Examination of the validity of RF power determination by auto prescan in T1-weighted images

In the sequence of spin echo MRI systems, RF power selects the output value from which the signal intensity of the whole photography volume changes to the maximum as a 90-degree pulse in auto tuning during prescanning by the SIGNA HORIZON LX 1.0 Tesla ver. 8.3. When it consists of two or more organizations like a human body, although the RF power to which signal intensity serves as the maximum is in agreement with the RF power of a 90-degree pulse if it is a uniform phantom, the RF power from which signal intensity reaches the maximum differs for every organization. When we determined RF power by the signal intensity of two or more whole organizations in this experiment, it was found that RF power was strongly influenced by a high signal organization. Moreover, if CNR in two or more organizations is considered, T1 contrast will be emphasized for the direction of an angle less than 90 degrees. It was possible for the same effect to be acquired by lowering the power of the RF pulse and emphasizing T1 contrast. (author)