Effect of body coil electric field distribution on receive-only surface coil heating.

Although in the design of transmit RF coils, B(1) homogeneity is crucial for good image quality, discussion of electric field (E-field) distribution in the literature has been mostly limited to specific absorption rate (SAR) and patient loading (dielectric) effects. In this work, we report on a different aspect of E-field: the receive-only surface coil heating resulting from the voltage drop across the blocking (decoupling) networks and cable traps that are used to minimize the transmit field distortion. The results show that the z-component (parallel to the coil cable) of the E-field has a significant effect on the temperature rise in the surface coil. Therefore, in the receive-only coil designs, it is not sufficient to consider only the induced voltage on the coil loop due to the B(1) field, as is generally done in blocking network analysis calculations. The body coil E-field distribution must be considered as well.