Objective: To investigate the associations of subregional striatal dopaminergic deficits with regional cerebral blood flow (CBF) and cognitive impairment in patients with Parkinson’s disease (PD).

Background: Dopaminergic degeneration is the key pathological feature of PD and has been implicated in both motor and cognitive dysfunction. While dopaminergic deficits may contribute to cognitive impairment, the neural mechanisms remain incompletely understood. Reduced regional cerebral blood flow (CBF) may be involved in this process.

Method: Pseudo-continuous arterial spin labelling (pCASL) MRI was performed to generate quantitative CBF maps. Dopamine transporter (DAT) availability was assessed using 11C-CFT PET imaging to reflect dopaminergic deficits. CBF maps and PET images were normalized into standard space. The DAT standardized uptake value ratios (SUVRs) of caudate nucleus (CAU_DAT), anterior putamen (aPUT_DAT), and posterior putamen (pPUT_DAT) were calculated using the occipital cortex as the reference region. Cognitive assessment included orientation, attention, language, visuospatial ability, and delayed recall. Total intracranial volume (TIV) was also calculated. Voxel-wise regressions were performed between normalized CBF maps and CAU_DAT, aPUT_DAT, pPUT_DAT, respectively, adjusting for age and sex.

Results: A total of 72 eligible patients with PD were analyzed. After adjusting for age, sex, educational level, and TIV, the CAU_DAT was negatively correlated with attention but positively correlated with language and delayed recall (all p<0.05). The aPUT_DAT only positively correlated with language performance, whereas no significant associations were observed between aPUT_DAT or pPUT_DAT and other cognitive domains. Voxel-wise regression analysis revealed that CAU_DAT was associated with widespread reduced CBF across frontal, temporal and occipital lobes.

Conclusion: Dopaminergic deficits in the caudate nucleus play an important role in cognitive impairment in PD, potentially involving widespread cerebral hypoperfusion.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/subregional-striatal-dopaminergic-deficits-cerebral-hypoperfusion-and-cognitive-impairment-in-parkinsons-disease/