Multiple-system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal syndrome (CBS) have signs and symptoms overlapping those of Parkinson disease (PD), complicating their clinical diagnosis. Although presynaptic dopaminergic brain imaging with PET and SPECT is clinically widely used for patients with suspected PD, the benefit of functional imaging in atypical parkinsonism syndromes remains unclear. We compared striatal presynaptic dopaminergic function in MSA parkinsonism variant (MSA-P), MSA cerebellar variant (MSA-C), PSP, CBS, and PD using combined quantitative data from all published studies. Methods: The PubMed database was searched from inception to August 2018 for the terms “dopamine” OR “dopaminergic” AND “PET” OR “SPECT” OR “SPET” and keywords related to PD, MSA, PSP, and CBS. In total, 1,711 publications were identified. PET or SPECT studies comparing patients with atypical parkinsonism to another diagnostic group (PD, MSA, PSP, or CBS) were included. Tracers for dopamine transporter (DAT), aromatic amino acid decarboxylase (AADC), or vesicular monoamine type 2 were investigated. Tracer binding data were extracted from the original articles. Heterogeneity of the data was examined using I² statistics, and a random-effects model was used to summarize data. Hedges g was used as an estimator of effect size in group comparisons. Results are reported according to PRISMA guidelines. Results: Thirty-five studies (29 DAT, 6 AADC, no vesicular monoamine type 2 studies) with 356 MSA-P patients, 204 PSP patients, 79 CBS patients, and 62 MSA-C patients were included in the metaanalysis. Caudate nucleus and putamen DAT function was clearly lower in PSP than in PD (caudate: 34.1% difference, g = −1.08, 95% confidence interval [CI] = −1.52 to −0.64; putamen: 18.2%, g = −0.86, 95% CI = −1.50 to −0.21) and MSA-P (striatum: 31.4%, g = −0.70, 95% CI = −1.21 to −0.19) and was clearly lower in MSA-P than in MSA-C (striatum: 46.0%, g = 1.46, 95% CI = 0.23 to 2.68). Although not significant because of limited data, aromatic l-AADC results paralleled the DAT findings. Conclusion: Striatal presynaptic DAT function is clearly lower in PSP patients than in PD and MSA-P patients and is clearly lower in MSA-P patients than in MSA-C patients.

多系统萎缩症（MSA），进行性核上性麻痹（PSP）和肾上腺皮质综合征（CBS）的症状和体征与帕金森病（PD）的症状和体征重叠，从而使其临床诊断复杂化。尽管临床上广泛使用PET和SPECT进行突触前多巴胺能脑成像在怀疑PD的患者中使用，但功能性成像在非典型帕金森综合征中的优势仍不清楚。我们使用来自所有已发表研究的定量数据，比较了纹状体突触前多巴胺能在MSA帕金森病变异（MSA-P），MSA小脑变异（MSA-C），PSP，CBS和PD中的作用。方法：从开始到2018年8月，在PubMed数据库中搜索了术语“多巴胺”或“多巴胺能”和“ PET”或“ SPECT”或“ SPET”，以及与PD，MSA，PSP和CBS相关的关键字。总共确定了1,711种出版物。PET或SPECT研究将非典型帕金森病患者与另一个诊断组（PD，MSA，PSP或CBS）进行了比较。研究了用于多巴胺转运蛋白（DAT），芳香族氨基酸脱羧酶（AADC）或2型囊泡单胺的示踪剂。示踪剂结合数据是从原始文章中提取的。使用I ²统计检查数据的异质性，并使用随机效应模型汇总数据。对冲g在小组比较中被用作效应大小的估计量。根据PRISMA指南报告结果。结果：荟萃分析纳入了356例MSA-P患者，204例PSP患者，79例CBS患者和62例MSA-C患者的35项研究（29项DAT，6项AADC，无2型囊泡单胺研究）。PSP的尾状核和壳状蛋白DAT功能明显低于PD（尾状：相差34.1％，g = -1.08，95％置信区间[CI] = -1.52至-0.64；壳状核：18.2％，g = -0.86， 95％CI = -1.50至-0.21）和MSA-P（纹状体：31.4％，g = -0.70，95％CI = -1.21至-0.19），并且在MSA-P中明显低于MSA-C（纹状体） ：46.0​​％，克= 1.46，95％CI = 0.23至2.68）。尽管由于有限的数据而并不重要，但是芳族1- AADC的结果与DAT的发现相似。结论： PSP患者纹状体突触前DAT功能明显低于PD和MSA-P患者，MSA-P患者明显低于MSA-C患者。