Brix G, Schreiber W, Hoffmann U, Gückel F, Hawighorst H, Knopp M V
Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum (dkfz), Heidelberg.
Radiologe. 1997 Jun;37(6):470-80. doi: 10.1007/s001170050241.
The development of rapid magnetic resonance imaging (MRI) sequences makes it possible to detect the fast kinetics of tissue response after intravenous administration of paramagnetic contrast media (CM), reflecting the status of tissue microcirculation. In this paper, the basic physical and tracer kinetic principles of dynamic relativity and susceptibility contrast MRI techniques are reviewed. The quantitative analysis of the acquired dynamic image data is broken up into an MR specific part, in which the observed signal variations are related to the CM concentration in the tissue, and an MR independent part, in which the computed concentration-time-courses are analyzed by tracer kinetic modeling. The purpose of the applied models is to describe the underlying physiological processes in mathematical terms and thus to enable the estimation of tissue specific parameters from measured dynamic image series. Whereas the capillary permeability can be estimated from dynamic relativity contrast enhanced MRI studies, the regional blood volume as well as the regional blood flow can be determined from dynamic susceptibility contrast enhanced image series. However, since there are no intravascular but only diffusible CM available at present, the application of the susceptibility technique is currently restricted to brain tissues with intact blood brain barrier. The practical realization of both dynamic MRI techniques is demonstrated by case studies.
快速磁共振成像（MRI）序列的发展使得在静脉注射顺磁性造影剂（CM）后检测组织反应的快速动力学成为可能，这反映了组织微循环的状态。本文回顾了动态对比增强和磁共振血管造影（MRA）技术的基本物理和示踪动力学原理。对采集到的动态图像数据的定量分析分为一个与磁共振相关的部分，其中观察到的信号变化与组织中的造影剂浓度相关，以及一个与磁共振无关的部分，其中通过示踪动力学建模分析计算出的浓度-时间曲线。应用模型的目的是以数学术语描述潜在的生理过程，从而能够从测量的动态图像序列中估计组织特异性参数。虽然可以从动态对比增强MRI研究中估计毛细血管通透性，但可以从动态对比增强图像序列中确定局部血容量和局部血流。然而，由于目前没有血管内造影剂，只有可扩散的造影剂，因此目前磁共振血管造影技术的应用仅限于血脑屏障完整的脑组织。通过案例研究展示了这两种动态MRI技术的实际应用。
