Contrast Media Or Contrast Agent Biology Essay

Normally the contrast media is in liquid signifier that introduce to patient. When utilizing contrast agent, it give the information about size, form and the location of the peculiar variety meats. Contrast media can administer to patient in several manner. Example through the oral cavity means imbibing the contrast solution. Through the injection from vena, arteria or through the anus.

Researchs try to bring forth ‘ideal ‘ contrast agent but there are no contrast agent in universe that can be consider as ‘ideal ‘ contrast agent. The demand for the ideal contrast for safe and effectual application is easy to administrate, non toxic, a stable compound, non carcinogenic, cost effectual, good tolerated by patient and quickly eliminated when necessary.

The choice for contrast media for radiographic scrutiny must be really careful. Because the specific contrast agent will give specific impact to patient. This of import for radiographer to cognize type of contrast had been use and the physical and physiological of the relevant contrast.

In radiology section, many process that utilizing contrast agent is inject through the blood vass and radiographer must cognize the sort of and the location of blood vass. Example of this process is endovenous urogrphy, and scrutiny of GI piece of land ( GIT ) .

Contrast media is categorization harmonizing to the osmolality ( mosm/kg water ) , iconicity ( ionic or non Attic ) , type of molecule ( monomer or dimmer ) and viscousness at 37 & A ; deg ; C

Osmolality is a concentration of osmotically active solute in organic structure fluids. Viscosity is opposition of fluid to flux. It is a criterion used as a force needed to travel H2O 1cm at 20 & A ; deg ; C and It express in term of centipoises ( CP ) .it depend on the molecular weight, construction and temperature.

Type of contrast media

Contrast media can be divided into two chief classs, which is:

1. Negative contrast media

2. Positive contrast media

Negative contrast media

Negative contrast media is a radiolucent mean can perforate or go throughing by X ray. This sort of contrast media usually have low atomic figure and more ready for penetrated by X ray than environing tissues. Negative contrast media appear darker in the image that produces due to the less effectiveness to absorb x-ray. Usually gasses are utilizing to bring forth negative in image.

Air, O and C dioxide can be use as a negative contrast media in diagnostic section and can blend with H2O suspension Ba sulfate to bring forth dual contrast media in scrutiny of GI piece of land. Air is usage in thorax scrutiny through the inspiration to bring forth dual contrast and appear in country of lung field. Oxygen is applied into organic structure pit for the scrutiny in the articulatio genus to demo the articulatio genus articulation. Carbon dioxide is use with Ba sulfate solution in GI piece of land scrutiny to demo mucosal form. Carbon dioxide besides use with iodized contrast media in diagnostic angiography and vascular interventionism both the arteria and venous circulation.

With development of new engineering today like Computed Tomography and Magnetic Resonance Imaging the utilizing of air as a negative contrast in encephalography and myelograophy about no more apply. One of the effectivity utilizing air as a negative contrast in alimental canal is no have any inauspicious consequence compared to other due to volume of gas

Positive contrast media

Positive contrast media is a wireless opaque ( opposite radiolucent ) and have high atomic figure. So, it made x-ray less penetrate mean less absorb by this sort of contrast. This will ensue this sort of contrast appear denser than organic structure tissue or look as a white in image. Barium and iodine based solution is one of the contrast usage as a positive contrast agent in radiology.

Normally positive contrast agent is divided into I based and non I based. Non I based is a Ba sulfate. Iodine based contrast media can split into four groups depending on their molecular construction ; there are:

1. Ionic monomer ( high osmolar )

2. Ionic dimmer ( low osmolar )

3. Non ionic monomer ( low osmolar )

4. Non ionic dimmer ( isosmotic )

# ionic contrast average I incorporating contrast

# Monomer mean individual molecule.

# osmolarity is measurement the solute concentration and express min term of osmoles.

# osmolality is measuring of the osmoles in solute in solvent per kilogram.

The basic molecule Iodine incorporating contrast media s benzene ring and the carboxyl acids is added to do it soluble.

Iodine based contrast agent chiefly is used to visualise blood vass and can non utilizing in urinary system scrutiny. They are utilizing in

a. angiography ( arterial probes )

b.venograhy ( venous probe )

c.VCUG ( invalidating cystourethrrography )

d.HSG ( hysterosalpinogam )

e.IVU ( endovenous urography )

Non I based contrast media

We have much type of contrast media that use much scrutiny in imaging section.

The choice of contrast media is depending on physical and chemical belongingss of relevant contrast media. For radiographic scrutiny of GI piece of land ( GIT ) , the contrast agent that we utilizing is barium sulfate ( BaSo4 ) is a type of non I based contrast media. Barium sulfate has few characteristics make it suited for imaging of GIT, which is:

1. High atomic figure ( 56 )



4. cost effectual

5.good coating belongingss.

Barium sulfate ever have good coating belongingss than I based contrast media and easy to organize thin bed at the surface of bowel. When there is perforation in GIT, the Ba sulfate flight from the GIT and run out into peritoneal pit will do inflammatory, peritoneal inflammation and hypovolaemic daze. Fluid replacing therapy, steroid and antibiotic is needed to handle complication that has reference.

The concentration of Ba in the solution usually is express as the per centum weight to volume ratio ( W/V ) .the significance of 100 % w/v solution is the solution contain 1 gm of Ba sulfate per 100 milliliter of H2O and the denseness of Ba is depend on the weight volume. When fixing the Ba solution for radiographic scrutiny, it is of import to look into the termination day of the months and guarantee the wadding is integral. Patient history besides must detect for the any contraindication. The following are contraindication for Ba sulphate solution:

a. Suspected perforation

b.suspected partial or complete stricture

c.paralytic intestinal obstruction

When there has contraindication for GIT scrutiny. Water soluble, iodine based contrast media ( gastrografin or gastromiro ) can be use either orally, rectally or automatically ( via pore ) .

