Multiparametric magnetic resonance imaging and repeated measurements of blood-brain barrier permeability to contrast agents.
Multiparametric magnetic resonance imaging and repeated measurements of blood-brain barrier permeability to contrast agents.
复制标题
多参数磁共振成像和血脑屏障对造影剂渗透性的重复测量。
DOI：
10.1007/978-1-60761-938-3_8
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Fenstermacher,JosephD
中科院分区：
文献类型：
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作者：
Nagaraja,TavarekereN;Knight,RobertA;Ewing,JamesR;Karki,Kishor;Nagesh,Vijaya;Fenstermacher,JosephD
血脑屏障（BBB）的破坏存在于多种神经系统疾病中，例如中风、脑肿瘤和多发性硬化症。 BBB 分解的无创评估对于监测疾病进展和评估此类疾病的治疗效果非常重要。磁共振成像 (MRI) 是少数可用于无创、重复定位和量化 BBB 损伤的技术之一。这通常涉及静脉注射含钆 MR 造影剂 (MRCA)，例如二亚乙基三胺五乙酸钆 (Gd-DTPA)，然后对大脑和血液进行动态对比增强 MR 成像 (DCE-MRI)，并对所得数据进行分析，得出血脑转移指数。这种方法有两个优点。首先，可以在同一只动物身上重复进行测量；例如，可以在药物治疗前进行，然后在治疗后再次进行以评估疗效。其次，MRI 研究可以是多参数的。也就是说，MRI 不仅可用于通过 DCE-MRI 评估血脑转移或流入速率常数 (KiorK1)，还可用于评估补充参数，例如： (1) 脑血流量 (CBF)，通过动脉自旋标记 (AST) 方法在我们手中完成； (2) 磁化转移 (MT) 参数，尤其是 T1sat，它似乎反映了脑水-蛋白质相互作用以及 BBB 和组织功能障碍； (3)水的表观扩散系数(ADCw)和/或扩散张量，其是细胞外空间的大小和曲折度的函数； (4) T2加权成像的横向弛豫时间，在许多情况下可以划分组织异常区域。其中两种多参数 MRI 测量（通过 AST 测定的 CBF 和通过 DCE-MRI 确定的 Gd-DTPA 流入）的准确性和可靠性已通过使用适当放射性示踪剂的几乎一致的定量放射自显影 (QAR) 研究确定。此外，它们与局部病理学的一些联系已通过相应的光学显微镜和荧光成像显示出来。本章介绍：（1）多参数MRI技术，重点是DCE-MRI和AST-MRI； (2)血脑流入速率常数和CBF的测量； (3) 各自在确定 BBB 通透性方面的作用。
Breakdown of the blood-brain barrier (BBB) is present in several neurological disorders such as stroke, brain tumors, and multiple sclerosis. Noninvasive evaluation of BBB breakdown is important for monitoring disease progression and evaluating therapeutic efficacy in such disorders. One of the few techniques available for noninvasively and repeatedly localizing and quantifying BBB damage is magnetic resonance imaging (MRI). This usually involves the intravenous administration of a gadolinium-containing MR contrast agent (MRCA) such as Gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), followed by dynamic contrast-enhanced MR imaging (DCE-MRI) of brain and blood, and analysis of the resultant data to derive indices of blood-to-brain transfer. There are two advantages to this approach. First, measurements can be made repeatedly in the same animal; for instance, they can be made before drug treatment and then again after treatment to assess efficacy. Secondly, MRI studies can be multiparametric. That is, MRI can be used to assess not only a blood-to-brain transfer or influx rate constant (KiorK1) by DCE-MRI but also complementary parameters such as: (1) cerebral blood flow (CBF), done in our hands by arterial spin-tagging (AST) methods; (2) magnetization transfer (MT) parameters, most notablyT1sat, which appear to reflect brain water-protein interactions plus BBB and tissue dysfunction; (3) the apparent diffusion coefficient of water (ADCw) and/or diffusion tensor, which is a function of the size and tortuosity of the extracellular space; and (4) the transverse relaxation time byT2-weighted imaging, which demarcates areas of tissue abnormality in many cases. The accuracy and reliability of two of these multiparametric MRI measures, CBF by AST and DCE-MRI determined influx of Gd-DTPA, have been established by nearly congruent quantitative autoradiographic (QAR) studies with appropriate radiotracers. In addition, some of their linkages to local pathology have been shown via corresponding light microscopy and fluorescence imaging. This chapter describes: (1) multiparametric MRI techniques with emphasis on DCE-MRI and AST-MRI; (2) the measurement of the blood-to-brain influx rate constant and CBF; and (3) the role of each in determining BBB permeability.