Comparison of the temporal response in perfusion and BOLD-based event-related functional MRI.
Event-related functional MRI (ER-fMRI) based on both blood oxygen level-dependent (BOLD) contrast and perfusion contrast has been recently developed to study human brain activation due to brief stimulation. In this report, both BOLD- and perfusion-based ER-fMRI were directly compared using repeated single-trial, short visual stimulation (1 sec) in six human volunteers. The results show that the cerebral blood flow change reached a maximum approximately 1 sec earlier than the BOLD signal change (4.2 +/- 0.2 sec vs. 5.1 +/- 0.2 sec after the stimulation, P < 0.05). The full width at half maximum of the hemodynamic response measured by perfusion was not significantly different from that measured with BOLD (5.1 +/- 0.6 sec vs. 5.9 +/- 0.6 sec). A positive linear correlation was found between the maximum perfusion and maximum BOLD signal changes (r = 0. 77, P = 0.07).
Liu
H L
HL
Research Imaging Center, University of Texas Health Science Center at San Antonio, 78284-6240, USA.
Pu
Y
Y
Nickerson
L D
LD
Liu
Y
Y
Fox
P T
PT
Gao
J H
JH
D002560:Cerebrovascular Circulation / Q000502:physiology; D017352:Echo-Planar Imaging / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010775:Photic Stimulation; D013997:Time Factors; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000098:blood supply