Key Properties of Iodinated Contrast Agents That Influence Their Behavior, Efficiency, and Adverse Reaction Risk

Contrast agentIodine concentration (mg/mL)Osmolality (mOsm/kg water)Viscosity (mPa/s) (37°C)
Ionic monomer (HOCM)Up to 4001,400–2,100
Ionic dimer (HOCM)320600
Nonionic monomer (LOCM)Up to 350600–800
Nonionic dimer (IOCM)320290
Human serum3.2–42901.5–2.0
Ionic monomers
 Amidotrizoic acid1461,6908.5
Ioxitalaminic acid2,130
Nonionic monomers
 Iohexol240, 300, 350500, 690, 8803.3, 6.1, 10.6
 Iopamidol200, 300, 370413, 616, 7962.0, 4.7, 8.6
 Ionic dimers ioxaglate3205807.5
Nonionic dimers
  • Optimizing key properties of intravenous CT contrast agents has resulted in evolution to those that are easier to use, with lower intravenous toxicity and fewer adverse effects (frequency and severity) (6,8,12).