Regional Uniformity

The regional uniformity displays lateral and AP direction profiles in an anterior and lateral uniformity region as seen in the image below.

Figure 5.1: Diagram of the regional uniformity areas and directions of the intensity profiles. These labels match those used in Smári.

The profiles are averaged over 5 pixels wide(rows or column as appropriate). The profile is fitted to a 2nd order polynomial to show low-frequency trends on the profile.

Figure 5.2: An example of the lateral intensity profile fitted to a 2nd order polynomial. Realistically, it is expected that the pixel intensities will vary slightly along the profile, but the user should set thresholds to determine when a difference is significant.

The mean and standard deviation range for each slice in the image set is displayed for all slices for both the lateral and AP directions. In the image below, ‘Slice nr’ stands for slice number on the x-axis of the graph.  Ideally, the blue mean pixel value line would be horizontal, and the standard deviations would be as small as possible and consistent. Realistically, the image could get noisier at different points on the z-axis, which is why the blue line is curved.

Figure 5.3: An example of the mean and standard deviation range plot for each slice used in the lateral and AP directions. The legend references the top ROI which is also considered the lateral region, and the mid ROI which is considered the anterior region.