[MRI in neurodegenerative Parkinsonian syndromes]

Parkinson's disease (PD) and atypical Parkinsonian syndromes (APS), including multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), are increasing worldwide. Early differential diagnosis is challenging due to overlapping symptoms and the often delayed appearance of pathognomonic signs.

Presentation of the role of structural magnetic resonance imaging (MRI) in the differential diagnosis of neurodegenerative Parkinsonian syndromes.

Literature review of current guidelines and studies on T1-weighted and T2-weighted sequences, susceptibility-weighted imaging (SWI), diffusion-weighted imaging, volumetry and multiparametric approaches. The focus was on disease-specific atrophy patterns, quantitative methods and automated analyses.

Structural changes in PD are usually subtle; the nigrosome‑1 (swallowtail) sign on SWI can provide diagnostic clues. The PSP shows pronounced midbrain atrophy, MSA demonstrates putaminal, pontine and cerebellar atrophy and CBD exhibits asymmetric cortical atrophy. Volumetric and multiparametric analyses increase the diagnostic accuracy, especially in early disease stages, although widespread clinical implementation remains limited.

Structural MRI provides early indicators of APS and aids the differential diagnosis. Quantitative and multiparametric methods improve objectivity and sensitivity, particularly for subtle or rare syndromes and could play an increasingly more important role in clinical practice.