Modeling of Look-Locker estimates of the magnetic resonance imaging estimate of longitudinal relaxation rate in tissue after contrast administration.
Modeling of Look-Locker estimates of the magnetic resonance imaging estimate of longitudinal relaxation rate in tissue after contrast administration.
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DOI：
10.1002/mrm.22852
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发表时间：
2011-11
影响因子：
3.3
通讯作者：
Ewing, James. R.
中科院分区：
文献类型：
--
作者：
Paudyal, Ramesh;Bagher-Ebadian, Hassan;Nagaraja, Tavarekere N.;Fenstermacher, Joseph D.;Ewing, James. R.
关键词：
本文模拟了组织水R1（R1 = 1/T1）的质子的纵向弛豫速率的行为，该弛豫速率是在施用顺磁造影剂（CA）后在7特斯拉下在Look-Scanning（LL）实验中测量的。它解决了Bloch-McConnell方程的纵向磁化水的质子在一个三个网站的两个交换（3S 2X）模型与边界条件适合重复采样的磁化。平衡房室间水交换动力学影响单指数估计的R1后，在动态对比度增强（DCE）实验中的CA管理的程度进行了说明。R1和组织CA浓度之间的关系，计算CA限制到血管内，或血管内和细胞外室，通过改变模型参数，以模拟在大鼠脑肿瘤模型中获得的实验数据。该模型描述了一个几乎线性关系之间的R1和CA的组织浓度，但表明，CA的表观纵向弛豫取决于组织类型。这一发现的实际结果是，扩展Patlak图线性化了微血管渗漏组织中的ΔR1数据，准确地确定了CA穿过这些微血管的流入速率，但低估了血管内血液的体积。
This paper models the behavior of the longitudinal relaxation rate of the protons of tissue water R1 (R1 = 1/T1), measured in a Look-Locker (LL) experiment at 7 Tesla after administration of a paramagnetic contrast agent (CA). It solves the Bloch-McConnell equations for the longitudinal magnetization of the protons of water in a three-site two-exchange (3S2X) model with boundary conditions appropriate to repeated sampling of magnetization. The extent to which equilibrium intercompartmental water exchange kinetics affect monoexponential estimates of R1 after administration of a CA in dynamic contrast enhanced (DCE) experiment is described. The relation between R1 and tissue CA concentration was calculated for CA restricted to the intravascular, or to the intravascular and extracellular compartments, by varying model parameters to mimic experimental data acquired in a rat model of cerebral tumor. The model described a nearly linear relationship between R1 and tissue concentration of CA, but demonstrated that the apparent longitudinal relaxivity of CA depends upon tissue type. The practical consequence of this finding is that the extended Patlak plot linearizes the ΔR1 data in tissue with leaky microvessels, accurately determines the influx rate of the CA across these microvessels, but underestimates the volume of intravascular blood water.
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DOI：
10.1073/pnas.0804224105
发表时间：
2008-11-18
影响因子：
11.1
作者：
Li, Xin;Huang, Wei;Springer, Charles S., Jr.
通讯作者：
Springer, Charles S., Jr.
影响因子：
3.3
作者：
Buckley, David L.;Kershaw, Lucy E.;Stanisz, Greg J.
通讯作者：
Stanisz, Greg J.
影响因子：
3.3
作者：
Li, X;Rooney, WD;Springer, CS
通讯作者：
Springer, CS
影响因子：
5.7
作者：
Bagher-Ebadian, Hassan;Paudyal, Ramesh;Ewing, James R.
通讯作者：
Ewing, James R.
影响因子：
3.3
作者：
Nagaraja, Tavarekere N.;Karki, Kishor;Knight, Robert A.
通讯作者：
Knight, Robert A.