Ionic and non-ionic contrast agents are used in diagnostic imaging to enhance visualization. Key differences are summarized below.
| Feature | Ionic Contrast | Non-ionic Contrast |
|---|---|---|
| Chemical Structure | Dissociate to release ions | Do not dissociate into ions |
| Osmolarity | High | Low or iso-osmolar |
| Incidence of adverse reactions | Relatively higher | Lower |
| Cost | Less expensive | More expensive |
| Example Agents | Diatrizoate, Iothalamate | Iohexol, Iodixanol, Iopromide |
| Clinical use (current) | Rarely used intravenously | Preferred for intravascular use |
| Use in at-risk populations | Less safe | Safer (renal impairment, allergies) |
Non-ionic agents are now preferred due to lower risk of allergic, chemotoxic, and physiologic reactions. Ionic agents are mainly high osmolar solutions with higher chances of nausea, pain, and adverse events. Non-ionic agents are lower in osmolarity, reducing discomfort and complications.