What do lung lesions on CT mean? Focal lesions in the lungs

A solitary foci or "foci in the form of a coin" is a focus< 3 см в диаметре, различимый на рентгенограмме легкого. Он обычно окружен легочной паренхимой.

2. What can be represented by a solitary focus in the lung?

Most often, it is a neoplasm (cancer) or a manifestation of infection (granuloma), although it can be a lung abscess, pulmonary infarction, arteriovenous anomaly, resolving pneumonia, pulmonary sequestration, hamartoma, and other pathology. The general rule is that the probability of a malignant tumor corresponds to the age of the patient.

Thus, lung cancer is rare (although it does occur) in 30-year-olds, while for 50-year-old smokers, the probability of a malignant tumor can be 50-60%.

3. How is a solitary focus found in the lung?

Usually, a solitary focus is detected by chance during a routine x-ray examination of the lung. Several large studies have found that more than 75% of lesions were unexpected findings on plain chest radiographs. Symptoms suggestive of lung disease were observed in less than 25% of patients. Now solitary lesions are detected in other highly sensitive studies, such as CT.

4. How often is a solitary lesion in the lung a tumor metastasis?

In less than 10% of cases, solitary foci are tumor metastases, so there is no need for an extended search for a tumor in organs other than the lungs.

5. Can a tissue sample be obtained from a lesion using a needle biopsy under fluoroscopy or CT?

Yes, but the result will not affect the treatment. If cancer cells are obtained from the biopsy, then the focus should be removed. If the biopsy result is negative, the lesion still needs to be removed.

6. What is the importance of X-ray findings?

They are not the most important. The resolution of modern CT devices allows you to better assess the signs characteristic of cancer:
a) Fuzzy or unevenly serrated edges of the focus.
b) The larger the focus, the more likely it is malignant.
c) Calcification of the focus usually indicates a benign formation. Specific central, diffuse or layered calcification is characteristic of a granuloma, while denser calcifications in the form of irregularly shaped grains are observed with a hamartoma. Eccentric calcifications or calcifications in the form of small specks may be in malignant lesions.
d) With CT, it is possible to examine the change in the relative density of lesions after the introduction of contrast. This information increases the accuracy of the diagnosis.

7. What social or clinical evidence suggests that the lesion is more likely to be malignant?

Unfortunately, there are no data that are sensitive or specific enough to influence the diagnosis. Both older age and long-term smoking are factors in which lung cancer is more likely. Winston Churchill was supposed to get lung cancer, but he didn't.

Therefore, information that the patient is the president of a speleological club (histoplasmosis), his sister breeds pigeons (cryptococcosis), he grew up in the Ohio River Valley (histoplasmosis), works as a gravedigger in a dog cemetery (blistomycosis), or simply took a tourist trip through the San Joaquin (coccidioidomycosis), are interesting related information, but do not affect the diagnostic measures for a solitary lesion in the lung.

8. What is the most important part of the medical history?

Old chest x-rays. If the focus appeared recently, then it is more likely that it is malignant, and if it has not changed in the last 2 years, then the likelihood of a malignant tumor is less. Unfortunately, even this rule is not absolute.

9. If a patient was previously treated for a malignant tumor, and now he has a solitary lesion in the lung, can it be argued that this lesion is a metastasis?

No. The probability that a lesion in the lung is a metastasis is less than 50%, even if the patient previously had a malignant tumor. Thus, diagnostic measures in such a patient will be the same as in any other patient with a newly appeared solitary focus in the lung.

10. What should be done with a solitary lesion in the lung?

Full travel and activity information is interesting, but does not affect the progress of the diagnosis. Due to the peripheral localization of most foci, bronchoscopy gives a result of less than 50%. A cytological examination of sputum is not very informative, even if it is performed by the best specialists. A CT scan is recommended because it can identify other potential metastatic lesions and visualize the mediastinal lymph nodes.

As stated above, percutaneous needle biopsy is approximately 80% informative, but its outcome rarely influences subsequent management.

It is important to determine whether the patient can undergo radical surgery. The function of the lungs, liver, kidneys and nervous system should be considered stable. If it is unlikely that the patient will live for a few more years, then it simply does not make sense to remove an asymptomatic lesion in the lung.

The main path for a patient who can undergo surgery is resection of the focus for diagnostic purposes, performed using thoracoscopy, which has the least invasiveness, or a small thoracotomy.

