1. A method for evaluating a temporal sequence of x-ray images of an examination region of an examination object, the method comprising: processing in a processor the sequence of x-ray images, said processing comprising: assigning a sequence of detection times each corresponding to each of the x-ray images; defining an evaluation region in the examination region; determining a temporal course of a temporal derivation of an average value of pixels of x-ray images located in the evaluation region based on the corresponding detection times; and assigning a type to the evaluation region based on the temporal course, wherein at least a first type group is assigned to the evaluation region if the temporal course has a local maximum and a local minimum, and further wherein at least a second type group is assigned to the evaluation region if the temporal course lacks the local maximum and the local minimum.