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Contrast media agents used to improve the imaging of organs in a similar range of contrast radiography.Â Contast technique provides detailed body size, shape, position and internal parts.Â In some cases, assessment of organ functions allowed.
Ideal material difference must be:
c) to continue for a long time
D) is simple and totally eliminated from the body
F) has a different absorption of a series of interest
Â Â Contrast agent in medical terminology, is defined as exogenous substances that are used to increase the visibility of the structure or fluid in the body.Â Exogenous substances to change the contrast in X-ray images with X-rays affects attenuation, allowing the visualization of anatomical structures not easily seen,
a) Blood vessels
c) Dyskinesia / liver channel
SchopnosÅ¥ contrast agent to reduce the x-ray based on the fundamental fact that this substance was introduced into the body becomes both an atomic number higher or lower than the surrounding tissue (this is the number of atoms of each substance that determines how much radiation will weaken)
By accident of history since 1986, the first successful arteriography performed at the hands amputated.
Â Â Â Â A contrast medium comprising a suspension of lime in the water injected into the arteries of the body.Â The first one in the water soluble iodine contrast media used in 1920 and met for the patient suffering from syphilis in those days was treated with sodium iodide.
Â Â Â Â The sodium iodide stomach as seen in the picture "to increase the density" of the kidney.Â Sodium iodide, however, has a high toxicity when used as contrast media
Â Â Â Â Â Â A number of research in radiology will require system administration of contrast into the body through a vein or artery.Â An example is usually an intravenous urogram.There are two types of iodine containing contrast media:
b) Non-ionic (in relation to chemical structure)
Â Â Usually, only the bone, and air, and views on plain radiography (x-ray).Â To illustrate the way pebglihatan urine or blood flow in blood vessels of contrast media, which contain iodine are introduced to increase the density of the urine or blood.Â They will appear in color "white" in the films, such as your bones on x-ray).
A substance used to illuminates certain structures that would otherwise be hard to see on the radiograph ( film)
Substance placed in the body to provide added contrast when subject contrast is low. Increase the radiographic contrast between the areas containing the CM & areas not containing contras media (CM)
Why do we need contrast??
Artificially increase subject contrast in body tissue and areas where there is little natural subject contrast.
Example abdominal viscera have very little natural subject contrast
very difficult to identify specific organ
very difficult to distinguish one organ from another
Factor effecting contrast media
- as concentration of iodine increase, the viscosity thickness increase
- as temperature increase viscosity decrease
Rate of injection
- as the rate increase, the concentration in the blood increased-resulting in a more apparent physiological effect.
Classification of reaction
- nasal stuffiness
- laryngeal edema mild
- laryngeal edema (severe)
Types of contras media
Contrast media can be broadly grouped into two categories
Positive contras media
Non iodine based
Negative contras media
Different types of Contrast Media (Ionic & Non ionic) The strategies above about handling water solubility:
have led to four different types of iodine contrast media for urography, angiography and
(i) Ionic monomeric contrast media
(ii) Ionic dimeric contrast media
(iii) Non-ionic monomeric contrast media
(iv) Non-ionic dimeric contrast media
As the ability to refine the atomic iodine X-rays are free of organic
molecules are chemically bound, the ratio between the side effects:
d) prices of different contrast media should always be made in the iodin equivalent to the amaunt and concentration.
Â (This is important because it is related to side effects;
prices, etc., with the effect of the desired effect of a contrast media, namely its X-ray attenuation, which is comparable to the amount of iodine.
Â Â Â Â
Â Â Â Â In general, a positive contrast media are those that have increased
absorption (attenuation increases) x-ray, and seen as white / gray, while areas
negative contrast are those who have less absorption (lower attenuation) of x-rays and appear as dark areas / gray.
Principles of contrast
Contrast is the difference in radiographic optical density of the radiograph.Â density or density on radiographs made at 50-70 kV is proportional to the square of the atomic number of the network under examination.
Â Â Â Â Contrast media can be divided into positive and negative contrast agents.Â Positive contrast agents have a higher atomic number of the network:
Barium = 56.
Iodine = 53.
Bone = 14.0.
Soft tissue = 7.4.
Fat = 5.9.
