Department of Radiology, Case Western Reserve University, Cleveland, Ohio.
Imaging Division, The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.
Magn Reson Med. 2018 Dec;80(6):2485-2500. doi: 10.1002/mrm.27227. Epub 2018 May 6.
The purpose of this study is to increase the robustness of MR fingerprinting (MRF) toward subject motion.
A novel reconstruction algorithm, MOtion insensitive MRF (MORF), was developed, which uses an iterative reconstruction based retrospective motion correction approach. Each iteration loops through the following steps: pattern recognition, metric based identification of motion corrupted frames, registration based motion estimation, and motion compensated data consistency verification. The proposed algorithm was validated using in vivo 2D brain MRF data with retrospective in-plane motion introduced at different stages of the acquisition. The validation was performed using qualitative and quantitative comparisons between results from MORF, the iterative multi-scale (IMS) algorithm, and with the IMS results using data without motion for a ground truth comparison. Additionally, the MORF algorithm was evaluated in prospectively motion corrupted in vivo 2D brain MRF datasets.
For datasets corrupted by in-plane motion both prospectively and retrospectively, MORF noticeably reduced motion artifacts compared with iterative multi-scale and closely resembled the results from data without motion, even when ∼54% of data was motion corrupted during different parts of the acquisition.
MORF improves the insensitivity of MRF toward rigid-body motion occurring during any part of the MRF acquisition.
本研究旨在提高磁共振指纹成像（MRF）对受试者运动的稳健性。
开发了一种新的重建算法，即运动不敏感磁共振指纹（MORF），该算法采用基于迭代重建的回顾性运动校正方法。每次迭代循环执行以下步骤：模式识别、基于度量的运动伪影帧识别、基于配准的运动估计和运动补偿数据一致性验证。使用体内 2D 脑 MRF 数据验证了所提出的算法，该数据在采集的不同阶段引入了回顾性的平面内运动。验证是通过 MORF、迭代多尺度（IMS）算法的定性和定量比较以及使用无运动数据的 IMS 结果进行的，以进行真实比较。此外，还在体内 2D 脑 MRF 数据中进行了前瞻性运动伪影的 MORF 算法评估。
对于前瞻性和回顾性的平面内运动伪影数据集，与迭代多尺度相比，MORF 明显减少了运动伪影，并且与无运动数据的结果非常相似，即使在采集的不同部分有大约 54%的数据受到运动的影响。
MORF 提高了 MRF 对 MRF 采集过程中任何部分发生的刚体运动的不敏感性。
