Neuroimaging Laboratory, Fondazione Santa Lucia, IRCCS, Rome, Italy.
Department of Neuroscience, University of Rome 'Tor Vergata', Rome, Italy.
J Alzheimers Dis. 2020;74(2):615-624. doi: 10.3233/JAD-191125.
The cognitive role of the cerebellum has recently gained much attention, and its pivotal role in Alzheimer's disease (AD) has now been widely recognized. Diffusion tensor imaging (DTI) has been used to evaluate the disruption of the microstructural milieu in AD, and though several white matter (WM) tracts such as corpus callosum, inferior and superior longitudinal fasciculus, cingulum, fornix, and uncinate fasciculus have been evaluated in AD, data on cerebellar WM tracts are currently lacking. We performed a tractography-based DTI reconstruction of the middle cerebellar peduncle (MCP), and the left and right superior cerebellar peduncles separately (SCPL and SCPR) and addressed the differences in fractional anisotropy (FA), axial diffusivity (Dax), radial diffusivity (RD), and mean diffusivity (MD) in the three tracts between 50 patients with AD and 25 healthy subjects. We found that AD patients showed a lower FA and a higher RD compared to healthy subjects in MCP, SCPL, and SCPR. Moreover, higher MD was found in SCPR and SCPL and higher Dax in SCPL. This result is important as it challenges the traditional view that WM bundles in the cerebellum are unaffected in AD and might identify new targets for therapeutic interventions.
小脑的认知作用最近引起了广泛关注，其在阿尔茨海默病（AD）中的关键作用已得到广泛认可。弥散张量成像（DTI）已被用于评估 AD 中微观结构环境的破坏，尽管已经评估了 AD 中的几个白质（WM）束，如胼胝体、下和上纵束、扣带束、穹窿和钩束，但目前尚无关于小脑 WM 束的数据。我们分别对小脑中间脚（MCP）、左和右小脑上脚（SCPL 和 SCPR）进行了基于束流的 DTI 重建，并分析了 50 名 AD 患者和 25 名健康受试者在这三个束中的各向异性分数（FA）、轴向扩散系数（Dax）、径向扩散系数（RD）和平均扩散系数（MD）的差异。我们发现，与健康受试者相比，AD 患者在 MCP、SCPL 和 SCPR 中的 FA 较低，RD 较高。此外，在 SCPR 和 SCPL 中 MD 较高，在 SCPL 中 Dax 较高。这一结果很重要，因为它挑战了传统观点，即 AD 中小脑的 WM 束不受影响，并可能为治疗干预确定新的靶点。
