Isovist® is a nonionic x-ray contrast agent. Isovist® is suitable for intrathecal applications for example CT myelography, cisternography, the evaluation of cerebrospinal fluid (CSF) circulation and for use in other body cavities. Opacification is directly visible after administration of Iotrolan to the spinal subarachnoid space and various open body cavities. Isovist® flows with the CSF through the arachnoid villi into the venous blood.

The Germany-based pharmaceutical company is the result of the take-over of Schering AG by Bayer AG in 2006. The Bayer Schering Pharma AG is part of the Bayer HealthCare AG, which represents the pharmaceutical part of the Bayer Group. Activities of the Bayer Schering Pharma AG are Diagnostic Imaging, Hematology & Cardiology, Oncology, Primary Care, Specialized Therapeutics and Women's Healthcare. The diagnostic imaging part's contrast agents for MRI, x-ray and CT are 'world-market leaders'.
See also Bayer HealthCare Pharmaceuticals.

A nonionic dimer consists of 2 joined nonionic monomers. Nonionic dimers are used as x-ray and CT contrast media.
Nonionic dimers have the lowest osmolarity. These contrast materials contain 6 iodine atoms for every 1 particle in solution (CM ratio=6). Modern CT techniques require fast bolus injections and thus low-viscosity, high-concentration, well-tolerated contrast agents. Nonionic dimers have the highest viscosity, which limits the clinical usefulness. Examples of nonionic dimers are iotrolan (Isovist®) and iodixanol (Visipaque).

See also Contrast Agents.