Perfusion-based event-related functional MRI

Perfusion-based event-related functional MRI was performed by measuring flow-sensitive alternating inversion recovery (FAIR) signal changes during repeated single-trial, short visual stimulation (250 msec), In the Visual cortex activation area, the blood flow increases immediately after the stimulus, reaches the maximum a sec later with a perfusion-sensitized signal change of 16.1 +/- 2.6 %, and then decreases to baseline approximately 11 sec after the stimuli. As it is a more direct reflection of the hemodynamic response, perfusion-based event-related functional MRI techniques may be more useful for human cognitive function studies, compared with blood oxygenation level-dependent (BOLD)-based event-related functional MRI techniques. (C) 1999 Wiley-Liss, Inc.