Ethyl cartrizoate has been used in diagnostics as a bronchographic agent.

Gadopenamide is an MRI contrast agent that was introduced in 1991. It has been investigated as a potential clinical contrast medium by Schering AG (Germany), but has never been used as such.

Ioglunide is an iodobenzene derivative patented by Laboratoires Andre Guerbet as an oil-based X-ray contrast medium. Iophendylate was commonly used in conventional myelography from the 1940s to the late 1980s before the utilization of computed tomography (CT), magnetic resonance imaging (MRI) and water-soluble contrast agents. Ioglunide, which was never shown to be safe, was initially introduced for use in small amounts for locating spinal tumors. It next appeared on the world scene for high volume, routine use, in diagnosing disc herniations.

Iofratol, is a dimeric, hexaiodinated radiographic contrast agent that was being developed by Bracco as a potential X-ray contrast medium for angiography and myelography.

Iolixanic Acid is triiodophenoxyalkoxyalkanoic acid derivative patented by Bracco Industria Chimica S.p.A. as a diagnostic agent for cholecystography and urinary tract imaging

Iosarcol (also known as Melitrast) is an iodinated nonionic monomeric contrast medium patented by Dr. Franz Koehler and Chemie KG for radiographic imaging.

Ioglucomide is triiodoanilide derivative patented by Mallinckrodt, Inc. as nonionic x-ray contrast media for myelography. In preclinical studies the efficacy of ioglucomide and metrizamide were comparable. However, acute toxicity after intravenous injection or installation into cerebrospinal fluid was significantly less for ioglucomide. Also, in contrast to metrizamide, ioglucomide produced no evidence of any type of convulsive activity after subarachnoid administration.

Iozomic Acid is triiodobenzoic acid derivative patented by Pharmacia Aktiebolag as X-ray contrast agent for Coronary Angiography.

Iolixanic Acid is triiodophenoxyalkoxyalkanoic acid derivative patented by Bracco Industria Chimica S.p.A. as diagnostic agent for cholecystography.

Ioseric Acid is triiodoisophthalamic acid derivative patented by Schering A.-G. as x-ray contrast media