11. What should be the scope of the operation if the focus is a cancerous tumor?

Although some studies suggest that wedge resection is sufficient, removal of the anatomic lobe of the lung remains the operation of choice. Cancer that is found as a solitary lesion is an early stage with a 65% 5-year survival rate (in the absence of visible metastases). Relapses are divided into local and remote.

Educational video of the anatomy of the roots and segments of the lungs

Focal formations in the lungs are tissue seals, which can be caused by various ailments. Moreover, to establish an accurate diagnosis, a doctor's examination and radiography is not enough. The final conclusion can only be made on the basis of specific examination methods, which involve the delivery of a blood test, sputum, tissue puncture.

Important: the opinion that only tuberculosis can be the cause of multiple focal lesions of the lungs is erroneous.

It could be about:

Therefore, the diagnosis should be preceded by a thorough examination of the patient. Even if the doctor is sure that a person has focal pneumonia, it is necessary to produce. This will identify the pathogen that caused the development of the disease.

Now some patients refuse to take some specific tests. The reason for this may be unwillingness or lack of opportunity to visit the clinic due to its remoteness from the place of residence, lack of funds. If this is not done, then there is a high probability that focal pneumonia will become chronic.

What are foci and how to identify them?

Now focal formations in the lungs are divided into several categories based on their number:

1. Single.
2. Single - up to 6 pieces.
3. Multiple - dissemination syndrome.

There is a difference between the internationally accepted definition of what lung lesions are and what is accepted in our country. Abroad, this term is understood as the presence of rounded areas and a diameter of not more than 3 cm. Domestic practice limits the size to 1 cm, and refers to other formations as infiltrates, tuberculomas.

Important: computer examination, in particular tomography, will allow you to accurately determine the size and shape of the lesion of the lung tissue. However, it must be understood that this method of examination has its own margin of error.

In fact, a focal formation in the lung is a degenerative change in the lung tissue or the accumulation of fluid (sputum, blood) in it. The correct characterization of single lung foci (LL) is one of the most important problems of modern medicine.

The importance of the task lies in the fact that 60-70% of cured, but then reappearing such formations are malignant tumors. Among the total number of AOLs detected during MRI, CT or radiography, their part is less than 50%.

An important role here is played by how the foci in the lungs are characterized on CT. With this type of examination, based on characteristic symptoms, the doctor can make assumptions about the presence of serious diseases such as tuberculosis or malignant neoplasms.

However, to clarify the diagnosis, it is necessary to pass additional tests. A hardware examination is not enough to issue a medical opinion. Until now, everyday clinical practice does not have a single algorithm for differential diagnosis for all possible situations. Therefore, the doctor considers each case individually.

Tuberculosis or pneumonia? What can prevent, with the current level of medicine, to make an accurate diagnosis using a hardware method? The answer is simple - the imperfection of the equipment.

In fact, when undergoing fluorography or radiography, it is difficult to detect OOL, the size of which is less than 1 cm. Interposition of anatomical structures can make larger lesions almost invisible.

Therefore, most doctors advise patients to give preference to computed tomography, which makes it possible to examine tissue in section and from any angle. This completely eliminates the possibility that the lesion will be covered by the heart shadow, ribs, or lung roots. That is, to consider the whole picture as a whole and without the possibility of a fatal error, radiography and fluorography simply cannot.

It should be borne in mind that computed tomography can detect not only AOL, but also other types of pathologies, such as emphysema, pneumonia. However, this survey method also has its weaknesses. Even with the passage of computed tomography, focal formations can be missed.

This has the following explanations for the low sensitivity of the apparatus:

1. Pathology is in the central zone - 61%.
2. Size up to 0.5 cm - 72%.
3. Low tissue density - 65%.

It has been established that with primary screening CT, the probability of missing a pathological tissue change, the size of which does not exceed 5 mm, is about 50%.

If the diameter of the focus is more than 1 cm, then the sensitivity of the device is more than 95%. To increase the accuracy of the data obtained, additional software is used to obtain a 3D image, volumetric rendering and projections of maximum intensities.

Anatomical features

In modern domestic medicine, there is a gradation of foci based on their shape, size, density, structure and condition of the surrounding tissues.

Accurate diagnosis based on CT, MRI, fluorography or radiography is possible only in exceptional cases.

