在同时进行的正电子发射断层扫描-磁共振成像（PET-MR）中使用有线有源磁共振微线圈的基于磁共振的PET成像运动校正：体模研究
MR-based motion correction for PET imaging using wired active MR microcoils in simultaneous PET-MR: phantom study.
作者信息
Huang Chuan, Ackerman Jerome L, Petibon Yoann, Brady Thomas J, El Fakhri Georges, Ouyang Jinsong
机构信息
Center for Advanced Medical Imaging Sciences, Division of Nuclear Medicine and Molecular Imaging, Department of Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115.
Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129 and Department of Radiology, Harvard Medical School, Boston, Massachusetts 02115.
出版信息
Med Phys. 2014 Apr;41(4):041910. doi: 10.1118/1.4868457.
PURPOSE
Artifacts caused by head motion present a major challenge in brain positron emission tomography (PET) imaging. The authors investigated the feasibility of using wired active MR microcoils to track head motion and incorporate the measured rigid motion fields into iterative PET reconstruction.
METHODS
Several wired active MR microcoils and a dedicated MR coil-tracking sequence were developed. The microcoils were attached to the outer surface of an anthropomorphic(18)F-filled Hoffman phantom to mimic a brain PET scan. Complex rotation/translation motion of the phantom was induced by a balloon, which was connected to a ventilator. PET list-mode and MR tracking data were acquired simultaneously on a PET-MR scanner. The acquired dynamic PET data were reconstructed iteratively with and without motion correction. Additionally, static phantom data were acquired and used as the gold standard.
RESULTS
Motion artifacts in PET images were effectively removed by wired active MR microcoil based motion correction. Motion correction yielded an activity concentration bias ranging from -0.6% to 3.4% as compared to a bias ranging from -25.0% to 16.6% if no motion correction was applied. The contrast recovery values were improved by 37%-156% with motion correction as compared to no motion correction. The image correlation (mean ± standard deviation) between the motion corrected (uncorrected) images of 20 independent noise realizations and static reference was R(2) = 0.978 ± 0.007 (0.588 ± 0.010, respectively).
CONCLUSIONS
Wired active MR microcoil based motion correction significantly improves brain PET quantitative accuracy and image contrast.
目的
头部运动引起的伪影是脑正电子发射断层扫描（PET）成像中的一个重大挑战。作者研究了使用有线有源磁共振微线圈跟踪头部运动并将测量的刚体运动场纳入迭代PET重建的可行性。
方法
开发了几个有线有源磁共振微线圈和一个专用的磁共振线圈跟踪序列。将微线圈附着在充满（18）F的拟人化霍夫曼体模的外表面，以模拟脑部PET扫描。通过连接到呼吸机的气球诱导体模进行复杂的旋转/平移运动。在PET-MR扫描仪上同时采集PET列表模式和MR跟踪数据。对采集到的动态PET数据进行有和没有运动校正的迭代重建。此外，采集静态体模数据并将其用作金标准。
结果
基于有线有源磁共振微线圈的运动校正有效地消除了PET图像中的运动伪影。与未应用运动校正时-25.0%至16.6%的偏差相比，运动校正产生的活度浓度偏差范围为-0.6%至3.4%。与未进行运动校正相比，运动校正使对比度恢复值提高了37%-156%。20个独立噪声实现的运动校正（未校正）图像与静态参考之间的图像相关性（平均值±标准差）分别为R(2)=0.978±0.007（0.588±0.010）。
结论
基于有线有源磁共振微线圈的运动校正显著提高了脑部PET的定量准确性和图像对比度。
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