Abstract: This document discusses, among other things, a computerized system comprising a perfusion analyzer circuit and a memory circuit to store a time sequence of volumetric image data. The image data is obtained in a time relation to arrival of a contrast agent at an anatomical region associated with the image. The perfusion analyzer circuit is configured to access the stored image data and receive a representation of an artery and a representation of tissue near the artery, shift the representation of the artery in time such that a time of arrival of the contrast at the artery precedes arrival of the contrast at the representation of tissue, automatically compute a perfusion parameter using the shifted representation of the artery, and provide the perfusion parameter as an output to a user or to an automated process.