A unified magnetic resonance imaging pharmacokinetic theory: Intravascular and extracellular contrast reagents
A unified magnetic resonance imaging pharmacokinetic theory: Intravascular and extracellular contrast reagents
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DOI：
10.1002/mrm.20684
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发表时间：
2005-12-01
影响因子：
3.3
通讯作者：
Springer, CS
中科院分区：
文献类型：
--
作者：
Li, X;Rooney, WD;Springer, CS
一个基本的药代动力学理论的改造使用造影剂（CRs）在t -1加权MRI研究提出。与常用的标准模型不同，这种推导从测量的数量开始，即血管内、间质和细胞内(H2O)-H-1信号。CR浓度的时间依赖性作为T值的扰动引入。由于对组织间水分子的平衡交换有明确的解释，这里的方法是新（第二）代快门速度模型（(SM)-M-2）。当测量CR外渗（K-trans）的一阶速率常数足够大时，本文的模拟证实忽略血浆CR（第一代(SM)-M-2的一个特征）是一个有效的近似。第二代(SM)-M-2代（S(2)M2）也自动适应两种主要平衡水交换系统（经表皮和经细胞膜）中的一种或两种进入任何或所有可能的交换条件，从它们的快速交换极限到慢速交换极限。这并不是因为交换动力学本身在等温CR通过过程中发生变化，而是因为这些过程的MR快门速度可以变化。当K-trans足够小时，S(2)M2也自然地解释了在高磁场下容易检测到的超细血药水平依赖（BALD）效应。这可以在几乎所有正常脑组织中的cr和几乎所有血管内cr充足的组织中看到。因此，S(2)M2代表了血管内和细胞外T-1造影剂的统一药代动力学理论。中华医学杂志，2005,44(4):551 - 559。(c) 2005 Wiley-Liss, Inc。
A fundamental reworking of pharmacokinetic theory for the use of contrast reagents (CRs) in T-1-weighted MRI studies is presented. Unlike the standard model in common use, this derivation starts with the quantities measured, the intravascular, interstitial, and intracellular (H2O)-H-1 signals. The time dependences of CR concentrations are introduced as perturbations of the T, values of these. Since there is an explicit accounting for the equilibrium exchange of water molecules between tissue compartments, the approach here is a new (second) generation of the shutter-speed model ((SM)-M-2). When the first-order rate constant measuring CR extravasation (K-trans) is of sufficient magnitude, simulations presented here confirm that neglect of plasma CR, a feature of the first generation of (SM)-M-2, is a valid approximation. The second (SM)-M-2 generation (S(2)M2) also automatically accommodates excursions of either or both of the two major equilibrium water exchange systems (transenclothelial and transcytolemmal) into any or all possible exchange conditions, from their fast-exchange limits to their slow-exchange limits. This can happen not because the exchange kinetics themselves vary during the isothermal CR passage, but because the MR shutter speeds for these processes can vary. When K-trans is sufficiently small, the S(2)M2 also naturally accounts for the hyperfine blood agent level dependent (BALD) effect that is easily detectable at high magnetic field. This can be seen for virtually all CRs in normal brain tissue and for virtually all tissues with sufficiently intravascular CRs. Thus, S(2)M2 represents a unified pharmacokinetic theory for intravascular and extracellular T-1 contrast reagents. Magn Reson Med 54:1351-1359, 2005. (c) 2005 Wiley-Liss, Inc.