A first method for processing of a radiological image to be used as a mask image in subtracted angiography wherein processing for reduction of noise present in the mask image adapted to preserve the aspect of the noise in the mask image. A second method for processing of a sequence of subtracted images (J.sub.n) obtained by subtraction of a mask image from each of the images in a sequence of images (I.sub.n) acquired during angiography of blood vessels in an area of interest (104) of a patient (200), wherein processing for reduction of noise present in the subtracted images (J.sub.n) adapted to preserve the aspect of vessels (80) in the subtracted images. A radiography apparatus for implementing a method according to one and/or the other of the first and second methods.