The usefulness of SPECT and MRI in the diagnosis of atypical parkinsonian syndromes

Clinico-pathological studies have shown that only three out of four patients with parkinsonism have idiopathic Parkinson's disease. In patients with so-called Parkinson plus syndrome, the degeneration in the brain is more widespread and the variety of neurological signs greater than in Parkinson's disease. The differentiation of these syndromes from Parkinson's disease can be difficult. Single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRl) can be of value in the differential diagnosis of parkinsonism. We present three patients with atypical parkinsonism in whom MRI and SPECT with β-CIT and epidepride was performed in addition to the clinical evaluation. The three patients all had a rapidly developing symmetric akinetic-rigid syndrome that responded poorly to levodopa. MRI showed findings regarded as typical for multiple system atrophy in two patients, but only nonspecific findings in the third patient. SPECT with β-CIT showed a pronounced bilateral and relatively symmetric reduction in the striatal dopaminergic activity in all patients. SPECT with epidepride showed a clearly reduced striatal D2-receptor binding bilaterally in only one of the patients. In patients with atypical parkinsonism, MRI and SPECT with β-CIT and epidepride can give valuable support to the clinical diagnosis of a Parkinson plus syndrome