Department of Imaging and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
Med Phys. 2011 Nov;38(11):6313-26. doi: 10.1118/1.3656951.
The authors aimed to develop an image-based registration scheme to detect and correct patient motion in stress and rest cardiac positron emission tomography (PET)/CT images. The patient motion correction was of primary interest and the effects of patient motion with the use of flurpiridaz F 18 and (82)Rb were demonstrated.
The authors evaluated stress/rest PET myocardial perfusion imaging datasets in 30 patients (60 datasets in total, 21 male and 9 female) using a new perfusion agent (flurpiridaz F 18) (n = 16) and (82)Rb (n = 14), acquired on a Siemens Biograph-64 scanner in list mode. Stress and rest images were reconstructed into 4 ((82)Rb) or 10 (flurpiridaz F 18) dynamic frames (60 s each) using standard reconstruction (2D attenuation weighted ordered subsets expectation maximization). Patient motion correction was achieved by an image-based registration scheme optimizing a cost function using modified normalized cross-correlation that combined global and local features. For comparison, visual scoring of motion was performed on the scale of 0 to 2 (no motion, moderate motion, and large motion) by two experienced observers.
The proposed registration technique had a 93% success rate in removing left ventricular motion, as visually assessed. The maximum detected motion extent for stress and rest were 5.2 mm and 4.9 mm for flurpiridaz F 18 perfusion and 3.0 mm and 4.3 mm for (82)Rb perfusion studies, respectively. Motion extent (maximum frame-to-frame displacement) obtained for stress and rest were (2.2 ± 1.1, 1.4 ± 0.7, 1.9 ± 1.3) mm and (2.0 ± 1.1, 1.2 ±0 .9, 1.9 ± 0.9) mm for flurpiridaz F 18 perfusion studies and (1.9 ± 0.7, 0.7 ± 0.6, 1.3 ± 0.6) mm and (2.0 ± 0.9, 0.6 ± 0.4, 1.2 ± 1.2) mm for (82)Rb perfusion studies, respectively. A visually detectable patient motion threshold was established to be ≥2.2 mm, corresponding to visual user scores of 1 and 2. After motion correction, the average increases in contrast-to-noise ratio (CNR) from all frames for larger than the motion threshold were 16.2% in stress flurpiridaz F 18 and 12.2% in rest flurpiridaz F 18 studies. The average increases in CNR were 4.6% in stress (82)Rb studies and 4.3% in rest (82)Rb studies.
Fully automatic motion correction of dynamic PET frames can be performed accurately, potentially allowing improved image quantification of cardiac PET data.
作者旨在开发一种基于图像的配准方案，以检测和纠正应激和静息心脏正电子发射断层扫描（PET）/CT 图像中的患者运动。患者运动校正为主要目的，并展示了使用氟比拉嗪 F 18 和（82）Rb 的患者运动的效果。
作者使用新的灌注剂（氟比拉嗪 F 18）（n=16）和（82）Rb（n=14）评估了 30 名患者（总共 60 个数据集，21 名男性和 9 名女性）的应激/静息 PET 心肌灌注成像数据集，这些数据集均在西门子 Biograph-64 扫描仪上以列表模式采集。使用标准重建（2D 衰减加权有序子集期望最大化）将应激和静息图像重建为 4（（82）Rb）或 10 个（氟比拉嗪 F 18）动态帧（每个 60 s）。通过使用结合全局和局部特征的改进归一化互相关的基于图像的配准方案来实现患者运动校正。为了比较，由两名经验丰富的观察者在 0 到 2 （无运动、中度运动和大运动）的范围内对运动进行视觉评分。
所提出的注册技术在去除左心室运动方面的成功率为 93%，如视觉评估所示。在氟比拉嗪 F 18 灌注研究中，应激和静息时检测到的最大运动程度分别为 5.2 mm 和 4.9 mm，（82）Rb 灌注研究中分别为 3.0 mm 和 4.3 mm。应激和静息时获得的运动程度（最大帧间位移）分别为氟比拉嗪 F 18 灌注研究的（2.2±1.1、1.4±0.7、1.9±1.3）mm 和（2.0±1.1、1.2±0.9、1.9±0.9）mm，（82）Rb 灌注研究分别为（1.9±0.7、0.7±0.6、1.3±0.6）mm 和（2.0±0.9、0.6±0.4、1.2±1.2）mm。建立了可检测到的患者运动阈值为≥2.2 mm，对应于视觉用户评分 1 和 2。运动校正后，大于运动阈值的所有帧的对比度噪声比（CNR）的平均增加分别为应激氟比拉嗪 F 18 中的 16.2%和静息氟比拉嗪 F 18 中的 12.2%。应激（82）Rb 研究和静息（82）Rb 研究中的 CNR 平均增加分别为 4.6%和 4.3%。
可以准确地进行动态 PET 帧的全自动运动校正，这可能允许改进心脏 PET 数据的图像定量。
