Iodinated contrast media contain small amounts of free iodide. Too much free iodide in the blood may cause hyperthyroidism in patients at risk, but contrast medium induced thyrotoxicosis is rare. The free iodide may also interfere with nuclear medicine diagnostic tests and treatment. However, iodinated contrast agents do not affect thyroid function tests (e.g., T3, T4, TSH) in patients with a normal thyroid.
Guidelines were prepared by the 'Contrast Media Safety Committee of the European Society of Urogenital Radiology' and discussed on the Tenth European Symposium on Urogenital Radiology in September 2003.
Tests of thyroid function before the injection of contrast agents may only be indicated in areas with dietary iodine deficiency. Patients with Graves' disease, multinodular goiter with thyroid autonomy, especially elderly and patients who lives in areas of iodine deficiency are at risk to develop thyrotoxicosis after IV contrast medium and should be monitored by endocrinologists after contrast enhanced CT exams. Prophylaxis may offer some protection in selected high-risk individuals but is not generally recommended.
The free iodide of iodinated contrast agents interferes with thyroidal iodide uptake and impedes diagnostic thyroid scintigraphy and radio-iodine treatment of thyroid malignancies for 2 months after administration.

Isovist® is a nonionic x-ray contrast agent. Isovist® is suitable for intrathecal applications for example CT myelography, cisternography, the evaluation of cerebrospinal fluid (CSF) circulation and for use in other body cavities. Opacification is directly visible after administration of Iotrolan to the spinal subarachnoid space and various open body cavities. Isovist® flows with the CSF through the arachnoid villi into the venous blood.

Isovue® is a nonionic contrast agent with a wide range of iodine concentrations.
Isovue-370 with its highest concentration of contrast approved for CT is an excellent agent to match the speed and power of multi-detector row CT (MDCT). Prefilled syringes provide easy and efficient contrast media handling. Isovue-M® is indicated for CT myelography.

See also Contrast Media Injector, Single-Head CT Power Injector, Multi-Head Contrast Media Injector, Syringeless CT Power Injector.

A joint scintigraphy is a nuclear medical study to detect active joint disease (for example arthritis, osteomyelitis and synovitis). Joint scintigraphies are possible with different radiopharmaceuticals as 99mTc-Tc04, 99mTc nanocolloid (NC) or 99mTc-IgG. Joint scintigraphy is a procedure for a specific purpose rather than a routine test.

See also Bone Scan, Bone Marrow Scintigraphy and Multiphase Bone Scintigraphy.

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.