Age correlation of the time lag in signal change on EPI-fMRI.
OBJECTIVE
We measured the time lags between the start or end of tasks and signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags.


METHODS
Forty subjects, 20-76 years old, were evaluated. fMRI was performed with and echo planar imaging sequence at 0.5 s intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after starting 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.


CONCLUSIONS
The time lag in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time lag in fMRI is influenced by some factors associated with aging.
Department of Radiology, Nara Medical University and Hospital, Japan.
T
T
Taoka
S
S
Iwasaki
H
H
Uchida
A
A
Fukusumi
H
H
Nakagawa
K
K
Kichikawa
K
K
Takayama
T
T
Yoshioka
M
M
Takewa
H
H
Ohishi
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology*; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D012016:Reference Values; D013997:Time Factors