Diseases of the respiratory system are considered the most common worldwide. The increasingly deteriorating state of the atmosphere and the environment, in general, only exacerbates this problem. Untimely seeking medical help when such alarming symptoms as a prolonged dry or wet cough, shortness of breath, chest pain appear, leads to an even greater spread of respiratory pathology, although there are currently effective methods for diagnosing lung diseases. One of these methods is computed tomography (CT scan of the lungs), which will be discussed in this article.
What is this survey about
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 an image of the internal organs on a computer monitor.
Unlike traditional plain chest radiography, the CT method is more advanced, as it allows you to instantly get images of organs in layers. As a result, the picturemore accurate and informative. In addition, the X-ray exposure for CT scans is much less than for plain radiographs.
What can be seen with CT
Why is having a CT scan so important? What does a lung CT show?
When using computed tomography, the following diseases can be diagnosed:
- Thoracic and mediastinal neoplasms (malignant and benign tumors).
- Pulmonary tuberculosis even at early stages.
- Emphysema of the lungs (increased airiness of the respiratory sacs of the lungs - alveoli).
- Purulent processes in the lungs and mediastinum (abscesses).
- Fistulas formed between the bronchi and pleura.
- Aortic aneurysm (thinning of its wall and saccular protrusion).
- Dissection of an aortic aneurysm.
- Inflammatory diseases of the lung tissue (pneumonia).
- Chronic diseases of the bronchial tree (chronic obstructive bronchitis, bronchiectasis).
- Rib disease.
- Inflammatory heart disease (pericarditis).
- Diseases of the thymus gland.
- Impaired circulation in the vessels of the lungs (pulmonary embolism, pulmonary infarction)
- 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, to find out whether the tumor formed primarily in the lungs orsecondarily metastasized from other tissues and organs, to 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 organs of the mediastinum (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 (drug, surgery, chemotherapy).
Preparation for examination
Special specific preparation for lung CT is not required. This is a really safe method of examination. The main thing during its implementation is to explain in detail to the patient how the examination will take place, as well as the basic principles of the CT machine.
If the patient is too nervous, in preparation for a CT scan of the lungs, the doctor may prescribe sedatives (valerian infusion) or stronger tranquilizers (diazepam). It is worth noting that taking any sedatives should only be prescribed by a doctor!
Contraindications
Because computed tomography is an x-ray method of examination, there are a number of conditions in which radiation is undesirable. If CT is necessary for vital reasons, and the benefits of performing it outweigh all the risks, it is still worth diagnosing using this method.
The following are the mainpathological conditions in which CT of the lungs is not recommended:
- Diabetes mellitus in a state of decompensation, diabetic coma.
- End-stage renal failure.
- Severe liver failure.
- Severe respiratory and cardiovascular failure.
- Stroke.
- Any serious condition of the patient, in which it is impossible to transfer them to the CT room.
- Mental disorders, claustrophobia.
- Myeloma.
- Leukemia.
- The period of pregnancy and lactation.
- People weighing over 150 kg.
How a CT scan is performed
Lung CT is performed using a special tomograph in a separate room. The patient lies down on the tomography table. The laboratory assistant puts him in the required position. Throughout the session, the patient must lie still to obtain clear pictures. On average, the duration of a tomography is 15-20 minutes.
Further, the sections processed by the tomograph are evaluated by a radiologist. After that, the images and the conclusion of the radiologist are transferred 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 introduction of a contrast agent into the peripheral vessels, which then fills the vascular bed of the lungs. In this case, it is necessary to find out if the patient hasallergies to components of the contrast agent.
Before the introduction of the procedure, it is necessary to conduct an allergic test. It is provided by subcutaneous injection of a small amount of a contrast agent. If unwanted reactions appear on the skin (redness, rash, itching, 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 can be missed on a CT scan without contrast (left photo).
Should children have CT scans
Many moms and dads are terrified of having to irradiate their baby. Because of this, caring parents refuse to conduct a CT scan of the child's lungs.
Parents need not worry. These fears are completely unfounded. Yes, radiation is definitely there. However, the radiation background is so small that it is slightly higher than the level of radiation that we receive daily. It is important to note that the radiation level in a CT machine is even lower than in a classic X-ray machine.
Therefore, there is no need to abandon this research method. If there is a need to diagnose a child's diseases, do not refuse to perform computed tomography.
Lung MRI
There is another modern method for diagnosing pulmonary pathology. This is an MRI of the lungs. The principle of its operation 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 infabrics.
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 tissues, such as the lung parenchyma and the heart, are better visualized on MRI. The disadvantage 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 entire diagnosis.
However, there is an absolute contraindication for MRI - the presence of any metal objects in the body (pacemaker, joint prostheses or heart valves, etc.). Therefore, people with these conditions should only have CT scans.
With this method of examination, the pathology of bone structures (ribs, sternum) is better visualized. Therefore, if bone disease is suspected, 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
When receiving 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 characteristics of interlobar fissures, bronchial tree, lung parenchyma, individual segments. The organs of the mediastinum, the vessels that are located in it are also examined.
No focal changes should be present on CT of he althy lungs, the bronchial tree should not beexpanded. The lung parenchyma is homogeneous. There should be no volumetric 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 the normal range.
At the conclusion of the CT scan of the lungs, the radiologist writes the proposed diagnosis and describes the pathology in the lungs, if any. However, the final diagnosis can only be made by the attending physician. After all, for its setting, not only CT data is needed. The clinical diagnosis is made on the basis of the patient's 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 case of lung tissue pathology, 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 considered to be an area up to 1 cm in diameter. Anything larger than 1 cm is called an infiltrate.
Focal changes on CT can be determined with pneumonia (focal pneumonia), purulent changes in the lung tissue (abscess), neoplasms (lung cancer), in the presence of a foreign body in the bronchial tree.
Advantages of CT
What features of computed tomography make this method so common in modern diagnostics of diseases of internal organs? Its Benefits:
- Absolutely painless.
- Non-invasive - does not require violation of the integrity of the skin (with the exception of CT with the introductioncontrast).
- Provides high information content even in the early stages of the disease.
- High availability.
- Minimum radiation exposure to the body.
- Ability to perform in people with heart implants, prostheses, pacemakers.
Possible side effects
Adverse reactions during computed tomography are very rare. They occur only in 1-4% of cases. Some people may experience allergic reactions to contrast injections. It can be either a mild allergy, manifested by itching, a rash on the body, redness of the skin, or severe manifestations, up to Quincke's edema and anaphylactic shock. If the patient's he alth has deteriorated significantly, it is urgent to interrupt the session and, if necessary, administer medications (antihistamines, corticosteroids).
The growth of neoplasms due to irradiation with a CT scanner is an unfounded fear. Indeed, as noted above, the radiation exposure during this examination is extremely small.
It can be concluded that CT of the lungs is an effective method for diagnosing diseases of the chest organs. Perhaps someone may be confused by the price of a computed tomography. 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 your doctor has ordered a CT scan, don't refuse. After all, only this method combines relative accessibility and high information content. CT can diagnose the diseaselungs at an early stage, which contributes to the appointment of timely treatment, and this increases the chances of recovery.
