1. A method for tracking a blood flow within a vessel of a patient comprising: acquiring one or more medical images of the patient using an imaging system, the one or more images comprising at least one vessel of the patient; identifying a vessel of interest on the acquired one or more medical images; tracking the vessel of interest; generating a composite image from the acquired one or more medical images, the composite image comprising a time to peak contrast agent intensity at a point on the vessel of interest; and calculating a graph comprising the time to peak contrast agent intensity at the point on the vessel of interest versus a distance of the point along the vessel of interest.