Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Department of Neurology, Mayo Clinic, Rochester, MN, USA.
J Alzheimers Dis. 2018;62(4):1713-1724. doi: 10.3233/JAD-170740.
Despite common pathology, Alzheimer's disease (AD) can have multiple clinical presentations which pathological studies suggest result from differences in the regional distribution of tau pathology. Positron emission tomography (PET) ligands are now available that can detect tau proteins in vivo and hence can be used to investigate the biological mechanisms underlying atypical AD.
To assess regional patterns of tau uptake on PET imaging in two atypical AD variants, posterior cortical atrophy (PCA) and logopenic progressive aphasia (lvPPA).
Eighteen PCA and 19 lvPPA subjects that showed amyloid-β deposition on PET underwent tau-PET imaging with [18F]AV-1451. Group comparisons of tau uptake in PCA and lvPPA were performed using voxel-level and regional-level analyses. We also assessed the degree of lobar tau asymmetry and correlated regional tau uptake to age and performance on clinical evaluations.
Both syndromes showed diffuse tau uptake throughout all cortical regions, although PCA showed greater uptake in occipital regions compared to lvPPA, and lvPPA showed greater uptake in left frontal and temporal regions compared to PCA. While lvPPA showed predominant left-asymmetric tau deposition, PCA was more bilateral. Younger subjects showed greater tau uptake bilaterally in frontal and parietal lobes than older subjects, and sentence repetition, Boston naming test, simultanagnosia, and visuoperceptual function showed specific regional tau correlates.
Tau deposition is closely related to clinical presentation in atypical AD with age playing a role in determining the degree of cortical tau deposition.
尽管存在共同的病理学，但阿尔茨海默病（AD）可能有多种临床表现，病理学研究表明这些临床表现是由于tau 病理学的区域分布差异所致。现在已经有正电子发射断层扫描（PET）配体可用于在体内检测 tau 蛋白，因此可用于研究非典型 AD 的生物学机制。
评估两种非典型 AD 变体（后部皮质萎缩症[PCA]和 logopenic 进行性失语症[lvPPA]）在 PET 成像上的 tau 摄取的区域模式。
18 名 PCA 和 19 名 lvPPA 患者在 PET 上显示淀粉样β沉积后接受了 [18F]AV-1451 的 tau-PET 成像。使用体素水平和区域水平分析对 PCA 和 lvPPA 中的 tau 摄取进行组间比较。我们还评估了额叶和颞叶区域的脑区 tau 不对称程度，并将区域 tau 摄取与临床评估的年龄和表现相关联。
两种综合征均显示整个皮质区域弥漫性 tau 摄取，尽管与 lvPPA 相比，PCA 显示出更大的枕叶区域摄取，而与 PCA 相比，lvPPA 显示出更大的左额颞叶区域摄取。尽管 lvPPA 表现出主要的左侧不对称 tau 沉积，但 PCA 更具双侧性。年轻受试者在额顶叶区域的 tau 摄取比老年受试者双侧更大，句子重复、波士顿命名测试、同时失认症和视知觉功能显示出特定的区域 tau 相关性。
tau 沉积与非典型 AD 的临床表现密切相关，年龄在确定皮质 tau 沉积程度方面起着作用。