Usually, in conclusion, only the probability of the presence of a particular ailment is given. At the same time, the location of the pathology itself is not given decisive importance.

A striking example is the location of the focus in the upper lobes of the lung. It has been established that this localization is inherent in 70% of cases of detection of a primary malignant tumor of this organ. However, this is also typical of tuberculous infiltrates. With the lower lobe of the lung, there is approximately the same picture. Here, cancer is detected that has developed against the background of idiopathic fibrosis and pathological changes caused by tuberculosis.

Great importance is given to what are the contours of the foci. In particular, a fuzzy and uneven outline, with a lesion diameter of more than 1 cm, indicates a high probability of a malignant process. However, if clear edges are present, this is not sufficient reason to stop diagnosing the patient. This pattern is often present in benign neoplasms.

Particular attention is paid to tissue density: based on this parameter, the doctor is able to distinguish pneumonia from scarring of the lung tissue, for example, caused.

The next nuance is that CT allows you to determine the types of inclusions, that is, to determine the structure of the OOL. In fact, after the examination, the specialist can say with high accuracy what kind of substance accumulates in the lungs. However, only fatty inclusions make it possible to determine the ongoing pathological process, since all the rest do not belong to the category of specific symptoms.

Focal changes in the lung tissue can be provoked by both a fairly easily treatable disease - pneumonia, and more serious ailments - malignant and benign neoplasms, tuberculosis. Therefore, it is important to identify them in a timely manner, which will help the hardware method of examination - computed tomography.

Lesions in the lungs on CT are local areas where the transparency of the lung tissue is reduced. These may be areas of darkening or compaction of different sizes, which are found during computed tomography. The cause of this pathological phenomenon can be various diseases of the respiratory organs. Despite the fact that CT is one of the most accurate diagnostic methods, it is impossible to make a diagnosis only on its results. The patient must pass a series of tests, which include blood and sputum tests.

Features of computed tomography

If a pathology of the lower respiratory organs is suspected, the doctor directs the patient for x-rays, tests and computed tomography. All these methods help to identify changes in the lung tissue and make an accurate diagnosis.

Advantages over other methods of examination can be distinguished by the following points:

• In a short time and with maximum accuracy, it is possible to determine what caused the disease. The foci in the lungs are clearly visible on CT, the doctor manages to determine their localization and structure.
• Due to this type of examination, it is possible to determine at what stage the disease is.
• Helps to give an accurate assessment of the condition of the lung tissue. Its density and the state of the alveoli are determined, in addition, the volume of the respiratory organs is measured.
• Thanks to CT, you can analyze the state of even the smallest vessels located in the lungs, as well as evaluate the aorta, heart, vena cava, trachea, bronchi and lymph nodes that are located in the chest.

Such a study helps to consider all segments in the lungs, due to which it is possible to reliably determine exactly where the pathological focus is localized.

Tomography is carried out in medical centers and the cost for it is quite high. However, if you need to clarify the diagnosis, this procedure is simply irreplaceable.

Focal changes

Focal changes in the lungs can be of different sizes. Foci of small diameter 1-10 mm are detected in various diffuse pathologies of the lung tissue. Foci with high density and fairly clear edges are mainly observed in the interstitium of the lung. Various foci of low density, resembling frosted glass, with fuzzy contours, occur with pathological changes in the respiratory sections of the respiratory organs.

It should be borne in mind that the density and size of the foci is of poor diagnostic value. For diagnosis, the distribution of pathological processes in the lung tissue may be more important:

