Age-related structural changes in the human midbrain: an MR image study.

We measured midbrain structures of 194 subjects without neurological disorders, using T2-weighted MR imaging. Age was negatively correlated with the maximum anteroposterior distance of the midbrain through the substantia nigra (MD), and the average distance from the substantia nigra to the red nucleus (SNRND), while a positive correlation was found between aging and the maximum distance of the substantia nigra (SND). Significant left-right differences were revealed in MD, SND, SNRND and the area of the red nucleus (RNA), which was possibly responsible for cerebral hemispheric dominance or handedness. There were gender differences in MD and the maximum interpeduncular distance (IPD) in age-matched groups. Age-related structural changes of the midbrain may have a close relation to a decline in motor performance with aging. These findings provide essential information to evaluate the MR images of neurodegenerative disorders.