MRI diagnostician

Head of the department, Doctor of Medical Sciences.

Computed tomography is a method of examining the body that uses x-ray radiation to obtain a series of images of the internal structure of the body.

This diagnostic option allows you to examine tissues, vessels, organs as a whole from all sides, from the inside, in section, to identify damage, hematomas, tumors.

A CT scan is more accurate and results in much more detailed images than an X-ray. For greater detail of the picture, if required, the patient is asked to inject a contrast agent.

Computed tomography with contrast - what is it?

CT with contrast is performed in cases where it is necessary to clearly separate normal and pathological structures in the human body, to differentiate organs by enhancing the signal received from veins and arteries. In the image, the contrast is highlighted in white, which allows you to see the details of the selected area of ​​​​the body and put accurate diagnosis.

The contrast agent for CT is usually injected into the cubital vein, but there is an option when the patient drinks a solution with it (only for diagnosing the gastrointestinal tract).

It enters the blood in one of two ways:

1. Manual;
2. Bolus.

In the first option, the injection is made directly by a health care worker, while in the second, a special syringe injector is used with a standardized delivery rate of the substance (3 milliliters per second). Thanks to this, experts easily calculated how many seconds after the arrival of contrast it is possible to record an image in a particular area of ​​the body.

Contrast agent

Many patients are interested in what drug is administered intravenously during CT with contrast? Answer: these are iodine-containing substances. It is iodine that increases the intensity of the image. Water-soluble drugs are quickly absorbed by tissues, therefore, in most cases, they are used. Substances are ionic (the most common, cheaper) and non-ionic (expensive, less toxic).

Before administering a contrast agent, the doctor determines the presence or absence of allergies in the patient, as well as diseases for which contrast is contraindicated. Are tests necessary for a CT scan with contrast? Yes, because this type of diagnosis has a number of contraindications:

• allergic reaction;
• bronchial asthma;
• diabetes mellitus (severe form);
• thyroid diseases;
• renal failure;
• multiple myeloma.

The patient will need to undergo a blood test for biochemical composition. As a result, level indicators are determined
urea, transaminases, creatinine. In this way, a picture of the patient’s condition is compiled before the start of the study - if functional activity is insufficient, or there are any of the above diseases or abnormalities, it will not be possible to perform a CT scan with contrast.

Also unacceptable is any computed tomography (with or without contrast) for pregnant women and people who are overweight (the machine has a kilogram limit).

CT scan with contrast, what drug is administered intravenously is a request of interest to people who want to receive the most detailed information in order to protect themselves from side effects and undesirable effects on the body. Below is a list of iodine-containing substances.

Contrast for CT name, composition:

1. Iopromide, non-ionic;
2. Metrizoate, ionic;
3. Diatrizoate, ionic;
4. Ioxaglate, ionic;
5. Yomeprol, non-ionic;
6. Iohexol, nonionic;
7. Iopamidol, nonionic;
8. Iodixanol, non-ionic;
9. Ioversol, non-ionic.

Survey

Before starting a CT scan, the doctor must give comprehensive information about this procedure. In particular, after administration of a contrast agent, the patient should increase daily norm consuming up to three liters of water - this will help remove the contrast from the body.

The examination process is painless and relatively quick (time depends on specific situation). The patient will need to remove all jewelry and elements that contain metal; if given the opportunity, change into a special robe.

When manual contrasting is done intravenous injection, and with a bolus, the healthcare worker installs a syringe dispenser with a contrast agent. The patient is covered with radiation protection and placed on a special table, which lifts him into the radiation zone of the device.

Within 15-18 seconds after the drug enters the blood, images of the ascending aorta and heart vessels can be obtained within 25 seconds. – aorta. As mentioned above, the further the organ being diagnosed is from the heart, the more time must pass before starting the study.

The image is displayed on the computer screen. The doctor is in complete control of the process computed tomography and sees all its stages during the examination. Undoubtedly, this is a significant advantage of CT, because the patient can communicate with the doctor and report problems if they arise. This relieves emotional stress.

By the way, a person does not fit completely into the device, the feeling of a closed space is not created - even people with claustrophobia tolerate the research process well.

Conclusion

Computed tomography is in a modern way diagnostics of various formations in the body, abnormalities in the functioning of blood vessels, consequences of injuries. For this purpose, there is X-ray radiation, as well as a special apparatus.

Thanks to contrast-enhanced CT, the doctor receives the most detailed layer-by-layer image of organs and tissues in the body due to the enhancement of the return signal. However, contrast can not be administered to all patients - for this, a blood test must be taken before the procedure. Immediately after the examination, the person can return to everyday life.

