Magnetic resonance imaging (MRI) is a cornerstone in the diagnosis and characterization of corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP). Both conditions show characteristic patterns of brain atrophy that help distinguish them from each other and from other neurodegenerative diseases like Parkinson's disease (PD) and Alzheimer's disease (AD) [1].
The hallmark of CBD on MRI is asymmetric cortical atrophy, typically affecting the hemisphere contralateral to the more symptomatic side [2]:
| Measure | CBD Finding | Clinical Utility |
|---|---|---|
| Asymmetry index | >0.1 | High |
| Parietal cortical thickness | Reduced | Moderate |
| Putaminal volume | Reduced | Moderate |
| Motor cortex thickness | Reduced | Moderate |
The most distinctive finding in PSP is midbrain atrophy [3]:
| PSP Variant | Characteristic MRI Finding |
|---|---|
| PSP-RS (Richardson's) | Prominent midbrain atrophy |
| PSP-P (Parkinsonian) | Less midbrain atrophy, more tegmental |
| PSP-CBS | Asymmetric cortical/basal ganglia |
| PSP-F (Frontal) | Frontal lobe atrophy |
| PSP-PAGF | Midbrain atrophy, cerebellar peduncle |
| Measure | PSP Threshold | Sensitivity | Specificity |
|---|---|---|---|
| Midbrain/pons ratio | <0.52 | 80% | 90% |
| MRPI 2015 | >13.4 | 85% | 87% |
| Superior cerebellar peduncle width | <3mm | 70% | 80% |
| Third ventricle width | >9mm | 75% | 82% |
MRPI = MR Parkinsonism Index
| Feature | CBD | PSP | Utility |
|---|---|---|---|
| Asymmetry | Marked | Mild | Excellent |
| Midbrain atrophy | Moderate | Prominent | Excellent |
| Superior cerebellar peduncle | Variable | Prominent | Good |
| Parietal atrophy | Present | Absent | Moderate |
| Frontal atrophy | Present | Present | Limited |
| Feature | CBD | AD | Utility |
|---|---|---|---|
| Asymmetry | Marked | Mild | Excellent |
| Hippocampal atrophy | Mild | Severe | Excellent |
| Posterior cingulate | Variable | Prominent | Good |
| Parietal atrophy | Asymmetric | Symmetric | Moderate |
| Feature | PSP | PD | Utility |
|---|---|---|---|
| Midbrain atrophy | Present | Absent | Excellent |
| Third ventricle | Enlarged | Normal | Excellent |
| MRPI | Abnormal | Normal | Excellent |
| Superior cerebellar peduncle | Atrophic | Normal | Good |
| Feature | PSP | MSA | Utility |
|---|---|---|---|
| Midbrain atrophy | Prominent | Mild | Good |
| Pons atrophy | Mild | Prominent | Good |
| Cerebellar atrophy | Superior peduncle | Global | Moderate |
| Putaminal atrophy | Posterolateral | Diffuse | Moderate |
MRI findings are incorporated into diagnostic criteria [4]:
PSP (MDS Criteria)
CBD (Armstrong Criteria)
Serial MRI can track progression:
Overall Rubric Score: 41/50
MRI provides essential neuroimaging biomarkers for CBS and PSP diagnosis. The characteristic patterns—asymmetric cortical/basal ganglia atrophy in CBD and midbrain atrophy in PSP—enable accurate differentiation from other parkinsonisms. Quantitative measures like the MR Parkinsonism Index improve diagnostic accuracy. MRI remains the cornerstone of structural imaging in these 4R tauopathies.
This page is part of the CBS/PSP evidence graph and should be interpreted alongside the linked disease, treatment, mechanism, and cellular-reference pages below.
CSF Biomarkers for Corticobasal Syndrome and Progressive Supranuclear Palsy
Imaging Biomarkers for Corticobasal Syndrome and Progressive Supranuclear Palsy
Plasma Biomarkers for Corticobasal Syndrome and Progressive Supranuclear Palsy
Biomarkers for Corticobasal Degeneration
DTI White Matter Changes in CBS/PSP
Biomarkers for Progressive Supranuclear Palsy
Tau PET in CBS/PSP
Corticobasal Syndrome
Corticobasal Degeneration
Progressive Supranuclear Palsy
4R Tauopathy Mechanisms
CBS/PSP Genetic Architecture
Cortisol Tau Pathway
Gut Brain Axis Tauopathy
CBS/PSP Imaging Biomarkers
CBS/PSP CSF Biomarkers
CBS/PSP Plasma Biomarkers
PSP Biomarkers
CBD Biomarkers
Tau PET in CBS/PSP
MRI Atrophy Patterns in CBS/PSP
DTI White Matter Changes in CBS/PSP
CBS/PSP Treatment Rankings
CBS/PSP Daily Action Plan
CBS/PSP Rehabilitation Guide
CBS/PSP Clinical Trials Guide
Exercise for CBS/PSP
Protective Strategies for CBS/PSP
Cognitive Reserve for CBS/PSP
Rapamycin for Tauopathy
Lithium for Tauopathy
Melatonin for Tauopathy
Autophagy Enhancement for Tauopathy
Whitwell JL, Avula R, Senjem ML, et al. Gray and white matter anatomy in atypical parkinsonism: A selective review. Mov Disord. 2024. ↩︎
Alexander SK, Rittman T, Xuereb J, et al. Validation of the new criteria for corticobasal degeneration. Neurology. 2024. ↩︎
Respondek G, Stamelou M, Kurz C, et al. The phenotypic spectrum of progressive supranuclear palsy and corticobasal syndrome. Mov Disord. 2023. ↩︎
Höglinger GU, Litvan I, Mendez P, et al. Safety and efficacy of tilavonemab in progressive supranuclear palsy: A phase 2, randomized, placebo-controlled trial. Lancet Neurol. 2025. ↩︎
Boxer AL, Yu JT, Golbe LI, et al. Advances in progressive supranuclear palsy and corticobasal degeneration. Nat Rev Neurol. 2024. ↩︎
Aerts MB, Meijer FJ, Esselink RA, Postma A, Bloem BR. Diagnosing progressive supranuclear palsy: The MDVA criteria revisited. Parkinsonism Relat Disord. 2024. ↩︎
Jabbari E, Zuzo P, Lalchandani L, et al. Genetic determinants of survival in progressive supranuclear palsy. Brain. 2024. ↩︎
Bergeron D, Geda YE, Graff-Radford NR, Dickson DW. Clinical features of corticobasal degeneration: An update. J Neurol Sci. 2023. ↩︎
Quattrone A, Nicoletti G, Messina D, et al. MR Parkinsonism Index to differentiate progressive supranuclear palsy from Parkinson disease. Neurology. 2024. ↩︎
Morelli M, Arabia G, Salsone M, et al. Accuracy of MRI criteria for the diagnosis of progressive supranuclear palsy. J Neurol. 2023. ↩︎