Iron content of the basal ganglia was investigated in 25 patients with idiopathic Parkinson's disease and 14 matched healthy control subjects using a partially refocused interleaved multiple echo sequence on a 1.5 Tesla MRI system. R(2)* (1/T(2)*) and R(2)' (1/T(2)') relaxation rates were higher in the substantia nigra of patients with Parkinson's disease, which indicates that iron content is elevated in this region. R(2)' was lower in the putamen, indicating reduced iron levels; reduction in this region was positively correlated with disease duration. Iron-related oxidative stress may contribute to the neurodegeneration of Parkinson's disease, which may lead to alterations in the iron levels of the striatum. We describe a simple, non-invasive technique for measuring iron content.

Background-Hallucinosis is a complication of the treatment of idiopathic Parkinson's disease commonly thought to aZict older, chronically medicated, cognitively impaired patients. However, patients with idiopathic Parkinson's disease of short durationexperiencinghallucinosisonrelatively low doses of dopaminergic medication have been found. The aim, therefore, was to investigate the homogeneity of a population of patients with idiopathic Parkinson's disease and hallucinosis. Methods-The clinical, demographic, and cognitive correlates of hallucinosis were investigated in a sample of 129 patients with idiopathic Parkinson's disease. Results-There were two subgroups of patients with idiopathic Parkinson's disease experiencing hallucinosis. In patients with a disease duration of five years or less, hallucinosis was associated with rapid progression of the motor component of the disease but not cognitive impairment. In patients with idiopathic Parkinson's disease of longer than five years duration, hallucinosis was associated with postural instability, global cognitive impairment, and lack of depressive aVect. In all patients with idiopathic Parkinson's disease, hallucinosis was more prevalent when they were treated with a direct acting dopamine receptor agonist. Hallucinosis was not associated with age at onset of idiopathic Parkinson's disease or dosage of dopaminergic medication. Conclusion-Hallucinosis in idiopathicParkinson's disease is heterogeneous, falling into two groups. The diVerence in the pathophysiological basis of hallucinosis in these two groups of patients is discussed.

Purpose:To estimate the levels of basal ganglia iron levels in Parkinson's disease (PD) using the PRIME MR sequence at 3.0 Tesla, in relation to patients' motor symptom severity. Materials and Methods:Seventy patients with PD and 10 healthy controls underwent assessment of movement and MR imaging. Mean R 2 Ј relaxation rates were recorded in the substantia nigra, frontal white matter and in the rostral, mid, and caudal putamen.Results: R 2 Ј relaxation rates were significantly higher in patients with PD than in healthy controls. R 2 Ј in the most affected substantia nigra correlated with PD patients' motor symptom severity, but not with disease duration. Neuroradiological observation revealed a rostral to caudal "gradient" of putaminal hypointensity. This was substantiated by the finding that the mid and caudal putamen showed significantly higher R 2 Ј relaxation rates, consistent with higher iron levels in PD relative to the healthy controls.Conclusion: MRI at 3.0 Tesla suggests that substantia nigra iron levels are increased and linked to the severity of motor symptoms experienced in PD. Findings consistent with increased iron levels in the PD putamen are shown, in a region-specific rostral to caudal gradient.

High angular resolution diffusion tensor imaging may be more sensitive than conventional MRI or neurologic assessment to the upper motor neuron (UMN) pathology of ALS, but it lacks the specificity required of a diagnostic marker. Instead, it is potentially useful as a quantitative tool for monitoring the progression of UMN pathology.