home Auditorium 7 CT scan and MRI. Difference between computed tomography and magnetic resonance imaging. What is the difference between MRI and CT in terms of application?

CT scan and MRI. Difference between computed tomography and magnetic resonance imaging. What is the difference between MRI and CT in terms of application?

CT scan– this is a type of analysis in which a layer-by-layer scan of the patient’s organ under study occurs. A tomograph is used to carry it out. The principle of its action is the reflection of X-ray radiation from tissues and bones. The result of the study is presented in the form of a 3D image on the doctor’s monitor, and can also be recorded on disk.

The CT machine consists of a table and a circle with movable sensors, which, rotating during the examination, take pictures from different angles.

Since using this method the patient receives a certain (but not very large) dose of radiation, this test should not be performed frequently.

Magnetic resonance imaging- This is an examination based on the effect of magnetic resonance and electromagnetic radiation, which is reflected differently from more or less dense tissues.

A tomograph is also used for it, but of a different, closed type. It is equipped with a retractable table on which the patient is placed, and a tube-shaped apparatus into which this table is pushed.

This is a fairly safe examination method, although there are a number of limitations in its use, mainly related to the presence of metal implants in the body.

In what cases is a CT scan prescribed, and in which MRI?

Because both types of examination rely on different physical and chemical phenomena, the effectiveness of each varies depending on the tissue being analyzed.

When a doctor prescribes a brain MRI or CT scan, he is guided by what exactly needs to be examined. Thus, a K-tomogram is considered more effective in examining hard tissues, skull bones and their disorders, and MR is considered more effective for analyzing soft tissues.

Main indications for CT scanning

This analysis is prescribed in the following cases:

The patient suffered a traumatic brain injury
He has constant headaches after the blow
Pathological change in the bone tissue of the head
Concussion diagnosed
It is necessary to confirm or deny the presence of hemorrhage
Brain structures have shifted
There is a possibility of a foreign body

When is the best time to do an MRI?

Such a study is prescribed in the following cases:

MRI is also prescribed to check:

Correct course of treatment
State of the brain after detection of a malignant tumor
Pre- and postoperative control

Children may be prescribed magnetic resonance imaging if:

He had pathologies during intrauterine development
He lags behind his peers in various indicators
Suffering from convulsions, dizziness, loss of consciousness
Stutters or has other speech problems

Contraindications

Both studies are quite safe, but a number of restrictions on their use still exist. They must be kept in mind when deciding which analysis to perform: brain MRI or CT.

Computed tomography is not done in the following cases:

When the patient is pregnant
With a large weight (more than 130 kg) of the patient

Use it with caution for nursing mothers, and if the analysis has been carried out, then you should not breastfeed the baby for another day.

If the study is carried out with a contrast agent, then there are more contraindications:

Allergy to iodine
Diabetes
Endocrine diseases
Problems with the liver and kidneys

MRI should not be performed in patients who:

There are metal prostheses made from materials that interact with a magnetic field
Heart valves and pacemakers
Metal clamps for vessels for aneurysm
Hearing Aids
Permanent dentures made of gold, steel and similar materials

The study is applicable with limitations when:

Patient in the first trimester of pregnancy
The patient suffers from a fear of enclosed spaces
He has crowns and braces

Also, an obstacle to both studies may be the patient’s inability to lie still for the required time due to severe back pain.

If the patient knows about the presence of any limitation (pregnancy, previously diagnosed diabetes, metal implants, etc.), he must inform the doctor in advance.

Advantages of each type of tomography

To make the right choice between brain MRI or CT, you need to consider their purpose and benefits for a particular diagnosis, as well as the types of tissue that need to be studied.

Benefits of CT

Computed tomography is one of the most accurate ways to study disorders associated with the state of the brain. It is especially effective when it comes to identifying abnormalities caused by traumatic brain injury, as well as other problems with the bones and dense tissues of the skull.

This happens because X-rays are reflected in a special way from dense bone tissue. At the same time, the radiation dose that the patient receives is much lower compared to other x-ray studies. In this way, various diseases can be diagnosed without the use of invasive methods, which makes the procedure painless.

