Objective Using manganese enhanced MR imaging(ME-MRI)as a standard to validate the accuracy of white matter diffusion tenor tractography(DTT)with different gradients orientations in macaque monkeys.Methods Seven adult male macaque monkeys were scanned for DTY images with different number of gradients orientations.When all data were acquired.3 μl of 0.8 mol aqueous solution of MnCl2 was injected into the primary motor cortex representing forelimb for ME-MRI scanning 48 hours later.On the images of fractional anisotropy(FA),seed region for fiber tracking was chosen according to the subcortical enhanced range on ME-MRI,then the DTT fiber tracts proiecting on axial images of FA were compared with enhancement region on T1WI of ME-MRI.Results Under the calculation method for fiber tracking in the study,different motion-probing gradients orientations led to results consistent with ME-MRI for the brain above the midbrain level.All group's concordance score of fibertracking results were good.Among them,30 and 64 orientation fiber tracking results were optimal.Below the midbrain level,there was significant difference between DTT fiber tracking and ME-MRI fiber tracking. Conclusion Different motion-probing gradients orientations do not influence DTT fiber tracking.But below the midbrain level.the results of DTT fiber tracking were not reliable according to the standard results of ME-MRI fibe tracking.