Iodinated contrast
Encyclopedia
Iodinated contrast is a form of intravenous radiocontrast
(radiographic dye) containing iodine
, which enhances the visibility of vascular structures and organs during radiographic
procedures. Some pathologies, such as cancer
, have particularly improved visibility with iodinated contrast.
Iodinated contrast media may either be oil
-based or water-soluble
, the former of which is slowly absorbed by body tissue and is usually only used in sialographic
and hysterosalpingographic
examinations. Water-soluble iodinated medium, which is more quickly absorbed, may be used in place of barium sulfate
for gastrointestinal studies that are contraindicated by the use of barium for that reason.
Iodinated medium may also be either ionic or non-ionic. The ionic type tends to create a high osmolality
in blood
and may cause a contrast media reaction in some individuals, which may be life-threatening for those with certain medical conditions. The non-ionic form decreases this risk, but is much more expensive. The non-ionic contrast media is much more widely used today.
Shortly after infusion, iodinated contrast medium causes a warming sensation throughout the body. Sometimes this feeling is more pronounced in the pelvic area. Patients receiving contrast via IV typically experience a hot feeling around the throat, and this hot sensation gradually moves down to the pelvic area.
Iodinated contrast is toxic to the kidneys
and kidney function of the patient receiving a dose should be considered before the exam. The estimated glomerular filtration rate (eGFR
) should be no lower than 30 mL/min in patients receiving iodinated contrast, and discretion should be used in patients with eGFR less 45 mL/min. Following up with extra fluids after an injection is highly recommended.
Radiocontrast
Radiocontrast agents are a type of medical contrast medium used to improve the visibility of internal bodily structures in an X-ray based imaging techniques such as computed tomography or radiography...
(radiographic dye) containing iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
, which enhances the visibility of vascular structures and organs during radiographic
Radiography
Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....
procedures. Some pathologies, such as cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, have particularly improved visibility with iodinated contrast.
Iodinated contrast media may either be oil
Oil
An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils....
-based or water-soluble
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
, the former of which is slowly absorbed by body tissue and is usually only used in sialographic
Sialography
Sialography or radiosialography is the radiographic examination of the salivary glands. It usually involves the injection of a small amount of contrast medium into the salivary ducts of a single gland, followed by routine X-ray projections....
and hysterosalpingographic
Hysterosalpingography
Hysterosalpingography is a radiologic procedure to investigate the shape of the uterine cavity and the shape and patency of the fallopian tubes. It entails the injection of a radio-opaque material into the cervical canal and usually fluoroscopy with image intensification...
examinations. Water-soluble iodinated medium, which is more quickly absorbed, may be used in place of barium sulfate
Barium sulfate
Barium sulfate is the inorganic compound with the chemical formula BaSO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium and materials prepared from it...
for gastrointestinal studies that are contraindicated by the use of barium for that reason.
Iodinated medium may also be either ionic or non-ionic. The ionic type tends to create a high osmolality
Osmole (unit)
Osmolarity is the measure of solute concentration, defined as the number of osmoles of solute per litre of solution . The osmolarity of a solution is usually expressed as Osm/L , in the same way that the molarity of a solution is expressed as "M"...
in blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
and may cause a contrast media reaction in some individuals, which may be life-threatening for those with certain medical conditions. The non-ionic form decreases this risk, but is much more expensive. The non-ionic contrast media is much more widely used today.
Shortly after infusion, iodinated contrast medium causes a warming sensation throughout the body. Sometimes this feeling is more pronounced in the pelvic area. Patients receiving contrast via IV typically experience a hot feeling around the throat, and this hot sensation gradually moves down to the pelvic area.
Iodinated contrast is toxic to the kidneys
Nephrotoxicity
Nephrotoxicity is a poisonous effect of some substances, both toxic chemicals and medication, on the kidneys. There are various forms of toxicity. Nephrotoxicity should not be confused with the fact that some medications have a predominantly renal excretion and need their dose adjusted for the...
and kidney function of the patient receiving a dose should be considered before the exam. The estimated glomerular filtration rate (eGFR
Renal function
Renal function, in nephrology, is an indication of the state of the kidney and its role in renal physiology. Glomerular filtration rate describes the flow rate of filtered fluid through the kidney...
) should be no lower than 30 mL/min in patients receiving iodinated contrast, and discretion should be used in patients with eGFR less 45 mL/min. Following up with extra fluids after an injection is highly recommended.