This book provides a comprehensive survey of the pharmacokinetic models used for the quantitative interpretation of contrast-enhanced imaging. It discusses all the available imaging technologies and the problems related to the calibration of the imaging system and accuracy of the estimated physiological parameters. Enhancing imaging modalities using contrast agents has opened up new opportunities for going beyond morphological information and enabling minimally invasive assessment of tissue and organ functionality down to the molecular level. In combination with mathematical modeling of the contrast agent kinetics, contrast- enhanced imaging has the potential to provide clinically valuable additional information by estimating quantitative physiological parameters.