Respiratory system diseases are considered the most common throughout the world. The increasingly deteriorating state of the atmosphere and the environment, in general, only exacerbates this problem. Failure to seek medical attention if such alarming symptoms appear as a prolonged dry or wet cough, shortness of breath, chest pain leads to an even greater spread of respiratory pathology, although at present there are effective methods for diagnosing lung diseases. One of these methods is computed tomography (CT of the lungs), which will be discussed in this article.
What is this examination
Computed tomography of internal organs, including CT of the lungs, was developed in 1972. The principle of this method is the passage of x-rays through the human body, which makes it possible to obtain images of internal organs on a computer monitor.
Unlike traditional chest radiography, the CT method is more advanced, as it allows you to instantly obtain images of organs in layers. As a result, the picture is more accurate and informative. In addition, x-ray irradiation when performing CT is much less than with panoramic radiography.
What can be seen with CT
Why is computed tomography so important? What does a CT scan of the lungs show?
When using computed tomography, the following diseases can be diagnosed:
- Neoplasms of the chest and mediastinum (malignant and benign tumors).
- Pulmonary tuberculosis even in the early stages.
- Emphysema (increase in airiness of the respiratory sacs of the lungs - alveoli).
- Purulent processes in the lungs and mediastinum (abscesses).
- Fistulas formed between the bronchi and pleura.
- An aortic aneurysm (thinning of its wall and saccular protrusion).
- Stratification of the aortic aneurysm.
- Inflammatory diseases of the lung tissue (pneumonia).
- Chronic diseases of the bronchial tree (chronic obstructive bronchitis, bronchiectatic disease).
- Diseases of the ribs.
- Inflammatory heart disease (pericarditis).
- Diseases of the thymus gland (thymus).
- Circulatory disturbance in the vessels of the lungs (pulmonary embolism, pulmonary infarction)
- The presence of foreign bodies in the respiratory tract.
The value of CT in the diagnosis of tumors
With the help of computed tomography, it is possible to determine the stage of the tumor process, find out whether the tumor first formed in the lungs or metastasized from other tissues and organs, characterize the state of the lymph nodes and other formations of the mediastinum.
Thus, when answering the question of what CT of the lungs shows, it is worth noting that this method not only allows you to determine the pathology of the respiratory system, but also the mediastinal organs (the space located in the chest cavity between the lungs). In addition, CT makes it possible to predict the further course of the disease and determine the tactics of treatment (medication, surgery, chemotherapy).
Examination preparation
Special specific preparation for CT of the lungs is not required. This is a really safe survey method. The main thing during its implementation is to explain in detail to the patient how the examination will be conducted, as well as the basic principles of the CT apparatus.
If the patient is too nervous, in preparation for lung CT, the doctor may prescribe sedatives (valerian infusion) or stronger tranquilizers (Diazepam). It should be noted that taking any sedatives should only be prescribed by a doctor!
Contraindications
Since computed tomography is an X-ray examination method, there are a number of conditions in which irradiation is undesirable. If a CT scan is necessary for vital reasons, and the benefits of carrying it out exceed all the risks, it’s still worth performing a diagnosis using this method.
The following are the main pathological conditions in which CT scan of the lungs is not recommended:
- Diabetes mellitus in a state of decompensation, diabetic coma.
- Terminal stages of renal failure.
- Severe liver failure.
- Severe respiratory and cardiovascular failure.
- Stroke.
- Any serious condition of patients in which it is impossible to move them to the CT room.
- Mental disorders, claustrophobia.
- Myeloma
- Leukemia
- During pregnancy and breastfeeding.
- People with body weight above 150 kg.
How is computed tomography performed
CT of the lungs is performed using a special tomograph in a separate room. The patient lies on the table of the tomograph. The laboratory assistant puts him in the necessary position. Throughout the session, the patient should lie still to get clear pictures. On average, the duration of tomography is 15-20 minutes.
Next, the sections processed by the tomograph are evaluated by a radiologist. After this, the pictures and the conclusion of the radiologist are transmitted to the attending physician. Only the attending physician can make a final diagnosis and prescribe the necessary therapy. The radiologist only describes what he sees in the picture.
Contrast CT
One of the varieties of this examination method is a contrast CT scan of the lungs. It consists in the administration of a contrast medium to the peripheral vessels, which further fills the vascular bed of the lungs. In this case, it is necessary to find out if the patient is allergic to the components of the substance for contrast.
Before the introduction of the procedure, it is necessary to conduct an allergic test. It is provided by subcutaneous administration of a small amount of contrast medium. If unwanted reactions appear on the skin (redness, rash, itching, an increase in local temperature), you should refuse to conduct a contrast CT scan or replace the drug with another one.
