Respiratory motion correction of PET using MR-constrained PET-PET registration.
Respiratory motion correction of PET using MR-constrained PET-PET registration.
复制标题
使用MR受限的PET-PET登记对PET进行呼吸运动校正。
DOI：
10.1186/s12938-015-0078-5
复制
发表时间：
2015-09-18
影响因子：
3.9
通讯作者：
King AP
中科院分区：
文献类型：
--
作者：
Balfour DR;Marsden PK;Polycarpou I;Kolbitsch C;King AP
正电子发射断层扫描（PET）中的呼吸运动是示踪剂摄取、病变位置和病变大小测量中不可避免的误差来源。PET-MR双模态扫描仪的引入为解决这一问题开辟了新的途径。运动模型提供了一种使用数量减少的参数来估计运动的方法。这对于从PET估计运动是有益的，否则由于数据的高噪声水平而难以估计运动。我们提出了一种新的技术，利用呼吸运动模型，形成从初始MR扫描数据。运动模型用于约束参考PET门和待校正门之间的PET-PET配准。为了进行评价，根据从4名志愿者获得的真实的、分段的、超短回波时间MR数据模拟添加FDG-亲合病变的PET。呼吸运动被包括在使用从相同志愿者获得的真实的动态3D MR体积导出的运动场的模拟中。将性能与MR衍生运动模型驱动方法（需要持续使用MR扫描仪）和PET门的无约束PET-PET配准进行了比较。在没有运动校正的情况下，相对于无运动模拟中的相应测量，观察到未校正病变强度的中值下降和由最小边界框指定的头足病变宽度的中值增加。所提出的方法将这些值分别校正为（）和（），在靠近横膈膜和肝脏的位置具有显著改善的性能。所有病变的中位病变位移在未进行运动校正的情况下观察到，在进行运动校正的情况下减少到（）。提出了一种新的PET-MR成像中PET数据的呼吸运动校正技术。在初始30秒MR扫描后，所提出的技术不需要使用MR扫描仪进行运动校正，使其适合于MR密集型研究或顺序PET-MR。所提出的技术的准确性与两种比较方法相似，但与PET-PET技术相比，鲁棒性得到了提高，特别是在具有较高噪声的区域，如肝脏。
Respiratory motion in positron emission tomography (PET) is an unavoidable source of error in the measurement of tracer uptake, lesion position and lesion size. The introduction of PET-MR dual modality scanners opens a new avenue for addressing this issue. Motion models offer a way to estimate motion using a reduced number of parameters. This can be beneficial for estimating motion from PET, which can otherwise be difficult due to the high level of noise of the data. We propose a novel technique that makes use of a respiratory motion model, formed from initial MR scan data. The motion model is used to constrain PET-PET registrations between a reference PET gate and the gates to be corrected. For evaluation, PET with added FDG-avid lesions was simulated from real, segmented, ultrashort echo time MR data obtained from four volunteers. Respiratory motion was included in the simulations using motion fields derived from real dynamic 3D MR volumes obtained from the same volunteers. Performance was compared to an MR-derived motion model driven method (which requires constant use of the MR scanner) and to unconstrained PET-PET registration of the PET gates. Without motion correction, a median drop in uncorrected lesion intensity to and an increase in median head-foot lesion width, specified by a minimum bounding box, to was observed relative to the corresponding measures in motion-free simulations. The proposed method corrected these values to () and () respectively, with notably improved performance close to the diaphragm and in the liver. Median lesion displacement across all lesions was observed to be without motion correction, which was reduced to () with motion correction. This paper presents a novel technique for respiratory motion correction of PET data in PET-MR imaging. After an initial 30 second MR scan, the proposed technique does not require use of the MR scanner for motion correction purposes, making it suitable for MR-intensive studies or sequential PET-MR. The accuracy of the proposed technique was similar to both comparative methods, but robustness was improved compared to the PET-PET technique, particularly in regions with higher noise such as the liver.