A method is disclosed for obtaining a 4D image data record of an object under examination using measured data from a computed tomography system in which projection data are accepted which were acquired by way of the computed tomography system at different imaging time points by way of an helical scan method following the administration of contrast medium to the object under examination). On the basis of the projection data, image data of the object under examination are then reconstructed and linked with the imaging time points to a space/time data record. Then, a parameterized 4D image data model is individualized with adaptation to the space/time data record by varying model parameters. An image processing device and a computed tomography system with an image processing device of this kind are also described.