IEEE Trans Biomed Eng. 2018 Jan;65(1):15-20. doi: 10.1109/TBME.2017.2687948. Epub 2017 Mar 28.
High-frequency ultrasound imaging (at >20 MHz) has gained widespread attention due to its high spatial resolution being useful for basic cardiovascular and cancer research involving small animals. The sampling rate of the analog-to-digital converter in a high-frequency ultrasound system usually needs to be higher than 120 MHz in order to satisfy the Nyquist sampling-rate requirement. However, the sampling rate is typically within the range of 40-60 MHz in a traditional ultrasound system, and so we propose a delayed-excitation method for performing high-frequency ultrasound imaging with a traditional data acquisition scheme. In this method, the transmitted pulse is delayed by a certain time period so that the ultrasound echo data are aligned into high-sampling-rate slots. Wire and tissue-mimicking phantoms were imaged to evaluate the performance of the proposed method, whereas a porcine small-intestine specimen and an excised rabbit eyeball were used for in vitro imaging evaluations. The test results demonstrate that the proposed method allows high-frequency ultrasound imaging to be implemented using a traditional ultrasound sampling system.
高频超声成像是一种高空间分辨率的成像技术，在小动物心血管和癌症研究中得到了广泛的关注。为了满足奈奎斯特采样率要求，高频超声系统中的模数转换器的采样率通常需要高于 120MHz。然而，在传统的超声系统中，采样率通常在 40-60MHz 范围内，因此我们提出了一种延迟激励方法，以便在传统的数据采集方案中进行高频超声成像。在该方法中，发射脉冲被延迟一定的时间间隔，以使超声回波数据对齐到高采样率的时隙中。我们使用线和组织模拟体模来评估所提出方法的性能，同时使用猪小肠标本和离体兔眼球进行了体外成像评估。实验结果表明，该方法允许使用传统的超声采样系统进行高频超声成像。
