The recent development of 3-D medical imaging devices has given access to the 3-D imaging of in vivo tissues, from an anatomical (MR, CT) or even functional point of view (fMRI, PET, SPECT). However, the resolution of these images is still not sufficient to image anatomical or functional details, that can only be revealed by in vitro imaging (e.g. histology, autoradiography). The deep motivation of this work is the comparison of activations detected by fMRI series analysis to the ones that can be observed in autoradiographic images. The aim of the presented work is to fuse the autoradiographic data with the pre-mortem anatomical MR image, to facilitate the above-mentioned comparison. We show that this fusion can be achieved by using only simple global transformations (rigid and affine), yielding a very satisfactory result.