The photo above shows how much you can skip when performing CT without contrast (photo on the left).
Should children have CT scans?
Many mothers and fathers are frightened by the need to irradiate their child. Because of this, caring parents refuse to have a CT scan of the child.
Parents don’t have to worry. These fears are completely in vain. Yes, irradiation is undoubtedly there. However, the radiation background is so small that it slightly exceeds the level of radiation that we receive daily. It is important to note that the level of exposure in the CT apparatus is even lower than in the classic X-ray apparatus.
Therefore, you do not need to abandon this research method. If there is a need for the diagnosis of diseases of the child, do not refuse to perform computed tomography.
MRI of the lungs
There is another modern method for the diagnosis of pulmonary pathology. This is an MRI of the lungs. The principle of its work is not in the passage of x-rays, but in the formation of a magnetic field and obtaining an image based on the difference in the concentration of hydrogen ions in the tissues.
Many patients ask which is better, CT or MRI of the lungs? In principle, each of these diagnostic methods has its own advantages.
MRI of the lungs is better to give preference in the diagnosis of diseases of infants, as young children are most sensitive to radiation. In addition, soft tissue — the lung parenchyma and heart — is better visualized on MRI. The drawback of MRI when it is necessary to diagnose lung diseases is poor visualization of tissues in motion, and it is simply impossible to make a person not breathe throughout the diagnosis.
However, to perform MRI there is an absolute contraindication - the presence in the body of any metal objects (pacemaker, prosthetic joints or heart valves, etc.). Therefore, people with such conditions can only have CT scans.
With this examination method, the pathology of bone structures (ribs, sternum) is better visualized. Therefore, if you suspect a bone disease, it is better to give preference to computed tomography. The undoubted advantage of CT is also its greater availability and cost-effectiveness.
Description of lung CT
Upon receipt of the results of computed tomography at the beginning of the sheet, the patient will see its description, performed by a radiologist. There will be given the characteristics of interlobar fissures, bronchial tree, pulmonary parenchyma, individual segments. Also examined are the organs of the mediastinum, the vessels that are located in it.
CT of healthy lungs should not have any focal changes, the bronchial tree should not be expanded. The lung parenchyma is homogeneous. There should be no volume formations in the lungs and mediastinum. The wall of the bronchi should not be thickened, and the size of the lymph nodes should be within normal limits.
In conclusion, a CT scan of the lungs, the radiologist writes the alleged diagnosis and describes the pathology in the lungs, if any. However, the final diagnosis can only be made by the attending physician. Indeed, for its formulation, not only CT data are needed. The clinical diagnosis is made on the basis of patient complaints, medical history, objective examination of all organ systems in the doctor’s office, data from all additional examination methods.
What are focal changes
In the pathology of lung tissue, the radiologist often describes focal changes in the lungs on CT. This symptom is characteristic of diseases that cause limited tissue damage. The focus is an area up to 1 cm in diameter. Everything that is larger than 1 cm is called the infiltrate.
Focal changes on CT can be determined with pneumonia (focal pneumonia), purulent changes in lung tissue (abscess), neoplasms (lung cancer), in the presence of a foreign body in the bronchial tree.
CT Benefits
What features of computed tomography make this method so common in the modern diagnosis of diseases of internal organs? Its advantages:
- Absolutely painless.
- Non-invasive - does not require violation of the integrity of the skin (with the exception of CT with the introduction of contrast).
- Provides high information content even in the early stages of the disease.
- High availability.
- Minimum radiation load on the body.
- The ability to perform in people with cardiac implants, prostheses, pacemakers.
Feasible side effects
Adverse reactions during computed tomography are very rare. They are found only in 1-4% of cases. Some people may experience allergic reactions to contrast. This can be both a mild allergy, manifested by itching, a rash on the body, redness of the skin, and severe manifestations, up to Quincke's edema and anaphylactic shock. If the patient's well-being worsened significantly, an urgent need to interrupt the session and, if necessary, introduce medications (antihistamines, corticosteroids).
The growth of neoplasms due to exposure to a computer tomograph is an unreasonable fear. After all, as already noted above, the radiation exposure during this examination is extremely small.
It can be concluded that lung CT is an effective method for diagnosing diseases of the chest organs. Perhaps someone may be confused by the price of a CT scan. In Moscow, it ranges from 3.5 to 7 thousand rubles. However, the price of MRI is even higher: from 6 to 12 thousand rubles.
If the doctor has prescribed you to have a CT scan, do not refuse. After all, only this method combines relative accessibility and high information content. Using CT, you can diagnose lung disease at an early stage, which contributes to the appointment of timely treatment, and this increases the chances of recovery.