Dados do Trabalho

Título

Structural MRI Differences Between Parkinson's Disease Motor Subtypes: A Multimodal Imaging Study

Descrição sucinta do(s) objetivo(s)

Parkinson's disease (PD) is a neurodegenerative disorder marked by dopaminergic neuron loss in the substantia nigra pars compacta, leading to diverse motor and neuropsychological symptoms. The motor subtypes, tremor-dominant (TD) and postural instability-gait disorder (PIGD), exhibit distinct clinical features. This study utilizes advanced neuroimaging techniques to explore variations among PD motor subtypes, including subcortical brain volumes, iron deposition patterns via Quantitative Susceptibility Mapping (QSM), and white matter microstructural changes using diffusion-weighted imaging.

Material(is) e método(s)

A cross-sectional study at the XXXX investigated PD motor subtypes using advanced neuroimaging. Ethical approval was secured, with recruitment commencing in 2019, briefly paused in 2020 due to COVID-19, and concluded in August 2021. Assessments, under 'on' levodopa conditions, encompassed motor evaluations, cognitive assessments, and subtype categorization. A 3T Philips Achieva MRI scanner captured T1-weighted, diffusion-weighted, and GRE multiecho sequences. Data underwent extensive processing, including FreeSurfer for cortical thickness and deep gray matter volume, TractoFlow and TractSeg for diffusion-weighted MRI, and QSM for brain iron content.

Resultados e discussão

Forty-six PD patients, including 23 PD-TD and 23 PD-PIGD, and 13 healthy controls were enrolled. Thalamic volume reduction was observed in both the TD subtype (p=0.043) and the PIGD subtype (p=0.050) compared to the control group. Additionally, increased susceptibility values in the substantia nigra were found in the TD group (p=0.011) compared to controls. No significant differences in subcortical structures or susceptibility values were identified between PD-TD and PD-PIGD. Positive correlations were noted between thalamic susceptibility values and MDS-UPDRS-3 scores, while negative correlations were observed between cerebellar cortex volume and MDS-UPDRS-3 scores. Tremor scores showed a positive association with iron deposition in the right substantia nigra. Fractional anisotropy differences in white matter tracts were identified between the PD-TD and PD-PIGD groups.

Conclusões

Our study employing advanced neuroimaging techniques elucidates structural disparities in PD motor subtypes. Both PD-TD and PD-PIGD groups exhibit thalamic volume reduction and substantia nigra susceptibility variations. Correlations with clinical scores highlight the relevance of these findings. Additionally, identified white matter tract differences contribute to understanding PD heterogeneity. This comprehensive approach enhances our grasp of the intricate neurodegenerative processes characterizing distinct PD motor subtypes.

Palavras Chave

Parkinson Disease; Brain; Magnetic Resonance Imaging

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