C-reactive protein in the diagnosis of various diseases. What are lesions in the lungs and why are they dangerous?

The density of lung tissue in the basal segments can decrease to –900…-950 HU, which indicates the development of emphysema. Emphysematous bullae can also form in the upper lobes along the surface of the costal, mediastinal and interlobar pleura. They lead to the pushing of foci and infiltrates into the center of the lung tissue, to the root of the lung. IN final stage these changes can be defined as “honeycomb lung” (Fig. 8).

Rice. 8. High-resolution CT. The outcome of chronic hematogenously disseminated tuberculosis in the “honeycomb lung” with fibrosis and a large number of polymorphic foci on both sides.

Lymphogenic tuberculous disseminations differ in features, on the basis of which it can be assumed that they are pathogenetic mechanism development. These include the predominance of focal rashes (usually miliary) in the middle sections, at the level of the roots, and their lesser severity in the apical and basal segments of the lungs. The greatest changes are localized in the anterior and posterior segments of the upper lobes, in the apical segments of the lower lobes, as well as in reed segments and middle lobe. Another distinctive feature of the lymphogenous nature of dissemination is the unevenness of lung damage with alternation of altered and normal areas. In this case, the location of the foci and the predominance of interstitial changes correspond to the boundaries of a certain lymphatic collector, deep or superficial. In most cases in pathological process the deep lymphatic network of the lung is involved, as a result of which changes are localized deep in the lung tissue, along the vessels and bronchi (Fig. 9).

Rice. 9. High-resolution CT. Lymphogenic disseminated tuberculosis. There are multiple small lesions on both sides against the background of interstitial changes. The distribution of foci in the lung tissue is uneven, with predominantly the deep lymphatic network involved in the pathological process (arrows).

In each lobe, one or several isolated areas of focal compaction of lung tissue can be identified irregular shape, with a wide base facing the pleura, and the apex towards the root of the lung. Fuzzy outlines of blood vessels, Kerley lines in combination with magnification

venous lymph nodes of the roots of the lungs and mediastinum, as well as signs of lymphogenous dissemination. In cases where pathological changes are located predominantly in the cortical parts of the lungs, on the border of the superficial and deep lymphatic network, the lesions are located in the form of a wide strip along chest wall and mediastinum. At the same time, the deep and hilar sections of the lungs remain little changed.

FOCAL TUBERCULOSIS

Focal pulmonary tuberculosis is characterized by the presence of a few foci, mostly productive, in a limited area and occupying 1-2 segments of one or both lungs. It includes both recently emerged, fresh processes with focal sizes less than 10 mm, and older (fibrous-focal) formations, but with clearly expressed signs of process activity. The use of CT is necessary in cases where, with a conventional X-ray tomographic examination, the presence of lesions is doubtful or it is not possible to assess their nature in detail. The outbreaks are located in respiratory department and deep in the lung tissue peribronchially. Their typical localization is the apical and posterior segments of the upper lobe, less often in the apical segment of the lower lobe. More often, the lesions are polymorphic in nature, typically a combination of one or two large lesions with a large number of small and medium ones (Fig. 10).

Fig. 10. High resolution CT. In the upper lobe of the left lung there are polymorphic foci with unclear contours, some of them merge with each other (arrow).

The lesions usually have a homogeneous structure; in the center of some large ones, transverse lumens of the bronchi may be visible, which differ from the cavities of destruction by the correspondence of the size of the clearing to the caliber of the bronchi of the same order on axial images and by a change in shape during reconstructions. True cavities in the lesions are larger in size, eccentric in location, and are detected only with high-resolution CT. When the tuberculosis process intensifies, the contours of large lesions become uneven and unclear, small lesions with a diameter of 1-3 mm are located around. They are localized mainly in the walls of the secondary pulmonary lobes and intralobular septa (interlobular septa). The development of lymphostasis leads to thickening and compaction of these interstitial structures, increasing the density of lung tissue during densitometry.

Rice. 11. High-resolution CT. Targeted reconstruction right lung. In S 1-2 there are polymorphic foci with a tendency to merge and unclear contours, in some with a subpleural location there are small cavities of decay (arrow).

Long course focal tuberculosis, especially against the background of antibacterial therapy, leads to a significant change in the computed tomographic picture. Along with focal changes in the lung tissue, areas of panlobular and paraseptal emphysema, small emphysematous bullae, as well as fibrous linear cords directed from the area pathological changes to the pleura.

