  In pTx MRI systems, the prediction of local SAR is based on numerical
electromagnetic (EM) simulations and used to scale RF power to ensure FDA SAR
limits are not exceeded. This prediction becomes more complex when
superposition of E-fields from multiple coupled coils are employed in parallel
transmission, each affected by dielectric and conductive properties of the
human body. It was demonstrated that incorrect inductive coupling used in
simulations of transmit array coil spatial excitation and SAR, leads to poor
accuracy of predicted excitation and SAR, and more importantly from a safety
perspective, underestimated local SAR by 19-40%.