Using CT, you can diagnose a stroke, arterial disorders due to atherosclerosis, changes in the structure of the cerebral cortex and lesions of the facial bones. It allows us to examine such disorders in great detail and identify the causes of diseases.

The procedure takes no more than fifteen minutes. With this type of analysis, there is no risk of distortion of the result if the patient accidentally moves.

Patients suffering from claustrophobia can easily tolerate a CT scan because an open machine is used, in which only the head is immersed, and not the whole body.

It is important that the CT result can be seen immediately, although in some cases the image may not have enough contrast.

Benefits of MRI

Magnetic resonance imaging is no less accurate than CT, but its scope is somewhat different. It allows you to examine and diagnose diseases of the soft tissues of the brain and shows results in three planes:

Axial (horizontal projection)
Frontal (direct projection)
Sagittal (lateral projection)

MRI allows you to very clearly see problems with soft tissues: benign and malignant (cancer) neoplasms (their shape, location and volume), dysfunction of the pituitary gland, nerve and muscle fibers. In this way, you can see and measure the volume of edema, tumors of the nervous system, and more. The bones will be displayed indirectly.

This test is safe, so it can be used to diagnose pregnant patients, but only in the second and third trimester. It is also allowed to be used for diagnosing children from the age of three. But it is necessary to explain to the child how the research will take place so that he is not afraid and tries not to move during the process.

MRI can be done several times over a short period of time.

The procedure lasts about half an hour. During this period, the patient is required to lie still. Otherwise, the image may be distorted and the result may not be reliable or accurate.

For patients with a fear of closed spaces, anesthesia can be used.

MRI of the brain or CT scan – which is better?

The answer to this question depends on the specific situation and individual characteristics of the body:

Suffering from certain diseases
Endocrine
Diabetes, liver and kidney diseases
Allergies
Pregnancy or lactation period
Patient age
His body weight
The existence of metal objects in the body (implants, fragments, etc.)

What will be checked?

It is important to understand what exactly needs to be diagnosed: a traumatic brain injury or tumor, a concussion or swelling and inflammation.

MRI is more suitable for diagnosing disorders in soft tissues: the composition of brain tissue, blood vessels, the presence of neoplasms of various types, edema and aneurysms.

CT helps to identify problems resulting from injury: fractures of the skull, facial bones, hemorrhages, stroke.

When there are restrictions

Magnetic resonance imaging can be done on pregnant women (excluding the first trimester) and children aged three years and older. Anesthesia can be used for a child, since he is not always able to remain motionless for a long period of time.

A CT scan for children and pregnant women is excluded, except in cases where the patient’s life depends on its implementation, and no other means can help, since during the procedure the patient receives a dose of X-ray radiation.

It can also be difficult for a patient with nervous disorders to remain motionless for the required period of time. In this situation, it is also possible to use anesthesia.

People who have metal objects in the body, as well as electronic pacemakers or heart valves, are contraindicated for MRI, since such things interact magnetically with the machine. Because of this, both distortion of the results and deterioration of the patient’s condition may occur. The exceptions are pins, crowns, removable braces and products made from non-inert materials (titanium and others). In this case, it is better for the patient to undergo a brain CT scan or similar analysis.

Patients who are claustrophobic can undergo a CT scan without discomfort because they do not have to lie down completely in the machine. If such a patient needs to have an MRI, he will have to use anesthesia, which seriously affects any body.

The restrictions on the patient’s weight do not differ very much, but in some cases this factor can play a role: a C-tomograph allows a patient to be analyzed up to 130 kilograms, and an MRI machine – up to 150.

CT with contrast should not be performed on people who have been diagnosed with an allergy to iodine and other components of the injected substance, as well as those who have diabetes mellitus and other kidney diseases. In this case, it is necessary to conduct a different analysis.

Technical specifications

MRI provides extremely clear images, excluding bones, in the form of projections from different angles; CT, on the other hand, has a less clear “picture,” but at the same time the structure of the bones is clearly visible in its results, and the image is presented on the monitor in the form of a 3D model.

