Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran,Iran.
Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran,Iran.
Curr Alzheimer Res. 2021;18(9):721-731. doi: 10.2174/1567205018666211124110710.
Mild cognitive impairment (MCI) is a state between normal cognition and dementia. However, MCI diagnosis does not necessarily guarantee the progression to dementia. Since no previous study investigated brain positron emission tomography (PET) imaging of MCI-- to-normal reversion, we provided PET imaging of MCI- to-normal reversion using the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.
We applied comprehensive neuropsychological criteria (NP criteria), consisting of memory, language, and attention/executive function domains, to include patients with a baseline diagnosis of MCI (n=613). According to the criteria, the year 1 status of the patients was categorized into three groups (reversion: n=105, stable MCI: n=422, conversion: n=86). Demographic, neuropsychological, genetic, CSF, and cognition biomarker variables were compared between the groups. Additionally, after adjustment for confounding variables, the deposition pattern of amyloid-β and cerebral glucose metabolism were compared between three groups via AV45- and FDG-PET modalities, respectively.
MCI reversion rate was 17.1% during one year of follow-up. The reversion group had the lowest frequency of APOE ε4+ subjects, the highest CSF level of amyloid-β, and the lowest CSF levels of t-tau and p-tau. Neuropsychological assessments were also suggestive of better cognitive performance in the reversion group. Patients with reversion to normal state had higher glucose metabolism in bilateral angular and left middle/inferior temporal gyri, when compared to those with stable MCI state. Meanwhile, lower amyloid-β deposition at baseline was observed in the frontal and parietal regions of the reverted subjects. On the other hand, the conversion group showed lower cerebral glucose metabolism in bilateral angular and bilateral middle/inferior temporal gyri compared to the stable MCI group, whereas the amyloid-β accumulation was similar between the groups.
This longitudinal study provides novel insight regarding the application of PET imaging in predicting MCI transition over time.
轻度认知障碍（MCI）是介于正常认知和痴呆之间的一种状态。然而，MCI 的诊断并不能保证一定会发展为痴呆。由于以前没有研究调查 MCI 向正常状态逆转的脑正电子发射断层扫描（PET）成像，因此我们使用阿尔茨海默病神经影像学倡议（ADNI）数据库提供了 MCI 向正常状态逆转的 PET 成像。
我们应用了综合神经心理学标准（NP 标准），包括记忆、语言和注意力/执行功能领域，将基线诊断为 MCI 的患者（n=613）纳入研究。根据标准，患者第 1 年的状态分为三组（逆转：n=105，稳定 MCI：n=422，转化：n=86）。比较了三组之间的人口统计学、神经心理学、遗传、CSF 和认知生物标志物变量。此外，在调整混杂变量后，分别通过 AV45-PET 和 FDG-PET 模式比较了三组之间的淀粉样蛋白-β和脑葡萄糖代谢沉积模式。
在一年的随访中，MCI 逆转率为 17.1%。逆转组 APOE ε4+ 受试者频率最低，CSF 中淀粉样蛋白-β水平最高，CSF 中 t-tau 和 p-tau 水平最低。神经心理学评估也表明，逆转组的认知表现更好。与稳定 MCI 状态相比，恢复正常状态的患者双侧角回和左侧中/下颞回的葡萄糖代谢更高。同时，逆转组的额区和顶区的淀粉样蛋白-β沉积在基线时较低。另一方面，与稳定 MCI 组相比，转化组双侧角回和双侧中/下颞回的脑葡萄糖代谢较低，而两组之间的淀粉样蛋白-β积累相似。
这项纵向研究为 PET 成像在预测 MCI 随时间的转变提供了新的见解。