Rice. 12. High-resolution CT. Targeted reconstruction of the left lung. Focal tuberculosis, chronic course. Large lesions with clear contours against the background of areas of swelling of the lung tissue (arrows).

The volume of the affected segments gradually decreases due to the development of local pneumosclerosis. In deciding the duration of the tuberculosis process, high-resolution CT has significant advantages over conventional X-ray examination. Objective measurement with a cursor of the reduction in the size of large lesions, the disappearance or reduction in the number of small lesions during dynamic observation, indicate the positive dynamics of the pathological process. The outcome of focal tuberculosis in most patients is the formation of small linear scars, inclusions of lime in the lesions, cavities of bullous emphysema and local thickening costal pleura. In contrast to the initial changes, there are no small foci in the interstitium of the walls of the lobules, which is important for determining the activity of the tuberculosis process.

I.E. Tyurin

Focal formations in the lungs represent an independent radiological and clinical syndrome; in most cases they are asymptomatic and are detected during preventive X-ray examinations.

Single lesion in the lungs (SLP) is defined as a local area of ​​compaction of pulmonary tissue of a round or similar shape with a diameter of up to 3 cm. This international definition differs from the traditional domestic concept of pulmonary foci, the source of which is TB practice(in the classification of pulmonary tuberculosis, the size of lesions does not exceed 1 cm, and compactions bigger size are defined as infiltrates, tuberculomas and other types of changes).

The maximum size of a single lesion, equal to 3 cm, corresponds to the currently accepted staging scheme for non-small cell disease. lung cancer, in which foci of this size are classified as stage T1 of tumor growth. Foci in the lung tissue can be single (from 2 to 6 inclusive) or multiple. The latter refer to X-ray syndrome dissemination and are usually considered in the context differential diagnosis interstitial (diffuse parenchymal) lung diseases.

Single lesions occupy an intermediate position, and their assessment is largely determined by the specific clinical situation (for example, screening for lung cancer, a history of a malignant tumor of extrathoracic localization, etc.). The presence of a single lesion is one of the main criteria for AOL syndrome.

Proper characterization of TLE remains an important clinical issue in thoracic radiology and respiratory medicine in general. It is known that 60-80% of resected AOLs are malignant tumor. Among all AOLs detected during X-ray examination, the frequency of tumors is much lower (usually it does not exceed 50%), however, even in this case, a correct assessment of changes in the lungs requires great importance for the patient.

The main task of radiation examination in AOL is the non-invasive differential diagnosis of malignant and benign processes, as well as the identification of forms of pulmonary tuberculosis among them. In some cases this is possible based on characteristic features detected by radiography or routine computed tomography(CT).

However, the specificity of most of these symptoms is low, so proper assessment of AML requires the involvement of additional techniques and alternative technologies. These include assessment of the growth rate of a lesion in the lung, analysis of probabilistic factors of malignancy, dynamics of accumulation contrast agent with CT and 18-fluorodeoxyglucose (18-FDG) with positron emission tomography (PET), as well as morphological study material obtained during transthoracic needle aspiration biopsy or videothoracoscopy.

It is obvious that in everyday life clinical practice It is unlikely that there can be a single algorithm for the differential diagnosis of AOL for all patients and for all clinical situations, and the task of any clinical recommendations is an accurate assessment of the opportunities provided by individual diagnostic methods and their combinations.

Detection of single lesions in the lungs. Until now, the method of primary detection of foci in the lung tissue remains the usual X-ray examination - radiography or fluorography. Single lesions are found in 0.2-1.0% of all X-ray studies chest. Plain radiographs or fluorograms rarely reveal a single lesion the size of<1 см.

Even larger lesions may be missed due to interposition of anatomical structures (heart shadow, roots of the lungs, ribs, etc.) or the presence of so-called distracting factors, such as developmental anomalies or cardiac pathology. More than 90% of all AOLs visible on radiographs can be detected retrospectively on previous images 1 or even 2 years ago.

CT scan is becoming increasingly important in the diagnosis of pulmonary lesions, which can be performed both when the presence of acute pulmonary disease is suspected based on radiography, and for other indications (to exclude pneumonia, when examining patients with chronic obstructive pulmonary disease and emphysema, etc.). In general, CT can detect 2-4 times more lesions in the lung tissue than radiography, while the average size of detected lesions is 2 times smaller.

