METHOD FOR MEASURING EDDY CURRENT BY USING STEAM SEQUENCE

摘要

PURPOSE: A method for measuring an eddy current is provided to measure the eddy current having a short time constant without dead time by moving a Voxel through a STEAM(stimulated acquisition mode) sequence of STEAM. CONSTITUTION: To measure an eddy current, a first gradient pulse(Gz2) is fed at the time prior to the time corresponding to an echo center point. The first gradient pulse changes the phase of STE(stimulated echo) generated at the time right after the time corresponding to the echo center point. The phase of an FID(free induction decay) signal is changed. To keep the phase of the gradient pulse to be changed by the effect of the first gradient pulse, a second gradient pulse(Gz1) is fed after feeding a first RF(radio frequency) pulse. After feeding the phase of the FID signal generated in a general STEAM sequence and the first and second gradient pulses, the phase of the FID signal generated in a deformed STEAM sequence is subtracted. An eddy current to a z axle is measured. Then, an eddy current to x and y axles is measured by equally performing an eddy current measurement process applied to the z axle.