Measuring coil sensitivities of transmit and receive arrays with demonstration of RF shimming
Callaghan M, Larkman D, Hajnal J, Irarrazaval P, Ulloa J
Hammersmith Hospital, Imperial College London
Operating with arrays of coils for both transmit and receive requires determination of spatially varying coil sensitivities in both modes. Using a duel spin echo - stimulated echo sequence the transmit fields of individual coils can be directly measured and receive coil sensitivities can also be obtained. Total time to determine transmit and all receive profiles is < 1min/transmit coil. The method has been tested at 3T with transmit-receive coils and separate transmit and receive array coils using phantoms and in vivo. Measured transmit fields have then been corrected using RF shimming taking into account off-resonance effects and eddy currents.