Age-related changes in proton T1 values of normal human brain.

To determine whether there were age-related changes in the brain tissue of 55 healthy adult volunteers (29 men, 26 women; 18-72 years old) without known brain abnormalities, a standard inversion-recovery technique was optimized for precise and accurate T1 measurement within the constraints of a 15-minute examination. Measurements of water proton T1 were obtained in eight brain regions. T1 increased with age in the genu (P < .001) (analysis of variance), frontal white matter (P < .05), occipital white matter (P < .05), putamen (P < .001), and thalamus (P << .001). A significant decrease in T1 with age was found in cortical gray matter (P < .05). Thus, age-related changes in T1 are present in a healthy population, even if extremes of age are excluded, suggesting that T1 values generally increase with age. However, increases in T1 were also observed in the genu, putamen, and thalamus of a substantial fraction of volunteers less than 35 years old. Aging healthy persons can show subtle, nonsymptomatic brain changes, suggesting that brain aging is associated with occult processes that can begin at a relatively early age.