Radiology Picture of the Day

This patient presented with progressive dementia, ataxia and incontinence. A clinical diagnosis of normal pressure hydrocephalus was entertained. Imaging did not support this, however, and on formal testing abnormal nystagmus and eye movements were detected. A sagittal T1-weighted image shows atrophy of the midbrain, with preservation of the volume of the pons. This appearance has been called the “penguin sign” (click image). There is also atrophy of the tectum, particularly the superior colliculi. These findings suggest the diagnosis of progressive supranuclear palsy.

In Parkinson’s disease there is typically preservation of midbrain and pontine volume. In multiple system atrophy there is typically atrophy of the pons with relative preservation of the midbrain.

Other imaging findings in PSP are elevated apparent diffusion coefficient in the putamen, globus pallidus and caudate nucleus. There may be iron deposition in the putamen, giving low signal on T2W imaging.

References:
1. Oba H et al. New and reliable MRI diagnosis for progressive supranuclear palsy. Neurology 2005; 64(12): 2050-5
2. www.STATdx.com, Amirsys 2007

• February 23rd, 2007
• Brain
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