Herbst Michael, Zahneisen Benjamin, Knowles Benjamin, Zaitsev Maxim, Ernst Thomas
Department of Radiology, Medical Physics, University Medical Center Freiburg, Germany.
Department of Radiology, JABSOM, Honolulu, Hawaii, USA.
Magn Reson Med. 2015 Dec;74(6):1675-81. doi: 10.1002/mrm.25547. Epub 2014 Dec 1.
Recently, a new algorithm was introduced to combine segments of under-sampled diffusion weighted data using multiplexed sensitivity encoding. While the algorithm provides good results in cooperative volunteers, motion during the data acquisition is not accounted for. In this work, the continuous prospective motion correction of a segmented diffusion weighted acquisition is combined with multiplexed sensitivity encoding.
Simulations investigate the influence of motion on the reconstruction. Additionally, the change in coil sensitivities due to patient motion is taken into consideration. Finally, in vivo experiments display the effects of motion and its prospective correction on high resolution diffusion weighted imaging.
Inconsistencies of the imaging plane lead to artifacts and blurring in the reconstructed dataset. Additionally, motion during the diffusion weighting period can lead to substantial image artifacts and signal dropouts. The change in coil sensitivities shows minor effect for the simulated range of motion (5°). Prospective motion correction is shown to improve image quality in the case of large motion (5°) and to reliably correct for small motion (1°).
The combination of prospective motion correction and multiplexed sensitivity encoding allows for high resolution diffusion weighted imaging even in the presence of substantial head motion.
最近，引入了一种新算法，该算法利用多路复用灵敏度编码来合并欠采样扩散加权数据的各段。虽然该算法在合作志愿者中能提供良好的结果，但未考虑数据采集期间的运动情况。在本研究中，将分段扩散加权采集的连续前瞻性运动校正与多路复用灵敏度编码相结合。
通过模拟研究运动对重建的影响。此外，考虑了患者运动引起的线圈灵敏度变化。最后，体内实验展示了运动及其前瞻性校正对高分辨率扩散加权成像的影响。
成像平面的不一致会导致重建数据集中出现伪影和模糊。此外，扩散加权期间的运动会导致大量图像伪影和信号丢失。对于模拟的运动范围（5°）而言，线圈灵敏度的变化显示出较小的影响。前瞻性运动校正表明，在大运动（5°）情况下可提高图像质量，并能可靠地校正小运动（1°）。
前瞻性运动校正与多路复用灵敏度编码相结合，即使在头部存在大幅运动的情况下，也能实现高分辨率扩散加权成像。