Application radiopaque drugs pose the greatest danger to patients due to high frequency and severity of complications. Harmful effects water-soluble radiocontrast media (RCM) used for excretory urography, renal CT, AGP and CT angiography, as well as other studies of the kidneys and urinary tract associated with chemotactic effect iodine, carboxyl groups on cells; with osmotic toxicity and local ionic imbalance that occurs in the lumen of the vessel during bolus administration of ionic radiocontrast agents. Phenomenon osmotic toxicity consists in a multiple increase in osmotic pressure at the site of drug administration, which causes dehydration and damage to endothelial cells and shaped elements blood. As a result, red blood cells lose their elasticity and ability to change shape as they move through the capillaries, an imbalance is observed between the formation of endothelin and endothelial relaxing factor (NO), the production of other biologically active molecules is activated, and regulation is disrupted vascular tone and microcirculation, thrombosis occurs.

The toxicity of RCS is determined by the structure of their molecule and its ability to dissociate into aqueous solution to ions. Until recently, only ionic or dissociating X-ray contrast agents (urografin, verografin, etc.), which consist of salts that dissociate into cations and anions. They are characterized by high osmolarity (5 times higher than that of blood plasma), therefore they are also called high osmolar contrast agents and may cause local ionic imbalance. When using them, side effects often develop, even the most severe ones. Are safer nonionic or non-dissociating, low osmolar X-ray contrast agents (iohexol, iopromide, iodixanol). They do not dissociate into ions and are characterized by a higher ratio of the number of iodine atoms to the number of drug particles per unit volume of solution (that is, good contrast is ensured with less osmotic pressure), iodine atoms are protected by hydroxyl groups, which reduces chemotoxicity. At the same time, the cost of low-osmolar radiocontrast agents is several times higher than high-osmolar ones. In addition, radiocontrast agents are divided according to their structure into monomeric And dimeric, depending on the number of benzene rings with embedded iodine atoms. When using dimeric drugs containing six instead of three iodine atoms in one molecule, a smaller dose of the drug is required, thereby reducing osmotoxicity. According to the mechanism of development, side effects are divided into:

• anaphylactoid, or unpredictable(anaphylactic shock, Quincke's edema, urticaria, bronchospasm, hypotension);
• direct toxic(nephrotoxicity, neurotoxicity, cardiotoxicity, etc.);
• local(phlebitis, necrosis of soft tissue at the injection site).

Anaphylactoid, or unpredictable, reactions to iodinated contrast media are so named because the cause and exact mechanism of their development are unknown, although certain conditions increase their risk. There is no clear connection between their severity and the dose of the administered drug. Activation of the secretion of serotonin and histamine plays a certain role. The difference between anaphylactoid reactions and true anaphylaxis is practical activities is not significant, since the symptoms and curative measures they do not differ.

By severity, side effects are divided into mild (not requiring intervention), moderate (requiring treatment, but not life-threatening) and severe (life-threatening or disabling).

TO mild side effects include the appearance of sensations of heat, dry mouth, nausea, lack of air, headache, and slight dizziness. They do not require treatment, but may be a warning sign of more severe effects. If they occur before the administration of the contrast agent is completed, it must be stopped. Without removing the needle from the vein, continue to monitor the patient and prepare medications in case more severe complications develop.

If side effects develop medium degree gravity(severe nausea, vomiting, rhinoconjunctivitis, chills, itching, urticaria, angioedema) an antidote is administered - sodium thiosulfate (10-30 ml of a 30% solution intravenously), adrenaline (0.5-1.0 ml of a 0.1% solution subcutaneously) , antihistamines- diphenhydramine (1-5.0 ml of 1% solution intramuscularly), chloropyramine (1-2.0 ml of 2% solution intramuscularly), prednisolone (30-90 mg intravenously in glucose solution). In the event of tachycardia, a drop in blood pressure, or the appearance of pallor, additional adrenaline is administered (0.5-1.0 ml intravenously), oxygen inhalation is started in a volume of 2-6 l/min. When signs of bronchospasm appear, bronchodilators are prescribed in the form of inhalations.

During development severe anaphylactoid reaction or true anaphylactic shock(pallor, sharp drop in blood pressure, collapse, tachycardia, status asthmaticus, convulsions), it is necessary to call a resuscitator, install an intravenous infusion system and begin inhalation oxygen administration at 2-6 l/min. Sodium thiosulfate (10-30 ml of a 30% solution), adrenaline 0.5-1.0 ml of a 0.1% solution, chloropyramine 1-2.0 ml of a 2% solution or diphenhydramine 1-2.0 ml of a 1% solution are administered intravenously. , hydrocortisone 250 mg in isotonic sodium chloride solution. If necessary, the resuscitator performs intubation and artificial ventilation lungs.

