1. A process for simulation or for digital synthesis of sonographic images to be carried out by a device comprising at least a computer processing unit and a memory readable by the computer processing unit, the process characterized by a direct transformation in real time, or quasi-real time, performed by the computer processing unit, of information contained in a medical or veterinary MRI image stored in the memory of the computer processing unit, without delimitation or segmentation of organs or structures that are contained in data of the image, according to one or more two-dimensional observation windows that can be modified in real time, or quasi-real time, in dimension, in position, in direction and in orientation, whose characteristics are based on a type of a determined virtual sonographic probe and that reproduces all effects of attenuation, reflection, refraction and dispersion and effects of adjusting a real sonographic image, whereby each sonographic image that is provided accumulates results of simulations of the above-mentioned effects.