Figure 4. The influence of vascular morphology on ΔR₂ ^* and ΔR₂.

(a–c) Sample microvascular networks simulated using a fractal tree model with increasing branching angle heterogeneity. (d) Three orthogonal slices through the magnetic field perturbation at the body center for the vascular network in (c). (e–f) Effect of branching angle heterogeneity on the concentration dependence of ΔR₂ ^* and ΔR₂ computed with FPFDM (B₀ = 4.7T, Δχ = 1×10⁻⁷, 2% target vascular volume fraction). Both ΔR₂ and ΔR₂ ^* increase with branching angle heterogeneity.