Another important point is the amount of time you need to spend in the device. For CT it ranges from 5 to 15 minutes, for MRI – about half an hour. During this period, the patient should be as motionless as possible. But it is not so critical for the results of a CT scan if the patient moves a little. Such movement can introduce serious distortion into magnetic resonance imaging data.

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When diagnosing diseases of the spine and organs of the sacrolumbar region, magnetic resonance and X-ray computed tomography are very widely used. Both of these methods are additional research methods and serve to confirm or refute suspicions of certain diseases of the internal organs.

MRI and CT are used if there are certain indications and clinical symptoms indicating the presence or development of a particular disease. Very often, the symptoms of diseases are similar or even identical, and only studies using a tomograph can show the real picture of what is happening.

Of course, Magnetic resonance imaging can also be used in studies for preventive purposes, for example, to search for incipient tumors, determine the condition of blood vessels or changes in the tissues of internal organs caused by external influences in the form of toxins or harsh working conditions.

But MRI is still a rather expensive research method and is used only if there are certain reasons for its use. Computed tomography is a cheaper method, but the X-rays used in the tomograph become an obstacle to too frequent use.

MRI and CT in spine studies

Tomography in the diagnosis of the spinal column, especially its lower part, is used quite actively. Such studies are prescribed for:

lower back pain
injuries to the spine area
suspected cancer
osteochondrosis
protrusions and herniations of intervertebral discs
disorders of the blood supply to this area
inflammatory processes in bone or cartilage tissues
disorders of the lymphatic ducts
spinal cord canal stenosis

Which is better, MRI or CT of the spine cannot be answered unequivocally. In order to understand the difference between these methods, it is necessary to briefly familiarize yourself with the physical and chemical processes underlying them.

Principle of spinal MRI diagnostics

Magnetic resonance imaging uses as a basic phenomenon the effect of a high-intensity magnetic field on atomic hydrogen, which is found in large quantities in the tissues of the body. The nuclei of hydrogen atoms are arranged in a certain order along the magnetic field lines, without, however, leaving their places. They just turn in a certain way. In this state, they can vibrate in resonance with external exciting electromagnetic radiation of a certain frequency.

The vibration frequencies of atoms located in different tissues and organs differ, therefore the intensity of the signal, which is recorded by special sensitive detectors, is different. The resulting photographs are in black and white, in which the boundaries of organs, tissue structure and other smallest elements are clearly visible.

Principle of back CT scanning

X-ray tomography is a modified fluoroscopy. Only the intensity of the radiation is much lower and the emitters themselves are built in such a way that the beam of rays illuminates a narrow strip of the body. To obtain an image of the entire organ, the emitter must describe a circle around the patient’s body several dozen times.

CT differs from MRI of the spine in that magnetic tomography more clearly photographs cartilage and soft tissues, blood and lymphatic vessels and the hollow intestine. CT is indispensable for studying bone formations and bleeding. Images of inflammatory processes, salt deposits or disturbances in nerve tissues are also very well demonstrated.

The difference between MRI and CT of the spine is that the magnetic field is absolutely safe for humans and MRI can be performed an unlimited number of times. Computed tomography, although it uses very low-intensity X-rays, still exposes the body to radiation. Therefore, it is not recommended for pregnant women, children, or people who have recently had fluoroscopy.

An MRI image of the spine is as informative as a CT image. MRI or CT scan of the spine is best used with a contrast agent. In this case, neoplasms, various tumors, blood vessels of even the smallest size and metastases penetrating from other organs are very clearly visible. Stenoses, blockages, narrowings and inflammatory processes are reliably recorded. In the case of using data level contrast, both of these methods are almost identical.

A full human life is possible only with the correct functioning of the most complex system of the human body - the brain. Many people suffer from periodic migraines, and sometimes more serious brain problems occur. Then the doctor is faced with the question of choosing the most reliable diagnostic method to clarify the source of the problem.

When it comes to the condition of the brain and blood vessels, the most modern examination methods are used - computed tomography (CT) and magnetic resonance imaging (MRI).

A CT scan of the brain is performed quickly, without preparation (which makes it indispensable for emergency screening), shows pathological changes in the organ under study, which is what differs from MRI: magnetic resonance allows you to visualize smaller pathologies, but the scanning process takes longer.

