Clinical applications, safety profiles, and future developments of contrast agents in modern radiology: A comprehensive review

Contrast agents have transformed the field of medical imaging, significantly enhancing the visualisation of internal structures and improving diagnostic accuracy across X-rays, computed tomography, magnetic resonance imaging (MRI), and ultrasound. This review explores the historical development, physicochemical properties, and mechanisms of action of iodinated, gadolinium-based, barium sulfate, microbubble, and nanoparticle contrast agents. It highlights key advancements, including the transition from high-osmolar to low- and iso-osmolar iodinated agents, the integration of gadolinium in MRI, and the innovative use of microbubbles and nanoparticles. The review critically examines the safety profiles and adverse reactions of these contrast agents, categorising them into hypersensitivity and physiological reactions. It outlines risk factors, common misconceptions, and management strategies for adverse reactions, emphasising the importance of personalised approaches in clinical practice. Additionally, it delves into broader implications, including ethical considerations, environmental impact, and global accessibility of contrast media. The review also discusses technological advancements such as targeted contrast agents and the integration of artificial intelligence to optimise contrast dosage. By synthesising current knowledge and emerging trends, this review underscores the pivotal role of contrast agents in advancing medical imaging. It aims to equip clinicians, researchers, and policymakers with a thorough understanding to enhance diagnostic efficacy, ensure patient safety, and address ethical and environmental challenges, thereby informing future innovations and regulatory frameworks to promote equitable access to advanced imaging technologies globally.