Patent ID: 7949165

Claim:
A method for determining a presence probability distribution with local three-dimensional resolution for a substance in a vascular system of a patient, comprising: predetermining a volume data set and a temporal sequence of x-ray images of the vascular system; assigning acquisition times to the x-ray images showing a presence distribution with local two-dimensional resolution for the substance in the vascular system at the acquisition times; determining a first preliminary presence probability distribution for a first acquisition time based on the x-ray images assigned to the first acquisition time and the volume data set with the substance at a first vascular location; determining a second preliminary presence probability distribution for a second acquisition time based on the first preliminary probability distribution and a migration probability distribution with the substance migrating to a second vascular location at the second acquisition time; and assigning a high probability to the first and the second vascular locations if both the first and the second preliminary presence probability distributions have a high probability value or assigning a low probability to the first or the second vascular location if the respective first or the second preliminary presence probability distribution has a low but greater than zero probability value.