The principle of operation of CT is based on transmitting X-rays to the human body and recording the attenuation of radiation depending on the density of the tissue. During the diagnostic process, they receive a small dose of X-ray radiation, so such an examination creates a limited radiation load on the body. The operating principle of magnetic resonance imaging scanners is based on the phenomenon of nuclear magnetic resonance when the patient is placed in a strong constant electromagnetic field.

For the patient, both examinations proceed very similarly: he is placed on the table of the device, then moved inside the scanning ring. The tomographs even have external similarities. A person needs to lie still for 10 to 40 minutes. Problems are likely to arise in people with unstable mental health, in serious condition, with claustrophobia, and in young children. If necessary, they are given sedatives or anesthesia.

How does a CT scan differ from an MRI of the brain?

MRI of the head differs from CT, as described in more detail in the table:

Comparison by indications and contraindications

Absolute contraindications to CT are pregnancy and the patient’s body weight is more than the maximum allowable for the tomograph to operate (for some devices this is 130 kg, for others – 150 kg).

Relative contraindications relate to the use of contrast:

allergy to contrast agent;
severe general condition of the patient;
renal failure;
thyroid diseases;
diabetes mellitus (severe forms);
myeloma (oncological disease of the blood system);
severe liver and heart failure.

Absolute contraindications to MRI:

presence of a pacemaker;
electronic or ferromagnetic middle ear implants;
the presence of large metal implants, fragments;
Ilizarov ferromagnetic implants.

Relative contraindications to MRI:

pregnant women (first trimester);
decompensated heart failure;
heart valve prostheses;
hemostatic clips;
presence of an insulin pump;
nerve stimulants;
hearing aids without ferromagnetic metal;
the presence of tattoos made using paint containing metal;
dentures, braces.

MRI is considered safer. Damage to tissues from ionizing radiation accumulates, so the doctor always has to decide on an individual basis whether a diagnostic CT scan is necessary.

The difference in capabilities, indications, and contraindications between CT and MRI is significant. It helps the doctor decide on the research method: choose a safer MRI or CT, which is convenient in an emergency, or even resort to other forms of diagnosis. Information about broken large bones of the extremities is easier to obtain using an X-ray machine - widely available, available in every clinic, giving a low dose of radiation. Duplex scanning of the brachiocephalic (carotid, vertebral) arteries, ultrasound of blood vessels and lymph nodes of the neck, extremities, sinuses, eyes, abdominal cavity, and other areas is a cheap and accessible alternative method for obtaining data for diagnosis. In order to diagnose diseases of the urinary system, excretory urography is traditionally used - a reliable, simple way to obtain images that study urine excretion over time. To check the pelvic organs, there is often no need to do CT and MRI - you can get by with more conventional studies.

In general, CT is more informative for injuries and swelling of the brain, damage to the inner ear, skull bones, neoplasms, abscesses, hematomas, hemorrhagic strokes, thrombosis and atherosclerotic changes in blood vessels. Magnetic resonance imaging better identifies pathologies of the meninges, inflammatory diseases of the brain, ischemic strokes, multiple sclerosis, pathologies of the pituitary gland, nerve disorders, vascular thrombosis, and benign tumors. The MRI method is more accurate, which allows you to visualize smaller pathologies of the vessels of the head and soft tissues, but the scanning process takes longer.

Difference in preparation

Carrying out a tomography does not require any special preparatory steps. Before diagnosis, it is necessary to remove metal objects and electronic devices (watches, jewelry, mobile phones, hairpins, belts with buckles, etc.). When scanning the pelvic organs, the bladder should be full. If all contraindications are taken into account, then the difference between CT and MRI does not affect the preparation for the examination in any way.

What does a tomography image show?

The information obtained as a result of tomography is recorded, the data is entered into a computer, processed, and a three-dimensional model of the body part being studied is visualized. Further information is provided in the form of layer-by-layer sections of the studied area with small steps. There are a lot of pictures, you can get images of projections in different axes, which allows you to examine in detail all possible changes in the soft tissues and skeletal system.

MRI and CT, as tools for studying the state of the brain, differ only in the presence of indications and contraindications.

