超声对比剂的材料学特点及临床应用

背景：目前临床上应用的超声对比剂均是含有不同包膜材料和气体成分的微泡对比剂，微泡对比剂的出现使超声诊断技术得到了较大的发展。目的：探讨超声对比剂的材料学研究特点，及超声对比剂在临床疾病治疗中的应用。方法：超声对比剂是由气体微泡和外部包裹的膜物质组成，包膜材料主要分为白蛋白、大分子脂质体、多聚体和各种表面活性剂等。超声造影是通过增强背向散射信号来成像。超声对比剂研究的发展大致分为3个阶段，造影相关技术包括二次谐波、组织特异性显像、反相脉冲谐波成像、相干造影成像技术、对比脉冲序列、能量多普勒谐波成像、间歇谐波成像技术、编码谐波成像和超声造影三维成像。结果与结论：超声对比剂形式的不同主要是通过改变微泡包膜和气体的性质和设计来实现的。微气泡能够实现超声对比剂的显影作用，还可在药物传输上发挥功能。新型的微泡超声对比剂不仅可以提供血流灌注学信息，还可以通过靶向作用于病变组织，分析病变的发生机制，使微泡对比剂的诊断更准确。随着微泡对比剂材料学研究以及制备工艺完善，使超声对比剂具有良好的生物相容性。不仅可以用于各种状态下的特异性超声造影，还可以利用空化效应携带药物或治疗基因向目标组织转移释放。微泡造影技术具有治疗、诊断和超声成像的功能，是一种安全、高效、无创的诊断和靶向传输治疗手段。

Characteristics and clinical application of polymer ultrasound contrast agents

BACKGROUND:Current clinically used ultrasound contrast agents are microbubble contrast agents containing different gas components. The microbubble contrast agents allow further development of ultrasonic diagnosis and have become a study focus in contrast agents.OBJECTIVE:To explore methods of preparing polymer ultrasound contrast agents and analyze their clinical application in disease treatment.METHODS:Ultrasound contrast agents are composed of gas microbubble and encapsulated membrane. The membrane materials contain albumin, macromolecule liposome, polymer and various surface active agents. Imaging of ultrasound contrast is achieved through enhancing backscatter signals. The development of ultrasound contrast agents is divided into three stages, and visualization-related techniques include second harmonic, tissue specific developing, pulse inversion harmonic imaging, coherent contrast imaging, contrast pulse sequence, energy Doppler harmonic imaging, intermittent harmonic imaging, coded harmonic imaging and contrast-enhanced ultrasound three-dimensional imaging.RESULTS AND CONCLUSION:Various ultrasound contrast agents differ in properties and designs of encapsulation. Microbubble enabled developing an image of ultrasound contrast and can play a role in transferring drugs. Novel microbubble contrast agents can provide blood perfusion information and target lesioned tissue to understand the mechanism of lesion to make the diagnosis of microbubble contrast agents more accurate. With developing preparation technique, microbubble contrast agents have good biocompatibility. They can be used for specific contrast-enhanced ultrasound imaging under various conditions, increase cell membrane permeability by carrying drugs or theoretical genes through transient cavatition erosion, and improve transfection efficiency of drugs or genes. Microbubble contrast would be developed to have multiple functions, such as treatment, diagnosis and ultrasonic imaging and become a safe, high-effective, non-invasive diagnostic and targeting transfer treatment tool.