International audienceThe registration of intraoperative ultrasound (US) images with pre- operative magnetic resonance (MR) images is a challenging problem due to the di erence of information contained in each image modality. To overcome this di culty, we introduce a new probabilistic function based on the matching of cerebral hyperechogenic structures. In brain imag- ing, these structures are the liquid interfaces such as the cerebral falx and the sulci, and the lesions when the corresponding tissue is hypere- chogenic. The registration procedure is achieved by maximizing the joint probability for a voxel to be included in hyperechogenic structures in both modalities. Experiments were carried out on real datasets acquired during neurosurgi...