However, CT is also not an absolute diagnostic method. The results of lung cancer screening using low-dose CT show that the main reasons for missing pathology are small lesion sizes (the sensitivity of CT in detecting lesions the size<5 мм равна 72%), низкая плотность очагов по типу “матового стекла” (чувствительность 65%) и их локализация в центральных зонах легкого (чувствительность 61%). В среднем частота пропусков патологии при первичном КТ-скрининге может достигать 50%. В выявлении ООЛ размером >1 cm CT sensitivity is usually above 95%.

A number of special techniques contribute to increasing the accuracy of CT in identifying small lesions in lung tissue - programs for computer-aided diagnosis (CAD) and three-dimensional reformation programs, such as maximum intensity projections (MIP) and volume rendering (volume rendering technique (VRT).

Anatomical assessment of single lesions in the lungs X. Assessing the skialological features of the AOL according to radiography or CT is of great importance for differential diagnosis. The lesions can be divided by size, nature of the contours, structure, density, and condition of the surrounding lung tissue. Almost all signs have a probabilistic meaning, being more or less characteristic of a benign or malignant process.

Only in exceptional cases Based on the X-ray data, a nosological diagnosis can be assumed. Thus, the presence of fatty inclusions is typical for hamartoma, ring-shaped or total calcification of the lesion is usually observed in tuberculomas, the presence of afferent and efferent vessels, along with typical contrast enhancement, distinguishes arteriovenous malformations.

The localization of the lesion in the lung tissue is not of fundamental importance, since exceptions and coincidences are observed here too often. More than 70% of lung cancer lesions are located in the upper lobes of the lungs, more often in the right lung than in the left. This localization is typical for most tuberculous infiltrates. Lower lobe localization is typical for lung cancer arising against the background of idiopathic pulmonary fibrosis. Tuberculous infiltrates located in the lower lobes are more often localized in their apical segments.

Lesions in the lung tissue can have different contours: smooth or uneven (wavy, bumpy), clear or unclear (radiant or blurred due to the “ground glass” zone along the periphery). In general, fuzzy and uneven contours are more characteristic of malignant neoplasms, although they can also be observed with inflammatory infiltrates. In one study, based on high-resolution CT (HRCT) data, all lesions with a low-density rim, 97% of lesions with pronounced radiant contours, 93% of lesions with uneven contours, and 82% with wavy contours were malignant.

With lesion sizes >1 cm, such contours serve as a strong argument in favor of a malignant process and, therefore, an indication for morphological verification. Clear, even contours can be observed when benign diseases, but are also constantly observed in single metastases, certain histological forms of lung cancer (squamous cell, small cell) and pulmonary carcinoids.

In one study, among lesions that had clear wavy contours, the incidence of malignant tumors reached 40%. Therefore, the round shape and clear contours of the lesion in themselves are not signs of a benign process and cannot serve as a reason to complete the diagnostic process.

The density of single lesions in the lungs, determined by CT, allows us to divide all lesions into three groups:

• “frosted glass” type lesions;
• mixed or partially solid lesions;
• solid type lesions.

Foci of the “frosted glass” type are characterized by low density; against their background, the walls of the bronchi, the contours of blood vessels and elements of the altered pulmonary interstitium are visible. They are observed in non-destructive inflammatory processes, atypical adenomatous hyperplasia and well-differentiated adenocarcinomas.

The morphological basis of this phenomenon is the thickening of the interalveolar septa in a limited area while maintaining the airiness of the alveoli, which can occur due to inflammatory infiltration, fibrotic changes or partial filling of the alveoli with exudate. With the development of adenocarcinoma (including bronchioloalveolar) tumor cells located along the walls of the alveoli, long time without filling their gap. As a result, a tumor focus appears as a “ground glass” type, which in most cases is not visible on radiographs and linear tomograms.

Lesions of mixed or partially solid type are characterized by the presence of a denser area in the center and a low-density “ground glass” zone along the periphery. Such lesions usually arise around old scars in the lung tissue, including post-tuberculosis scars. In most cases, they represent the growth of a glandular tumor. Up to 34% of non-solid lesions are a malignant tumor, and among lesions of a partially solid type the size<1,5 см этот показатель достигает 50%.

Solid lesions have a typical structure of local compaction of a round shape, soft tissue density, with various contours. They can be observed in almost any pathological process in the lung tissue.

The structure of the pulmonary tract, detected by CT, can be different: homogeneous, with areas of low density caused by necrosis, with air, fat, liquid and high-density inclusions, with visible lumens of the bronchi. None of these symptoms are specific to any particular pathological process, with the exception of the already mentioned fatty inclusions in hamartomas.

