AGE CORRELATION OF THE TIME-LAG IN SIGNAL CHANGE ON EPI-FMRI

Purpose: We measured the time lags between the start or end of tasks a nd signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags. Method: Forty subjects , 20-76 years old, were evaluated, fMRI was performed with an echo pla nar imaging sequence at 0.5 a intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after s tarting the task (T-inc) and the time to reach the initial level after ceasing the task (T-dec). Results: Average T-inc was 3.09 s and T-dec was 6.63 s. The values of T-inc could be correlated to age. T-dec had no age correlation. Conclusion: The time lan in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time la g in fMRI is influenced by some factors associated with aging.