Planimetric and Linear MRI Markers for Progressive Supranuclear Palsy Classification: A Large Multicohort...

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• Differentiating progressive supranuclear palsy (PSP) from Parkinson disease and other parkinsonisms is clinically challenging.
• Previous MRI studies often used small sample sizes, limiting the reliability of findings.
• Objective MRI measures are needed for accurate diagnosis and patient management.

Purpose of the Study:

• To compare the diagnostic performance of existing planimetric and linear MRI measurements for differentiating PSP.
• To identify an optimized linear MRI marker for improved PSP diagnosis.
• To validate the new marker in independent cohorts and pathologically confirmed cases.

Main Methods:

• A secondary analysis of international prospective studies including participants with PSP, non-PSP parkinsonisms, and controls.
• Comparison of established MRI markers (midbrain line, midbrain area, pons to midbrain area ratio, MR parkinsonism index) with a novel marker, the dual-line midbrain PSP index (DMPI).
• Logistic regression models incorporating DMPI, age, and sex were used for differentiation in large independent and pathologically confirmed cohorts.

Main Results:

• The DMPI and midbrain area demonstrated high accuracy in differentiating PSP from non-PSP parkinsonisms (AUCs of 0.97 and 0.95, respectively).
• The DMPI exhibited the lowest percentage of uncertain cases (7.97%), indicating superior diagnostic clarity.
• Excellent performance was consistent across large independent cohorts, early-stage disease, and pathologically confirmed cases.

Conclusions:

• The dual-line midbrain PSP index (DMPI) and midbrain area are effective MRI markers for distinguishing PSP from other neurodegenerative parkinsonisms.
• The DMPI offers a reliable and accurate tool for clinical diagnosis, potentially improving patient outcomes.
• Further validation and clinical implementation of the DMPI are warranted for routine diagnostic use.