University of Southern California, Department of Biomedical Engineering, Los Angeles, CA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2010 Jul;57(7):1548-57. doi: 10.1109/TUFFC.2010.1585.
High-frequency (HF) ultrasound imaging has been shown to be useful for non-invasively imaging anatomical structures of the eye and small animals in biological and pharmaceutical research, achieving superior spatial resolution. Cardiovascular research utilizing mice requires not only realtime B-scan imaging, but also ultrasound Doppler to evaluate both anatomy and blood flow of the mouse heart. This paper reports the development of an HF ultrasound duplex imaging system capable of both B-mode imaging and Doppler flow measurements, using a 64-element linear array. The system included an HF pulsed-wave Doppler module, a 32-channel HF B-mode imaging module, a PC with a 200 MS/s 14-bit A/D card, and real-time LabView software. A 50 dB SNR and a depth of penetration of larger than 12 mm were achieved using a 35-MHz linear array with 50 μm pitch. The two-way beam widths were determined to be 165 to 260 μm and the clutter-energy-to-total-energy ratio (CTR) were 9.1 to 12 dB when the array was electronically focused at different focal points at depths from 4.8 to 9.6 mm. The system is capable of acquiring real-time B-mode images at a rate greater than 400 frames per second (fps) for a 4.8 x 13 mm field of view, using a 30- MHz 64-element linear array with 100 μm pitch. Sample in vivo cardiac high frame rate images and duplex images of mouse hearts are shown to assess its current imaging capability and performance for small animals.
高频（HF）超声成像是一种非侵入性的成像技术，可用于生物和制药研究中对眼部和小动物的解剖结构进行成像，实现了更高的空间分辨率。心血管研究需要利用小鼠进行实时 B 型扫描成像，还需要使用超声多普勒来评估小鼠心脏的解剖结构和血流情况。本文报告了一种 HF 超声双工成像系统的开发，该系统能够进行 B 型模式成像和多普勒血流测量，使用 64 阵元线性阵列。该系统包括一个 HF 脉冲波多普勒模块、一个 32 通道 HF B 型成像模块、一个带有 200 MS/s 14 位 A/D 卡的 PC 机，以及实时 LabView 软件。使用 35 MHz、50μm 阵元间距的线性阵列，实现了 50 dB 的 SNR 和大于 12mm 的穿透深度。当阵列在 4.8 到 9.6mm 的不同深度处进行电子聚焦时，双向波束宽度分别确定为 165 到 260μm，杂波能量与总能量比（CTR）为 9.1 到 12dB。该系统能够以大于 400 帧/秒（fps）的速率获取实时 B 型图像，对于 4.8×13mm 的视野，使用 30MHz、100μm 阵元间距的 64 阵元线性阵列。显示了用于评估其当前成像能力和小动物成像性能的心脏高帧率图像和小鼠心脏双工图像。
