Development of Functional Ultrasonic Contrast Agent

本研究获得的主要成果如下：1。研制了一种可由外部磁场控制的超声造影剂，其比重可根据环境流体的比重进行调节。该剂由中空的两层球体制成。研制了一种谐振型超声示踪剂，阐明了谐振频率与空心磁微球直径的关系。使用该示踪剂证明了缓慢流体流动的流动可视化。提出了一种利用图像序列进行二维场检测和计算的新方法。该计算模型具有多通道运动检测器。实验结果表明，与单通道模型相比，该模型检测出更可靠的运动场。该方法应用于血流检测。

Main results obtained in this research are as follows ;1. An ultrasonic contrast agent which can be controlled by an external magnetic field, and whose specific gravity is adjustable to that of the ambient fluid is developed. The agent is made of hollow two-layred spheres.2. A resonant type ultrasonic tracer is developed and the relation between the resonance frequency and the diameter of hollow magnetic micro spheres is clarfied. Flow visualization of slow fluid flow was demonstrated using this tracers.3. A new approach for the detection and computation of two dimensional field using image sequence is presented. This computational model has a multi-channel motion detector. Experimental results shows that this model detects more reliable motion fields compared to one-channel model.3. The approach was applied for the detection of blood flow.