Contrast Media

This chapter sets out the role and application of contrast media within diagnostic radiography. As demonstrated, there are a range of media that may be applied, dependent upon the examination required. These range from negative medias such as air, oxygen and carbon dioxide to positive medias such as barium for the gastrointestinal tract, iodine-based media for Computed Tomography (CT) and Gadolinium for Magnetic Resonance Imaging (MRI). Consideration is given to what constitutes the ‘ideal’ contrast medium, it’s development and structure. This is important in enabling an understanding of its application and the potential risks that may be incurred through its use. An evaluation of the effects of the contrast media used is undertaken, both in terms of the primary effects – the image contrast, and the secondary effects – adverse reactions, recognition of these and their management. The chapter explores the routes of administration of contrast media such as oral, rectal, intravenous or arterial and the patient preparation that maybe required. An exploration is made of the use of contrast media in other examinations such Endoscopic Retrograde Cholangiopancreatograhy (ERCP) and Ultrasound (US).