Manual MRI morphometry in Parkinsonian syndromes

Area of Science:

• Neuroimaging
• Radiology
• Neurology

Background:

• Differential diagnosis of parkinsonism can be challenging.
• Morphometric magnetic resonance imaging (MRI) parameters offer potential diagnostic value.
• Identifying the most effective MRI parameters for routine clinical use is crucial.

Purpose of the Study:

• To evaluate and compare the diagnostic performance of various morphometric MRI parameters in differentiating parkinsonism subtypes.
• To determine which MRI metrics are most reliable for clinical routine diagnosis of Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA).

Main Methods:

• Multicentric magnetization-prepared rapid gradient echo MRI sequences were acquired.
• Patients included: PD (n=204), PSP (n=106), MSA-cerebellar (n=21), MSA-parkinsonian (n=60), and healthy controls (n=73).
• Manual planimetric measurements of midbrain and pons areas were performed, with receiver operator characteristics and leave-one-out cross-validation used to determine cutoff values.

Main Results:

• Reduced midsagittal midbrain area was characteristic of PSP compared to all other groups (P < 0.001).
• Reduced midsagittal pons area was observed in MSA-cerebellar, MSA-parkinsonian, and PSP compared to PD and controls (P < 0.001).
• The midbrain/pons area ratio was lower in PSP and higher in MSA subtypes versus PD and PSP (P < 0.001).

Conclusions:

• The midsagittal midbrain area is a reliable indicator for differentiating PSP.
• The midsagittal pons area effectively aids in the diagnosis of MSA-cerebellar.
• The midbrain/pons area ratio demonstrated superior differentiation of MSA-cerebellar and PSP compared to the magnetic resonance-Parkinson index.