Embodiments of the present invention provide a method for generating a synthetic diffusion image. The method comprises the steps of acquiring multiple sets of initial diffusion scan data by means of diffusion weighted magnetic resonance scans at multiple initial b-values, deriving an initial diffusion image from at least part of the initial diffusion scan data, acquiring target diffusion scan data by means of a diffusion weighted magnetic resonance scan at a target b-value higher than each of the initial b-values, and generating the synthetic diffusion image by performing a cost function based reconstruction to apply a fidelity term ink space to the synthetic diffusion image based on at least the initial diffusional image, and the target diffusion scan data.
