Seidel Jurgen, Bernardo Marcelino L, Wong Karen J, Xu Biying, Williams Mark R, Kuo Frank, Jagoda Elaine M, Basuli Falguni, Li Changhui, Griffiths Gary L, Green Michael V, Choyke Peter L
Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA; Contractor to Leidos Biomedical Research, Inc., Frederick, MD, USA.
Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA; Leidos Biomedical Research, Inc., Frederick, MD, USA.
Nucl Med Biol. 2014 Aug;41(7):582-6. doi: 10.1016/j.nucmedbio.2014.03.015. Epub 2014 Mar 29.
We describe and illustrate a method for creating ECG-gated PET images of the heart for each of several mice imaged at the same time. The method is intended to increase "throughput" in PET research studies of cardiac dynamics or to obtain information derived from such studies, e.g. tracer concentration in end-diastolic left ventricular blood.
An imaging bed with provisions for warming, anesthetic delivery, etc., was fabricated by 3D printing to allow simultaneous PET imaging of two side-by-side mice. After electrode attachment, tracer injection and placement of the animals in the scanner field of view, ECG signals from each animal were continuously analyzed and independent trigger markers generated whenever an R-wave was detected in each signal. PET image data were acquired in "list" mode and these trigger markers were inserted into this list along with the image data. Since each mouse is in a different spatial location in the FOV, sorting of these data using trigger markers first from one animal and then the other yields two independent and correctly formed ECG-gated image sequences that reflect the dynamical properties of the heart during an "average" cardiac cycle.
The described method yields two independent ECG-gated image sequences that exhibit the expected properties in each animal, e.g. variation of the ventricular cavity volumes from maximum to minimum and back during the cardiac cycle in the processed animal with little or no variation in these volumes during the cardiac cycle in the unprocessed animal.
ECG-gated image sequences for each of several animals can be created from a single list mode data collection using the described method. In principle, this method can be extended to more than two mice (or other animals) and to other forms of physiological gating, e.g. respiratory gating, when several subjects are imaged at the same time.
我们描述并展示了一种为同时成像的几只小鼠创建心脏心电图门控正电子发射断层扫描（PET）图像的方法。该方法旨在提高心脏动力学PET研究中的“通量”，或获取从此类研究中得出的信息，例如舒张末期左心室血液中的示踪剂浓度。
通过3D打印制造了一张具备加温、麻醉输送等功能的成像床，以允许对两只并排的小鼠同时进行PET成像。在连接电极、注射示踪剂并将动物放置在扫描仪视野中后，对每只动物的心电图信号进行连续分析，每当在每个信号中检测到R波时生成独立的触发标记。PET图像数据以“列表”模式采集，这些触发标记与图像数据一起插入该列表中。由于每只小鼠在视野中的空间位置不同，首先使用来自一只动物的触发标记对这些数据进行排序，然后再使用另一只动物的触发标记进行排序，从而产生两个独立且正确形成的心电图门控图像序列，这些序列反映了“平均”心动周期中心脏的动态特性。
所描述的方法产生了两个独立的心电图门控图像序列，每个动物的序列都表现出预期的特性，例如在处理过的动物中，心动周期中心室腔体积从最大到最小再回到最大的变化，而在未处理的动物中，这些体积在心动周期中几乎没有变化。
使用所描述的方法，可以从单个列表模式数据采集中为几只动物中的每只创建心电图门控图像序列。原则上，当同时对多个受试者进行成像时，该方法可以扩展到两只以上的小鼠（或其他动物）以及其他形式的生理门控，例如呼吸门控。
