Rotating Frame RF Current Density Imaging
Rotating Frame RF Current Density Imaging
复制标题
旋转框架射频电流密度成像
DOI：
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发表时间：
1995
影响因子：
3.3
通讯作者：
Durand 339. Stanford
中科院分区：
文献类型：
--
作者：
G. Scott;M. Joy;R. Armstrong;R. Henkelman;Durand 339. Stanford
RF电流密度成像（RF‐CDI）是一种新的MRI技术，用于成像电解质介质中平行于B0的拉莫尔频率电流密度。为了将RF‐CDI的使用扩展到生物组织以产生电导率对比，必须提高灵敏度并降低数据要求。一个旋转框架的方法，其中一个大的B1场同时施加作为旋转回波与RF电流，提出了满足这些要求。在MRI图像的相位中对旋转帧磁场进行编码。目前已在含有掺杂水或矿物油的三室圆柱体模中使用该序列进行试验，以检测位移、传导和边缘场电流。在一项大鼠死后研究中，由于组织的电特性，由植入电极注入的85.56 MHz射频电流产生了组织依赖性对比度。还进行了灵敏度和伪影分析。该方法的灵敏度由最大RF脉冲持续时间决定。SAR限制对该时间和B1施加上限，而避免相位伪影对B1施加下限。
RF current density imaging (RF‐CDI) is a new MRI technique for imaging the Larmor frequency current density parallel to B0 in electrolytic media. To extend the use of RF‐CDI to biological tissue for generating conductivity contrast, the sensitivity must be increased and the data requirements reduced. A rotating frame approach, in which a large B1 field is applied simultaneously as a rotary echo with RF current, is proposed to meet these requirements. Rotating frame magnetic fields are encoded in the phase of an MRI image. Trials have now been performed with this sequence in a three‐compartment cylindrical phantom containing doped water or mineral oil for detecting displacement, conduction and fringe field currents. In a postmortem rat study, 85.56 MHz RF currents injected by implanted electrodes created tissue dependent contrast because of the electrical properties of tissue. A sensitivity and artifact analysis was also performed. The sensitivity of this method is determined by the maximum RF pulse duration. SAR limits pose an upper bound on this time and B1, whereas the avoidance of phase artifacts imposes a lower bound on B1.
影响因子：
6.7
作者：
STAEWEN, RS;JOHNSON, AJ;GARWOOD, M
通讯作者：
GARWOOD, M
绝热重聚焦脉冲，可补偿可变射频功率和偏共振效应。
影响因子：
3.3
作者：
Bendall,MR;Garwood,M;Uğurbil,K;Pegg,DT
通讯作者：
Pegg,DT
改善极不均匀射频场中的 MR 成像。
影响因子：
2.5
作者：
Bansal,N;Nunnally,RL
通讯作者：
Nunnally,RL