Osmolality is the number of moles of osmotically active particles (molecules) present in solution per kilogram of water.
High osmolality of contrast agents is related to some of the adverse reactions.

Osmolality of iodinated contrast media:

Conray® is a contrast agent intended for intravascular administration as a diagnostic radiopaque medium. Conray® is rapidly transported through the circulatory system to the kidneys and is excreted unchanged in the urine by glomerular filtration.
See also Ionic Contrast Agents, Contrast Media Injector, Dual-Head CT Power Injector, CT Power Injector.

Hypaque 76 is a radiopaque contrast agent supplied as a 76 percent sterile aqueous solution providing 66 percent (w/v) diatrizoate meglumine and 10 percent (w/v) diatrizoate sodium.

GE Healthcare has discontinued Hypaque 76 for unknown reasons.

Hypaque Meglumine is an ionic contrast agent. Hypaque Meglumine 60 percent (w/v) is an aqueous solution containing 60 g of the meglumine salt of diatrizoic acid per 100 mL of solution.
The degree of contrast enhancement at computed tomography is directly related to the amount of iodine administered. In adults the amount of iodine usually required for contrast enhancement ranges from 28 to 42 g.
Hypaque Meglumine is also available in concentrations of 18% and 30%.

Hypaque Sodium is a high-osmolar, water-soluble contrast agent. In pure form, it contains 59.87 percent organically bound iodine.
The dosage of contrast media is depended on the type of radiological procedure and should be tailored individually according to age, body size, and indication for examination.