$$$ {\mathrm{B}}_1^{+} $$$ inhomogeneity correction of volumetric brain NOE_MTR via high permittivity dielectric padding at 7 T

Figure S1. Histogram distributions of NOE_MTR contrast value without linear correction (A), NOE_MTR contrast values with linear correction (B), and relative $$$ {\mathrm{B}}_1^{+} $$$ strength (C) concatenated across all six subjects. Distribution narrowing can be seen in all data acquired with pads, reflecting an increase in homogeneity of $$$ {\mathrm{B}}_1^{+} $$$ maps and contrast in resulting NOE_MTR images. It should be noted that histograms show data across the entire 3D slab of each subject dataset, with the first and last slices being omitted.

Figure S2. Illustration of segmented subcortical regions viewed in orthogonal space. The subcortical regions that can be seen are left hippocampus (yellow), right hippocampus (light green), left amygdala (light blue), right amygdala (dark blue), left thalamus (dark green), and right thalamus (pink).

Figure S3. Histogram comparisons for NOE_MTR brain segmentations showing distribution narrowing and shifting when pads were used versus absent, reflecting an increase in contrast and homogenization on a regional level. Data in these histograms acquired across all slices from all subjects where the corresponding segmentations were present.

Figure S4. Volumetric representation of $$$ {\mathrm{B}}_1^{+} $$$ maps acquired without (A) and with (B) dielectric pads. A volume rendering of the $$$ {\mathrm{B}}_1^{+} $$$ difference values across the whole brain (C) showing the increase is localized to the temporal lobes while the decrease is present across the posterior of the brain and majority of superior slices. It should be noted that difference values close to 0 were filtered out of the image to show the larger numeric differences more clearly. An MPRAGE acquisition across the same whole brain volume can be seen (D) as an anatomic reference.