1. A method comprising: receiving data corresponding to an original three-dimensional (3D) reconstructed image; smoothing substantially homogenous areas and enhancing edges of the original reconstructed image using edge enhancing diffusion (EED) to create edge-enhanced image data; calculating a structural importance map, wherein calculating the structural importance map includes calculating a measure of structural importance for voxels of data in the original reconstructed image; and determining a voxel intensity to be used to create a filtered image according to at least one rule, wherein the rule is applied to the measure of structural importance.