Structural changes in the midbrain with aging and Parkinson's disease: an MRI study.

We measured midbrain structures of 59 subjects with Parkinson's disease (PD) and 140 age- and gender-matched normal subjects without neurological disorders by using T2-weighted MR imaging. There is a significant increase in the maximum distance of the substantia nigra (SND) and a significant decrease in the average distance from the substantia nigra to the red nucleus (SNRND) in patients with PD compared with normal subjects in the 70 years old or less group. These findings may reflect the pathologic increase of iron concentration and the neuronal loss in the region. However, it is difficult to find differences between normal subjects and patients with PD in the greater than 70 years old group in the midbrain structures. These findings based on a large-scale morphometric study provide essential information to evaluate conventional MR images of PD.