Figure 3. Diffusion MRI Measures.

Diffusion basis spectrum imaging measures across 3 critical white matter tracts in infants born very preterm without brain injury (VPT), with high-grade intraventricular hemorrhage (IVH), and with post-hemorrhagic hydrocephalus (PHH) requiring treatment. While the tract-specific patterns were variable, in comparison to VPT and IVH groups, infants with PHH had the most severe white matter disruption, marked by the lowest fiber fraction (FF), fiber fractional anisotropy (FFA), and fiber axial diffusivity (FAD, μm²/s), as well as the highest measures of fiber radial diffusivity (FRD, μm²/s) and markers of inflammation including cellular infiltration and vasogenic edema reflected as restricted fraction (RF) and nonrestricted fractions (NRF), respectively. All comparisons are Bonferroni corrected with ***, **, and * representing p values <0.001, <0.01, and <0.05, respectively, between the PHH and corresponding group.