A sensitive TLRH targeted imaging technique for ultrasonic molecular imaging.
A sensitive TLRH targeted imaging technique for ultrasonic molecular imaging.
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DOI：
10.1109/tuffc.2010.1411
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Ferrara KW
中科院分区：
文献类型：
--
作者：
Hu X;Zheng H;Kruse DE;Sutcliffe P;Stephens DN;Ferrara KW
超声分子成像的主要目标是超声造影剂（微泡）的检测和成像，超声造影剂与特定的血管表面受体结合。能够灵敏、选择性地检测和区分结合微泡与自由循环微泡（游离微泡）和周围组织的成像方法对于超声造影分子成像的实际应用至关重要。低频声脉冲激发的微泡会发出带宽超过 20 MHz 的宽带回波；我们将此技术称为 TLRH（低频传输和高频接收）。利用这种宽带瞬态回波，我们开发并实施了一种结合多频共线阵列和西门子 Antares® 成像系统的目标成像技术。多频共线阵列集成了一个中心5.4 MHz阵列，用于接收回波并产生辐射力，以及两个外部1.5 MHz阵列，用于发射低频入射脉冲。靶向成像技术利用声辐射力子序列来增强累积，并利用 TLRH 成像子序列来检测结合的微泡。对从 TLRH 成像子序列获得的射频 (RF) 数据进行处理，以分离组织、游离微泡和结合微泡之间的回波特征。通过对抗生物素蛋白包被的纤维素管上的生物素包被的微泡进行成像，我们证明了所提出的方法具有高组织对比比（高达 34 dB）和对结合微泡的高灵敏度（来自结合微泡与游离微泡的回波比率高达 23 dB）。研究了成像脉冲声压、辐射力子序列以及各种慢时滤波器的使用对目标成像质量的影响。本研究证明 TLRH 靶向成像方法可为超声分子靶向成像提供灵敏且选择性的结合微泡检测。
The primary goals of ultrasound molecular imaging are the detection and imaging of ultrasound contrast agents (microbubbles), which are bound to specific vascular surface receptors. Imaging methods that can sensitively and selectively detect and distinguish bound microbubbles from freely circulating microbubbles (free microbubbles) and surrounding tissue are critically important for the practical application of ultrasound contrast molecular imaging. Microbubbles excited by low frequency acoustic pulses emit wide-band echoes with a bandwidth extending beyond 20 MHz; we refer to this technique as TLRH (transmission at a low frequency and reception at a high frequency). Using this wideband, transient echo, we have developed and implemented a targeted imaging technique incorporating a multi-frequency co-linear array and the Siemens Antares® imaging system. The multi-frequency co-linear array integrates a center 5.4 MHz array, used to receive echoes and produce radiation force, and two outer 1.5 MHz arrays used to transmit low frequency incident pulses. The targeted imaging technique makes use of an acoustic radiation force sub-sequence to enhance accumulation and a TLRH imaging sub-sequence to detect bound microbubbles. The radiofrequency (RF) data obtained from the TLRH imaging sub-sequence are processsed to separate echo signatures between tissue, free microbubbles, and bound microbubbles. By imaging biotin-coated microbubbles targeted to avidin-coated cellulose tubes, we demonstrate that the proposed method has a high contrast-to-tissue ratio (up to 34 dB) and a high sensitivity to bound microbubbles (with the ratio of echoes from bound microbubbles versus free microbubbles extending up to 23 dB). The effects of the imaging pulse acoustic pressure, the radiation force sub-sequence and the use of various slow-time filters on the targeted imaging quality are studied. The TLRH targeted imaging method is demonstrated in this study to provide sensitive and selective detection of bound microbubbles for ultrasound molecularly-targeted imaging.