Contrast agents (also known as contrast agents and contrast media) is to enhance the imaging observation of effect of injection (or take) to tissue or organ of the body chemical. These product density is higher or lower than the surrounding tissue, form a contrast with some devices display image.
With the development of imaging diagnosis instruments and equipment, not only have x ray contrast agent, also ultrasound contrast agent, computer tomography, digital subtraction angiography and the special contrast agent for magnetic resonance imaging. So many types of contrast agents how to differentiate, we now regarding the classification of the type of contrast agent.
Contrast agents can be divided into two categories, high atomic weight, heavy, dense contrast medium and low atomic weight, the proportion of small low density contrast. High density contrast agents: commonly used high density contrast barium sulfate and iodine preparations.
1, barium sulfate: generally used for gastrointestinal examination, by pure medicinal powder made from water suspension of barium sulfate. Barium sulfate concentrations are usually based on the weight/volume (W/V) said that according to check sites and for different purposes, with barium sulfate concentration is different.
2, iodine preparations: many kinds of iodine preparations, can be divided into three categories, namely, organic of inorganic iodine iodide iodide and iodized oil or fatty acids.
⑴ General inorganic iodide with sodium 12.5% iodide aqueous solution.
Can be used for a fistula, urethra, bladder, or retrograde pyelography. When used for cystography, 1 time diluted concentrations.
B organic iodide: water-soluble iodine preparations, variety, can be divided into:
① Ionic: Ionic contrast media according to the structure into a single acid monomer and Dimer acid. Representatives of acid monomer drug meglumine diatrizoate (can be used for a variety of contrast-enhanced angiography and intravenous Renal pelvis. When used in different organs and different concentrations), meglumine iodine him. Acid Dimer represents ioxaglic acid.
High incidence of side effects of ionic contrast medium, the body of poor tolerance.
Second, the non-ionic: such as Iodobenzene six alcohol (iohexol), iopromide (iopromide) and iodine (iopamidol).
Non-ionic iodinated contrast Ionic low toxicity and can be used for every kind of angiography and vascular angiography. Non-ionic contrast medium low incidence of side effects, the body is well tolerated.
③ non-ionic Dimer such as iodine Qu Lun (iotrolan), used for spinal canal myelography.
C oil or fatty acid-iodide iodide: 40% iodized oil is mainly used for bronchial, fistulas and an HSG (cannot be used for angiography). Iodo ester of fatty acid-iodide, is an oily liquid, because of its less irritating to the Organization, it applies to the spinal canal and ventriculography, in recent years has to be non-ionic Dimer Qu Lun instead of iodine.