Background: A significant proportion of patients with clinically diagnosed Alzheimer’s Disease (AD) and an even higher proportion of patients with amnestic mild cognitive impairment (aMCI) do not show evidence of amyloid deposition on Positron Emission Tomography (PET) with amyloid-binding tracers such as ¹¹C-labeled Pittsburgh Compound B (PiB).

Objective: This study aimed to identify clinical, neuropsychological and neuroimaging factors that might suggest amyloid neuropathology in patients with clinically suspected AD or aMCI.

Methods: Forty patients with mild to moderate AD and 23 patients with aMCI who were clinically diagnosed in our memory clinic and had PiB PET scans were included. Clinical, neuropsychological, and imaging characteristics, such as Medial Temporal lobe Atrophy (MTA) and White Matter Hyperintensities (WMH) on MRI and metabolic pattern on ¹⁸F-labeled fluorodeoxyglucose (FDG) PET, were compared between patients with PiB positive and negative PET results for AD, aMCI, and all subjects combined, respectively.

Results: Compared with PiB positive patients, PiB negative patients had a higher prevalence of hypertension history, better performance on the Mini-Mental State Examination, the Rey Auditory Verbal Learning Test, and the Judgement of Line Orientation, lower score of MTA, and were less likely to have temporoparietal-predominant hypometabolism on FDG PET. Affective symptoms were less common in PiB negative patients diagnosed with AD, and the Animal Fluency Test score was higher in PiB negative patients diagnosed with aMCI.

Conclusion: In patients with clinically diagnosed AD or aMCI, absence of a history of hypertension, deficits in verbal learning and memory, visuospatial function, semantic verbal fluency, presence of affective symptoms, MTA on MRI, and temporoparietal hypometabolism on FDG PET suggested amyloid deposition in the brain.

背景：相当比例的临床诊断为阿尔茨海默病 (AD) 的患者和更高比例的遗忘性轻度认知障碍 (aMCI) 患者在使用淀粉样蛋白结合示踪剂（如作为¹¹ C 标记的匹兹堡化合物 B (PiB)。

目的：本研究旨在确定临床疑似 AD 或 aMCI 患者可能提示淀粉样蛋白神经病理学的临床、神经心理学和神经影像学因素。

方法：纳入在我们的记忆诊所临床诊断并进行 PiB PET 扫描的 40 名轻度至中度 AD 患者和 23 名 aMCI 患者。比较 PiB 阳性和阴性 PET 患者的临床、神经心理学和影像学特征，例如 MRI 上的内侧颞叶萎缩 (MTA) 和白质高信号 (WMH) 以及¹⁸ F标记的氟脱氧葡萄糖 (FDG) PET上的代谢模式AD、aMCI 和所有受试者的结果分别合并。

结果：与 PiB 阳性患者相比，PiB 阴性患者高血压病史患病率较高，在简易精神状态检查、Rey 听觉言语学习测试、线方向判断等方面表现较好，MTA 得分较低，在 FDG PET 上不太可能出现颞顶叶为主的低代谢。在被诊断为 AD 的 PiB 阴性患者中，情感症状不太常见，在被诊断为 aMCI 的 PiB 阴性患者中，动物流畅性测试得分较高。

结论：在临床诊断为 AD 或 aMCI 的患者中，无高血压病史、语言学习和记忆障碍、视觉空间功能、语义语言流畅性、存在情感症状、MRI 上的 MTA 和 FDG PET 上的颞顶叶代谢减退提示淀粉样蛋白沉积在大脑中。