To the development of such a serious complication as acute heart failure, can lead to dysregulation of the heart (hyperactivation of parasympathetic influence, leading to severe bradycardia and decreased cardiac output), myocardial damage due to ischemia and direct toxic effect contrast agent with the development of arrhythmia and a drop in the pumping function of the heart, a sharp increase in afterload in the systemic and pulmonary circulation due to vasoconstriction and microcirculation disorders. For hypotension resulting from vagal vascular response and associated, in contrast to anaphylactoid hypotension, with severe bradycardia, in addition to intravenous administration of isotonic sodium chloride solution, atropine (0.5-1.0 mg intravenously) is used. For acute left ventricular failure, inotropic agents (dopamine, 5-20 mcg/kg/min) are administered intravenously. With normal or high blood pressure to reduce afterload, use nitroglycerin (0.4 mg sublingually every 5 minutes or 10-100 mcg/min), sodium nitroprusside (0.1-5 mcg/kg/min) to reduce afterload.

NB! A history of adverse reactions to contrast agents is an absolute contraindication for their repeated use.

Risk factors for complications when using iodinated contrast media:

• previous allergic reactions to medications;
• history of allergies;
• bronchial asthma;
• serious illnesses heart, lungs;
• dehydration;
• chronic renal failure;
• elderly and senile age.

Prevention of complications involves a thorough history taking and examination before examination by the attending physician in order to identify risk factors. If at least one of them is present, and especially if they are combined, a careful and rigorous assessment of the relationship between the potential benefits and dangers of the planned study is required. It should be carried out only if its results can influence treatment tactics and thereby improve the prognosis and quality of life of the patient. The most important preventive measure is the use of low-osmolar (non-ionic) RCS, at least in patients at risk. According to numerous studies, the incidence of side effects when using high-osmolar contrast agents is 5-12%, low-osmolar - 1-3%. In case of a reaction, help is provided in the diagnostic room, where you should have it on hand required set medicines. Some centers have adopted premedication with prednisolone in patients at risk to prevent anaphylactoid reactions (50 mg orally 13, 5 and 1 hour before administration of the contrast agent). However, there is no convincing evidence that this preventative measure significantly reduces the risk of complications, so its widespread implementation should be considered insufficiently justified.

The nephrotoxicity of RKS requires special consideration. It consists of the direct toxic effect of the drug on the epithelium of the renal tubules and renal endothelium, as well as osmotic toxicity. Severe endothelial dysfunction occurs with increased production of both vasopressor and vasodilating agents endothelin, vasopressin, prostaglandin E2, endothelial relaxing factor (NO), atrial natriuretic peptide; however, more is happening early exhaustion depressor system with a predominance of vasoconstriction. As a result of this, as well as an increase in blood viscosity and deterioration of microcirculation, glomerular perfusion is disrupted, ischemia and hypoxia of the tubulointerstitium develops. Under conditions of hypoxia and increased osmotic load of renal tubular epithelial cells, their death occurs. One of the factors affecting the epithelium of the renal tubules is the activation of lipid peroxidation and the formation of free radicals. Fragments of destroyed cells form protein casts and can cause obstruction of the renal tubules. Clinically, kidney damage is manifested by proteinuria and impaired renal function - from reversible hypercreatininemia to severe acute renal failure, which can occur with or without oliguria. The prognosis for the development of acute renal failure in response to the administration of radiocontrast agents is serious. Every third patient with oliguric acute renal failure experiences an irreversible decrease in kidney function, while half require permanent treatment hemodialysis. In the absence of oliguria, chronic renal failure develops in every fourth patient, and every third of them requires constant treatment with hemodialysis.

Proven risk factors for acute renal failure when using radiocontrast agents largely coincide with risk factors for extrarenal complications. These include:

• chronic renal failure;
• diabetic nephropathy;
• severe congestive heart failure;
• dehydration and hypotension;
• high dose and frequency reintroduction radiocontrast agents.

If in the general population nephrotoxicity of radiocontrast agents, defined as an increase in serum creatinine level by more than 0.5 mg/dl or more than 50% from the initial level, is observed in 2-7% of cases, then in patients with impaired renal function (creatinine serum level more than 1.5 mg/dL) or other proven risk factors, it is observed in 10-35% of cases. In addition, possible risk factors for worsening renal function should be considered, such as arterial hypertension, widespread atherosclerosis, impaired liver function, hyperuricemia. Adverse effect on the risk of myeloma nephrotoxicity and diabetes mellitus without kidney damage have not been proven.

Prevention of acute renal failure when using RCS includes:

• taking into account risk factors and contraindications;
• conducting studies with RCS in patients at risk only in cases where its results can significantly affect the prognosis;
• use of safer low-osmolar drugs;
• use of the lowest possible doses;
• hydration of patients for 12 hours before and after the study;
• normalization of blood pressure.

Among medical prescriptions proposed for the prevention of acute renal failure when using radiocontrast agents, only hydration significantly improves the prognosis of patients. The effectiveness of other methods based on prospective studies clinical trials is questionable (prescription of dopamine, mannitol, calcium antagonists) or insufficient evidence (prescription of acetylcysteine).

