Objectives. This study is aimed at investigating the impact of frame numbers in preclinical electrocardiogram- (ECG-) gated ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) on systolic and diastolic left ventricular (LV) parameters in rats. Methods. ¹⁸F-FDG PET imaging using a dedicated small animal PET system with list mode data acquisition and continuous ECG recording was performed in diabetic and control rats. The list-mode data was sorted and reconstructed with different numbers of frames (4, 8, 12, and 16) per cardiac cycle into tomographic images. Using an automatic ventricular edge detection software, left ventricular (LV) functional parameters, including ejection fraction (EF), end-diastolic (EDV), and end-systolic volume (ESV), were calculated. Diastolic variables (time to peak filling (TPF), first third mean filling rate (1/3 FR), and peak filling rate (PFR)) were also assessed. Results. Significant differences in multiple parameters were observed among the reconstructions with different frames per cardiac cycle. EDV significantly increased by numbers of frames (353.8 ± 57.7 μl, 380.8 ± 57.2 μl, 398.0 ± 63.1 μl, and 444.8 ± 75.3 μl at 4, 8, 12, and 16 frames, respectively; vs. 16 frames), while systolic (EF) and diastolic (TPF, 1/3 FR and PFR) parameters were not significantly different between 12 and 16 frames. In addition, significant differences between diabetic and control animals in 1/3 FR and PFR in 16 frames per cardiac cycle were observed (), but not for 4, 8, and 12 frames. Conclusions. Using ECG-gated PET in rats, measurements of cardiac function are significantly affected by the frames per cardiac cycle. Therefore, if you are going to compare those functional parameters, a consistent number of frames should be used.

中文翻译：

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心电门控 18F-FDG 小动物 PET 上的帧数对 LV 收缩和舒张功能参数有显着影响

目标。本研究旨在调查临床前心电图 (ECG-) 门控¹⁸ F-氟脱氧葡萄糖 ( ¹⁸ F-FDG) 正电子发射断层扫描 (PET) 中帧数对大鼠左心室 (LV) 收缩期和舒张期 (LV) 参数的影响。方法。¹⁸在糖尿病大鼠和对照大鼠中使用具有列表模式数据采集和连续心电图记录的专用小动物 PET 系统进行 F-FDG PET 成像。列表模式数据被分类并在每个心动周期使用不同数量的帧（4、8、12 和 16）重建成断层图像。使用自动心室边缘检测软件，计算左心室 (LV) 功能参数，包括射血分数 (EF)、舒张末期 (EDV) 和收缩末期容积 (ESV)。还评估了舒张期变量（达到峰值充盈时间 (TPF)、前三分之一平均充盈率 (1/3 FR) 和峰值充盈率 (PFR)）。结果. 在每个心动周期不同帧的重建中观察到多个参数的显着差异。EDV 通过帧数显着增加（分别在 4、8、12 和 16 帧时为 353.8 ± 57.7  μl 、380.8 ± 57.2  μl 、398.0 ± 63.1  μl和444.8 ±  75.3 μl ；与 16 帧相比），而收缩压 (EF) 和舒张压 (TPF、1/3 FR 和 PFR) 参数在 12 和 16 帧之间没有显着差异。此外，观察到糖尿病动物和对照组动物在每个心动周期 16 帧的 1/3 FR 和 PFR 之间存在显着差异（)，但不适用于 4、8 和 12 帧。结论。在大鼠中使用 ECG 门控 PET，心脏功能的测量受到每个心动周期帧数的显着影响。因此，如果要比较这些功能参数，则应使用一致的帧数。