T1 and T2 in the brain of healthy subjects, patients with Parkinson disease, and patients with multiple system atrophy: Relation to iron content

PURPOSE: To investigate the potential of magnetic resonance imaging for ide ntification and quantification of brain iron in healthy subjects, patients with Parkinson disease, and patients with multiple system atrophy. MATERIALS AND METHODS: Forty-nine subjects were studied at 1.5 T. Regional T1 and T2 values were compared among groups and also with histopathologic e stimates of iron concentration. RESULTS: In healthy subjects, interregional T1 and T2 differences in the co rtex and basal ganglia showed a good correlation with reported values for i ron concentration, and intraregional variations were generally consistent w ith reported variability of iron concentration. Patients with multiple syst em atrophy had Tl and T2 shortening in the globus pallidus consistent with reported increases in ferritin-bound iron and changes in the putamen consis tent with accumulation df hemosiderin (posterior portion);and neuromelanin (remainder). Both groups of-patients had changes in the cortex that are con sistent-with decreased ferritin concentration and T2 changes in white matte r consistent with demyelination. Patients with Parkinson disease also had a (nonsignificant) T2 shortening in the substantia nigra that was suggestive of iron accumulation. CONCLUSION: Most of the T1 and T2 findings appear to be related to changes in iron content and form and may possibly be used as indicators of such cha nges.