Progressive Supranuclear Palsy (PSP)


KEY FACTS

Terminology

  • Neurodegenerative disease characterized by supranuclear palsy, postural instability, mild dementia

Imaging

  • Midbrain atrophy (penguin or hummingbird sign)

    • Sagittal T1WI shows concave/flat upper border of midbrain (normally convex)

    • Axial T1WIs show abnormal concavity of lateral margins of midbrain tegmentum (morning glory or Mickey Mouse sign)

    • Thinning of superior colliculus

  • Midsagittal 3D-MP-RAGE or FS-PGR images

    • Voxel-based morphometry used to calculate ratio of midbrain to pons area

    • Midbrain area < 70 mm² (50% of normal)

    • Midbrain to pons ratio < 0.15 strongly suggests PSP

    • MR Parkinsonism index: Allows discrimination of PSP from MSA-P, Parkinson disease, and control

Top Differential Diagnoses

  • Multiple system atrophy, Parkinsonian type; corticobasal degeneration; dementia with Lewy bodies; Parkinson disease

Pathology

  • Neurofibrillary tangles and neuropil threads in globus pallidus, subthalamic nucleus, substantia nigra; cerebral cortex relatively preserved except for perirolandic cortex; neuronal loss, gliosis

Clinical Issues

  • PSP-RS (Richardson syndrome)

  • Lurching gait, axial dystonia, vertical supranuclear palsy

  • PSP-P (Parkinsonian type)

  • Bradykinesia, rigidity, normal eye movements

  • 2nd most common neurodegenerative cause of Parkinsonism overall

Sagittal T1WI MR in a patient with bradykinesia and suspected Parkinson disease shows the classic penguin or hummingbird sign of progressive supranuclear palsy (PSP). Note thinning of the midbrain
with atrophy of the tectum
, also consistent with PSP. In contrast to the strikingly abnormal midbrain findings, here the pons appears normal.

Axial T2WI MR in the same patient shows volume loss of the midbrain with thinned tectum
and concave lateral midbrain margins
.

Axial T2* GRE MR in the same patient shows no evidence for abnormal iron accumulation in the midbrain, which helps to distinguish PSP from Parkinson disease.

Axial T2* GRE MR shows no evidence for abnormal iron accumulation in the striatum, another location in which iron is commonly found in Parkinson disease.

TERMINOLOGY

Abbreviations

  • Progressive supranuclear palsy (PSP)

Synonyms

  • Steele-Richardson-Olszewski syndrome

Definitions

  • Neurodegenerative disease characterized by supranuclear palsy, Parkinsonism, postural instability, pseudobulbar syndrome, & dementia

IMAGING

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