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Positive and Negative Compare Media

In the field of radiology, some exploration or method on a patient looking for contrast into the patient's body through a vein, artery, mouth area or anus, which is situated in the body. Because the technology of the age of the 1950s, iodine distinction marketing (ICM) is obviously more secure have been used thoroughly, almost daily use and is a widely used drug in health background. Various varieties and types of distinction mass media was used for the introduction of medical imaging. Most up to date diagnostic imaging comparison agents is determined by this. Such as for example pharmaceutical drugs most others, this distinction agent was minimal negative effects even with a good basic safety record and proven drugs/drug is safe for use.

If seen on x-ray film, there are usually pictures of the anatomy such as bone, and there also shows up a white colored gas that surrounds round the organs. The true aim is the utilization of contrast multimedia to boost the thickness of the organ is usually not visible on radiographs, such as passage of urine or blood vessels, which originally didn't look at regular breasts x-ray contrast mass media aren't used. After software of contrast mass media, the causing image will be white showing a hidden organ. Contrast media is composed of two types of ionic and non ionic distinction media is devided into two categories

  • Positive comparison media
  • Negative compare media

Positive compare media

Positive contrast agents are agents that have the atomic mass and a higher rate of obstruction (attenuation) high. So these real estate agents are indeed radiopaque material. Positive contrast media are as iodine, bromine, and barium.

Typically, these materials will be included into the body (relating to appropriate steps) and comparison agents will meet the target organ. Effects ensuing radiopaque would explain the problem and framework of the body organ / tissue directed at radiographic images. Generally, a confident contrast agent is the key to making certain the individual has allergy symptoms or not for selecting the contrast press can be personalized to the patient to avoid the effects of anaphylactic distress.

Negative contrast media

One of x-ray absorption is the weight of the atomic mass of a substance. In the event the atomic mass is low, the result of obstructions (attenuate) is low and the change occurs when the atomic mass rises. Once the mass of the atom is high, it will produce an impact of density / contrast radiography of the image because the image can be more permeable and dark. This feature pays to when an anatomical composition is shown with a background of very permeable and the large difference in contrast between the image and the background (without producing blur the limitations between image and track record).

Contrast media such as air (air, skin tightening and, etc. ) are good examples as negative distinction agents. Negative comparison agents often found in conjunction with distinction providers positf and one common procedures often incorporate the utilization of these real estate agents were negative dual barium enema.

Examples of gas used to create negative compare in radiographic images:

Carbon dioxide

Produced in the gastrointestinal tract (GIT) with barium sulfate to demonstrate mucosal pattern. Two times contrast barium meals for example. Carbon dioxide can even be produced by the colon when given two times contrast advertising, as it reduces pain and reducing stomach uncomfortableness immediately.


Produced in the torso cavities such as in the knee when analyzing arteriogram to show the leg joint.


Produced by the patient through the radiographic exam, for example, required a deep breath and carry during chest evaluation.

Basic iodine comparison media

Several investigations in the radiology needs of this contrast in to the patient's body by way of a artery or a vein. A consistent example is the intravenous urogram. Usually only the bones and the wind flow will be visible on x-ray images. To distinguish the road of blood vessels in the urine or blood vessels, contrast media including iodine to be put into increase the intensity of blood vessels or urine. Then, this may cause the structure to look 'white' in films such as the bone fragments of patients in x-ray images.

Classification of Compare Media

There are two parts: the ionic and non ionic.

Ionic mixture is divided into two parts; higher level of osmolar comparison media(hocm), and low level of osmolar contrast media(locm). This classification is based on the iodine amount of allergens (generally as components of contrast media is generally used in the procedure IVU) soaked up / dissolved into the blood. When the rate of absorption of iodine is too much, it can decrease the blood circulation in to the central anxious system (hyperosmolality). This situation is a significant factor many negative reactions to patients anticipated to contrast marketing that aren't appropriate.


Rate of osmolality(mOsm/kg)

High-osmolar distinction media


low-osmolar comparison media


Non-ionic compounds




Cerebrospinal Fluids



Content molecules tightly to the anion and cation (positive and negative) in the bloodstream leading to high osmolality - harmful / response high. Properties of molecules containing benzene rings, for example - salt mixture meglumine diatrizoate and diatrizoate sodium (Renografin 60 and Hypaque 76 - osmolaliti high)

Characteristics of iodine comparison agents;

i. Osmolality (no liquid particles in 1 kg of drinking water)

ii. viscosity - how big is the rejection of (resistant) to the stream of essential fluids (viscosity / focus)

iii. Toxicity - (poisoning / injury), it is dependant on the molecular settings.


Molecules are not settled in the fluid / blood. For instance, a mixture of sodium diatrizoate (iopamidol, isovue, iohexol / omnipaque)

- Methods of health care;

i. Cannot exceed the medication dosage.

ii. Stay away from sunlight.

iii. Stored at room heat.

