A method includes obtaining contrast enhanced perfusion imaging data of at least two vessel regions, one downstream from the other, and at least one tissue of interest, which receives blood from the circulatory system, of a scanned subject. The method further includes determining a blood flow time difference between contrast material peaks of the at least two vessel regions based on the image data. The method further includes determining an absolute perfusion of the tissue of interest based on the image data. The method further includes computing a standardized perfusion value based on the absolute perfusion and the time difference. The method further includes displaying the standardized perfusion value.
