A method for suppressing noise in a diagnostic image executes one or more iterations of segmenting the image to identify and label one or more regions in the image; and performing selective diffusion on at least one of the one or more labeled regions in the image. A homogeneity value is computed for the region. A diffusion conductance function is generated for the region according to an intensity gradient between adjacent digital image elements within the region. The diffusion process is applied to a plurality of digital image elements within the region.