SAR Behavior During Whole-Body MultiTransmit RF Shimming at 3.0T

Paul R. Harvey¹, Zhiyong Zhai², Michael Morich², Giel Mens¹, Gert van Yperen¹, Gordon DeMeester², Ingmar Graesslin³, Romhild Hoogeveen¹

The dielectric properties of human tissue influence the RF uniformity that is achievable in MRI. Clinical 3.0T MRI systems capable of MultiTransmit RF technology have recently been introduced. Electromagnetic (EM) simulations have been used to evaluate the relationship between whole-body SAR, local SAR and head SAR as a function of patient and anatomy specific uniformity optimized RF shim settings. Results indicate that improved RF uniformity is consistent with reduced SAR thereby enabling shorter scan times in cases where SAR is limiting.