Which type of contrast media is associated with higher osmolality?

Ionic contrast media are associated with higher osmolality due to their molecular structure. These types of contrast agents have charged particles, which increase the number of osmotically active particles in a solution. The higher osmolality can lead to increased risk of adverse reactions, such as renal effects or discomfort for the patient during administration.

In contrast, nonionic contrast media have lower osmolality, which results in fewer charged particles in solution and generally a better safety profile with reduced adverse reactions. The presence of CO2 as a contrast medium does not pertain to osmolality in the same way, as it's a gas rather than an ionic saline solution. Isotonic solutions maintain normal bodily fluid osmolality, but they don't specifically refer to the properties of contrast agents used in imaging. Thus, ionic contrast media are distinctly characterized by their higher osmolality compared to nonionic alternatives.