1. Perilymphatic focus - often observed in the bronchi, vessels, interlobular septa and pleura. In this case, uneven contours of the anatomical structures are visible, while the partitions and walls of the bronchi are somewhat thickened, as are the walls of the vessels. Similar pathological changes are often found in tuberculosis, silicosis, sarcoidosis, and carcinomatosis. With these pathologies, the foci are small and do not exceed 2-5 mm. Such foci consist of granulomas or metastatic nodules, they are observed along the lymph nodes in the tissue of the lungs and pleura.
2. polymorphic focus. Such focal formations in the lung tissue occur with tuberculosis. In this case, CT allows you to see areas of different density and size. In some cases, this pattern is observed in oncological pathologies.
3. centrilobular foci. Observed in the arteries and bronchi or in their immediate vicinity. They can be quite dense, well-defined and uniform. Changes in the lung tissue of this type are observed in pneumonia, endobronchial tuberculosis and various types of bronchitis, mainly of bacterial origin. There is another type of centrilobular foci, in this case, the lung tissue has small seals and looks like ground glass.
4. Perivascular foci are pathological formations that are in close proximity to blood vessels. This condition is observed in oncological pathologies and tuberculosis. Foci can be either single or multiple.
5. Chaotically located foci. Such formations are characteristic of pathological hematogenous processes. It can be a hematogenous infection, tuberculosis or hematogenous type metastases. Large multiple foci, about 10 mm in size, are often observed with septic emboli, granulomatosis, fungal infections and metastases. All these diseases have some differences by which they can be differentiated.
6. Subpleural foci are pathologically altered areas located under the pleura. The observation of such areas in the picture always indicates the development of tuberculosis or oncological diseases.
7. Pleural foci. Such pathological formations are located on the pleura. Observed in inflammatory and infectious pathologies of the lower respiratory organs.
8. The apical focus is an overgrowth of fibrous tissue, which over time replaces healthy cells.
9. Lymphogenic carcinomatosis. This concept includes two types of pathological changes in the lungs. On the right side, there is alveolar infiltration, with visible lumen of the bronchi. On the left side, the density of the lung tissue is slightly increased. In the compaction zone, the walls of the bronchi and vessels are observed.

In focal diseases, areas of pathologically altered tissue can be of different sizes. They can be small, no more than 2 mm in size, medium - up to 5 mm in diameter and large, the size of the latter exceeds 10 mm.

Pathological foci are dense, medium density, and loose. If single seals are observed in the lungs, then this can be both an age-related change that does not pose a danger to humans, or a dangerous disease. If multiple foci are observed, then we are talking about pneumonia, tuberculosis or rare forms of cancer.

When mycobacterium tuberculosis enters the lungs, the primary focus develops, which in the picture is very similar to pneumonia. However, the difference is that the inflammatory process can last a very long time, sometimes even for years.

What are dangerous focal changes

Focal changes in the lung tissue almost always indicate a pathological process. In most cases, doctors refer patients to a CT scan if the x-ray does not help to make a correct diagnosis. Usually the diagnosis has already been previously made and it is only confirmed by the results of tomography.

Quite often, according to the results of CT, a diagnosis of tuberculosis or lung cancer is made. With these diseases, it is very important to start therapy in a timely manner. At an early stage, these dangerous diseases respond well to treatment and the prognosis for patients is very good.

Cons of tomography

Computed tomography also has its weaknesses. So, this method does not always allow to see focal changes, the size of which is less than 5 mm and the tissue density is low. If the diameter of the focus does not exceed 0.5 cm, then the chance of detecting it is about 50%. When the size of the modified area is about 10 mm, the chance to see it is equal to 95%.

In conclusion, health workers indicate the likelihood of developing a particular disease. The localization of pathologically altered tissue does not play a role, but close attention is paid to the contours. If they are fuzzy and the foci are more than 1 cm, then this always indicates a malignant process. With clear edges, we can talk about tuberculosis or neoplasms of a benign nature.

If the doctor has doubts about the diagnosis, he can refer the patient to computed tomography. This research method is quite accurate, but even with the help of CT, it is not always possible to see small focal changes in the lungs.

WHAT IS A FOCUS IN THE LUNG TISSUE?

A pulmonary focus is a limited area of ​​reduced transparency of the lung tissue (darkening, compaction) of small size, detected by X-ray or computed tomography (CT) of the lungs, which is not combined with the pathology of the lymph nodes or the collapse of part of the lung - atelectasis. In Western terminology, the term "node" or "center" about a blackout less than 3 cm in size is indicated; if the diameter of the area is greater than 3 cm, the term "mass formation" is used. The Russian school of radiology traditionally calls an area with a diameter of up to 10-12 mm a "center".

If radiography or computed tomography (CT) reveals one such area, we are talking about a single (or solitary) focus; when several areas are found - about single foci. With multiple foci, capturing to one degree or another the entire lung tissue, they speak of, or dissemination of foci.

This article will focus on single foci, their radiographic manifestations, and medical actions when they are detected. There are a number of diseases of a very different nature, which can manifest as a focus on x-rays or computed tomograms.