Possible side consequence of contrast media

Possible side consequence of contrast media can split into primary consequence and secondary consequence.

Primary consequence is involved the image quality that have produce. For illustration when compare the ionic monomer contrast media with the ionic dimmer contrast media, ionic dimmer contrast media have big molecular compared to monomer and easy spread across vas wall from vascular infinite. The osmotic consequence will decreased by utilizing monomer due to the little size molecular.

Secondary consequence is reaction of patient toward the contrast media. The reaction of patient toward the sort consequence can divide into three type, which is mild, moderate and terrible reaction. The inauspicious consequence can happen instantly, hold, after, or during administered of the contrast media. The per centum when utilizing high osmolality contrast media and low osmolality contrast media is 5-10 % and 1-3 % .

The mild reaction merely needed a careful observation of the patient. The most the mark and the symptom will look few minute after administrate of contrast media. The mark and the symptom including:

Nausea giddiness

purging agitating

cough flushing

heat nasal stuffiness

concern swelling oculus

This sort of reaction does non required intervention and the mark and the symptom that appears is a ego limited, without farther proggession.requires observation to corroborate declaration or deficiency of patterned advance.

The mark and the symptoms of moderate reaction are more pronuced.The mark and the symptoms including:

Tachycardias generalized or spread erythema

bradycardia brochospasm

high blood pressure laryngeal hydrops

dsypnea mild hypotension

Moderate reaction require intervention, near and careful observation for possible patterned advance to a life threatening.

The terrible reaction frequently is life endangering and the intervention including drug therapy, which is:

Laryngeal edema paroxysm

unresponsiveness profound hypotension

cardiorespiratory apprehension clinically manifest arrthymias

This requires prompt acknowledgment and aggressive intervention, manifest actions and the intervention often require hospitalization. It is of import to detect the patient during and after contrast media.the volume of contrast media that administrate to patient is no straight relationship to the consequence. Cardiopulmonary resuscitation ( CPR ) equipment should be available when the contrast media are utilizing. The radiographer must hold trained how to use CPR.

The ABCD attack system is apply to handle the patient. While ABCD is represent Airway unfastened, Breathing restored, Circulation maintained and Drug and unequivocal therapy. Emergency carts should act in imaging section.

Airway unfastened

Use the O when hypoxia occurs to the patient. Administrate O by the mask is critical and should make instantly

Assessment, assess the patient blood force per unit area, pulsation to look into normal or non. Electrocardiogram proctor may necessitate to for measure the cardiac beat.

Aid, name the infirmary aid squad when necessary to guarantee patient safety.

Breathing restored.

Breathing, get down the CPR when necessary and utilize the oral cavity proactive barrier for safety safeguard. Radiographer must hold knowledge how to execute CPR. If the radiographer does n’t cognize how to make CPR, do n’t blow the clip and instantly name cardiorespiratory squad.

Bag valve ( ambu bag ) or mouth mask can be use to administer O to patient. Radiographer must do certain the equipment is available in where the contrast media is used.

Beware of typically manifestation

Circulation maintained

Circulatory aid, to administrate isosmotic fluid ( normal saline ) , infuse quickly and may utilize force per unit area bag or forceful extract

categorise the reaction and patient position.

Drug therapy

utilizing the drug therapy when demand. Make certain utilizing right sum, dosage and route drug.

Make monitoring, buttocks and reassure the patient

do n’t detain name for aid

do n’t utilizing incorrect dose and drug.

Equipment for exigency carts

Radiographer is responsible to look into out the all the of import equipment are available before the administer the contrast media in imaging section. The followers should be in the exigency carts:

Oxygen cylinders

Oxygen mask or ambu bag

Normal saline

Acerate leafs

Necessary drug and medicine



Blood force per unit area or pulse proctor

Pulse oximeter.

Medicine like adrenaline, histamine, and acetylsalicylic acid should act.

Allergy reaction

it is hard to cognize what sort of contrast media will give allergy action to patient. So, this really of import to look into the patient history sing the contrast media. If patient have history of hypotension, inborn bosom failure, diabetes mellitus, kidney severe, the contrast media can non be usage to the patient. Non ionic contrast media can be applied after given antihistamine to the patient. Must ever observe the patient.

General considerations

The attack to patient about to undergo a contrast media scrutiny to heighten the image quality has 3 general ends: assure that the disposal of contrast is suited for the patient and run into the demand of the indicant.

2. To minimise the similar goon of contrast reaction to patient be to the full fix the intervention for the reaction that occur.

Before the disposal of contrast media, the readying must be done is:

1.get appropriate and equal history of each patient

2.preparing the patient suitably for the scrutiny

3.having equipment available to handle the reaction

4.ensure the expertness is sufficient to handle even the most terrible reaction.

For any scrutiny that involved the contrast media, seek to take the contrast which is non ionic, monomer, low osmolality and low viscousness.

Why low osmolality and viscousness:

a. can minimise hazard of harm to the blood-brain barrier

b. less clip and cost

c. less radiation exposure

d.smooth blood flow

e. no harm to endothelium and to blood cell

Patient attention

The whole process must explicate to the patient including the side consequence and complication of contrast agent and do certain the patient understanding the process and why utilizing contrast media. After that patient are required to subscribe the consent signifier before scrutiny.

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