Multishot rosette trajectories for spectrally selective MR imaging
Multishot rosette trajectories for spectrally selective MR imaging
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DOI：
10.1109/42.611345
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发表时间：
1997-08-01
影响因子：
10.6
通讯作者：
Noll, DC
中科院分区：
文献类型：
--
作者：
Noll, DC
在核磁共振中，不同的光谱成分往往对应于不同的化学物质，因此，光谱选择性可以是一个有价值的工具，用于诊断成像，在这里提出的工作中，基于玫瑰花形kappa空间轨迹的多拍摄图像采集方法已经开发和实施的光谱选择性磁共振成像（MRI）。导出了梯度波形和设计约束的参数形式，并且给出了示例性多激发梯度设计。在仿真模型中分析了该成像方法的频谱行为。对于接近谐振频率的频率，该方法导致较低强度但不失真的图像，而对于大量偏离谐振的频率，对象被非相干地移相为噪声，引入了一种方法，通过该方法，采集被延迟了少量，以进一步减少非共振信号的残留强度，基于卷积网格的图像重建方法，包括少量的磁场不均匀性的校正方法，实现。最后，在体内的研究中，其中水和脂质图像都是从一个单一的成像数据集生成的光谱选择性被证明。
In nuclear magnetic resonance, different spectral components often correspond to different chemical species and as such, spectral selectivity can be a valuable tool for diagnostic imaging, In the work presented here, a multishot image acquisition method based upon rosette kappa-space trajectories has been developed and implemented for spectrally selective magnetic resonance imaging (MRI). Parametric forms for the gradient waveforms and design constraints are derived, and an example multishot gradient design is presented, The spectral behavior for this imaging method is analyzed in a simulation model, For frequencies that are near to the resonant frequency, this method results in a lower intensity, but undistorted image, while for frequencies that are off-resonance by a large amount, the object is incoherently dephased into noise, A method by which acquisitions are delayed by small amounts is introduced to further reduce the residual intensity for off-resonant signals, An image reconstruction method based on convolution gridding, including a correction method for small amounts of magnetic field inhomogeneity, is implemented, Finally, the spectral selectivity is demonstrated in vivo in a study in which both water and lipid Images are generated from a single imaging data set.