Solitary or single foci in the lungs are most common in the following diseases:

1. such as lymphoma or
2. Benign tumors - hamartoma, chondroma
3. Pulmonary cysts
4. Tuberculosis, in particular the focus of Gon or
5. Fungal infections
6. Inflammatory non-infectious processes such as rheumatoid arthritis or Wegener's granulomatosis
7. Arteriovenous malformations
8. Intrapulmonary lymph nodes

The detection of a single nodule on a chest x-ray poses a challenge faced by many physicians: the differential diagnostic series for such changes can be long, but the main challenge is to determine whether the nature of the lesion is benign or malignant. The solution of this issue is key in determining the further tactics of treatment and examination. In controversial and unclear cases, in order to accurately determine the benignity or malignancy of a focal lesion, a Second Opinion is recommended - a revision of the CT or X-ray of the lungs in a specialized institution by an experienced specialist.

METHODS FOR DIAGNOSTICS OF LUNGS IN THE LUNGS

The primary method of research is usually a chest x-ray. With it, most of the solitary pulmonary foci are found by chance. Some studies have examined the use of low-dose chest CT as a screening tool for lung cancer; thus, the use of CT leads to the detection of smaller nodes that need to be assessed. As availability increases, PET and SPECT will also play an important role in the diagnosis of solitary lung lesions.

The criteria for benignness of the detected focus are the patient's age less than 35 years, the absence of other risk factors, the stability of the node for more than 2 years according to radiography, or external signs of benignness found on radiographs. These patients are not likely to be malignant and require periodic chest x-rays or CT scans every 3 to 4 months for the first year and every 4 to 6 months for the second year.

LIMITATIONS AND ERRORS OF DIAGNOSIS METHODS

Chest X-ray is characterized by better resolution than CT in determining the severity of calcification and its size. At the same time, visualization of some pulmonary nodules can be complicated due to overlaps of other organs and tissues.

The use of CT is limited by the high cost of this study and the need for intravenous contrast, the risk of adverse reactions after its administration. CT is not as accessible a research method as radiography; in addition, a CT scanner, unlike X-ray machines, cannot be portable. PET and SPECT are much more expensive than CT and MRI, and the availability of these diagnostic methods may vary.

RADIOGRAPHY

Often, solitary pulmonary nodules are first detected on chest radiographs and are an incidental finding. The first question that needs to be answered is whether the detected lesion is located in the lung or is located outside it. In order to clarify the localization of changes, radiography is performed in the lateral projection, fluoroscopy, CT. Nodules usually become visible on radiographs when they are 8–10 mm in size. Occasionally, nodules as small as 5 mm can be found. On radiographs, you can determine the size of the focus, its growth rate, the nature of the edges, the presence of calcifications - changes that can help evaluate the identified node as benign or malignant.

Peripheral formation of the right lung with a cavity (abscess). X-ray in direct projection.

Node size

Nodules larger than 3 cm are more likely to reflect malignant changes, while those smaller than 2 cm are more likely to be benign. However, the size of the node itself is of limited value. In some patients, small nodules may be malignant, while large nodules may reflect benign changes.

Node Growth Rate

Comparison with previously performed radiographs allows us to estimate the growth rate of the focus. The growth rate is related to the time it takes for the tumor to double in size. On radiographs, the node is a two-dimensional image of a three-dimensional object. The volume of a sphere is calculated using the formula 4/3*πR 3 , therefore, an increase in the diameter of a node by 26% corresponds to a doubling of its volume. For example, an increase in the size of a node from 1 to 1.3 cm is equivalent to one doubling of volume, while a change in size from 1 to 2 cm corresponds to an increase in volume of 8 times.

The doubling time for bronchogenic cancer is usually 20–400 days; the time interval required to double the volume, which is 20–30 days or less, is characteristic of infections, pulmonary infarction, lymphoma, and rapidly growing metastases. If the volume doubling time is greater than 400 days, this indicates benign changes, with the exception of a low-grade carcinoid tumor. The absence of changes in the size of the node for more than 2 years with a high degree of probability indicates a benign process. However, it is impossible to determine the size of the focus without error. On a chest x-ray, estimating a 3 mm increase in nodule size can be difficult; measurements on radiographs after digital processing allows you to more accurately determine the size of the focus.

