Fast spin echo(FSE)sequence has been widely recognized that the contrast of T2 weighted image was affected by multi-refocusing pulses. The contrasts have never been investigated in case of echo space(ES)below 20msec although magnetic resonance imaging(MRI)developed such that the ES of multi-refocusing pulses could set at 5msec. To evaluate the contrasts of fat with short ES, we determined the signal intensities of the brain tissues and bottle phantom which consists of lard, water and bean oil. The signal intensities of all regions increased with decreasing echo spaces, due to the decoupling of J-coupling, excepting water signal intensity. In addition, the contrasts between the white matter and each region decreased with decreasing ES until 10ms and, however, did not change with decreasing ES over 10ms. The contrast between white and gray matter is also discussed. It is concluded that the contrast does not change in case of the echo space below 10ms.
