The development of iodine contrast agents has gone through stages from inorganic iodine to organic iodine, from mono-iodine, di-iodine to tri-iodine, from ionic to non-ionic, etc. The ionic monomeric contrast agents developed in the 1950s were stable and had good contrast, but their osmotic pressure was high and their toxic side effects were large. derivatives. The difference with ionic monomeric contrast agents is that: the cation is removed to reduce osmotic toxicity; the carboxyl group is removed to reduce neurotoxicity; 4-6 hydroxyl groups are added to increase hydrophilicity, improve water solubility, and reduce viscosity and chemical toxicity. It has been widely used in cardiac and angiography and CT enhancement scans. At present, the non-ionic iodine contrast agents commonly used in domestic clinics include iopromide (Uvexan, Iopromide, Ultravist), iodopaxol (Onepac, Iohexol, Omnipaque), iopamidol (Iopbil, Iopamiro), iodophorol (Anjali, Ioversol, Optiray), iodixanol (Nuctech Pike, Iodixnaol, Visipaque), Iodotrien (Isoxian, Iotrolan, Isovist) and several other products. 1.Onepac: iodine content of 46.4%, different iodine concentration, respectively, 140, 180, 240, 300 or 350mg iodine per ml. 2.Visionpak: iodine concentration of 270mg/ml and 320mg/ml are both isotonic with plasma. 3.Isoxian: Its concentration is 40.6% (containing 19% iodine), 51.3% (containing 24% iodine) and 64.1% (containing 30% iodine), so its trade names are: Isoxian 190, Isoxian 240 and Isoxian 300 (named according to the iodine content mg/ml). 4.Pantethine glucosamine: iodine concentration 306mg/ml; iodine content 15.3g per 50ml, 30.6g per 100ml.