Midbrain-to-pons ratio in autopsy-confirmed progressive supranuclear palsy: replication in an independent cohort

Area of Science:

• Neurology
• Radiology
• Pathology

Background:

• Clinical data suggest the midbrain-to-pons ratio from MRI is a sensitive and specific diagnostic marker for progressive supranuclear palsy (PSP).
• Replication of these findings is crucial in independent cohorts to validate diagnostic utility.

Purpose of the Study:

• To validate the diagnostic accuracy of the midbrain-to-pons ratio in an independent, autopsy-confirmed cohort for progressive supranuclear palsy (PSP).
• To assess the specificity and sensitivity of this ratio in distinguishing PSP from non-PSP conditions.

Main Methods:

• Retrospective analysis of conventional brain MRI scans from 6 autopsy-confirmed PSP patients and 23 non-PSP patients.
• Calculation of the midbrain-to-pons ratio for all participants.
• Statistical comparison of ratios between PSP and non-PSP groups.

Main Results:

• Patients with confirmed PSP exhibited significantly lower midbrain-to-pons ratios compared to non-PSP patients (p < 0.0001).
• A ratio below 0.50 was observed in all but one PSP patient, while all non-PSP patients had ratios above 0.50.
• The ratio demonstrated a 100% positive predictive value and 95.8% negative predictive value for PSP diagnosis.

Conclusions:

• The midbrain-to-pons ratio is a reliable and clinically useful imaging biomarker for assessing midbrain atrophy in progressive supranuclear palsy (PSP).
• This MRI-based ratio provides a valuable, non-invasive tool for the diagnosis of PSP, supported by autopsy confirmation.