In MRI, for the purpose of contrast, drugs containing the rare earth metal gadolinium are used, the atoms of which have special properties. magnetic properties. The toxicity of gadolinium preparations is significantly lower (10 times or more compared to iodine-containing RCS) due to the fact that its atoms are surrounded by chelate complexes of diethylenetriamidepentaacetic acid. However, with its use, severe side effects of the anaphylactoid type, similar to the side effects of iodine-containing RCS, have been described, as well as cases of acute renal failure. The treatment tactics for these complications are not fundamentally different compared to complications of radiocontrast agents.

Today, magnetic resonance imaging is one of the most accurate non-invasive methods for diagnosing diseases. This study allows you to see the internal organs, and modern computers create three-dimensional models of them. However, in some cases it is necessary to examine a particular internal organ in more detail for a more accurate diagnosis. Then doctors resort to the procedure of conducting an MRI with contrast. A special substance injected into the patient's body is called gadolinium. This product practically does not cause allergies, unlike other iodine-containing drugs.

Features of the impact

The rare earth element, which is the basis of medical products used by specialists, contains molecules held together by chemical bonds. The compound contains a chelating agent, which allows the gadolinium to be evenly distributed and prevent intoxication associated with the accumulation dangerous doses drug in the body. In our country, doctors use Omniscan, Dotrem, Gadovist and other drugs.

What is contrast MRI and why is a contrast agent administered to the patient? This is an opportunity to increase the information content of diagnostic results and improve the visibility of inflammation, metastases, and neoplasms in the image. early stage. Also, the introduction of a special composition simplifies the work of the diagnostician when it is necessary to assess cerebral and cardiac blood flow.

The use of a gadolinium-based product allows you to assess the nature of pathologies and anomalies with maximum accuracy. Carrying out such a study is possible only as prescribed by a radiologist, who determines whether the patient should be prepared for the clearest visualization of changes in the body.

So, what is the difference between an MRI with and without contrast? The procedure, which is preceded by the introduction of a solution with gadolinium, allows you to obtain more detailed information, set boundaries and identify the nature of the pathology more accurately. The area being examined is studied in more detail than during a similar examination, in which no special substance enters the cavity or bloodstream. More often similar method used to assess condition internal organs, soft tissues, spinal cord and brain.

Progress of the procedure: how to do an MRI with contrast

The contrast agent is administered intravenously using a special syringe or injector that automatically regulates the dose of the drug. On average, the necessary manipulations preceding the actual examination take from 10 to 30 seconds - this is approximate duration injections.

Preparation for the examination and the procedure itself include several stages:

Most often, a drug containing gadolinium is administered after photographs have been taken that do not require the use of contrast. At this moment, the patient is in the MRI room, in the tunnel of the device.

When a laboratory assistant or doctor approaches the tomograph, the table with the patient moves out.

After this, a tourniquet is applied and the substance used when scanning the body with contrast is introduced.

Then the subject again enters the apparatus tunnel.

You have every right to receive information about the peculiarities of conducting magnetic resonance tomography, possible contraindications to MRI with contrast, consequences and the availability of alternative diagnostic methods. A detailed story from the doctor will help you choose best option, allowing you to get accurate results as quickly as possible comfortable conditions. If you feel afraid of the injection or the examination itself, inform the specialist in time.

Most patients do not report any discomfort or significant discomfort after undergoing such a procedure. Some report nausea, a cold feeling in the arm, or a slight headache. It is worth noting that adverse reactions occur in no more than 1% of all examinations using drugs containing gadolinium salts.

What does an MRI with contrast show?

This method allows you to “highlight” internal organs in the image. This is necessary so that they are visible more clearly, which significantly increases the accuracy of diagnosis. This method also makes it possible to determine the dimensions malignant neoplasms, their structure and locations of tumors and metastases. The solution penetrates into defective cells, making them more visible and making their contours clearer.

MRI with contrast of the brain shows already in the first hours of the development of a stroke the extent of the focus of death nerve cells. In this case, this method is one of the most informative. One of the most important advantages of such an examination is the natural visibility of the affected area due to the movement of blood.

How is contrast agent administered during MRI?

As mentioned above, in some cases the magnetic tomography procedure is preceded by the introduction special solution to the patient. There are 2 options for preparing a person for a gadolinium scan.

In the first case active substance administered intravenously. The injection is performed once before the start of the examination (0.2 mg of solution per 1 kg of the subject’s weight)

The second option involves drip administration of the drug. The amount of drug entering the blood is measured with a special device. This method is called bolus and is widely used when a solution is administered directly during scanning.

Since the contrast agent is administered during MRI in doses, as the diagnosis proceeds, the substance gradually reveals all areas of the organ being examined. Therefore, it is possible to study processes in the body in real time. About 10 ml of the substance is injected at a time. You should then lie still for about an hour before proceeding with the re-diagnosis. All actions of doctors are carried out exclusively with the consent of the patient.

