[Contrast agent strategies in elective oncological imaging]

Computed tomography (CT) and magnetic resonance imaging (MRI) are central to staging, treatment planning and response assessment in oncology. For many tumor entities, clinical guidelines specify the recommended imaging frequency and appropriate modality; however, the practical implementation, including the applied imaging protocols, varies in clinical routine. Intravenous contrast agents are indispensable in oncological imaging for a variety of specific clinical questions, particularly for the detection and characterization of intraparenchymal lesions. In addition to the general indications for contrast administration, the selection of the optimal contrast phase for subsequent imaging is crucial. This article outlines the fundamentals of iodine-based and gadolinium-based contrast agents, their pharmacokinetics and safety aspects that should be considered in the context of a risk-benefit assessment for their use in oncological imaging. Furthermore, typical contrast phases and imaging protocols are presented as representative examples. Future developments in this field include spectral imaging and photon-counting CT, quantitative imaging and artificial intelligence (AI)-based methods as well as contrast agent-free functional MRI techniques. All of these approaches aim to achieve more precise tissue characterization, a potential reduction of radiation dose and/or contrast agent use as well as automated optimization of image acquisition and interpretation and are also discussed in this article.