Magnetic field and tissue dependencies of human brain longitudinal 1H2O relaxation in vivo
Magnetic field and tissue dependencies of human brain longitudinal 1H2O relaxation in vivo
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DOI：
10.1002/mrm.21122
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发表时间：
2007-02-01
影响因子：
3.3
通讯作者：
Springer, Charles S., Jr.
中科院分区：
文献类型：
--
作者：
Rooney, William D.;Johnson, Glyn;Springer, Charles S., Jr.
在0.2T、1.0T、1.5T、4.0T和7.0T的磁场强度（B-O）下，测量了3名健康人的脑水质子（（H_2O）-H ~（-1））纵向弛豫时间常数（T ~（-1））。采用改良的Look-Righting技术，以1.5 mm的平面内分辨率和绝热反转后32个时间点对5 mm的心室中部轴向切片进行采样。结果证实，对于大多数脑组织，T1值在0.2T和7 T之间增加超过3倍，并且在该范围内通过T-1（s）= 0.583（B-0）良好拟合。（0.382），T-1（s）= 0.857（B-0）（0.376），T-1（s）= 1.35（B-0）（0.340）。脑室脑脊液（CSF）（H2O）-H-1 T-1值不随B 0变化，受试者和磁场的平均值（标准差（SD））为4.3（+/- 0.2）s。每个区域的组织1/T-1值与大分子质量分数密切相关，并且在较小程度上与组织铁含量密切相关。（H2O）-H-1 T-1值的场依赖性增加超过了典型MR 1造影剂（CR）弛豫率的众所周知的降低，并且模拟预测这导致CR浓度检测阈值随磁场增加而降低。Magn Reson Med 57：308-318，2007。(c)2007 Wiley-Liss，Inc.
Brain water proton ((H2O)-H-1)) longitudinal relaxation time constants (T-1) were obtained from three healthy individuals at magnetic field strengths (B-O) of 0.2 Tesla (T), 1.0T, 1.5T, 4.0T, and 7.0T. A 5-mm midventricular axial slice was sampled using a modified Look-Locker technique with 1.5 mm in-plane resolution, and 32 time points post-adiabatic inversion. The results confirmed that for most brain tissues, T, values increased by more than a factor of 3 between 0.2T and 7T, and over this range were well fitted by T-1 (s) = 0.583(B-0)(0.382), T-1(s) = 0.857(B-0)(0.376), and T-1(s) = 1.35(B-0)(0.340) for white matter (WM), internal GM, and blood (H2O)-H-1, respectively. The ventricular cerebrospinal fluid (CSF) (H2O)-H-1 T-1 value did not change with B0, and its average value (standard deviation (SD)) across subjects and magnetic fields was 4.3 (+/- 0.2) s. The tissue 1/T-1 values at each field were well correlated with the macromolecular mass fraction, and to a lesser extent tissue iron content. The field-dependent increases in (H2O)-H-1 T-1 values more than offset the well-known decrease in typical MR1 contrast reagent (CR) relaxivity, and simulations predict that this leads to lower CR concentration detection thresholds with increased magnetic field. Magn Reson Med 57:308-318, 2007. (c) 2007 Wiley-Liss, Inc.