Contrast media

This article reviews the most recent papers on contrast media reported from October 1989 to September 1990. Areas of focus include water-soluble contrast agents and barium agents.     

Contrast media research

This selective review highlights research in contrast media development and application in the field of diagnostic radiology in 1998 and 1999. The focus is on research published in Investigative Radiology, supplemented with work from other publications in the few areas not extensively covered by the journal. Studies continue to be performed, although at a low level, examining safety issues. Most preclinical investigations have focused on MR and ultrasound agents. In MR, the research effort is concentrated on the development of targeted agents; in ultrasound, work is focused on the characterization of basic contrast mechanisms. The demonstration of clinical applications is still dominated by work with MR, both in disease models and human investigations. The use of extracellular gadolinium chelates to enhance visualization of blood vessels (the field of contrast-enhanced MR angiography) is the largest single new clinical application of contrast media to emerge in several years. New clinical applications continue to be pursued with contrast media in CT, ultrasound, and x-ray angiography. As intravenously injected ultrasound contrast agents come to market, trials demonstrating clinical applications and subsequent scientific publications will increase in number.     

Radiological contrast media

1. This author believes that the present evidence (water shifts and vasodilatation) strongly indicates that low osmolality is probably the main advantage of the new contrast media. 2. Arteriographic adverse reactions (pain, vasodilatation) are less marked with the contrast medium of the lowest osmolality--i.e. ionic ioxaglate salts. 3. Minor adverse reactions (nausea and vomiting) are less marked with some non-ionic media (e.g. iohexol, iopamidol) than with ioxaglate but there are no data concerning the relative incidence of severe reactions or fatalities. 4. Dr. Lasser's suggestion in 1987, that 12 hours of corticosteroid prophylaxis reduces the adverse reaction rate of intravenous HOCM to the rate of LOCM reactions, awaits confirmation. However, corticosteroid prophylaxis will not reduce the side effects due to hyperosmolality, e.g. vasodilation, hypervolemia, and pain (on arterial injection). 5. Unless and until the necessary finances are available, I suggest LOCM (costing 12 times the price of HOCM in Canada and America) be used on a selective and discriminatory basis in three groups of patients: those undergoing painful procedures (e.g. peripheral arteriography), those undergoing potentially dangerous procedures (e.g. spinal angiography, coronary angioplasty) for patients considered on account of their previous medical history (e.g. asthma, allergy, previous adverse reactions, cardiac failure) to be at greater risk than the normal population.     

Catalog of intravascular contrast media

The ionic intravascular contrast media formulations now commercially available are presented, along with those new formulations, nonionic and ionic, that have a significant reduced osmolality compared with those previously available.