Susceptibility contrast in high field MRI of human brain as a function of tissue iron content.
Susceptibility contrast in high field MRI of human brain as a function of tissue iron content.
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人脑高场MRI的敏感性对比与组织铁含量的关系。
DOI：
10.1016/j.neuroimage.2008.10.029
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发表时间：
2009-02-15
期刊：
影响因子：
5.7
通讯作者：
Duyn JH
中科院分区：
文献类型：
--
作者：
Yao B;Li TQ;Gelderen Pv;Shmueli K;de Zwart JA;Duyn JH
磁化率为MRI提供了重要的对比机制。越来越多地，基于磁化率的对比度被用于研究脑组织的微观结构，并检测脑铁的异常水平，因为这些已经与各种神经退行性疾病有关。然而，目前尚不清楚在多大程度上磁化率相关的对比度在高场涉及到实际的脑铁浓度。在这项研究中，我们进行了磁敏感加权成像作为一个功能的场强在健康的大脑在体内和死后的脑组织在1.5T，3 T和7 T。对组织样本进行铁组织学检查以进行比较。在四个富铁区域（壳核、苍白球、尾状核和丘脑）中计算的磁化率相关参数R2* 和信号频移显示出对场强的几乎线性依赖性（R2* r=0.90;相位r=0.83，p<0.01），表明潜在的铁蛋白饱和效应与场强高达7 T的磁化率加权对比度无关。R2* 对推定（基于文献）铁浓度的依赖性为0.048 Hz/Tesla/ppm。来自脑样品的组织学数据证实了R2* 对场强的线性依赖性，并显示出相对于铁浓度的0.0099 Hz/Tesla/ppm干重的斜率，其相当于0.05 Hz/Tesla/ppm湿重，并且与体内计算值密切匹配。这些结果证实了使用磁化率加权对比度作为富铁脑区铁含量指标的有效性。不存在饱和效应开辟了利用MRI在高场强下的优势以高灵敏度和分辨率检测铁分布的途径。
Magnetic susceptibility provides an important contrast mechanism for MRI. Increasingly, susceptibility-based contrast is being exploited to investigate brain tissue microstructure and to detect abnormal levels of brain iron as these have been implicated in a variety of neuro-degenerative diseases. However, it remains unclear to what extent magnetic susceptibility-related contrast at high field relates to actual brain iron concentrations. In this study, we performed susceptibility weighted imaging as a function of field strength on healthy brains in vivo and post-mortem brain tissues at 1.5T, 3T and 7T. Iron histology was performed on the tissue samples for comparison. The calculated susceptibility-related parameters R2* and signal frequency shift in four iron-rich regions (putamen, globus pallidus, caudate, and thalamus) showed an almost linear dependence (r=0.90 for R2*; r=0.83 for phase, p<0.01) on field strength, suggesting that potential ferritin saturation effects are not relevant to susceptibility-weighted contrast for field strengths up to 7T. The R2* dependence on the putative (literature-based) iron concentration was 0.048 Hz/Tesla/ppm. The histological data from brain samples confirmed the linear dependence of R2* on field strength and showed a slope against iron concentration of 0.0099 Hz/Tesla/ppm dry-weight, which is equivalent to 0.05 Hz/Tesla/ppm wet-weight and closely matched the calculated value in vivo. These results confirm the validity of using susceptibility-weighted contrast as an indicator of iron content in iron-rich brain regions. The absence of saturation effects opens the way to exploit the benefits of MRI at high field strengths for the detection of iron distributions with high sensitivity and resolution.
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影响因子：
3.3
作者：
de Zwart, JA;Ledden, PJ;Duyn, JH
通讯作者：
Duyn, JH
DOI：
10.1073/pnas.0610821104
发表时间：
2007-07-10
影响因子：
11.1
作者：
Duyn, Jeff H.;van Gelderen, Peter;Fukunaga, Masaki
通讯作者：
Fukunaga, Masaki
影响因子：
6
作者：
Kosta, P;Argyropoulou, MI;Konitsiotis, S
通讯作者：
Konitsiotis, S
影响因子：
2.5
作者：
Ogg, RJ;Langston, JW;Taylor, JS
通讯作者：
Taylor, JS
影响因子：
39.3
作者：
Anderson, LJ;Holden, S;Pennell, DJ
通讯作者：
Pennell, DJ