Abstract
The pupose of this study was to evaluate blood oxygenation level-dependent(BOLD)contrast and the inflow effect in functional MRI. Nine normal volunteers underwent an activation test using right finger tapping on a 1.5T machine. A triple gradient echo sequence(TE=21, 44, 67msec)was repeated to obtain rest and activated images, and the functional image was calculated b subtraction. The excitation angle of the sequence was varied at 10 degree, 40 degree, and 70 degree. The activated region coincided with a cortical vein on 2D-TOF-MRA(v-group)or not (c-group). BOLD contrast was dominant in the both groups. The v-group had a larger inflow effect than the c-group. The activation ratio was independent of the excitation angle, which also suggested that BOLD contrast is dominant in functional MRI.
