In vivo 3D brain and extremity MRI at 50 mT using a permanent magnet Halbach array.
In vivo 3D brain and extremity MRI at 50 mT using a permanent magnet Halbach array.
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DOI：
10.1002/mrm.28396
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发表时间：
2021-01
影响因子：
3.3
通讯作者：
Webb AG
中科院分区：
文献类型：
--
作者：
O'Reilly T;Teeuwisse WM;de Gans D;Koolstra K;Webb AG
目的：设计一种低成本、便携的永磁型磁共振成像系统，能够在合理的扫描时间内获得活体磁共振图像。设计了一种净径为27 cm的离散Halbach永磁体阵列，工作在50mT。定制的梯度线圈、射频线圈、梯度放大器和射频放大器被集成在一起，并在模体和活体上进行了测试。仿真结果表明，在15 cm视场范围内，y方向和z方向的梯度非线性小于5%，不需要校正。对于x方向，它明显更大，但可以在后处理中部分校正。使用Turbo自旋回波序列对健康志愿者的大脑进行了三维活体扫描，扫描的空间分辨率为4×4×4 mm，扫描时间约为2分钟。T1加权和T2加权扫描显示良好的组织对比度。此外，在12分钟内，以约3×2×2 mm的空间分辨率采集了一名健康志愿者的膝关节活体扫描，以显示该系统对肢体成像的适用性。这项工作表明，有可能用不到10000欧元的硬件组件构建一个低场磁共振成像单元，它能够在合理的数据采集时间内获取活体人体图像。该系统具有高度的便携性，磁体重量约为75公斤，梯度和射频放大器各15公斤，梯度线圈10公斤，光谱仪5公斤。
To design a low‐cost, portable permanent magnet‐based MRI system capable of obtaining in vivo MR images within a reasonable scan time. A discretized Halbach permanent magnet array with a clear bore diameter of 27 cm was designed for operation at 50 mT. Custom‐built gradient coils, RF coil, gradient amplifiers, and RF amplifier were integrated and tested on both phantoms and in vivo. Phantom results showed that the gradient nonlinearity in the y‐direction and z‐direction was less than 5% over a 15‐cm FOV and did not need correcting. For the x‐direction, it was significantly greater, but could be partially corrected in postprocessing. Three‐dimensional in vivo scans of the brain of a healthy volunteer using a turbo spin‐echo sequence were acquired at a spatial resolution of 4 × 4 × 4 mm in a time of about 2 minutes. The T1‐weighted and T2‐weighted scans showed a good degree of tissue contrast. In addition, in vivo scans of the knee of a healthy volunteer were acquired at a spatial resolution of about 3 × 2 × 2 mm within 12 minutes to show the applicability of the system to extremity imaging. This work has shown that it is possible to construct a low‐field MRI unit with hardware components costing less than 10 000 Euros, which is able to acquire human images in vivo within a reasonable data‐acquisition time. The system has a high degree of portability with magnet weight of approximately 75 kg, gradient and RF amplifiers each 15 kg, gradient coils 10 kg, and spectrometer 5 kg.
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DOI：
10.1007/s10334-018-0683-y
发表时间：
2018-10
期刊：
Magma (New York, N.Y.)
影响因子：
--
作者：
Obungoloch J;Harper JR;Consevage S;Savukov IM;Neuberger T;Tadigadapa S;Schiff SJ
通讯作者：
Schiff SJ
影响因子：
3.3
作者：
McDaniel, Patrick C.;Cooley, Clarissa Zimmerman;Wald, Lawrence L.
通讯作者：
Wald, Lawrence L.
影响因子：
3.2
作者：
Ní Mhíocháin, TR;Weaire, D;Coey, JMD
通讯作者：
Coey, JMD
影响因子：
3.3
作者：
Man, LC;Pauly, JM;Macovski, A
通讯作者：
Macovski, A
DOI：
10.1002/cmr.b.21320
发表时间：
2016-02-01
影响因子：
0.9
作者：
Bluemler, Peter
通讯作者：
Bluemler, Peter