Lead = 82
Negative contrast agents are relatively radiolucent due to low specific gravity. Before performing any contrast study plain radiographs must be taken to identify lesions that may be masked by contrast administration, eg radioopaque foreign bodies which may be masked by barium administration.
Risk Contras Media
Grant of contrast material is usually quite safe. However, injection of any kind will bring little dangerous risk including :
a)injury to the nerves
b) vessels artery (artery) or veins (vein)
c) inflammation (infection)
d) an allergic reaction to the injected materials.
Injured blood vessels will cause leakage of contrast material into the surrounding muscle tissue / tissues (Extravasation). This risk was estimated in 0.04% to 1.3%.Other risks / complications of the injection of contrast material especially allergic reaction, and may include:
Mild reactions such as the body feels :
a) Warm (flushes)
c) Itching of red spots
d) swelling (hives)
(A little dizzy with the feeling like vomiting that will disappear in a few minutes)
For the basic iodine contrast material is injected to iron taste in mouth, bad breath out of sorts and body feels warm in the lower abdomen (pelvic) andon the back of the throat.
Rarely a stronger reaction such as asthma(Asthma), shock (shock) and seizures (convulsions).
Emergency supplies are available for events this rare
Death in extremely rare cases, about 1 in injection of 250,000 to 400,000 (0.0004%).
Although less than 1% injected dose absorbed into the ASI (Air Susu Ibu), breastfeeding isrecommended that patients stopped breast feeding (breast milk) for 24 hours afterinjection and discard breast milk after injection of contrast.
Radiographic contrast material
Contrast materials are compounds used to improve visualization (visibility) on the internal structures of a medical diagnostic imaging. Contrast material used in the X-ray imaging to improve X-ray attenuation (positive contrast material) that will be discussed here or greater reduce the power of X-ray attenuation (negative contrast material with air base or gas).
In addition to the contrast material is also used in examining MRI (Magnetic Resonance Imaging), but this method is not based on X-rays, but vary magnetic properties of the hydrogen nucleus absorbs the contrast material. Materials Such contrast MRI with Gadolinium is :
a) Barium sulfate
Barium sulfate, a white powder that was insoluble. This powder is mixed with water and some additional components to make the mixture contrast.
This material is generally only used in the digestive tract, usually ingested or given as an enema. Upon examination, this material will come out of the body along with the feces.
b) Iodine contrast material
Iodine contrast material can be bound to organic compounds (non-ionic) or a ionic compounds. Ionic materials was first made and is still widely used to depend on the intended inspection. Ionic materials have side effect profile is worse. Organic compounds have side effects because there are fewer molecules berdisosiasi the components.
Many of the side effects caused by the hyperosmolar solution which is injected, which These substances lead to more iodine atoms per molecule. The more iodine, then force X-ray attenuation increases. There are many different molecules.
Media iodine based contrast to water soluble and not harmful to the body. Contrast materials are widely sold as a solution of clear, colorless liquid. Concentration is usually expressed in mg I / ml. Modern teriodinasi contrast material can be used in almost all parts of the body.
Most of them used intravenous, but for different purposes can also be used in intraarterial, intrathecal (spinal) and intraabdominally - almost the entire body cavity or a potential space.
c) Chemical composition
Based on the stages of its development, shape and chemical composition of the contrast media :
Before 1950 In this period, all ionic contrast media is iodine, which in arrangement.There is a chemical ion. Ions composing the contrast media consist of :
Mid Year 1950, starting mid-year 1950 established the molecular basis of the use of benzoic each molecule binds three atoms of iodine. At this stage the development of shared becomes :
= Ionic Contrast Material
Ions composing contrast media cations that consist (+ve charge) and anions (-ve charge) ions. Cations bound to the acid radical (-COO-) chain ring C1 benzene.
Cation also gives the characteristics of contrast media, in which each type give different characteristics to each other. There are several kinds of cation.
The use of contrast media, including:
* Sodium (Natrium)
The nature of the sodium in contrast medium was reduced viscosity (viscosity), and fewer anaphylactic reactions caused by reducing substances mnuculnya histamine that cause allergic reactions. On the other hand is more sodium corrosive of cells endothelium and parenchyma of certain organs, making it more toxic of other substances.
