imaging performance, acoustic output, thermal characteristics, and applications in musculoskeletal imaging.
The prototype TDS system is capable of imaging up to 6 cm of depth with signal-to-noise ratio of up to 42 dB at a spatial resolution of 0.33 mm. Acoustic and thermal radiation measurements were within clinically safe limits for continuous ultrasound imaging. We demonstrated the ability to use a 4-channel wearable system for dynamic imaging of muscle activity.
We developed a wearable ultrasound imaging system using TDS to mitigate challenges with pulse echo-based wearable ultrasound imaging systems. Our device is capable of high-resolution, dynamic imaging of deep-seated tissue structures and is safe for long-term use.
This work paves the way for low-voltage wearable ultrasound imaging devices with significantly reduced hardware complexity.
可穿戴式超声技术作为一种在自由移动的人体中进行实时成像的新范例正在出现，并在心血管健康监测到人体手势识别等领域有着广泛的应用。然而，目前的可穿戴式超声设备通常采用需要高激励电压和采样率的脉冲回波成像，这带来了安全风险，并需要专门的硬件。我们的目标是开发和评估一种基于时移谱（TDS）的可穿戴式超声系统，该系统利用低电压激励并显著简化了仪器。
我们开发了一种基于 TDS 的超声系统，该系统利用低频激励的连续调频扫描。通过混合发射和接收信号，该系统以音频（kHz）采样率对超声信号进行数字化。开发了可穿戴式超声换能器，并从成像性能、声输出、热特性以及在肌肉骨骼成像中的应用等方面对系统进行了表征。
原型 TDS 系统能够以高达 42dB 的信噪比在 0.33mm 的空间分辨率下对 6cm 深度进行成像。声学和热辐射测量值在连续超声成像的临床安全范围内。我们证明了使用 4 通道可穿戴系统进行肌肉活动动态成像的能力。
我们使用 TDS 开发了一种可穿戴式超声成像系统，以减轻基于脉冲回波的可穿戴式超声成像系统的挑战。我们的设备能够对深层组织结构进行高分辨率、动态成像，并且可以安全地长期使用。
这项工作为具有显著降低硬件复杂性的低电压可穿戴式超声成像设备铺平了道路。
