[I-123]beta-CIT SPECT in multiple system atrophy, progressive supranuclearpalsy, and corticobasal degeneration

Differentiation between Parkinson's disease (PD) and other neurodegenerativ e disorders with parkinsonian features, such as multiple system atrophy (MS A), progressive supranuclear palsy (PSP), and corticobasal degeneration (CB D), is difficult on clinical,grounds. We studied the pattern of dopaminergi c degeneration in 18 patients with probable MSA, 8 patients with PSP, 4 pat ients with CBD, 48 patients with PD and a similar degree of disability, and 14 control subjects per forming single photon emission computed tomography (SPECT) 20 hours after injection of [I-123]beta -CIT. Overall striatal bin ding was significantly reduced in MSA (-51% of normal mean), PSP (-60%), CB D (-35%), and PD (-58%), without overlap with control values. Asymmetry of striatal beta -CIT binding was significantly increased in patients with CBD and PD, as compared with control subjects. Although asymmetry seemed to be less pronounced in MSA and PSP than in PD, this was not statistically sign ificant. Putamen-caudate nucleus ratios in patients with PD, MSA, and PSP, but not with CBD, were significantly reduced, as compared with control subj ects. In conclusion, [I-123]beta -CIT SPECT reliably enables the visualizat ion of the presynaptic dopaminegic lesion in patients with MSA, PSP, and CB D. In most patients, however, it does nor seem to be possible to differenti ate these disorders from PD with this method.