Comparison of the effectiveness of two methods using the example of different types of cerebral strokes

Strokes happen:

ischemic – caused by vasospasm;
hemorrhagic – resulting from rupture of blood vessels.

Magnetic resonance provides greater resolution when examining the condition of soft tissues; tomography using X-rays better “sees” more radiopaque blood in the area of hemorrhage. MRI is more effective for both types of stroke unless there is great urgency. But, with pronounced signs of a severe, life-threatening stroke, CT will help quickly make a diagnosis and begin treatment. The doctor makes the decision.

What is the best choice for examination for migraine?

Migraines and headaches of unknown origin, neurological disorders are the scourge of modern man. The relevance of identifying the causes of such painful conditions and the selection of effective treatment methods is increasingly necessary for patients. The MRI method is more effective and safer (no radiation) for soft tissue pathologies, therefore it is used primarily for complaints of headaches. If necessary, the doctor can refer the patient for a computed tomography scan.

Advantages and disadvantages

A huge advantage of computed tomography is the possibility of emergency use in case of a threat to the patient’s life, especially in cases of traumatic brain injury, cerebral edema, or suspected stroke. CT can also be used in the presence of implants, vascular stents, pacemakers, and tattoos. CT machines are becoming increasingly widespread and are available in most major trauma centers.

MRI is safer. The absence of radiation makes it possible to use it even for pregnant women and children. An MRI scanner provides more accurate information for headaches and neurological problems.

Headaches after an MRI procedure

Exposure to a magnetic field sometimes causes minor headaches after an MRI procedure in sensitive people. These residual effects of the procedure do not pose any danger and disappear in the shortest possible time.

The decision on the need for CT and MRI should be made by a neurologist, neurosurgeon, or angiosurgeon. Both of these methods are modern, informative and indispensable when examining the brain, the most important system of the human body.

When preparing for spinal surgery, patients at our center often ask the question: what is the fundamental difference between MRI and CT studies?

This article provides the most important information about these methods, on the basis of which visitors to our center and people reading the site will be able to make a balanced, informed decision.

Computed tomography (CT/MSCT)

This study method is based on the use of X-rays. An X-ray tube rotates around the patient along a spiral path, making a fixed number of cross sections of the body per second. This reduces the examination time and allows you to obtain the most accurate results at the moment. The second method, MRI, is based on the principle of a magnetic field, we will return to this a little later.

Note: Compared to standard computed tomography, the sections obtained during MSCT of the spine are almost 10 times thinner. This allows you to accurately see the smallest details of the pictures. At the same time, the radiation exposure to the human body is lower, since MSCT takes 2 times less time than conventional CT. A spiral tomograph has better resolution, so it can be used to diagnose the initial stages of diseases and detect small tumors in a state in which they are amenable to conservative treatment.

Installed in our center multispiral computer (MSCT) 128-slice expert class tomograph TOSHIBA AQUILION. The examination results obtained with its help are much more accurate than diagnostics carried out on devices of lower classes.

MSCT is performed for certain indications. It allows you to assess the degree of degeneration and the presence of intervertebral disc protrusion, determine the presence of cartilaginous growths, and bone density.

Magnetic resonance imaging (MRI)

This method is based on nuclear magnetic resonance. The object being studied is located in a magnetic field. The MRI machine delivers different combinations of radiofrequency pulses that cause the internal magnetization to fluctuate, eventually returning to its original level. The tomograph recognizes, deciphers these vibrations and creates multilayer images.

MRI and CT are completely different methods; the choice of a specific method is influenced by the specifics of the disease and the structural features of the objects being studied. Computed tomography makes it possible to study the condition of bone tissue (intervertebral discs, vertebrae and spinal column). MRI provides the most accurate examination results of soft tissues, spinal cord, muscles, ligaments, internal organs, and nervous tissue.

Indications for MRI and CT procedures

Diagnosis of a number of diseases is carried out using any of these methods; the results obtained on both types of tomographs will be accurate. But there are pathologies in the diagnosis of which the choice of one method or another is fundamentally important. Magnetic resonance imaging is predominantly used to study soft tissues, muscles, and joints. And for the analysis of the skeletal system, computed tomography is preferred, because bones contain a small amount of hydrogen protons and react slightly to electromagnetic radiation. This may affect the reliability of the result. The most accurate images are also obtained with CT scans of hollow organs (gastrointestinal tract).

