Directional Intravoxel Incoherent Motion (IVIM) MR in Rodent Brain

The measurement of white matter flow, which is directional along the neuronal fibers, is challenging due to inherent limitations of low sensitivity and signal-to-noise ratio with arterial spin labeling(ASL)- and dynamic susceptibility contrast(DSC)-MRI acquisitions mainly due to low blood volumes. Recently, flow sensitive intravoxel incoherent motion(IVIM)-diffusion MR has been recognized as being particularly sensitive to directional flows. However, the multi-variable fittings usually suffer from over-fitting and thresholding issues. This study investigated the feasibility of constrained non-negative matrix factorization(cNMF) implementation to IVIM-MR for the automatic segmentation of directional IVIM signals for the purpose of robust detection of directional white matter flow.