摘要
磁共振成像(MRI)是临床上使用非常广泛的一种医学成像技术,其具有成像质量高、便于三维立体成像和功能成像等优点,适用于对各种器官组织进行疾病的诊断。随着MRI的快速发展和普及,基于MRI的组织弹性测量或成像技术(MRelastography或MRE)也相应地受到广泛的重视并且获得了许多应用。在准静态激励条件下,MRI可以直接用来测量组织的位移和形变。在动态激励情况下,因为成像速度较慢的原因,MRI一般不适合直接用于动态位移的测量。这个时候就可借助标记法或者剪切波传播法实现MRE。目前,动态剪切波传播法已成为MRE的主流。在剪切波传播弹性测量方法上,借助于运动敏感的成像序列,可获得剪切波的时空相位信息,然后计算传播速度用以实现弹性的测量。相对于传统的基于超声的弹性测量技术,MRE有许多独特的优点,如基于三维空间测量的位移更加准确、观察范围大(超声只限于探头成像范围),以及特别适合于脑部等超声无法进入的组织进行弹性特征的研究等。本文主要介绍基于MRE,首先介绍MRE相关的测量技术及特点,然后介绍目前MRE在几种典型组织的应用情况,最后总结该领域存在的问题并对未来的发展方向进行展望。
Magnetic resonance imaging is a medical imaging technology which has gained widespread popularity in clinical applications.The advantages of MRI as a medical imaging modality include its high image quality,3D imaging and functional imaging capabilities,which render it particularly useful for the diagnosis of diseases in various tissues and organs.With the fast development and fast increasing popularity of this modality,special interest has been attracted to the MRI-based elasticity measurement and imaging techniques（called MR elastography or MRE） and they have also gained many applications nowadays.With the quasi-static loading,MRI can be directly applied to measure the displacement and deformation of the tested tissue.With a dynamic loading,conventional MRI may not be a good choice for this purpose because of its limited imaging speed.In this case,MRE can be achieved by applying the tagging technique or shear wave propagation measurement,the latter of which has been the mainstream of current research.In shear wave-MRE,the motion-sensitive pulses can be designed to measure the spatiotemporal phase information of the propagating shear wave and then to extract its propagation speed for the measurement of tissue elasticity.Compared to traditional ultrasound-based elasticity measurement and imaging methods,MRE has its own advantages such as the more accurate 3D displacement measurement,the larger field of view（limited by the probe size in ultrasound） and the capability in brain elasticity measurement,for which otherwise it is unpractical for ultrasound.This paper mainly introduces the MRI-based techniques for tissue elasticity imaging and measurement（MRE）.Firstly the related techniques and their characteristics in MRE are introduced,followed by relevant applications of current MRE in several soft tissues.At the end of this paper we summarize the problems and look forward into some future perspectives of this field.
出处
《中国医疗设备》
2011年第12期9-16,共8页
China Medical Devices
基金
香港研究资助局(PolyU5354/08E)
香港理工大学(J-BB69)支持
关键词
磁共振成像
超声
弹性
磁共振弹性成像
位移
剪切波
速度
软组织
乳腺癌
大脑
肝纤维化
软骨
诊断
magnetic resonance imaging
ultrasound
elasticity
MR elastography
displacement
shear wave
speed
soft tissues
breast cancer
brain
liver fibrosis
cartilage
diagnosis
