B0 dependence of the on-resonance longitudinal relaxation time in the rotating frame (T1p) in protein phantoms and rat brain in vivo
B0 dependence of the on-resonance longitudinal relaxation time in the rotating frame (T1p) in protein phantoms and rat brain in vivo
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DOI：
10.1002/mrm.10669
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发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Kauppinen, RA
中科院分区：
文献类型：
--
作者：
Mäkelä, HI;De Vita, E;Kauppinen, RA
旋转框架的共振纵向松弛时间（T-1p）已被证明在急性卒中的早期几分钟提供独特的信息。在本研究中，通过测定2.35、4.7和9.4 t时蛋白幻象和大鼠脑中的弛豫率（R-1p）来评估不同弛豫机制对共振T-1p弛豫的贡献。与横向弛豫率（R-2）相似，R-1p随着磁场强度的增加而显著增加（B-0）。在弱自旋锁场中，B-0依赖性更为明显。与R-1p相比，纵向弛豫速率（R-1）随B-0场的增大而减小。目前的数据表明，偶极-偶极相互作用只形成了T-1p弛豫的一条途径，需要考虑其他物理化学因素的贡献。(C) 2003 Wiley-Liss, Inc。
On-resonance longitudinal relaxation time in the rotating frame (T-1p) has been shown to provide unique information during the early minutes of acute stroke. In the present study, the contributions of the different relaxation mechanisms to on-resonance T-1p relaxation were assessed by determining relaxation rates (R-1p) in both protein phantoms and in rat brain at 2.35, 4.7, and 9.4 T. Similar to transverse relaxation rate (R-2), R-1p increased substantially with increasing magnetic field strength (B-0). The B-0 dependence was more pronounced at weak spin-lock fields. In contrast to R-1p, longitudinal relaxation rate (R-1) decreased as a function of increasing B-0 field. The present data argue that dipole-dipole interaction forms only one pathway for T-1p relaxation and the contributions from other physicochemical factors need to be considered. (C) 2003 Wiley-Liss, Inc.