Robust MRI assessment of cerebral microvasculature using stimulated-echo diffusion-imaging method

Stimulated-echo diffusion-imaging method was employed to reduce the effect of macroscopic field inhomogeneity and large vessel overestimation on the quantification of blood volume fraction and mean vessel radius. Stimulated-echo diffusion-imaging method were compared with conventional spin-echo and gradient-echo methods by Monte Carlo (MC) proton diffusion simulations and in vivo rat experiments on a 7 T system. The results of this study showed that stimulated-echo based MR relaxation-rates, ∆R_{STE,long TD} (ΔR₂^* like) and ∆R_{STE,short TD} (ΔR₂ like), provide the robust means of assessing cerebral microvasculature where the macroscopic field inhomogeneity is severe and signal contamination from adjacent large vessel is significant without necessity of co-registering gradient- and spin-echo images.