Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, USA.
Phys Med Biol. 2013 Dec 21;58(24):8663-75. doi: 10.1088/0031-9155/58/24/8663. Epub 2013 Nov 21.
SampLe Interval Modulation-magnetic resonance elastography (SLIM-MRE) is introduced for simultaneously encoding all three displacement projections of a monofrequency vibration into the MR signal phase. In SLIM-MRE, the individual displacement components are observed using different sample intervals. In doing so, the components are modulated with different apparent frequencies in the MR signal phase expressed as a harmonic function of the start time of the motion encoding gradients and can thus be decomposed by applying a Fourier transform to the sampled multidirectional MR phases. In this work, the theoretical foundations of SLIM-MRE are presented and the new idea is implemented using a high field (11.7 T) vertical bore magnetic resonance imaging system on an inhomogeneous agarose gel phantom sample. The local frequency estimation-derived stiffness values were the same within the error margins for both the new SLIM-MRE method and for conventional MRE, while the number of temporally-resolved MRE experiments needed for each study was reduced from three to one. In this work, we present for the first time, monofrequency displacement data along three sensitization directions that were acquired simultaneously and stored in the same k-space.
样本间隔调制磁共振弹性成像（SLIM-MRE）用于将单频振动的所有三个位移投影同时编码到磁共振信号相位中。在 SLIM-MRE 中，使用不同的样本间隔观察各个位移分量。通过这种方式，在磁共振信号相位中，各分量以运动编码梯度开始时间的谐波函数的形式用不同的表观频率进行调制，因此可以通过对采样的多方向磁共振相位进行傅里叶变换来分解。在这项工作中，介绍了 SLIM-MRE 的理论基础，并在不均匀琼脂糖凝胶模型样本上的高磁场（11.7T）垂直孔磁共振成像系统上实现了这一新想法。对于新的 SLIM-MRE 方法和传统的 MRE，基于局部频率估计的杨氏模量值在误差范围内是相同的，而对于每项研究所需的时间分辨 MRE 实验次数从三个减少到一个。在这项工作中，我们首次展示了沿着三个敏感化方向同时采集并存储在同一个 k 空间中的单频位移数据。
