2D multi-spectral imaging for fast MRI near metal.
2D multi-spectral imaging for fast MRI near metal.
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DOI：
10.1002/mrm.26724
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发表时间：
2018-03
影响因子：
3.3
通讯作者：
Yoon D
中科院分区：
文献类型：
--
作者：
Hargreaves BA;Taviani V;Litwiller DV;Yoon D
旨在开发一种用于近金属MRI的快速2D方法，减少B 0平面内伪影和穿透切片伪影。最近的多光谱成像（MSI）方法减少了金属附近的MR图像中的伪影，但无论成像几何结构或伪影严重程度如何，都需要对多个激发体积进行3D成像。所提出的2D MSI方法使用激励和重聚焦脉冲之间的梯度反转快速激励有限的切片和光谱区域，然后使用标准2D成像，重复该过程以覆盖如在其他MSI技术中组合的多个光谱偏移。2D MSI在自旋回波序列中实现，并通过与标准自旋回波成像和现有MSI技术进行比较，在体模和体内进行验证。每个空间-光谱区域的2D MSI图像遵循偶极样B 0场变化的等值线，并且因此遵循金属器件附近的频率变化。在使用金属的体模和人类受试者中的磁共振校正与3D MSI方法相当，并且优于标准自旋回波技术上级。与3D MSI方法相比，在需要有限数量切片的情况下，扫描时间减少，但信噪比也如预期的那样降低。2D MSI提供了3D MSI的快速、灵活的替代方案，可减少金属附近的伪影。
To develop a fast 2D method for MRI near metal with reduced B0 in-plane and through-slice artifacts. Recent Multi-spectral imaging (MSI) approaches reduce artifacts in MR images near metal, but require 3D imaging of multiple excited volumes regardless of imaging geometry or artifact severity. The proposed 2D MSI method rapidly excites a limited slice and spectral region using gradient reversal between excitation and refocusing pulses, then uses standard 2D imaging, with the process repeating to cover multiple spectral offsets that are combined as in other MSI techniques. 2D MSI was implemented in a spin-echo-train sequence and validated in phantoms and in vivo by comparing it with standard spin-echo imaging and existing MSI techniques. 2D MSI images for each spatial-spectral region follow isocontours of the dipole-like B0 field variation, and thus frequency variation, near metal devices. Artifact correction in phantoms and human subjects with metal is comparable to 3D MSI methods, and superior to standard spin-echo techniques. Scan times are reduced compared with 3D MSI methods in cases where a limited number of slices is needed, though signal-to-noise ratio is also reduced as expected. 2D MSI offers a fast and flexible alternative to 3D MSI for artifact reduction near metal.