CT scans are used to examine:

Brain;

Spine, skeletal system;

Organs of the respiratory system;

Sinuses;

Coronary arteries;

Abdominal organs;

Areas of the body when determining the exact location of injuries.

Contraindications to magnetic resonance imaging

Factors in the presence of which MRI is absolutely contraindicated in a patient:

Pregnancy (first trimester);

Presence of a pacemaker;

Claustrophobia;

The presence of metal implants in the body;

Large body weight (over 110 kg).

Contraindications to computed tomography

CT scanning is not performed in the following groups of patients:

Pregnant women (due to the likelihood of negative effects of X-rays on the fetus);

Women who are breastfeeding;

People suffering from kidney failure;

For young children;

For those who have the part being examined covered with plaster.

Advantages of computed tomography

Due to the specific nature of CT, it has a number of undeniable advantages over MRI:

Makes it possible to obtain high-quality images of the skeletal system.

The patient does not experience any discomfort or pain during the examination.

The procedure takes only a few minutes.

The results obtained are reliable and can be easily deciphered.

The study is available to people with metal implants, pacemakers and other electrical devices.

The radiation dose from a CT scanner is lower than from an X-ray machine.

Based on the resulting series of images, a three-dimensional model of the area under study is obtained.

Allows you to quickly obtain accurate data in the presence of internal bleeding.

Makes it possible to detect small tumors.

These features allow you to obtain the most accurate data on the condition of the area of the body being studied.

What is the difference between CT and MRI photos?

Below are images of computed tomography and magnetic resonance imaging. The advantages of a particular type of examination based on an image can only be determined by a specialist.

If the advent of radiography at one time made a real revolution among methods of diagnosing diseases and made it possible to clarify the condition of many organs and bones, then MRI and CT further increased the accuracy of instrumental studies. But not everyone knows what the difference is between CT and MRI. Despite a lot of similarities, the methods have many differences, which will be discussed below.

Currently in medicine there are several highly accurate instrumental diagnostic methods, of which both CT and MRI are distinguished by their relatively low cost (compared to PET or scintigraphy). Both techniques are now available for most patients, but it is important to know the differences between these studies.

The main point of difference between CT and MRI is the principle of their operation. A computer tomograph uses X-rays: such rays pass through soft tissues and linger on hard, dense structures. Conventional radiography is no better than CT - during it, the rays, having passed through the body, are focused on the film. During a CT scan, the images are three-dimensional and the image is three-dimensional, which provides enormous advantages in accuracy and information content. The amount of radiation exposure with CT is comparable to less than with radiography, that is, the method is safer.

What is the difference between CT and MRI? Magnetic resonance imaging does not use x-rays. The huge difference between MRI and CT scans is the nature of the waves. Magnetic resonance imaging uses electromagnetic radiation that is safe for the body. In response to such waves hitting them, tissues give a unique response, which is transformed by equipment into a series of layer-by-layer images.

When choosing whether to do a CT or MRI, it is worth knowing: there are also similarities between the methods. Both of them allow you to scan different organs and systems with many sections as small as 1 millimeter, which will not allow you to miss even the smallest tumor or other tissue abnormalities. The doctor, having seen a series of three-dimensional images, will draw the necessary conclusions and make the correct diagnosis.

Indications for tomography

When assessing the difference between CT and MRI, you need to know the exact indications for both techniques. The fact is that some problems of the body are visualized better by MRI, others by CT. Magnetic resonance imaging is a good method for diagnosing the condition of soft tissues, and computed tomography is a good method for assessing the health of bones and other hard structures.

If it is necessary to examine the intestine, MRI is usually recommended, although both techniques will give similar results and should be used with the introduction of a contrast agent. The intestine is a hollow organ, and good visualization of it will be possible by staining the walls with a contrast agent.

