Experimental demonstration of the proportionality of the RF reception field to a complex conjugate of B₁⁻.

We demonstrated that the radiofrequency (RF) reception field is proportional to B₁⁻* straightforwardly in magnetic resonance (MR) imaging experiments at 4.7 T. We compared maps of the reception field and the B₁⁻ of a saline phantom in magnitude and phase. First, we measured the image using an adiabatic spin echo (ASE) sequence with homogeneous excitation. That image corresponds to a map of the reception field. Next, we rotated the RF coil with the sample 180° around the vertical axis to measure the map of the transmission field that corresponded to B₁⁻ in the original configuration. The magnitude of the distribution fields of the reception field and B₁⁻ maps was almost identical. Examining the phases of the ASE images in the original and inverted configurations, we observed almost the same distribution in both phase maps, which indicated the proportionality of the reception field to B₁⁻*.