ST and DTI putative sheetlet normal orientations compared voxel-wise to the FI normal
|). These frequency distributions summarize the orientations from the interactively segmented sheetlets of Figure 3 for the lateral ROI (left) and for the septal ROI (right). A - distributions produced for the first set of imaging/image-processing parameters compared to FI (DTI: Scan #1, 6-direction, b = 1000 s/mm2; ST: Scan #8, DTW = 3, STW = 3). B - distributions for the second set of imaging/image-processing parameters compared to FI (DTI: Scan #2, 12-direction, b = 1000 s/mm2; ST: Scan #8, DTW = 5, STW = 5) allow assessment of sensitivity of the measured laminar normals to these parameters. Note: the deviation angles shown in these histograms are not on a circular scale as they are absolute values and 0° ≠ 90°. FLASH: fast low angle shot; ST: structure tensor of FLASH data; DTI: diffusion tensor magnetic resonance imaging; FI: FLASH isosurface data; DTW: derivative template width STW: smoothing template width. The symbols for vectors and derived angles are defined in Table 2.