The contours of the hearth

Nodules of a benign nature usually have well-defined, even contours. Malignant nodules are characterized by typical irregular, multicentric, spiky (crown radiant) margins. At the same time, the most significant sign that allows us to assume the malignancy of the changes is the radiance of the edges; extremely rarely, malignant tumors have smooth edges.

Calcined

Deposits of calcium salts, calcifications are more typical for benign focal formations, however, they are also found on CT in approximately 10% of malignant nodes. In benign processes, five typical types of calcification are commonly found: diffuse, central, laminar, concentric, and popcorn. Calcifications in the form of "popcorn" are characteristic of hamartomas, dotted or eccentrically located calcifications are observed mainly in malignant nodes. Calcifications can be more accurately detected and assessed using CT.

Benign tumors in the lungs are relatively rare, but in typical cases, CT can clearly distinguish them from a malignant tumor. Volumetric formation of the left lung - hamartoma. Calcification in the form of "popcorn".

LUNGS ON CT - WHAT IS IT?

Focal lesions in the lungs are better detected on CT than on plain radiography. On CT, focal changes of 3-4 mm in size can be distinguished, and specific morphological signs are also better visualized (characteristic, for example, for rounded atelectasis or arteriovenous malformation). In addition, CT allows better assessment of those areas that are usually difficult to distinguish on radiographs: the apices of the lungs, the hilar zones, and the costophrenic sinuses. Also on CT, the multiple nature of the focal lesion can be detected; CT can be used for tumor staging; in addition, a needle biopsy is performed under CT guidance.

Peripheral formation of the left lung. Typical CT signs of peripheral cancer: rounded shape, uneven radiant contours.

Subpleural foci in the lungs - what is it? Computed tomography demonstrates a nodular mass adjacent to the interlobar pleura. Signs of such foci are not specific and require additional examination. The biopsy confirmed a fungal infection.

X-ray density of the focus on CT

With the help of computed tomography, a certain indicator can be measured - the attenuation coefficient, or the x-ray density of the focus. Measurement results (CT densitometry) are displayed in units of the Hounsfield scale (Unit X, or HU). Below are some examples of attenuation factors:

Air: -1000 EX

Fat: -50 to -100 EX

Water: 0 EX

Blood: 40 to 60 EX

Non-calcified node: 60 to 160 EX

Calcified Node: Over 200 EX

Bone: 1000 EX

When using CT densitometry, it becomes possible to detect hidden calcifications that may not be visible visually even on thin high-resolution CT sections. In addition, the measurement of density helps to detect fatty tissue inside the node, which is a sign of its goodness, especially in cases of hamartoma.

CT with contrast enhancement

Malignant nodes are usually richer in blood vessels than benign ones. The assessment of the contrast enhancement of the node is performed by measuring its density before and after the introduction of contrast with an interval of 5 minutes. Less than 15 density increase X suggests a benign nature of the node, while a contrast enhancement of 20 units. X or more is characteristic of malignant lesions (sensitivity 98%, specificity 73%).

Symptom of the feeding vessel

The symptom of the feeding vessel is characteristic of intrapulmonary nodules of vascular etiology, for example, hematogenous pulmonary metastases or septic emboli.

The wall thickness of the cavity formation

The cavity can be found in both malignant and benign nodes. The presence of a cavity with a thin wall (1 mm or less) is a sign indicating the benign nature of the changes, while the presence of a thick wall does not allow us to conclude that the formation is benign or malignant.

MAGNETIC RESONANCE IMAGING (MRI) OF THE LUNGS

When staging lung cancer, MRI provides better visualization of lesions in the pleura, diaphragm, and chest wall compared to CT. At the same time, MRI is less applicable in assessing the lung parenchyma (especially for detecting and characterizing focal pulmonary changes) due to lower spatial resolution. Since MRI is more expensive and less available, this diagnostic method is used as a backup for the evaluation of tumors that are difficult to assess by CT (for example, Pancoast's tumor).

Ultrasound of the lungs

Ultrasonography is infrequently used in the evaluation of solitary lung lesions; this method is of limited value and is used to guide percutaneous biopsy of larger nodes located in the peripheral regions.

RADIONUCLIDE DIAGNOSTICS OF FOCAL LUNG CHANGES

The use of nuclear medicine techniques (scintigraphy, SPECT, PET) in the evaluation of solitary intrapulmonary nodules has been studied through research studies. Thus, the use of PET and SPECT has been approved in the United States for the evaluation of intrapulmonary nodules.

