Different types of iodinated contrast
What different types of iodinated contrast are available?
Clinical studies have suggested that the osmolality of contrast might have an impact on the development of CIN. Iodinated contrast media are either ionic or non-ionic, and they are further classified by their osmolality.
Is there one contrast agent that is more nephrotoxic than others?
The first-generation contrast media are ionic high-osmolal agents with an osmolar range of 1500 to 1800 mOsm/kg, compared to plasma osmolality of 290 mOsm/kg.
These high-osmolal agents are no longer used for intravascular contrast administration. In the 1980s, second-generation contrast media replaced high osmolal ionic contrast media because they were less nephrotoxic and better tolerated by the patient.
Second-generation contrast media are known as low-osmolal non-ionic agents, although they are still hyperosmolar at 600 to 700 mOsm/kg. Third-generation contrast media, referred to as iso-osmolol agents, such as iodixanol, typically have an osmolality around 290 mOsm/kg.
Since low-osmolal contrast agents were shown to be less nephrotoxic than high-osmolal contrast agents, it was hoped that iso-osmolal contrast agents would be less nephrotoxic than low-osmolal contrast agents.
While early studies did show a reduction in CIN, subsequent studies were unable to confirm the benefit of iso-osmolal contrast agents.
The current recommendation by experts is to use either low-osmolal or iso-osmolal agents in high-risk patients.