iohexol

Iohexol is a contrast agent, sold under the trade names Omnipaque and Exypaque; this compound is also sold as a density gradient medium under the names Accudenz, Histodenz and Nycodenz. It is available in various concentrations, from 140 to 350 milligrams of iodine per milliliter. Omnipaque 350 is commonly used as a contrast agent during coronary angiography.
The osmolality of iohexol ranges from 322 mOsm/kg—approximately 1.1 times that of blood plasma—to 844 mOsm/kg, almost three times that of blood. Despite this difference, iohexol is still considered a low-osmolality contrast agent; the osmolality of older agents, such as diatrizoate, may be more than twice as high.