PET-CT

Malignant neoplasm cells are characterized by greater metabolic activity compared to non-tumor cells, as a result of which the level of glucose accumulation in them is higher. Chest PET uses a compound of a radioactive fluorine nuclide with a mass number of 18 and a glucose analog (F 18-fluorodeoxyglucose, FDG). An increase in FDG accumulation is found in most malignant tumors, and this point is fundamental in the differential diagnosis of benign and malignant pulmonary nodules.

FDG uptake can be quantified using a standardized uptake factor, which is used to unify values ​​based on patient weight and amount of radioisotope administered, allowing comparison of uptake of the radiopharmaceutical in different lesions in different patients. A standardized accumulation factor value greater than 2.5 is used as a "marker" for malignancy. Another advantage of FDG PET is better detection of mediastinal metastases, which allows for more optimal staging of lung cancer.

SPECT

The advantage of single photon emission tomography (SPECT) over PET is greater availability. Scanning uses deptreotide, a somatostatin analog labeled with technetium-99m, which binds to somatostatin receptors that are expressed in non-small cell cancer. However, the use of SPECT has not been studied in large samples. Overall, both PET and SPECT are promising non-invasive techniques to differentiate between malignant and benign lesions and to assist in the evaluation of lesions of uncertain nature.

Confidence level of PET and lung SPECT

Using the meta-analysis, the mean sensitivity and specificity for detecting malignant changes in focal lung lesions of any size was 96% and 73.5%, respectively. In the case of pulmonary nodules, the sensitivity and specificity were 93.9% and 85.8%, respectively.

Errors in PET-CT of the lungs

In FDG PET, false-positive results may be due to other metabolically active nodules, such as infectious granulomas or inflammatory lesions. In addition, tumors with low metabolic activity, such as carcinoid tumor and bronchioloalveolar carcinoma, may not show up at all. At high serum glucose concentrations, it competes with FDG in cells, resulting in a decrease in the accumulation of the radioisotope.

Vasily Vishnyakov, radiologist

Lesions in the lungs often attack the respiratory organs, since many of their diseases cause cavities that are similar in appearance and purpose to foci. Such education in the respiratory organs is dangerous to health, especially if the patient is not going to treat the pathology. The causes of the formation of foci are various ailments that greatly impair the functioning of organs. In most cases, when diagnosing a disease that causes seals or cavities, it will not be enough for a doctor to examine the patient and take an x-ray. In this case, the patient will have to donate blood for analysis, sputum and puncture of the lung tissue in order to make an accurate diagnosis.

Foci in the lungs - what can it be? The opinion that a single or multiple focus causes only pulmonary tuberculosis is considered erroneous. Many diseases of the respiratory organs can lead to the development of foci, so they should be paid special attention when making a diagnosis.

If the doctor noticed a formation in the lung cavity (tomography can reveal this), he suspects the following diseases in the patient:

• violation of fluid metabolism in the respiratory system;
• neoplasms in the lungs, which are not only benign, but also malignant;
• pneumonia;
• cancer, in which there is a large-scale damage to the organ.

Therefore, in order to correctly diagnose the diseased, it is necessary to examine it. Even if the doctor implies that pneumonia caused inflammation, before prescribing a therapeutic course, he needs to conduct a sputum analysis in order to be sure of the correctness of the diagnosis.

Currently, indurated, calcified, and centrilobular lung lesions are frequently diagnosed in humans. However, their course is too complicated due to the fact that few patients agree to take a number of specific tests, on which their health and general condition of the body directly depend.

The genesis of pulmonary foci is not always favorable for a person, this indicates serious violations in the work of the respiratory system. Based on the type (it can be dense or liquid), it becomes clear what kind of damage the disease will cause to human health.

Focal lesion of the lungs - what is it? This pathology is a serious disease, during the development of which seals begin to appear in the lung tissue, resembling foci in appearance.

Depending on their number, such neoplasms have a different name:

1. If the patient after the tomography showed only one focus, it is called single.
2. If a patient has several neoplasms after diagnostic procedures, they are called single. Most often, there are no more than 6 such seals in the cavity.
3. If a large number of formations of various shapes are found in the lungs, they are called multiple. Doctors call this condition the syndrome of dissemination.