Reactions to contrast agencies - iodine:

Use of Iodine compare press (ICM) can cause negative effects and manifestations of anaphylaxis. Symptoms include nausea, throwing up, erythema area, generally a hot feeling, frustration, coryza or larynx edema, fever, sweating, astenia, dizziness, paleness, dyspnoea and moderate low blood pressure. more serious reactions in such as vasodilatation cardiovasluar system with pronounced peripheral hypotension, tachycardia, dyspnoea, action, bluish condition of the skin(cynosis) and lack of consciousness, needs disaster treatment. With respect to this reason the use of contrast press should be limited in conditions of diagnostic techniques must be shown. Unwanted effects associated with use of intravascular comparison medium is frequent iodinated of natural light to average and temporary, and less often by non-ionic than ionic preparations. Unwanted effects to ICM are categorised as special and nonidiosyncratic. The pathogenesis of the effects may involve direct effects of mobile phone; enzyme induction, and activation of quinine, fibrinolytic go with, and other systems.


Firstly, check the history of the individual. Make certain the reading of the BUN-blood urea nitrogen (8-25mg/dl kretinin) - (0. 6-1. 5 mg / dl). Activities taking steroid / anti-histamine before comparison examination. Check patient center condition. If the individual have Multiple myeloma or myelo dysplastic symptoms or severe diabetes (preferred drink a great deal of water).

Anaphylactic great shock.

The other name is Vasogenic shock. Histamine is released in respond to an antigen (foreign substance). They give effect to;soft muscle - triggering bronchial spasm (bronchospasm) respiratory (sneezing, wheezing, a pilot). Increased vascular permeability - (urticaria, edema of the mucosa, red areas (rash). Increased secretion of mucous glands (nausea, throwing up).

Sign of the sign(anaphylactic surprise) are patients will start to be Agitated. Rate of pulse will be increased greatly. The patient came out pale and weak and lifeless body. They do not be capable of think too long. The patient seems chilly, sticky and itchy skin area. skin of the patient will be reddish and noticed (urticaria). Patient's throat just like a choking / strangulation and Trouble deep breathing.

Mild symptoms

Weak medical indications include the following disease: dispersed urticaria, which is the very commonly stated as adverse effect; sickness of pruritus; rhinorrhea; quick retching or nausea / vomiting; dizziness, diaphoresis; coughing. Patients with slight symptoms should be seen about the development or development of a more severe impact, which needs treament.

Moderate symptoms

Medium symptoms include the following: regular vomiting; diffuse urticaria; pain in mind; facial oedema; laryngeal oedema; weak bronchospasm or difficulty in respiration; palpitations, rapid heart beat(tachycardia), or slowness of pulse (bradycardia);high blood circulation pressure; and abdominal spasms or cramps.

Severe symptoms

Acute symptoms include the next: life-threatening arrhythmias (in example; ventricular tachycardia), laryngeal oedema, faint, over bronchospasm, pulmonary oedema, spasm, low blood pressure, and fatality.

Comparison of compare agents:

Ionic agent

Non-ionic agent

Toxicity - high risk of allergy

Toxicity - less / low risk



Osmolality high

low Osmolality

High viscosity

low viscosity

Contrast media necessary for Radiological exam:

To distinguish the path of blood in the urine or bloodstream vessel, usually just the bones and mid-air will be visible on x-ray also to improve the thickness of urine or bloodstream.

Advantages of contrast media:

  • easily dissolved.
  • Inert
  • Provide better mucosal detail
  • There is not a osmotic effect, so the radio density is long-lasting.
  • Cheap
  • Relatively delicious

Disadvantages of comparison media:

  • Aspiration pneumonia if inhaled.
  • If got leakage in to the cavity or organs of the body. It can't survive indefinitely and may cause granulomatous reactions.

Contrast advertising management

Reactions that occur as the procedure of compare media are not predictable, and the individual should be observed carefully through the procedure. The following is standard advice to be given by an x-ray comparison multimedia as well as released to the individual.

  • explain to the patient about the task in detail
  • the patient and medical history
  • approved by doing the individual consent form
  • check the serial amount or code and expiry date of contrast material
  • free virus check up on each machine and packaging that will be used
  • ensure that crisis equipment used are provided
  • patients should drink plenty of water and make sure the patient's body dehydration. A lot of the contrast mass media will be away through the urine after four hours
  • make sure the distinction agent used was based on body temperature
  • need to consider special protection and be alert of additional hazards that may be produced as severe cardiovascular disease, severe renal impairment, asthma or a brief history of allergies, suspected a higher awareness of iodine, an extremely old (> 65 years) and incredibly young (
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