Indications for MRI with contrast

Diagnosis various types malignant neoplasms.

The presence of an unknown infection in the body.

Checking the functioning of blood vessels.

Detection of metastases of the spinal cord and brain. Since these neoplasms are relatively small in size, a gadolinium-based drug helps to see them at an early stage of development.

Determining the stage of multiple sclerosis.

Rehabilitation after surgical intervention on the spine and removal of intervertebral hernias.

More detailed diagnostics a disease detected during resonance imaging without injection of a special drug.

Benefits of MRI with contrast

The advantages and benefits of MRI with contrast have already been listed above. It is more informative than a standard examination performed without the administration of gadolinium salts, which characterizes it as a method that:

determines the degree of malignancy of the tumor;

shows the size of the affected area with extreme accuracy;

makes it possible to identify pathologies on initial stages development.

The injected solution is safe for your health in the absence hypersensitivity to its components.

Is contrast agent harmful?

In Russia, magnetic resonance imaging preparations containing intracomplex compounds of the gadolinium ion have been registered and approved for use. These are gadovist, dotarem, primovist and other means used in many countries. All drugs underwent preliminary clinical trials, which revealed no complications with the correct administration of the solution and proper calculation of the optimal dosage.

Diagnostic imaging is a field of medicine that uses only proven substances whose safety has been confirmed by specialists. A variety of contrast agents developed for X-ray and CT procedures are successfully used throughout the world. This technology has raised the standards of non-invasive research methods to new level and allowed us to make diagnoses as accurately as possible, guided by optimal image quality when conducting MRI in patients with acute conditions.

If you are asking the question “Is a contrast agent harmful or not,” then these are objective factors that indicate the benefits of using contrast in magnetic resonance imaging. Let's get back to the side effects. We said earlier that this procedure is safe for most people, but in rare cases it can cause harm to the body of the subject. The isotope used as a marker can become toxic if it is difficult to remove the active substance from the body. This is why MRI with contrast is not prescribed to patients with renal failure.

Another side effect that may occur in some cases is an allergic reaction to the active substance of the administered drug. However, such consequences can be avoided by indicating sensitivity to one of the components of the composition at an appointment with a doctor before the procedure. The specialist will find alternative method diagnostics, which will minimize the risk of complications.

Preparing for an MRI with contrast

The patient's actions in preparation for an MRI with contrast, prior to the procedure, depend on which organ will be examined. So, in case of scanning abdominal cavity necessary:

Switch to a low-carbohydrate diet 2-3 days before the magnetic resonance imaging scan and refrain from eating foods containing fiber - they can cause increased gas formation.

Completely avoid morning breakfast (the results of the procedure will be more informative if the diagnosis is carried out on an empty stomach).

It is possible to take an antispasmodic drug.

Over the course of several days (usually 2 days), all foods that cause flatulence are excluded from the patient’s diet (as in the case discussed above). This precaution is necessary when scanning the abdominal cavity, lumbar spine, Bladder, uterus, etc.

You cannot eat 5 hours before the procedure.

Any drinks are prohibited 3 hours before. An exception is a pelvic examination (doctors do not recommend emptying your bladder before the scan).

Otherwise, preparing the patient for MRI with contrast is completely the same as similar actions when performing tomography without administering a drug based on the rare earth element gadolinium. It is necessary to leave metal jewelry and accessories outside the office, remove all objects that could distort the image in the photo (jewelry, hairpins, glasses, Hearing Aids, removable dentures)and get ready for the procedure. The patient must bring a passport, a referral and medical card with the results of previous examinations.

Contraindications for MRI with contrast

thickening of the skin;

kidney pathologies;

various types of asthma;

anemia and other blood diseases;

pregnancy in the first trimester;

lactation.

Although gadolinium is the safest metal used in contrast media, there is minimal risk of side effects.

skin irritation;

Mild itching;

slight decrease in blood pressure.

These complications occur in 2% of patients. Their occurrence is associated with individual intolerance contrast agent components.

Magnetic resonance imaging with contrast is an advanced method in diagnosing and studying many diseases. It is distinguished by its safety and variability of the procedure. There is a small number of contraindications and side effects (sensitivity to the components of the drug, renal failure, allergies, slight decrease in blood pressure), which the doctor must inform about during the preliminary consultation. In most cases, the procedure goes without complications, allowing you to identify initial stages development of pathologies, carry out maximum accurate diagnosis and prescribe the right treatment.

Modern x-ray method with a high degree of information content - computed tomography - has taken a leading position in the diagnosis of most diseases. Contrast enhances the capabilities of CT and, if necessary, allows you to study the area under study in more detail. Using this procedure, not only the pathological focus in the body is revealed, but also its location, outline, structure, structure of the blood vessels and lymphatic vessels. The result of CT with contrast is high-quality and informative images.

