In an apparatus and a method for modeling momentary conditions of a medical object dependent on at least one time-variable body function, at least one further status value of the time-variable body function is calculated on the basis of the geometry of the medical object that is acquired from data obtained with a medical imaging method for at least one status value of the time-variable body function, and the geometry of the medical object is made available approximately synchronously with the currently measured status value of the time-variable body function.