Abstract:
BACKGROUND: Positron emission tomography (PET) is increasingly being used as an imaging modality for clinical and research applications in veterinary medicine. Amyloid PET has become a useful tool for diagnosing Alzheimer\'s disease (AD) in humans, by accurately identifying amyloid-beta (Aβ) plaques. Cognitive dysfunction syndrome in dogs shows cognitive and pathophysiologic characteristics similar to AD. Therefore, we assessed the physiologic characteristics of uptake of 18F-flutemetamol, an Aβ protein-binding PET tracer in clinical development, in normal dog brains, for distinguishing an abnormal state. Static and dynamic PET images of six adult healthy dogs were acquired after 18F-flutemetamol was administered intravenously at approximately 3.083 MBq/kg. For static images, PET data were acquired at 30, 60, and 90 min after injection. One week later, dynamic images were acquired for 120 min, from the time of tracer injection. PET data were reconstructed using an iterative technique, and corrections for attenuation and scatter were applied. Regions of interest were manually drawn over the frontal, parietal, temporal, occipital, anterior cingulate, posterior cingulate, and cerebellar cortices, cerebral white matter, midbrain, pons, and medulla oblongata. After calculating standardized uptake values with an established formula, standardized uptake value ratios (SUVRs) were obtained, using the cerebellar cortex as a reference region.
RESULTS: Among the six cerebral cortical regions, the cingulate cortices and frontal lobe showed the highest SUVRs. The lowest SUVR was observed in the occipital lobe. The average values of the cortical SUVRs were 1.25, 1.26, and 1.27 at 30, 60, and 90 min post-injection, respectively. Tracer uptake on dynamic scans was rapid, peaking within 4 min post-injection. After reaching this early maximum, cerebral cortical regions showed a curve with a steep descent, whereas cerebral white matter demonstrated a curve with a slow decline, resulting in a large gap between cerebral cortical regions and white matter.
CONCLUSIONS: This study provides normal baseline data of 18F-flutemetamol PET that can facilitate an objective diagnosis of cognitive dysfunction syndrome in dogs in future.
摘要:
背景:正电子发射断层扫描(PET)越来越多地用作兽医临床和研究应用的成像方式。淀粉样蛋白PET已成为诊断人类阿尔茨海默病(AD)的有用工具,通过准确识别淀粉样β(Aβ)斑块。犬的认知功能障碍综合征表现出与AD相似的认知和病理生理特征。因此,我们评估了18F-氟美他莫摄取的生理特征,临床开发中的Aβ蛋白结合PET示踪剂,在正常的狗大脑中,用于区分异常状态。在以约3.083MBq/kg静脉内施用18F-氟美他莫后,获得六只成年健康狗的静态和动态PET图像。对于静态图像,在注射后30、60和90分钟采集PET数据。一周后,动态图像采集120分钟,从示踪剂注射的时间。使用迭代技术重建PET数据,并对衰减和散射进行校正。感兴趣的区域是在额叶上手动绘制的,顶叶,temporal,枕骨,前扣带,后扣带回,和小脑皮质,大脑白质,中脑,pons,和延髓.用既定公式计算标准化吸收值后,获得标准化摄取值比率(SUVR),使用小脑皮层作为参考区域。
结果:在六个大脑皮层区域中,扣带回皮质和额叶表现出最高的SUVR。在枕叶中观察到最低的SUVR。注射后30、60和90分钟皮质SUVR的平均值分别为1.25、1.26和1.27,分别。动态扫描上的示踪剂摄取迅速,在注射后4分钟内达到峰值。在达到这个早期的最大值之后,大脑皮层区域显示出陡峭的下降曲线,而脑白质表现出缓慢下降的曲线,导致大脑皮层区域和白质之间有很大的间隙。
结论:本研究提供了18F-flutemetamolPET的正常基线数据,可以促进未来犬认知功能障碍综合征的客观诊断。