Distinctive regional asymmetry in dopaminergic and serotoninergic dysfunction in degenerative Parkinsonisms

Abstract

Purpose: This study aimed to identify regional asymmetry in dopaminergic and serotoninergic dysfunction in degenerative parkinsonisms, using dopamine transporter single-photon emission computed tomography images.

Material and methods: This study included 213 consecutive participants (Parkinson's disease [n = 111], dementia with Lewy bodies [n = 64], progressive supranuclear palsy with Richardson's syndrome [n = 18], and healthy participants [n = 20]) who underwent both magnetic resonance imaging and ¹²³I-labelled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane single-photon emission computed tomography/computed tomography. Using normalized specific binding ratio images, we created voxel-wise regional asymmetry index images to identify the regional specific pattern of regional asymmetries in degenerative parkinsonisms.

Results: Compared with healthy controls, patients with Parkinson's disease showed a regional asymmetry index increase in the nigrostriatal dopaminergic pathway, and those with dementia with Lewy bodies showed a regional asymmetry index increase confined to the bilateral caudate. Individuals with progressive supranuclear palsy exhibited a distinct regional asymmetry index increase in the pallido-subthalamic pathway. Notably, the regional asymmetry index increase in the subthalamic nucleus was significantly greater in progressive supranuclear palsy than in Parkinson's disease.

Conclusion: The current study revealed distinctive regional asymmetry in dopaminergic and serotoninergic dysfunction in degenerative parkinsonisms. The present findings highlight the potential application of visual diagnosis in degenerative parkinsonisms.

Keywords: 123I-labelled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane; Asymmetry index; Dopamine transporter; Parkinsonism; Progressive supranuclear palsy; Voxel.