Volumetric spectroscopic imaging with spiral-based k-space trajectories
Volumetric spectroscopic imaging with spiral-based k-space trajectories
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DOI：
10.1002/mrm.1910390606
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发表时间：
1998-06-01
影响因子：
3.3
通讯作者：
Spielman, DM
中科院分区：
文献类型：
--
作者：
Adalsteinsson, E;Irarrazabal, P;Spielman, DM
基于螺旋的k空间轨迹应用于具有时变读出梯度的光谱成像序列中，以收集体积化学位移信息。除了低信噪比（SNR）脑代谢物的光谱成像外，螺旋轨迹还用于快速收集来自高SNR水信号的参考信号，以自动定相光谱并帮助重建代谢物图。光谱空间脉冲用于激发和水抑制。这些脉冲旨在在射频场存在高达 20% 变化的情况下实现稳定的相位分布。在快速傅里叶变换之前，使用网格算法将数据重新采样到直线网格上。该方法通过在 1.5 T 下对大脑代谢物进行体内成像（每张 10 个 18 x 18 像素的切片）得到证明。标称体素大小为 1.1 cc，光谱带宽为 400 Hz，代谢物扫描的扫描时间为 18 分钟，参考扫描的扫描时间为 3 分钟。
Spiral-based k-space trajectories were applied in a spectroscopic imaging sequence with time-varying readout gradients to collect volumetric chemical shift information, In addition to spectroscopic imaging of low signal-to-noise ratio (SNR) brain metabolites, the spiral trajectories were used to rapidly collect reference signals from the high SNR water signal to automatically phase the spectra and to aid the reconstruction of metabolite maps. Spectral-spatial pulses were used for excitation and water suppression. The pulses were designed to achieve stable phase profiles in the presence of up to 20% variation in the radiofrequency field. A gridding algorithm was used to resample the data onto a rectilinear grid before fast Fourier transforms. This method was demonstrated by in vivo imaging of brain metabolites at 1.5 T with 10 slices of 18 x 18 pixels each. Nominal voxel size was 1.1 cc, spectral bandwidth was 400 Hz, scan time was 18 min for the metabolite scan and 3 min for the reference scan.