CT is based on the effect of X-rays on organs and tissues. As a result, after multi-layer scanning, a special computer converts the received data into high-quality images. Contrast agents enhance the image of the area under study.

CT scan with and without contrast, differences

Conventional computed tomography provides images from natural throughput x-rays various organs and fabrics. Contrasting in some cases is necessary for a more detailed study of a certain area. The contrast agent enhances the image of the necessary structures due to its absorption properties X-rays. This increases the information content of the image, and hence the accuracy of the diagnosis. This effect is especially important for studying blood vessels and identifying cancer formations.

CT in oncology

Contrast-enhanced CT is widely used in oncology to detect malignant and benign neoplasms and differentiating them from each other.
Computed tomography reveals:

• Abdominal cavity formations (intestines, liver, gallbladder)
• Tumors chest cavity(heart, mediastinum, lungs)
• Neoplasms of the retroperitoneal space (adrenal glands, kidneys, ureters)
• Formations of the osteoarticular system (bones, ligaments, spine, joints)

CT with contrast allows you to determine the degree of malignancy, i.e. spread of the tumor process. It is also prescribed for suspected malignancy benign education. It is also effective for detecting cancer metastases.

Preparing for a CT scan with contrast agent

1. Limit food intake 4-8 hours before the test.
2. Clothes should be comfortable and not restrict movement.
3. During the examination digestive tract Avoid taking gas-forming products the day before the procedure. The day before, take a drug that reduces gas formation.
4. Immediately before the examination, remove all jewelry and any devices on the body.

The procedure lasts about 45 minutes. During this procedure, the patient must lie still. If necessary, at the doctor's command, you need to hold your breath.

The subject lies down on the table. If required, he is given a contrast agent intravenously. Through certain time The procedure begins - the patient is placed in a tomograph and the necessary areas are scanned.

Results in electronic and printed form are prepared within an hour after the study.

Feelings during a CT scan

The procedure itself is absolutely painless. Discomfort may occur during the administration of a contrast agent: a feeling of heat in the body, discomfort at the injection site, a metallic taste in the mouth. During scanning, the subject hears the noise of the device. To eliminate this, you can use headphones with music.

Contrast agents

There are different classifications of contrast media. In each specific case, it is selected by the doctor individually, depending on the method of administration and the area being examined. The most commonly used are iodine-containing contrast agents, with the help of which the image is enhanced as clearly as possible. However, this remedy is contraindicated for people who are allergic to iodine and seafood.

Its disadvantage is that it is quite common side effects, such as a feeling of warmth in the body, discomfort in the injection projection. Such effects do not require treatment and go away on their own within a few minutes. In some cases, swelling of the larynx and difficulty breathing, urticaria, occurs. Then it is necessary drug therapy to avoid the development of anaphylactic shock.

Modern non-ionic contrasts also contain iodine, but of a special structure, which reduces the risk of allergic reactions.

Contrasts are distinguished by solubility in certain media: fat-, water-, alcohol-soluble and insoluble.

For example, barium sulfate is insoluble and is used to study the gastrointestinal tract.

Urografin, Omnipaque are water-soluble drugs used to study the urinary system, blood and lymphatic vessels.

To study the structure of the spine, spinal cord, bronchi, and also for contrasting pathological structures (fistulas, diverticula), fat-soluble agents such as iodolipol are used.

Alcohol-soluble substances are used to examine the gallbladder and bile ducts.
It is worth noting that CT scans also use gases as contrast that do not transmit X-rays well. Their properties are used to create transparent background when examining tumor formations.

Methods of administering contrast agent:

• Intravenous - injected into a vein using a syringe required amount contrast.
• Bolus - a pre-installed intravenous syringe injector injects contrast as a bolus, i.e. at a given speed and dose, to maintain a constant concentration of contrast in the blood during the study.
• Oral - through the mouth. The method is effective for detailed study upper sections Gastrointestinal tract.
• Rectal - administration of contrast through the rectum. Used to scan the pelvic organs (uterus, bladder), colon.
• The drug can also be injected into the cavity of any organ, pathological formation to obtain accurate data about their structure and the presence of additional formations.
• Sometimes used combined methods administration of drugs, for example, oral and intravenous.

In any case, before performing a CT scan with contrast, the specialist always clarifies any possible allergic reactions to drugs and food. The dose of the administered medication is selected based on body weight. Also taken into account accompanying pathologies in the subject and the degree of influence of contrast and radiation dose on them. If the risk is high, if possible, computed tomography is performed using a non-contrast method.

How is the contrast agent removed after the examination?

• Oral medications are eliminated naturally. In some cases, they may be accompanied by constipation.
• Contrast administered rectally after the examination is removed independently.
• Intravenous contrast is gradually eliminated from the body by the kidneys. Therefore, in case of renal failure, the method is contraindicated, since the kidneys may not be able to cope with the load.

