Figure 2:

Transmit efficiency maps acquired from a subject, without (left column, top row) and with (left column, middle row) the uHDC helmet in the V1 configuration. The ratio (with/without) is displayed in the bottom row. The white dashed lines denote the location of the axial slices. The units are given in uT divided by the square root of the power delivered (forward-reflected) to the body coil, as measured by the system. The efficiency was strongly enhanced by the uHDC helmet, reaching up to 300% of the baseline value in some regions of the maps. The right column displays the simulated transmit efficiency. There is a slight rotation of the field pattern in the simulated data relative to the experimental data, and the field enhancement reached values of up to 400% of baseline.