(LOCM) Low-osmolar contrast media have a wide range of indications due to their lower side effects. The type of contrast media is an important risk factor for an adverse reaction.
LOCM have not completely replaced contrast media with higher osmolality due to their higher cost. Guidelines of professional organizations give recommendations for the selective use of low-osmolar contrast media for certain high-risk patients.
There are ionic and nonionic iodinated contrast materials with low osmolality available:
An adverse reaction occurs in low-risk patients who receive conventional ionic contrast agents more often than in high-risk patients who receive nonionic LOCM.

See also Contrast Enhancement, Biliary Contrast Agents, Safety of Contrast Agents and Contrast-Induced Nephropathy.

Nonionic contrast agents are a group of contrast media that do not dissociate into charged particles. Many of the side effects of contrast agents are due to the injection of a solution with high osmolality compared to blood. Nonionic contrast agents have a low osmolality and tend to have less toxicity. However, as with all iodinated contrast agents, serious or fatal reactions have been associated with their use.
Due to their lower neurotoxicity, nonionic contrast agents can also be used for myelography. The only FDA approved agent, iodixanol, is iso-osmolar to blood, which makes it preferable for examinations of the central nervous system and cardiovascular studies. Because of its higher costs relative to other nonionic agents, the use is sometimes reserved for patients with high risk of nephrotoxicity.

See also Nonionic Dimer, Nonionic Monomer and CM Ratio.

Omnipaque (iohexol) is a nonionic, low-osmolar contrast agent and is also available for oral use, offering gastrointestinal (GI) visualization with minimal side effects. Omnipaque has a neutral taste that even kids will drink.
Orally administered iohexol is poorly absorbed from the normal gastrointestinal tract. Omnipaque is well tolerated and absorbed if leakage into the peritoneal cavity occurs.
The recommended dosage of undiluted Omnipaque (at a concentration of for example 350 mg/mL) for computed tomography of the abdomen in adults is 500 mL to 1000 mL, diluted to concentrations of 6 mg/mL to 9 mg/mL. The oral dose should be administered about 20 to 40 minutes prior to the CT scan.

Smoothies are barium sulfate suspensions with different flavor. The good taste improves the patient compliance. Smoothies have minor side effects such as nausea, diarrhea and bloating.
Smoothies fast transit time allows imaging the abdomen 30 min and the pelvis 90 min after application.

A coronary angiogram (or cardiac catheterization) is the radiographic visualization of the coronary arteries after the introduction of a contrast agent. A coronary angiography can be performed for both diagnostic and interventional (treatment) purposes.
A catheter, inserted into a major blood vessel has to be maneuvered up to the coronary arteries to inject a blood compatible iodinated contrast material (dye). The x-ray visible catheter allows injecting a small amount of contrast agent selectively in the coronary arteries or the heart chambers. Continuous images are recorded (movies or cineangiogram) in multiple views from different angles are in order to ascertain the precise location and severity of coronary artery blockages. Digitized images are also saved on computer and replayed onto a video screen as needed.
A coronary angiogram is more invasive and requires more patient recovery time than coronary CT angiography. In the past, the gold standard for detecting atherosclerotic plaque was a coronary angiography and intravascular ultrasound. Today, the American Heart Association considers CT scanning to be one of the most effective, non-invasive methods for the detection of calcification in the coronary arteries.

See also Interventional Radiology.