Griswold M A, Jakob P M, Nittka M, Goldfarb J W, Haase A
Department of Physics, University of Würzburg, Würzburg, Germany.
Magn Reson Med. 2000 Oct;44(4):602-9. doi: 10.1002/1522-2594(200010)44:4<602::aid-mrm14>3.0.co;2-5.
In this study a novel partially parallel acquisition method is presented, which can be used to accelerate image acquisition using an RF coil array for spatial encoding. In this technique, Parallel Imaging with Localized Sensitivities (PILS), it is assumed that the individual coils in the array have localized sensitivity patterns, in that their sensitivity is restricted to a finite region of space. Within the PILS model, a detailed, highly accurate RF field map is not needed prior to reconstruction. In PILS, each coil in the array is fully characterized by only two parameters: the center of coil's sensitive region in the FOV and the width of the sensitive region around this center. In this study, it is demonstrated that the incorporation of these coil parameters into a localized Fourier transform allows reconstruction of full FOV images in each of the component coils from data sets acquired with a reduced number of phase encoding steps compared to conventional imaging techniques. After the introduction of the PILS technique, primary focus is given to issues related to the practical implementation of PILS, including coil parameter determination and the SNR and artifact power in the resulting images. Finally, in vivo PILS images are shown which demonstrate the utility of the technique.
在本研究中，提出了一种新型的部分并行采集方法，该方法可用于使用射频线圈阵列进行空间编码来加速图像采集。在这种称为局部灵敏度并行成像（PILS）的技术中，假设阵列中的各个线圈具有局部灵敏度模式，即它们的灵敏度被限制在空间的有限区域内。在PILS模型中，重建前不需要详细、高精度的射频场图。在PILS中，阵列中的每个线圈仅由两个参数完全表征：线圈敏感区域在视野中的中心以及该中心周围敏感区域的宽度。在本研究中，证明了将这些线圈参数纳入局部傅里叶变换可使每个组件线圈从与传统成像技术相比减少了相位编码步数采集的数据集中重建全视野图像。在引入PILS技术后，主要关注与PILS实际应用相关的问题，包括线圈参数确定以及所得图像中的信噪比和伪影功率。最后，展示了体内PILS图像，证明了该技术的实用性。