CT with contrast indications

Computed tomography with contrast found wide application to identify heart pathologies, vascular diseases and neoplasms.

It also effectively diagnoses:

1. Diseases of hollow organs (stomach, intestines, esophagus). Contrasting allows you to obtain a clearer structure of the walls of hollow organs, provides a detailed structure of the mucous membrane and reveals additional education(polyps, diverticula, tumors).
2. Vascular pathology (aorta, large arteries and veins, neck vessels). The injected contrast shows a complete vascular picture of the examined area. The condition of the vascular wall itself and the intraluminal space is determined, blood flow parameters are assessed, blood clots are identified, atherosclerotic plaques, aneurysms.
3. Liver examination to detect vascular pathology, inflammatory diseases, space-occupying formations, cysts, abscesses, abnormalities of organ development.
4. Pathology of the mediastinal organs. Computed tomography with contrast visualizes the structure and location of the bronchi, lungs, and blood vessels, and identifies neoplasms, inflammation, abscesses, and cysts.
5. Diseases of the kidneys and adrenal glands. Using contrast-enhanced CT, an accurate diagnosis is established and tumor-like formations are identified.

CT with contrast contraindications:

• Allergy to contrast, seafood (contain iodine)
• Bronchial asthma
• Diabetes
• Hyperthyroidism
• Kidney failure
• Pregnancy
• Lactation period
• Liver failure
• Myeloma
• Serious condition of the patient
• The patient is overweight (more than 200 kg)
• Mental disorders

Is CT harmful?

During the procedure itself, the subject receives a certain dose of radiation. For a one-time study, it is quite acceptable and does not harm the body. However, you cannot get too carried away with this procedure unless absolutely necessary. Without indications, you should not perform it more than once a year. But if the potential risks of the disease exceed the unsafety of radiation exposure, then the study is performed more often.
It is important to know that X-rays have a more negative effect on dividing cells. Therefore, for a child’s growing body, computed tomography is used only in complex diagnostic cases.

Abdominal CT is a diagnostic method that describes the condition of the internal organs of the abdominal cavity (together with blood vessels and abdominal lymph nodes) and retroperitoneal space layer by layer with a step size from 0.5 to 10 mm.

Computed tomography provides an informative, highly accurate three-dimensional image, revealing small changes in organs that are invisible with other studies. High speed scanning makes it possible to obtain results within 2 hours, and the low radiation exposure to the human body expands the indications for use. With CT it is possible to differentiate tissues due to the difference in their density with an accuracy of 0.5%.

A computed tomography scan of the abdominal organs includes the following:

• organs of the gastrointestinal tract (pancreas, liver, colon and small intestine, stomach, spleen, gall bladder);
• retroperitoneal space (kidneys, adrenal glands, blood vessels, urinary system, lymphoid tissue).

CT scan describes the structure of parenchymal organs, its painful changes, and the patency of tubular organs.

What does it show

CT scan of the abdominal cavity can show volumetric processes of pathological changes (size of the inflammation, its boundaries and extent of spread) and failure in the functionality of organs, namely:

• foreign bodies;
• damage to the lymph nodes;
• hemorrhages and injuries;
• vascular changes and atherosclerosis;
• cysts, malignant and benign tumors;
• abscesses;
• blood diseases;
• hepatitis, cirrhosis, liver hepatosis;
• kidney and gallstones;
• echinococcosis;
• congenital anomalies.

Indications for a computed tomography scan of the abdominal cavity may also include:

• preparation for surgery;
• resolving the issue of operability;
• acute conditions and pain of unknown etiology;
• chronic digestive and urinary disorders that cannot be explained by other diagnostics;
• obstructive jaundice and sudden weight changes;
• acute abdominal injuries;
• suspicion of extensive education in the abdominal cavity;
• treatment control.

This is the most reliable way identifying cancer at an early stage. The pictures show the size, boundaries of the inflammation zone, local metastases and the degree of tumor germination in neighboring organs and lymph.

Abdominal CT can accurately diagnose such complex diseases How:

• mediastinal tumors - lymphoma and lymphogranulomatosis;
• hemangioma and hepatocellular carcinoma;
• hemochromatosis;
• pheochromocyotoma;
• kidney cancer, hydronephrosis;
• polycystic disease;
• nephroptosis;
• hemoblastosis;
• abdominal aortic aneurysms, stenoses, kinks of blood vessels;
• portal and mesenteric thrombosis;
• cholangitis, diverticulitis, appendicitis;
• intervertebral hernia or pinched nerve;
• gallbladder pathology;
• pancreatitis;
• adenoma or cyst of the adrenal gland.

With contrast

Native CT is performed without the use of contrast. But most often more accurate data is needed, then a targeted CT scan of a specific abdominal organ using contrast is prescribed.

