Distinctive regional asymmetry in dopaminergic and serotoninergic dysfunction in degenerative Parkinsonisms

Abstract

PurposeThis 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 methodsThis 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. ResultsCompared 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. ConclusionThe 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.