Medical imaging informatics is the rapidly evolving field that combines biomedical informatics and imaging, developing and adapting core methods in informatics to improve the usage and application of imaging in healthcare; and to derive new knowledge from imaging studies. This chapter introduces the ideas and motivation behind medical imaging informatics. Starting with an illustration of the importance of imaging in today's patient care, we demonstrate imaging informatics' potential in enhancing clinical care and biomedical research. From this perspective, we provide an example of how different aspects of medical imaging informatics can impact the process of selecting an imaging protocol. To help readers appreciate this growing discipline, a brief history is given of different efforts that have contributed to its development over several decades, leading to its current challenges. © Springer Science + Business Media, LLC 2010.