The brain in healthy aged individuals: MR imaging.

Twenty-four healthy aged individuals with above-average intellectual function were studied with use of a low-field-strength (0.02-T) magnetic resonance (MR) imager. The group was carefully selected so as not to include persons with signs of arteriosclerotic diseases, major somatic disease, or a history of brain disease or dementia in the family. The width of the subarachnoid spaces and lateral ventricles, as well as the frequency and degree of brain white-matter lesions, were described with the use of a visual rating scale. White matter lesions were found in less than 9% of the subjects. The lateral brain ventricles were enlarged in 8% of all individuals and the cortical cerebrospinal fluid (CSF) spaces in more than 40% of all individuals. Moreover, T1 and T2 were estimated in different brain areas, and a positive correlation between T1 in the frontal white matter and age was found. A computer-assisted classification procedure was used to estimate brain tissue and CSF areas. The results of this procedure strongly correlated with the visually estimated ventricular size.