* Meglumine (NMG, N-Methylglucamine)
Meglumine have toxic properties are smaller than sodium, but meglumine diuretic effect (reducing the concentration of iodine in the urine).
In the acid type and concentration of meglumine less the same cause increase in blood pressure, bradycardia, and convulsions than sodium.
These substances have properties that are not owned by sodium meglumine maupub, is not have toxic properties and has a low viscosity, but this substance vasodilatation cause strong enough.
In addition to the above materials are sometimes also used cation of calcium (Ca) and magnesium (Mg). To obtain the desired properties of contrast media in radiology pemeriksann usually done some combination of several types of cations in a types of contrast media.
= Ionic Contrast Material Monomer
Monomer ionic contrast materials is a form of ionic contrast material that has one ring in a molecule of benzoic acid.
= Ionic Contrast Material dimmer
Ionic contrast media is having two rings of benzoic acid in one molecule. One example of the shape and chemical composition of this type of contrast material is Oxalate (Hexabrix) which is the first demerit ionic contrast media made :
* Non-ionic contrast materials.
Du the chemical composition of non-ionic contrast media have not found the existence of ionic bonds between the atoms composing the molecule.
If the ionic contrast media, there are two penyususn molecular particles (cations and anions) in the non-ionic contrast material There is only one particle that has a molecular construct its own characteristics.
+ Non-ionic contrast material Manome
Contrast material was derived from an ionic monomer contrast media, which is the replacing the carboxyl group by a radical group that is non-ionic amide (-CONH2).
+ Ingredients Non-ionic dimeric contrast
Formation of the chemical structure of contrast material through the process of replacing the group carboxyl dimmer ionic contrast media as well as by groups of non-ionic radicals, which in kahir sisntesa produce iodine to particle ratio contrast media 6 : 1.
The concentration of active molecules that provide the solution osmotic pressure, so provide the capability of a solvent (water) through a membrane. To set with milliosmol per liter (osmolarity) or milliosmol per kilogram water (H2O) in the 37oC (osmolality).
Osmolality was not influenced by particle size, but its value depends. The total particle concentration and iodine. Ionic contrast material has a number of particles greater than non-ionic contrast material because of the ionic contrast media are two particles (cations and anions) to two times higher osmolality.
OSMOLALITY (m 0sm/Kg) = mgI/ml . K.G
e) Side Effects
Iodine contrast materials that modern medicines are safe reactions dangerous could happen, but not common. The main side effects are anaphylactic reactions and nephropathy.
Anaphylactic reactions are rare, but can occur as a response to the contrast material is injected or given via oral and rectal pyelografi and even worsen. Symptoms are similar to anaphylactic reactions, but not caused by IgE mediated immune response. Patients who have a history of reaction to contrast, at high risk for experiencing reactions anaphylactic.
Anaphylactic reactions ranging from urticaria and can itch, until bronchospasma and facial and laryngeal enema. For cases of moderate and urticaria itching. Benadryl (Diphenhydramine) through the mouth or IV (intravenous) can be given. For reactions are more severe, such bronchospasma and neck or facial edema can be given subcutaneous or epinephrine IV or albuterol inhaler, add Diphenhydramine may required. If respiration is affected, the airway should be released.
Nephropathy caused by Contrast Medium
Contrast media nephropathy could be caused by both the increase in blood keratinize level greater than 25%.
There are three factors associated with increased risk of nephropathy is influenced by the contrast medium, renal disorders are diabetes, and intravascular volume is reduced.
Osmolality contrast material is believed to play an important role in nephropathy. Ideally, contrast material should iso-osmolar of blood. Iodized contrast material that modern typically non ionic, ionic types of old-type common cause harmful effects over and not used again.
To minimize the risk of contrast medium nephropathy as a result, the various actions could be done, all of which have been analyzed in a meta-analysis are :
The dose of contrast media should be tried as low as possible, although still able to conduct inspections added.
Non ionic contrast material
And nonionic contrast media iso-osmolar. One of controlled trials Random discovered that a substance iso-osmolar nonionic contrast is better compared to non-ionic contrast media of low-osmolar.
Hydrasi intravenous fluids with a salt solution.
Intravenous fluid hydration with saline solution plus sodium bicarbonate.