Kurzawski Jan W, Cencini Matteo, Peretti Luca, Gómez Pedro A, Schulte Rolf F, Donatelli Graziella, Cosottini Mirco, Cecchi Paolo, Costagli Mauro, Retico Alessandra, Tosetti Michela, Buonincontri Guido
Pisa Division, National Institute for Nuclear Physics (INFN), Pisa, Italy.
Imago7 Foundation, Pisa, Italy.
Magn Reson Med. 2020 Nov;84(5):2606-2615. doi: 10.1002/mrm.28301. Epub 2020 May 5.
To obtain three-dimensional (3D), quantitative and motion-robust imaging with magnetic resonance fingerprinting (MRF).
Our acquisition is based on a 3D spiral projection k-space scheme. We compared different orderings of trajectory interleaves in terms of rigid motion-correction robustness. In all tested orderings, we considered the whole dataset as a sum of 56 segments of 7-s duration, acquired sequentially with the same flip angle schedule. We performed a separate image reconstruction for each segment, producing whole-brain navigators that were aligned to the first segment using normalized correlation. The estimated rigid motion was used to correct the k-space data, and the aligned data were matched with the dictionary to obtain motion-corrected maps.
A significant improvement on the motion-affected maps after motion correction is evident with the suppression of motion artifacts. Correlation with the motionless baseline improved by 20% on average for both T and T estimations after motion correction. In addition, the average motion-induced quantification bias of 70 ms for T and 18 ms for T values was reduced to 12 ms and 6 ms, respectively, improving the reliability of quantitative estimations.
We established a method that allows correcting 3D rigid motion on a 7-s timescale during the reconstruction of MRF data using self-navigators, improving the image quality and the quantification robustness.
利用磁共振指纹识别（MRF）获得三维（3D）、定量且对运动具有鲁棒性的成像。
我们的采集基于三维螺旋投影k空间方案。我们在刚性运动校正鲁棒性方面比较了轨迹交织的不同排序。在所有测试的排序中，我们将整个数据集视为56个时长为7秒的段的总和，按照相同的翻转角调度顺序采集。我们对每个段进行单独的图像重建，生成全脑导航图，这些导航图使用归一化相关性与第一段对齐。估计的刚性运动用于校正k空间数据，对齐后的数据与字典匹配以获得运动校正图。
运动校正后，受运动影响的图有显著改善，运动伪影得到抑制。运动校正后，对于T和T估计，与静止基线的相关性平均提高了20%。此外，T值的平均运动诱导定量偏差70毫秒和T值的18毫秒分别降低到12毫秒和6毫秒，提高了定量估计的可靠性。
我们建立了一种方法，该方法允许在使用自导航器重建MRF数据期间在7秒时间尺度上校正三维刚性运动，提高了图像质量和定量鲁棒性。