With conventional radiography, it is possible to identify only part of the calcifications and air inclusions in the form of cavities, air cells (honeycombs, pores) or bronchial lumens. CT scans reveal calcifications in the primary area 2 times more often than conventional X-ray examinations. Calcifications can be focal (like “puffed corn”), layered (including in the form of calcification of the lesion capsule) and diffuse, occupying the entire volume of the lesion.

Such calcifications are typical of benign processes. The only exceptions are metastases of bone sarcomas, glandular cancer of the colon and ovaries after chemotherapy, and pulmonary carcinoids. In all other cases, the probability of a non-tumor process is extremely high. In malignant foci, including adenocarcinomas, dotted or amorphous, without clear contours, calcium inclusions are often detected.

In general, the incidence of calcification in peripheral cancer tumors according to CT data reaches 13%. Exceptions to this rule are ground-glass lesions seen on CT and lesions of any structure on x-ray that represent bronchioloalveolar carcinoma. Patients with these types of lesions require longer follow-up.

Another factor limiting the possibilities of dynamic or retrospective observation is the size of the TLC.<1 см. Удвоение объема опухолевого очага диаметром 5 мм приводит к увеличению его диаметра всего на 1,5 мм (до 6,5 мм). Оценка подобной динамики находится за пределами возможностей не только традиционной рентгенографии, но и в большинстве случаев КТ.

In this regard, today great importance is attached to computer assessment of the volume of lesions based on spiral CT data, when the computer builds three-dimensional models of identified lesions and compares their volumes. This technique, which is part of CAD systems, is designed for solid lesions and cannot be used with confidence for ground glass lesions and partially solid lesions.

Probabilistic Analysis. Clinical assessment of patients with identified AML is of great importance in differential diagnosis, although it is often underestimated by attending physicians and radiologists. Probabilistic analysis takes into account the quantitative significance of risk factors or the lack thereof to make assumptions about the nature of the AOL. Using such calculations, it is possible to determine the individual risk of a malignant tumor in a specific clinical situation. Both clinical factors and radiological symptoms are taken into account.

The most important factors in favor of a malignant process are:

• cavity wall thickness in the lesion >16 mm;
• uneven and unclear contours of the lesion on CT;
• hemoptysis;
• history of malignant tumors;
• age >70 years;
• lesion size 21-30 mm;
• doubling time of lesion volume<465 дней;
• low-intensity shadow on radiography.

The factor of long-term smoking and amorphous calcifications in the lesion, detected by CT, are also of great importance. Unfortunately, existing probabilistic analysis models do not include data from modern technologies such as dynamic CT and PET.

Characteristics of single lesions in the lungs with dynamic CT. Assessing the blood supply to the peripheral tract using dynamic spiral CT has shown its effectiveness in numerous studies. It is known that the density of the TLC during native examination varies widely and does not have any diagnostic value (except for inclusions of fat and calcium).

With dynamic CT, pathological formations that have their own vascular network actively accumulate intravenously administered contrast agent, and their density increases. A typical example of such lesions are malignant tumors. On the contrary, formations that are devoid of their own vessels or filled with avascular contents (pus, caseosis, exudate, etc.) do not change their density. Such lesions can be represented by tuberculomas, cysts, abscesses and other pathological processes.

The dynamic CT technique for AOL is of greatest importance in regions with a high incidence of tuberculosis, since it allows one to accurately distinguish between malignant tumors and tuberculomas. Dynamic CT is performed in the form of a series of tomographic slices through the pathological formation, which are performed initially, during the administration of a contrast agent and 1, 2, 3 and 4 minutes after it. The lesion density is measured in a zone of interest (ROI), which occupies at least 3/4 of the lesion cut area.

To distinguish between benign and malignant processes, it is necessary to select the so-called enhancement threshold - a numerical value of the attenuation coefficient, the excess of which suggests the presence of a malignant tumor. This threshold, determined empirically in a large multicenter study, is 15 HU. At this gain threshold, the sensitivity of dynamic CT in detecting malignant tumors reaches 98%, the specificity is 58%, and the overall accuracy is 77%.

Despite its high sensitivity for malignant tumors, the technique has a number of disadvantages. These include difficulties in assessing small (<1 см) очагов, низкую специфичность, технические ошибки, связанные с дыханием пациента и артефактами от костных структур и контрастного вещества. Эти недостатки частично компенсированы внедрением в клиническую практику многослойной КТ (МСКТ).

