Usefulness of proton magnetic resonance spectroscopy in differentiating parkinsonian syndromes

Proton magnetic resonance spectroscopy ((1)H-MRS) was performed in patients with a clinical diagnosis of idiopathic Parkinson's disease (IPD), multiple system atrophy (MSA) or progressive supranuclear palsy (PSP) in order to assess metabolic differences between the three groups of patients. Single-volume (1)H-MRS, localized to the lentiform nucleus, was carried out in 19 IPD patients, 14 MSA patients, 11 PSP patients and 12 age-matched healthy subjects. The signals of N-acetylaspartate (NAA), choline-containing compounds (Cho) and creatine-phosphocreatine (Cr) were evaluated as peak area ratios. The NAA/Cho peak ratio was significantly reduced in MSA and in PSP patients compared to IPD patients and to controls. The NAA/Cr peak ratio was significantly reduced in MSA, in PSP and in IPD patients compared to controls, but only in MSA compared to IPD patients. The NAA reduction in the basal ganglia of MSA and PSP patients may reflect a neuronal loss or damage. Single-volume (1)H-MRS may be a useful tool in differentiating MSA and PSP from IPD patients.