Department of Investigative Radiology, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
Ann Nucl Med. 2010 Jan;24(1):1-11. doi: 10.1007/s12149-009-0323-8. Epub 2009 Dec 3.
Cardiac (15)O-water PET studies provide an accurate quantitation of regional myocardial blood flow (rMBF). We developed a motion correction system using an optical motion-tracking device to detect a subject's global movement for cardiac study.
PET studies were carried out on a cardiac phantom and a healthy volunteer at rest. The three-dimensional locations of the markers attached to the subjects during scans were measured using an optical motion-tracking system. In the phantom study, we performed a transmission scan and seven (18)F emission scans of a baseline and with artificial misalignment of shifts and rotations. The correlation coefficients between the baseline and the other images before and after the corrections for the misalignment were calculated. In the human study, we performed a (15)O-water dynamic scan with a transmission and axially 30 mm-shifted transmission scans. Motion of the subject was estimated by the information from the system, and was corrected on each sinogram using attenuation maps realigned to dynamic frames. Reconstructed dynamic images were then realigned to the transmission data. We calculated rMBF values for nine segments and myocardial images from the emission images, which were reconstructed with the first attenuation map (reference) and with the misaligned attenuation map before and after our corrections.
In the phantom study, the correlation coefficients were improved from 0.929 +/- 0.022 to 0.987 +/- 0.010 (mean +/- SD) after the corrections. In the human study, the global and cyclic movements were detected. The cyclic movement due to respiration was smoothed by frame-averaging, and reasonable information of the global movement was obtained. The rMBF value (mean +/- SD) was 0.94 +/- 0.12 mL/min/g for the reference. The rMBF values using the misaligned attenuation map changed from 1.03 +/- 0.21 to 0.93 +/- 0.11 mL/min/g after the correction, and spurious defects in myocardial images were also recovered.
Our technique provided reasonable information for correcting the global movement of the subject. It was shown that this system was applicable to detect and correct subject movement in cardiac PET studies at rest.
心脏（15）O-水 PET 研究提供了局部心肌血流（rMBF）的准确定量。我们开发了一种使用光学运动跟踪设备来检测受试者整体运动的运动校正系统，用于心脏研究。
在休息时对心脏模型和健康志愿者进行 PET 研究。使用光学运动跟踪系统测量扫描期间附着在受试者上的标记的三维位置。在模型研究中，我们进行了一次透射扫描和七次（18）F 发射扫描，包括基线和人工错位的平移和旋转。计算了校正错位前后与基线相关的相关系数。在人体研究中，我们进行了（15）O-水动态扫描，包括透射和轴向 30mm 移位的透射扫描。通过系统提供的信息来估计受试者的运动，并在每个正弦图上使用重新对准动态帧的衰减图进行校正。然后将重建的动态图像重新对准到传输数据上。我们从发射图像计算了九个节段和心肌图像的 rMBF 值，这些图像是使用第一个衰减图（参考）和校正前后未对准的衰减图重建的。
在模型研究中，校正后相关系数从 0.929 +/- 0.022 提高到 0.987 +/- 0.010（平均值 +/- SD）。在人体研究中，检测到整体和循环运动。通过帧平均平滑呼吸引起的循环运动，并获得合理的整体运动信息。参考的 rMBF 值（平均值 +/- SD）为 0.94 +/- 0.12 mL/min/g。校正后，使用未对准衰减图的 rMBF 值从 1.03 +/- 0.21 变为 0.93 +/- 0.11 mL/min/g，心肌图像中的虚假缺陷也得到了恢复。
我们的技术为校正受试者的整体运动提供了合理的信息。结果表明，该系统适用于在静息状态下检测和校正心脏 PET 研究中的受试者运动。
