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Cerebral blood flow SPECT may be helpful in establishing the diagnosis of progressive supranuclear palsy and corticobasal degeneration.

BACKGROUND
We present 4 cases, which illustrate the usefulness of neuroimaging studies in atypical forms of Parkinsonism. Progressive Supranuclear Palsy (PSP) and Corticobasal Degeneration (CBD) are rare neurodegenerative progressive disorders of the central nervous system of unknown cause. The clinical accuracy in this diagnosis is not very high even in centres specialising in movement disorders. Functional imaging can be helpful in diagnosing PSP and CBD.


MATERIAL AND METHODS
We present the results of cerebral blood flow (CBF) SPECT scanning in 2 patients with PSP and 2 patients with CBD. This was performed using a triple-head gammacamera and 99m Tc-HMPAO.


RESULTS
In PSP patients a diffuse frontal perfusion deficit was seen, eventually with striatal and occipital hypoperfusion. CT/MRI was either normal or showed a diffuse cortical-subcortical atrophy. In CBD patients left fronto-parieto-temporal cortex and a striatal hypoperfusion were shown. CT scanning was normal in one case and showed an asymmetrical temporo-parietal atrophy in second one.


CONCLUSIONS
The pattern of diffuse frontal perfusions deficit in PSP and asymmetrical, contralateral to symptoms of CBD, cortico-subcortical hypoperfusion may be helpful in establishing the correct diagnosis.