1. A method for compensating for respiration-induced motion of a structure imaged by a magnetic resonance scanner, comprising the steps of: in a first time interval ( 20 ): obtaining from the magnetic resonance scanner a sequence of navigator samples ( 22 ) representative of the progressive displacement of the structure; and adjusting a waveform model ( 14 ) of predefined initial parameters to follow the sequence of navigator samples; in a second time interval ( 24 ) which follows the first time interval and during which the magnetic resonance scanner takes an imaging segment ( 16 ) composed of a number of image projection views or lines ( 17 ): estimating the expected displacement of the structure at the times at which at least some of the image projection lines are taken by extrapolating the waveform model and estimating the displacements ( 26 ) predicted by the extrapolated waveform model ( 15 ); and adjusting the position at which at least some of the image projection lines are taken based on the estimated displacement ( 26 ) of the structure at the time that those image projection lines are taken.