Atypical Parkinsonian Syndromes: Structural, Functional, and Molecular Imaging Features

Area of Science:

• Neurology
• Neuroimaging
• Movement Disorders

Background:

• Atypical parkinsonian syndromes, or Parkinson-plus syndromes, encompass dementia with Lewy bodies (DLB), progressive supranuclear palsy (PSP), multisystem atrophy (MSA), and corticobasal degeneration (CBD).
• These disorders present heterogeneous clinical and pathological features, posing diagnostic challenges.

Purpose of the Study:

• To review the characteristic structural, functional, and molecular imaging findings in DLB, PSP, MSA, and CBD.
• To highlight the utility of advanced neuroimaging techniques in the diagnosis and differentiation of these conditions.

Main Methods:

• Review of structural MRI, FDG-PET, tau-PET, and dopaminergic imaging (DaTscan, FDOPA-PET).
• Analysis of characteristic imaging patterns for each atypical parkinsonian syndrome.

Main Results:

• DLB: Parieto-occipital hypometabolism (FDG-PET).
• PSP: Midbrain atrophy (structural), frontal hypometabolism (FDG-PET), tauopathy (tau-PET).
• MSA: Putaminal/cerebellar atrophy (structural), nigrostriatal/olivopontocerebellar hypometabolism (FDG-PET).
• CBD: Asymmetric atrophy (structural), asymmetric hemispheric involvement (FDG/tau-PET).

Conclusions:

• Neuroimaging plays a crucial role in diagnosing and differentiating atypical parkinsonian syndromes.
• Advanced modalities like FDG-PET, tau-PET, and dopaminergic imaging offer valuable insights beyond structural changes.
• Emerging techniques show promise for future diagnostic advancements.