1. A system for filtering a sequence of medical images, the system comprising: a memory operable to store at least first data of a first medical image; and a filter operable to determine a first similarity between a first value of the first data, the first value corresponding to a first location in the first medical image, and a second value of a second location in a second image, the second image corresponding to a different time than the first image, the first location corresponding to a spatial offset from the second location, the filter operable to weight a first contribution of the first value to a filtered result for the second value as a function of the first similarity.