X-ray computed tomography (CT) is a widely used diagnostic imaging technique that allows for 3D visualization and segmentation of tissues. CT scanners use X-rays to generate images, with contrast agents enhancing the visibility of specific tissues. Iodine-based contrast agents are commonly used due to their high X-ray attenuation properties. These agents are typically water-soluble and come in various forms, including small-molecule and nanoparticulate structures. Small-molecule iodinated agents, such as iohexol, iopromide, and iodixanol, are widely used in clinical settings. However, they can have high osmolality and viscosity, leading to potential adverse effects. Nanoparticulate iodinated agents, such as liposomes, nanosuspensions, and polymeric nanoparticles, offer improved blood circulation times and reduced renal toxicity. These agents are designed to target specific tissues and organs, enhancing CT imaging capabilities. Recent advancements include the development of stealth liposomes, which have prolonged blood circulation times and reduced uptake by the reticuloendothelial system. Additionally, dendrimer-based and coordination-polymer-based contrast agents are being explored for their potential in enhancing CT imaging. Despite these advancements, challenges remain in optimizing the safety, efficacy, and toxicity of CT contrast agents. Overall, the field of CT contrast agents continues to evolve, with a focus on improving imaging quality, reducing side effects, and enhancing diagnostic capabilities.X-ray computed tomography (CT) is a widely used diagnostic imaging technique that allows for 3D visualization and segmentation of tissues. CT scanners use X-rays to generate images, with contrast agents enhancing the visibility of specific tissues. Iodine-based contrast agents are commonly used due to their high X-ray attenuation properties. These agents are typically water-soluble and come in various forms, including small-molecule and nanoparticulate structures. Small-molecule iodinated agents, such as iohexol, iopromide, and iodixanol, are widely used in clinical settings. However, they can have high osmolality and viscosity, leading to potential adverse effects. Nanoparticulate iodinated agents, such as liposomes, nanosuspensions, and polymeric nanoparticles, offer improved blood circulation times and reduced renal toxicity. These agents are designed to target specific tissues and organs, enhancing CT imaging capabilities. Recent advancements include the development of stealth liposomes, which have prolonged blood circulation times and reduced uptake by the reticuloendothelial system. Additionally, dendrimer-based and coordination-polymer-based contrast agents are being explored for their potential in enhancing CT imaging. Despite these advancements, challenges remain in optimizing the safety, efficacy, and toxicity of CT contrast agents. Overall, the field of CT contrast agents continues to evolve, with a focus on improving imaging quality, reducing side effects, and enhancing diagnostic capabilities.