The challenge
Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease that can resemble Parkinson’s disease, multiple system atrophy, or corticobasal syndrome, particularly at early stages. This overlap makes diagnosis difficult and may delay appropriate counselling, treatment decisions, and inclusion in clinical trials. Several MRI-based markers have been proposed to support PSP diagnosis, but many require complex planimetric measurements, specialized software, or considerable expertise. In everyday hospital practice, such tools are not always available, may fail in noisy images, or are too time-consuming for routine use. A simple, robust, and reproducible MRI marker is therefore needed to help clinicians identify PSP more reliably across different centers and patient groups.
Our approach
We compared established planimetric and linear MRI markers with a new measure called the dual-line midbrain PSP index. The index averages two simple midbrain measurements on midsagittal T1-weighted MRI scans and was tested in large Italian and international cohorts.
Our findings
The study included 2,111 participants with PSP, non-PSP parkinsonism, or no neurodegenerative disease. The new dual-line midbrain PSP index showed excellent diagnostic performance, with AUC values of 0.97 in the Italian cohort and 0.96 in the international validation cohort. It also performed well in early-stage disease and in participants with pathologically confirmed diagnoses. Compared with other MRI markers, it produced fewer uncertain cases and could be measured quickly and reliably.
The implications
This simple MRI marker may help bring more objective PSP classification into routine neuroradiology and improve patient selection for clinical trials.
Creating SyNergies.
This study highlights how clinical neurology, neuroradiology, imaging analysis, and multicenter cohort research can jointly improve diagnosis in complex neurodegenerative diseases. Within the SyNergy network, the work connects expertise represented by Martin Dichgans, Robert Perneczky, Johannes Levin, Josef Priller, Paul Lingor, Jochen Herms, Nicolai Franzmeier, and Günter Höglinger, strengthening translational research from imaging biomarkers to clinical application.
