BACKGROUND The clinical differentiation between Parkinson disease (PD) and multiple system atrophy (MSA) is difficult. OBJECTIVES Arterial spin labeling (ASL) is an advanced MRI technique that obviates the use of an exogenous contrast agent for the estimation of cerebral perfusion. We explored the value of ASL in combination with structural MRI for the differentiation between PD and MSA. METHODS Ninety-four subjects (30 PD, 30 MSA and 34 healthy controls) performed a morphometric and ASL-MRI to measure volume and perfusion values within basal ganglia and cerebellum. A region-of-interest analysis was performed to test for structural atrophy and regional blood flow differences between groups. RESULTS MSA patients showed higher subcortical atrophy than both PD patients and HC, while no differences were observed between the latter. MSA and PD showed lower volume-corrected perfusion values than HC in several cerebellar areas (Crus I, Crus II, right VIIb, right VIIIa, right VIIIb), right caudate and both thalami. MSA and PD patients displayed similar perfusion values in all aforementioned areas, but the right cerebellar area VIIIb (lower in MSA) and right caudate and both thalami (lower in PD). Similar results were obtained when comparing PD and MSA patients with the parkinsonian variant. CONCLUSIONS A perfusion reduction was equally observed in both MSA and PD patients in cerebellar areas that are putatively linked to cognitive (i.e., executive) rather than motor functions. The observed hypo-perfusion could not be explained by atrophy, suggesting the involvement of the cerebellum in the pathophysiology of both MSA and PD.

中文翻译：

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帕金森病和多系统萎缩中的皮质下萎缩和灌注模式。

背景技术帕金森氏病（PD）和多系统萎缩症（MSA）之间的临床区分是困难的。目的动脉自旋标记（ASL）是一种先进的MRI技术，可避免使用外源性造影剂来估计脑灌注。我们探讨了ASL与结构MRI结合在PD和MSA鉴别中的价值。方法94名受试者（30名PD，30名MSA和34名健康对照）进行了形态计量学和ASL-MRI，以测量基底神经节和小脑内的体积和灌注值。进行了感兴趣区域分析以测试组之间的结构性萎缩和区域血流差异。结果MSA患者的皮质下萎缩程度高于PD患者和HC，而后者之间无差异。MSA和PD在几个小脑区域（Crus I，Crus II，右VIIb，右VIIIa，右VIIIb），右尾状和两个丘脑中均显示出比HC低的体积校正灌注值。MSA和PD患者在所有上述区域均显示相似的灌注值，但右小脑区VIIIb（MSA较低）和右尾状及两个丘脑（PD较低）。比较帕金森氏病和帕金森病患者的PD和MSA患者，可获得相似的结果。结论在小脑区域的MSA和PD患者中均观察到灌注减少，这些小脑区域被认为与认知（即执行）而非运动功能有关。萎缩不能解释观察到的血流不足，提示小脑参与了MSA和PD的病理生理。