DIRECT VISUALIZATION OF B-1 INHOMOGENEITY BY FLIP ANGLE DEPENDENCY

Inhomogeneities in the spatial distribution of the excitatory Radio Fr equency (RF) field, are still a dominant source of artifacts and loss of signal to noise ratio in MR imaging experiments, A number of strate gies have been proposed to quantify this distribution, However, in thi s technical note we present a relatively simple MR imaging procedure w hich can be used to visualise RF inhomogeneities directly either by me ans of the magnitude or the phase of an image. To visualise the RF fie ld distribution in both the inner and outer volumes of the coil, we ha ve performed experiments in which the entire coil is submerged in a no n-conducting fluid, To the best of our knowledge this strategy has not been used previously in order to evaluate coil performance, Finally, we demonstrate that the method is sensitive enough to reveal the effec ts of the sample properties on the effective RF wavelength of the tran smitted field. (C) 1997 Elsevier Science Inc.