Barium sulfate, an insoluble in water substance, which was approved under the brand name E-Z-HD for use in double-contrast radiographic examinations of the esophagus, stomach and duodenum to visualize the gastrointestinal (GI) tract in patients 12 years and older. Due to its high atomic number, barium is opaque to x-rays and therefore acts as a positive contrast agent for radiographic studies.

Iomeprol is a nonionic, monomeric iodinated contrast medium. Iomeprol helps optimize images obtained with sophisticated multidetector computed tomography (MDCT) technology, especially for neurological, brain, liver, cardiac and vascular scanning. The mechanism of action of Iomeprol is as a X-Ray Contrast Activity. Launched by the Bracco Group in 1995, Iomeprol (Iomeron) currently is registered in more than 40 countries worldwide, including all major European markets, Japan, and major Middle East and Asian Pacific countries.

Mangafodipir (sold under the brand name Teslascan as mangafodipir trisodium) is a contrast agent delivered intravenously to enhance contrast in magnetic resonance imaging (MRI) of the liver. Mangafodipir is a manganese (Mn2+) chelate with the ligand fodipir (dipyridoxyl diphosphate or DPDP). Mangafodipir trisodium is metabolised (dephosphorylated) and partially transmetallated (manganese exchanged for zinc) after intravenous administration. Manganese that is released from mangafodipir is taken up by hepatocytes thereby increasing the SI of normal liver tissue. This may result in an improvement of the detection of liver metastases, which usually have no hepatocytes. The metabolites of fodipir are renally excreted, whilst the biliary route mainly excretes manganese. Mangafodipir was withdrawn from the US market in 2003 and the European market in 2012.

Ioxilan is a nonionic X-ray contrast agent approved by the United States Food and Drug Administration for X-ray imaging contrast enhancement. Ioxilan can be administered intravenously for excretory urography and contrast-enhanced computed tomography (CT) imaging of the head and body. Ioxilan can also be given intraarterially for cerebral arteriograpy, coronary arteriography and left ventriculography, visceral angiography, aortography, and peripheral arteriography.

Perflubron is a contrast agent used for signal enhancement during the indicated ultrasound imaging procedures. Perflubron is a constituent of blood substitute, indicated for liquid breathing.

Iotrol, a nonionic dimeric, intrathecal contrast medium for myelography. This agent does not exhibit any cytotoxic effect on human healthy nucleus pulposus (NP) cells.

Ioxaglate Sodium Meglumine (trade name Hexabrix) is a new low osmolality ionic contrast agent, that used as a diagnostic radiopaque medium. Following intravascular injection, Ioxaglate Sodium Meglumine is rapidly transported through the circulatory system to the kidneys and is excreted unchanged in the urine. The joint spaces as well as the uterus and fallopian tubes may be visualized by the direct injection of the contrast medium into the region to be studied. The usual adult dose for left coronary arteriography is 8 mL (range 2-14 mL) and for right coronary arteriography is 5 mL (range 1-10 mL). The doses may be repeated as necessary Patients may have clinically insignificant ECG changes during the procedure. The following adverse effects have occurred in conjunction with the administration of iodinated intravascular contrast agents for this procedure: hypotension, shock, anginal pain, myocardial infarction, cardiac arrhythmias (bradycardia, ventricular tachycardia, ventricular fibrillation) and cardiac arrest.

Iodoxamic acid (previously sold under the brand name Cholovue) is an organoiodine compound that was used as a contrast medium. It is intravenous cholecystocholangiographic agent. It features both a high iodine content as well as several hydrophilic groups.

Iodamide is an ionic monomeric iodinated radiographic contrast medium. It was used in many procedures and may be given intravenously or by other routes, for example by instillation into the bladder or uterus; it has also been used for computed tomography. It is usually given as a 24 to 65% solution of the meglumine salt, or as a mixture of the sodium and meglumine salts; solutions of the sodium salt have also been used. Iodamide is no longer marketed in the US.

Metrizamide is a glucosamine derivative of metrazoic acid, used as a contrast medium for myelography. Metrizamide is no longer marketed in the US.