Feindel Brain and Mind Seminar Series: Contribution of MRI to the understanding and diagnosis of Parkinsonism
La série Feindel Brain and Mind Seminar s’inscrit dans la ligne de pensée du Dr William Feindel (1918-2014), directeur du Neuro de 1972 à 1984, qui consiste à maintenir un lien constant entre pratique clinique et recherche. Les présentations porteront sur les dernières avancées et découvertes en neuropsychologie, en neurosciences cognitives et en neuro-imagerie.
Les scientifiques du Neuro, ainsi que des collègues et collaborateurs venus du milieu ou du monde entier, se chargeront des conférences. Cette série se veut un forum virtuel pour les chercheurs et les stagiaires en vue de favoriser les échanges interdisciplinaires sur les mécanismes des troubles cérébraux et cognitifs, leur diagnostic et leur traitement.
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Lydia Chougar
Post-doctoral fellow, The Neuro, McGill University
Hôte:
Abstract:
Parkinson’s disease, the second most common neurodegenerative disease after Alzheimer’s disease, is the main cause of Parkinsonism, which is defined by a combination of resting tremor, rigidity, bradykinesia, and postural instability. Atypical Parkinsonism refers to other rare neurodegenerative disorders characterized by a poorer diagnosis, including progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration. Degeneration of the substantia nigra pars compacta is the pathological hallmark of neurodegenerative Parkinsonian disorders. These diseases present significant challenges in terms of early diagnosis, differentiation, and understanding of pathophysiology.
Neuroimaging has profoundly changed the landscape of research and clinical management of Parkinsonism over the past twenty-five years. Magnetic resonance imaging (MRI) provides several in vivo quantitative biomarkers sensitive to different tissue properties that inform about the underlying pathological processes. Regional brain atrophy, detected using T1-weighted three-dimensional (3D) sequences, reflects neuronal loss. Diffusion anomalies indicate the presence of microstructural alterations in the tissues related to neuroinflammation, while iron-sensitive imaging detects iron deposits. Neuromelanin-sensitive MRI serves as a proxy for the degeneration of the substantia nigra. More recently, positron emission tomography (PET) has specifically allowed for the detection of misfolded protein aggregates, such as Tau and alpha-synuclein, observed in these diseases, giving access to an ante-mortem pathological diagnosis.
In the first part of my talk, I will illustrate how neuroimaging biomarkers contribute to a better understanding of the pathophysiology of Parkinson’s disease and how they can be used to provide an early diagnosis, quantify disease severity and progression, and monitor treatment effects. The second part will highlight the contribution of neuroimaging to the differential diagnosis of Parkinsonian disorders, with a focus on the recent applications of machine learning algorithms trained with MRI features.