MRI when examining the brain is an indispensable research method that allows you to accurately determine a number of pathologies of the meninges, the actual brain tissue and blood vessels, as well as the nerve plexuses. A CT scan of the head is usually done to evaluate the health of the hard membranes, bones of the skull, the junction of the base of the skull and the spine, and facial bones.

A doctor can accurately answer which of the two types of tomography is better, depending on the specific indications. CT and MRI will differ in the preferred area of examination, although in many cases they can still replace each other. Main indications for CT:

Any diseases of the intestines and stomach
Pathologies of the lungs and kidneys
All diseases of bones, joints, spine
Finding damage sites in case of trauma
Damage to jaws and teeth
Problems of the thyroid and parathyroid glands
Vascular diseases

What is the difference between CT and MRI: magnetic resonance imaging is usually recommended for examining the nervous system, blood vessels, soft tissues - ligaments, muscles, internal organs, brain. MRI is indicated for all diseases of the abdominal and pelvic organs, retroperitoneal space, as well as the larynx and trachea, and lymph nodes.

Is it harmful to have a CT scan?

The dose of radiation received during a CT scan is small. However, you can do the examination no more than 2 times a year - six months after the previous procedure. Such a limitation is not strict and unambiguous: firstly, it will depend on the scale of the procedure performed and the specific radiation dose, which is always indicated in the study protocol. Secondly, if absolutely necessary, CT can also be performed earlier.

Computed tomography is harmful for pregnant women, because even minimal doses of X-rays have a negative effect on the fetus. Also, X-rays are undesirable for use in nursing mothers, and in this case you will have to stop breastfeeding for at least a day.

Other contraindications to CT mainly relate to examinations with contrast. They are as follows:

Kidney failure.
Pathologies of the thyroid gland.
Multiple myeloma.
Severe heart disease.
Diabetes.

With a body weight of more than 200 kg, the patient is unlikely to be able to fit on the tomograph table, so there are also weight restrictions. CT is less sensitive to movement than MRI, but in case of severe pain or mental abnormalities, the study cannot be performed qualitatively.

Is MRI examination harmful?

This diagnostic method is considered absolutely harmless, because it does not provide radiation exposure at all. But in the first trimester of pregnancy, even an MRI is done only according to strict indications, because it is believed that electromagnetic waves can provoke problems in the condition of the fetus or cause an increase in the tone of the uterus.

Other contraindications to MRI are as follows:

The presence of metal implants in the body, especially endoprostheses, as well as various electronic devices (pacemakers, defibrillators, insulin pumps, vascular stents)
Patient weight more than 160-200 kg (depending on the specific tomograph model)
Claustrophobia and mental disorders

For children and people who, due to health reasons, are unable to lie still during the procedure, it can be performed under anesthesia or sedation.

Preparing and performing tomography

There is practically no difference between MRI and CT for a patient. The preparation is also indistinguishable. If an examination with contrast is performed, then you must refuse to eat 6-8 hours before it. CT and MRI of the intestine require more careful preparation, including cleansing the colon with an enema. Before examining the abdominal organs, it is recommended to avoid foods that contribute to gas formation.

The tomography procedure itself takes place in a lying position. After the person is positioned on the couch, the doctor leaves the room. As the series of images is completed, the patient is released, and after 20-60 minutes he is given an examination protocol. If a study with contrast is planned, the contrast agent is administered intravenously, drip, orally or rectally before the procedure.

The duration of a CT scan usually does not exceed 15-20 minutes, while an MRI can last from 10-15 minutes to an hour.

Diseases for which computed tomography is prescribed:

Herniated disc
Protrusion
Osteochondrosis
Fractures of bones or spine
Hematomas and bleeding
Osteoporosis
Scoliosis
Lung cancer
Pneumonia
Chronical bronchitis
Asthma
Tuberculosis of any organs
Cancerous tumors of any location
Neoplasms and areas of autoimmune thyroiditis of the thyroid gland
Adenoma, parathyroid cancer
Aneurysms
Stomach ulcer
Atherosclerosis
Urolithiasis disease

Diseases for which magnetic resonance imaging is prescribed:

It is almost impossible to answer the question which type of tomography is better. They have their own indications and contraindications. There is a difference between CT and MRI, but in terms of information content, these techniques are not inferior to one another.