White Matter Alteration in Idiopathic Normal Pressure Hydrocephalus: Tract-Based Spatial Statistics Study

Region-of-interest analysis and tract-specific analysis of the CST. A, Regions of interest were plotted on the 4 points of the corpus callosum (a), the genu, anterior third of the body (b), the posterior third of the body (c), and splenium (d) on the sagittal section (FA map), the juxtacortical white matter in the frontal (e) and parietal cortices (f), the periventricular white matter around the posterior part (g) or anterior horn (h) of the lateral ventricle, the anterior limbs of the internal capsule (i), and the periventricular white matter around the posterior horn of the lateral ventricle (j) white matter in the temporal lobe (k) on the axial section (left, FA map; right, color-coded FA map). B, The voxelized diffusion tensor tractography of the CST is separated into 4 areas, (1), (2), (3), and, (4) shown with a color-coded FA map (coronal section). In the color-coded FA maps, the orientation of the axial eigenvector was color-coded per voxel according to the red-green-blue convention: red indicating a predominant left-right orientation within each voxel, green indicating an anteroposterior orientation, and blue indicating a superior-inferior orientation. The SLF (green area) is indicated by arrows.