Subjective cognitive decline (SCD), characterized by self-perceived subtle cognitive impairment ahead of the appearance of explicit and measurable cognitive deficits, is regarded as the preclinical manifestation of the pathological change continuum of Alzheimer’s disease (AD). We were committed to exploring the amyloid and glucose metabolic signatures related to imminent brain metabolic changes in SCD subjects. This study included 39 subjects (mean age = 71.9 years; 14 males and 25 females) diagnosed with SCD disease and 39 gender-matched healthy controls (HCs) (mean age = 75.2; 16 males and 23 females) with brain [18F] fluorodeoxyglucose positron emission tomography (PET) images and [18F] florbetapir PET images. The standardized uptake value ratios (SUVRs) of PET images within the regions of interest (ROIs) were calculated. Inter-group SUVR differences were assessed by two-sample t-testing and receiver operating characteristic curve (ROC) analyses. A generalized linear model (GLM) was employed to evaluate the correlations between amyloid and FDG uptake. Compared with HCs, SCD subjects showed significantly increased amyloid SUVR, as well as significantly increased glucose SUVR in the olfactory, amygdala, thalamus, heschl gyrus, superior and middle temporal gyrus and temporal pole (all P<0.05). The amyloid SUVR of thalamus was found to have a better ROC result (area under the curve (AUC): 0.77, 95% confidence interval (CI): 0.66–0.86) in the HC group, as was the case with the glucose SUVR of the middle temporal gyrus (AUC: 0.83, 95% CI: 0.73–0.91). There were significant positive correlations between amyloid and glucose SUVRs (P<0.05). The amyloid SUVR of the thalamus showed a significantly better main effect (odd ratio = 2.91, 95% CI: 1.44–6.7, P<0.001), and the glucose SUVR of the heschl gyrus indicated an enhanced main effect (odd ratio = 5.08, 95% CI: 1.86–18.15, P<0.001). SCD subjects demonstrated significant amyloid accumulation and glucose hypermetabolism in specific brain regions, and amyloid pathology overlapped with regions of glucose abnormality. These findings may advance the understanding of imminent pathological changes in the SCD stage and help to provide clinical guidelines for interventional management.

中文翻译：

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主观认知衰退受试者中淀粉样蛋白和葡萄糖特征的体内评估

主观认知衰退 (SCD) 的特征是在出现明显和可测量的认知缺陷之前出现自我感知的细微认知障碍，被认为是阿尔茨海默病 (AD) 病理变化连续体的临床前表现。我们致力于探索与 SCD 受试者即将发生的脑代谢变化相关的淀粉样蛋白和葡萄糖代谢特征。这项研究包括 39 名被诊断患有 SCD 疾病的受试者（平均年龄 = 71.9 岁；14 名男性和 25 名女性）和 39 名性别匹配的健康对照（HCs）（平均年龄 = 75.2；16 名男性和 23 名女性）脑 [18F] 氟脱氧葡萄糖正电子发射断层扫描 (PET) 图像和 [18F] florbetapir PET 图像。计算感兴趣区域 (ROI) 内 PET 图像的标准化摄取值比 (SUVR)。吨-测试和接受者操作特征曲线（ROC）分析。采用广义线性模型 (GLM) 来评估淀粉样蛋白和 FDG 摄取之间的相关性。与 HCs 相比，SCD 受试者的嗅觉、杏仁核、丘脑、赫氏回、颞上回和颞中回以及颞极的淀粉样蛋白 SUVR 显着升高，葡萄糖 SUVR 显着升高（均磷<0.05）。发现丘脑的淀粉样蛋白 SUVR 在 HC 组中具有更好的 ROC 结果（曲线下面积（AUC）：0.77，95% 置信区间（CI）：0.66-0.86），与葡萄糖 SUVR 的情况一样颞中回 (AUC: 0.83, 95% CI: 0.73–0.91)。淀粉样蛋白和葡萄糖 SUVR 呈显着正相关（磷<0.05）。丘脑的淀粉样蛋白 SUVR 表现出明显更好的主效应（比值比=2.91, 95% CI: 1.44–6.7,磷<0.001), heschl gyrus 的葡萄糖 SUVR 表明增强的主效应 (odd ratio=5.08, 95% CI: 1.86–18.15,磷<0.001）。SCD 受试者在特定脑区表现出明显的淀粉样蛋白积累和葡萄糖代谢亢进，并且淀粉样蛋白病理与葡萄糖异常区域重叠。这些发现可能会促进对 SCD 阶段即将发生的病理变化的理解，并有助于为介入管理提供临床指南。