Today there is a slight difference in the concept of definition, what are pulmonary foci that develop in the cavity of the respiratory system. This difference is formed in the opinions of scientists from our country and foreign researchers. Abroad, doctors believe that a single or secondary focus, seen in the respiratory system, is a small compaction of a round shape. At the same time, the diameter of the neoplasm does not exceed 3 cm. In our country, seals larger than 1 cm are no longer considered foci - these are tuberculomas or infiltrate.

It is important to note that the examination of the affected lung on a computer called tomography helps to accurately identify the type, size and shape of neoplasms that have appeared in the lung tissues. However, do not forget that this method often has failures.

Polymorphic foci in the lungs - what is it? Such a formation in the respiratory organs is a change in the composition of the lung tissue as a result of stagnation of a certain fluid in them. Often this is blood, sputum, and so on. In order to correctly prescribe treatment, the patient will need to undergo a number of modern procedures to accurately determine the type of focal formation.

A focus in the lungs, what could it be? As mentioned earlier, various diseases can cause the appearance of a focus. Why do they need to be treated immediately after detection? The fact is that often diseases re-attack the respiratory organs of a person. In 70% of cases, a secondary disease is considered malignant, which means that the wrong tactics of its treatment cause the development of cancer.

Therefore, in order to avoid serious health problems, the patient will need to undergo some diagnostic procedures, namely:

• radiography;

It is especially important for the patient to undergo a CT scan, because it will be able to identify the danger of foci, which may consist in the formation of cancer or a complex form of tuberculosis. However, in order to accurately identify the type of disease that caused the appearance of foci in the respiratory organs, it will be necessary to undergo additional types of examinations, since hardware methods alone are often not enough. Nowadays, not a single clinic or hospital has a single algorithm of actions according to which diagnostics would be carried out.

Lesions in the lungs on CT, the classification of formations allows us to understand their type and cause of occurrence, so this procedure must be completed by the patient. But the rest of the methods are prescribed by the doctor, after a complete examination of the patient and familiarization with his medical record.

Why doctors are not always able to make a correct diagnosis of the patient? To detect the course of tuberculosis, pneumonia or other diseases, the desire of doctors alone is not enough. Even if all analyzes are carried out and correctly deciphered, imperfect equipment will not allow to identify some foci of the disease. For example, during a trip to x-ray or fluorography, it is impossible to identify foci with a diameter of less than 1 cm. Also, it is not always possible to correctly examine large foci, which aggravates the diagnosis of pathology.

Unlike the above procedures, tomography is able to correctly determine the location and type of foci, as well as identify the disease that initiated the development of the disease. For example, it is pneumonia, emphysema, or just an accumulation of fluid in a person's lungs.

It is important to note that during the first computer procedure, small foci are skipped - this happens in 50% of cases. However, it is possible to judge the course of the disease and prescribe treatment for large neoplasms.

Features of the disease

In modern medicine, there is a specific gradation of lung foci that differ in shape, density, and damage to nearby tissues.

It is important to note that an accurate diagnosis with a single computer procedure is unlikely, although such cases have been seen in the modern world. Often it depends on the anatomical features of the body.

After going through all the diagnostic procedures prescribed by the doctor, in order to understand the subpleural lung focus - what it is, first you need to figure out what the classification of pulmonary foci is. After all, the accuracy of the diagnostic measures depends on it.

For example, often with tuberculosis of the lungs, seals are located in the upper parts; during the development of pneumonia, the disease evenly affects the respiratory organs, and during the course of cancer, the foci are localized in the lower parts of the lobe. Also, the classification of pulmonary neoplasms depends on the size and shape of the seals, which are different for each type of disease.

Having found one or another symptom of pulmonary diseases, it is necessary to consult a doctor who will prescribe a series of studies, and then prescribe the correct treatment that can benefit the patient's body.

Signs of the development of compaction in the lungs include:

• breathing difficulties;
• accumulation of fluid in the lungs, which causes a wet cough or wheezing when talking;
• frequent sputum discharge;
• the appearance of shortness of breath;
• coughing up blood;
• inability to breathe deeply;
• pain in the chest after physical labor.

It is strictly forbidden to self-diagnose and prescribe treatment if the above symptoms are detected, because this will only aggravate the course of the disease, and also allow it to go into a neglected form.