In general, only one diffusion model would be applied to whole field-of-view voxels in the intravoxel incoherent motion-magnetic resonance imaging study. However, the choice of the applied diffusion model can significantly influence the estimated diffusion parameters. The quality of the diffusion analysis can influence the reliability of the perfusion analysis. This study proposed an optimal model mapping method to improve the reliability of the perfusion parameter estimation in the IVIM study. Six healthy volunteers. Volunteers were examined using a 3.0 Tesla (...) scanner. IVIM-MRI of the brain was applied at 17 b-values ranging from 0 to 2,500 s/mm2. The Gaussian model, the Kurtosis model, and the Gamma model were found to be optimal for the CSF, white matter, and gray matter, respectively. In the mean perfusion fraction analysis, the GM/WM ratios were 1.16, 1.80, 1.94, and 1.54 ; in the mean pseudo diffusion coefficient analysis, the GM/WM ratios were 1.18, 1.19, 1.56, and 1.24. With the optimal model mapping method, the estimated fp and D* were reliable compared with the conventional methods. In addition, the optimal model maps, the associated products of this method, may provide additional information for clinical diagnosis. (shrink)