1. A computer-implemented method, comprising: determining, based on a set of biomedical images, a first concentration-activity curve and a second concentration-activity curve, wherein each of the first concentration-activity curve and the second concentration-activity curve indicates a concentration of a respective contrast agent within a respective region of tissue; determining a value of at least one pharmacokinetic (PK) parameter based on the first concentration-activity curve and the second concentration-activity curve, wherein determining the value of the at least one PK parameter comprises: (i) determining a linear model that relates the first concentration-activity curve to the second concentration-activity curve, wherein the linear model comprises the at least one PK parameter; and (ii) determining the value of the at least one PK parameter based on application of a linear least square fitting (LLSQ) algorithm to the linear model; and causing a graphical display to provide a visual indication of the value of the at least one PK parameter.