Quantitative 1H magnetic resonance spectroscopy and MRI of Parkinson's disease

Magnetic resonance imaging (MRI) and (1)H magnetic resonance spectroscopy (MRS) of the substantia nigra, basal ganglia, and cerebral cortex were performed on 10 patients with Parkinson's disease (PD) and 13 age-matched, healthy control subjects. Compared to controls, PD patients had approximately 24% lower creatine in the region of the substantia nigra and smaller volumes of the putamen (11%), globus pallidus (16%), and prefrontal cortex (6%; all P < 0.05). No other significant between-group differences were found in nine regions examined. Thus, quantitative MRI may show regional neurodegenerative changes outside the substantia nigra in PD but PD-linked extranigral metabolic abnormalities, if they exist, may be difficult to detect with current (1)H MRS methods. In additional, exploratory tests, volumes of the caudate (r = -0.56), putamen (r = -0.66), and globus pallidus (r = -0.60; all P < 0.05) were negatively correlated with the volume of the substantia nigra pars compacta in controls. In PD these correlations did not hold. Instead, pallidal volume in PD was positively correlated with compacta volume (r = 0.64; P < 0.05). This relationship suggests that basal ganglia volumes may be influenced by dopaminergic innervation from the substantia nigra in normal and PD subjects.