Dynamic Contrast Enhanced MRI (DCE-MRI) is often employed as an indicator of drug activity in clinical trials of angiogenic inhibitors. The data obtained with DCE-MRI is reported semi quantitatively using parameters derived from pharmacokinetic models. Most MRI kinetic models were developed from Nuclear Medicine quantitative studies but the limitations of MRI dictated specific modifications. A number of these MRI models are in current use. In this work, we review several pharmacokinetic models used in DCE-MRI in order to determine the most appropriate model to assess tumor angiogenesis. These models are compared with respect to their physiological appropriateness; compartmental analysis; initial and boundary conditions; and clinically relevant output parameters.