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 identification 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 estimates of iron concentration.

RESULTS

In healthy subjects, interregional T1 and T2 differences in the cortex and basal ganglia showed a good correlation with reported values for iron concentration, and intraregional variations were generally consistent with reported variability of iron concentration. Patients with multiple system atrophy had T1 and T2 shortening in the globus pallidus consistent with reported increases in ferritin-bound iron and changes in the putamen consistent with accumulation of hemosiderin (posterior portion) and neuromelanin (remainder). Both groups of patients had changes in the cortex that are consistent with decreased ferritin concentration and T2 changes in white matter 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 changes.