Midbrain MRI assessments in progressive supranuclear palsy subtypes

Area of Science:

• Neurology
• Radiology
• Neuroimaging

Background:

• Progressive Supranuclear Palsy (PSP) is a rare neurodegenerative disease with distinct clinical subtypes.
• Accurate differentiation of PSP subtypes is crucial for appropriate patient management and research.
• Midbrain morphometry via MRI is explored as a potential tool for diagnosing PSP and its subtypes.

Purpose of the Study:

• To evaluate midbrain-based MRI morphometric assessments for differentiating PSP subtypes (PSP-RS, PSP-P, vPSP).
• To assess the diagnostic utility of these MRI measures in distinguishing PSP subtypes from Parkinson's Disease (PD) and healthy controls (HC).

Main Methods:

• Analysis included 78 PSP patients (38 PSP-RS, 21 PSP-P, 19 vPSP), 35 PD patients, and 38 HC.
• Midbrain-based MRI morphometric assessments, including MR Parkinsonism Index (MRPI) and pons-to-midbrain area ratio (P/M), were calculated.

Main Results:

• Current MRI midbrain assessments show insufficient sensitivity and specificity for differentiating PSP subtypes.
• MRPI and P/M ratio demonstrated diagnostic value for PSP-RS against PD and HC, but not for PSP-P.
• These measures showed acceptable accuracy for vPSP versus HC, but not versus PD.

Conclusions:

• Available midbrain MRI morphometric assessments currently lack diagnostic value for differentiating Movement Disorder Society PSP subtypes.
• MRPI and P/M ratio show potential in supporting the clinical diagnosis of PSP-RS.
• Further research is needed to identify reliable neuroimaging biomarkers for PSP subtype classification.