Contrast is the introduction of an x-ray contrast agent (the amount is proportional to the patient’s weight) to increase the accuracy and reliability of diagnosis due to the fact that the contrast agent enters the painful tissues through the blood and makes them brighter and clearer in the image.

To get more detailed information For parenchymal (solid tissue) organs such as the liver, pancreas and kidneys, oral contrast is used. To study blood vessels, contrast is administered intravenously. There are situations when it is most advisable to administer contrast through an enema. Bolus intravenous administration contrast is carried out at a given speed using a special automatic injector.

During the scan, the patient will have to lie quietly on his back for several minutes, breathing evenly, possibly holding his breath for a few seconds. The uniform is loose, metal accessories will need to be removed. Native diagnosis will take up to 15 minutes, with the introduction of contrast – about 30 minutes. Probability of occurrence adverse reactions, such as nausea, anxiety, fever, is observed in only 1% of cases out of 100.

With decoding of finished photographs, especially in controversial issues, a radiologist is the best person to handle it. Specialists in a narrow field - surgeons, oncologists, gastroenterologists can also decipher. It usually takes no more than 1.5 hours to evaluate the results and prepare a conclusion.

Preparation

Preparing for an abdominal CT scan requires careful planning and compliance. At the time of tomography gastrointestinal tract The gastrointestinal tract should be freed from food as much as possible.

Diagnostics is carried out on an empty stomach, so if it is prescribed:

• in the morning - a light liquid dinner is allowed;
• for lunch - 5 hours before you can afford a very light breakfast;
• in the evening - the patient takes a light liquid breakfast and refuses lunch.

Since food passes through the esophagus for about 2 days, it is necessary to refuse food during this period, causing bloating and from complex products: alcohol, carbonated drinks, fermented milk products, fermented food, apples and cabbage, legumes, yeast products, solid and indigestible foods.

Immediately before the procedure, a cleansing enema is performed, or in the evening before the test day, you can cleanse the intestines with Fortrans solution (oral administration of a laxative solution). The bladder may be slightly full.

From the evening until the start of the CT scan, you need to drink up to 4 liters of still water in equal portions, with 2 ampoules of 20 ml of pharmaceutical Urografin 76% or Triombrast 60% diluted in it. If a change in the source of inflammation is suspected, the doctor may prescribe intravenous administration of Omniopak (50 ml).

Regardless of the area of ​​study, after CT scanning, plenty of still water at room temperature is required.

Contraindications

CT is a safe examination; the radiation dose of the longest diagnostic procedure does not exceed the average dose of a conventional X-ray of the gastrointestinal tract.

The main restrictions for its implementation are: large body weight (over 120 kg), pregnancy, restless state of the subject.

Relative contraindications in each individual case may be:

• age up to 14 years, only if it is impossible to establish a final diagnosis using other studies;
• acute kidney inflammation;
• Breastfeeding is not recommended within 24 hours after a CT scan with contrast;
• CT with contrast is not performed in cases of severe diabetes mellitus;
• allergic reaction to contrast agents (iodine and derivatives);
• at serious illnesses the liver and cardiovascular system do not use contrast;
• blood diseases;
• taking adrenergic blockers and other incompatible drugs;
• if in less than 7 days the patient underwent an X-ray of the gastrointestinal tract with barium contrast.

Exploratory survey

Before undergoing a CT scan, you may need to undergo other examinations, such as abdominal ultrasound, colonoscopy, FGS of the stomach and duodenum, conventional x-rays, or a referral from an oncologist to draw up a report.

Before performing a computed tomography scan with contrast, it is necessary to consult an anesthesiologist, clarify contraindications with a doctor, and obtain written consent for the administration of a contrast agent.

When performing a CT scan of the kidneys, adrenal glands, bladder and ureters, the patient must have fresh (2-3 days) results on hand biochemical analysis blood for ALT, AST, urea and creatine

The doctor's referral for a CT scan will indicate the research method, area of ​​examination, presumptive diagnosis and purpose of the diagnosis.

Examination price

The price of diagnostics using a computed tomograph depends on the complexity of the study and the location of the inflammation. The average cost of an abdominal CT scan is determined by the availability and cost of its components and consumables:

• post-diagnostic consultation;
• consultation and management of an anesthesiologist during CT;
• recording images on electronic media;
• tomography;
• administration of contrast;
• administration of contrast intravenously;
• bolus intravenous contrast;
• cost of contrast agent;
• printed photographs, research package and duplicates;
• intravenous anesthesia;
• puncture (puncture) of the organ being examined for diagnostic and treatment purposes.

Primary native CT scan of the abdominal cavity usually costs from 3,500 rubles in Moscow. The average cost of a CT scan with contrast includes only basic services and ranges from 6,000 rubles. When studying cancer patients, the required accuracy increases to a cutting step of 0.5-3 mm and proportionally affects the price.