AUTHOR=Zhang Junjiao , Jin Jianing , Su Dongning , Feng Tao , Zhao Huiqing 

TITLE=Tau-PET imaging in Parkinson's disease: a systematic review and meta-analysis

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1145939

DOI=10.3389/fneur.2023.1145939

ISSN=1664-2295

ABSTRACT=Background: Pathological tau accumulates in the cerebral cortex of Parkinson's disease (PD), resulting in cognitive deterioration. Positron emission tomography (PET) can be used for in vivo imaging of tau protein. Therefore, we conducted a systematic review and meta-analysis of tau protein burden in PD cognitive impairment (PDCI), PD dementia (PDD) as well as other neurodegenerative diseases, and to explored the potential of tau PET tracer as a biomarker for the diagnosis of PDCI.
Methods: PubMed, Embase, the Cochrane Library, and Web of Science databases were systematically searched for studies published up to June 1,2022, which used PET imaging to detect tau burden in the brains of PD patients. Standardized mean differences (SMDs) of tau tracer uptake were calculated using random effects models. Subgroup analysis based on type of tau tracers, meta-regression and sensitivity analysis were conducted.
Results: Fifteen eligible studies were included in the meta-analysis. PDCI patients (n=109) had a significantly higher tau tracer uptake in the inferior temporal lobe than healthy controls (HCs) (n=237), and had a higher tau tracer uptake in the entorhinal region than PD with normal cognition (PDNC) patients (n=61). Compared with progressive supranuclear palsy (PSP) patients (n=215), PD patients (n=178) had decreased tau tracer uptake in the midbrain, subthalamic nucleus, globus pallidus, cerebellar deep white matter, thalamus, striatum, substantia nigra, dentate nucleus, red nucleus, putamen, and frontal lobe. Tau tracer uptake values of PD patients (n=178) were lower than that of patients with Alzheimer's disease (AD) (n=122) in frontal lobe and occipital lobe, and lower than that in patients with dementia with Lewy bodies (DLB) (n=55) in occipital lobe and infratemporal lobe.
Conclusion: In vivo imaging studies with PET could reveal region-specific binding pattern of tau tracer in PD patients and help in the differential diagnosis of PD from other neurodegenerative diseases.