Magnetresonanztomographie bei Parkinson-Syndromen

Abstract

The clinical distinction of Parkinson's disease (PD) from other disorders with parkinsonian features is often difficult. Routine magnetic resonance imaging of the brain (MRI) is typically normal in patients with PD. However, it can be helpful in supporting a diagnosis of atypical parkinsonian disorders and excluding non-parkinsonian disorders that can mimic parkinsonism, such as vascular parkinsonism or hydrocephalus. MRI in atypical parkinsonian syndromes, such as multiple-system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) can reveal characteristic features that cannot only differentiate these syndromes from PD, but also help to differentiate between these atypical disorders. These features include a hyperintense rim at the lateral putaminal edge and infra-tentorial signal change and atrophy in MSA, marked atrophy and hyperintensity of the midbrain on T2-weighted images in PSP, and asymmetrical parieto-frontal atrophy in CBD. Although these findings are very specific, they are present in only a proportion of patients with these diseases. MRI-spectroscopy (1H-MRS) of the lentiform nucleus is similarly normal in patients with PD, but can show a reduced ratio of N-acetyl-aspartate (NAA) to creatine-phosphocreatine (Cre) or choline (Cho) concentration in atypical parkinsonian disorders. The pattern of reduction of NAA/Cre or NAA/Cho in other areas of the brain may also help to differentiate between atypical parkinsonian syndromes. Routine-MRI and MRI-spectroscopy are useful tools to improve clinical diagnosis of parkinsonian syndromes.