Contrast agents have become an indispensable part of everyday life in diagnostic radiology. In multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI), they provide essential diagnostic information, especially for vascular, inflammatory or oncologic diseases, which otherwise could not be answered. The two most important groups are iodine- and gadolinium-containing contrast agents. Rare side effects include PC-AKI (post-contrast acute kidney injury); more common are allergic and chemotoxic reactions. Since the introduction of guidelines, nephrogenic fibrosis has not been reported anymore, whereas gadolinium deposition in the central nervous system (CNS) has become a new topic. Concerning contrast media use in patients with reduced renal function, at a eGFR threshold of <45 ml/min or <30 ml/min, hydration and a review of indication for enhanced MDCT, depending on the application, is recommended. Low kV and DE-scan protocols with MDCT can help to reduce the amount of iodinated contrast agents. In MRI examinations, only macrocyclic contrast agents should be used for enhanced MRI exams. There has to be a careful risk-benefit analysis with enhanced studies in pregnancy, during lactation and in the pediatric population. Patient information and legal aspects with nonapproved indications are indispensable parts of daily clinical routine. The continuous updating and broadening of knowledge regarding the appropriate use of the various contrast agents has to be an integral part of clinical diagnostic radiology.
Keywords: Acute kidney injury; Anaphylaxis; Gadolinium; Magnetic resonance imaging; Multidetector computed tomography.