Most studies evaluate the accumulation, but not the clearance, of contrast from the lesions. Meanwhile, it has been shown that an increase in density by more than 25 HU and a rapid decrease in density by 5-30 HU when using MSCT is typical for malignant neoplasms. Benign lesions are characterized by an increase in density by less than 25 HU (in some cases, the density increases by more than 25 HU, but then there is a rapid decrease in density by more than 30 HU or no decrease in density at all). If we choose an enhancement threshold of 25 HU and a density reduction range of 5-30 HU, then the sensitivity, specificity and overall accuracy of the technique for malignant tumors will be 81-94, 90-93 and 85-92%, respectively.

Metabolic characteristics of single lesions in the lungs with PET. All anatomical imaging modalities, including X-ray, ultrasound, CT, and magnetic resonance imaging, focus on macroscopic features of pulmonary lesions, most of which are not specific enough. In recent years, studies of the metabolic characteristics of the lesion using 18-FDG PET have become increasingly widespread. Malignant tumors are characterized by higher metabolic activity, which is characterized by rapid and significant accumulation of 18-FDG in the lesion and its long-term persistence.

Numerous studies have shown that PET is characterized by high sensitivity (88-96%) and specificity (70-90%) for malignant lesions in the lungs. Even better results are obtained with the combined use of PET and CT scanners - PET/CT studies with subsequent combination of the metabolic and anatomical picture. False-positive PET results are observed in active inflammatory processes, including active pulmonary tuberculosis.

A negative PET result is considered extremely important for excluding the malignant nature of the tumor, however, false-negative conclusions can be observed in primary lung tumors of the “ground glass” type and lesions of<7 мм. Поэтому данные ПЭТ должны обязательно сопоставляться с результатами КТ для более точного понимания их клинического значения. В целом в настоящее время ПЭТ является наиболее точным методом для разграничения доброкачественных и злокачественных очагов в легочной ткани размером >1 cm.

Biopsy. For lesions that have anatomical or metabolic features of malignancy, morphological verification is necessary before any treatment is initiated. This rule is mandatory, since the tactics of examination and treatment for primary non-small cell, small cell and metastatic tumors in the lung can be completely different.

There are several methods for collecting material from a pulmonary lesion, including transthoracic needle aspiration and biopsy, transbronchial biopsy, video-assisted thoracoscopic resection of the lesion followed by biopsy, and open biopsy during minithoracotomy. Transthoracic biopsy is performed under the guidance of fluoroscopy, CT, and, in recent years, increasingly under CT fluoroscopy. Transbronchial biopsy is usually performed under fluoroscopic guidance. Puncture of lesions adjacent to the chest wall can be performed using ultrasound guidance.

Transthoracic fine-needle aspiration biopsy of pulmonary lesions, performed using CT and CT fluoroscopic guidance, has a sensitivity of 86% and a specificity of 98% for malignancy, but its sensitivity for lesions<7 мм в диаметре составляет лишь 50%. Все пункционные методы биопсии отличаются низкой чувствительностью при лимфомах с поражением легочной ткани (12%) и доброкачественных образованиях (до 40%).

In these cases, preference should be given to core needle biopsy, the sensitivity of which in these categories reaches 62 and 69%, respectively. Complications with transthoracic biopsy (mainly pneumothorax and intrapleural bleeding) occur in approximately 25% of patients. After a biopsy, no more than 7% of patients require drainage, so this procedure can be performed on an outpatient basis. Contraindications to a biopsy include severe respiratory and heart failure, severe pulmonary emphysema, and location of the lesion in close proximity to the diaphragm or pericardium.

Transbronchial biopsy can be performed when the lesion is localized in the hilar regions, especially in cases of so-called “centralization” of the malignant tumor. In this case, the endobronchial component can be detected during bronchological examination. Another verification option is a brush biopsy, in which material is taken from the inner surface of the bronchus located next to the lesion or inside it. To carry out such a procedure, a preliminary assessment of the lesion and the adjacent bronchi using HRCT is mandatory.

Diagnostic algorithms for single lesions in the lungs. Currently, there is no unified approach to determining the nature of OOL. Obviously, in patients with a high risk of malignant tumor, the optimal approach is the earliest possible morphological verification of the diagnosis with transthoracic biopsy. In patients with a low risk of a malignant process, it is more rational to conduct dynamic monitoring.

In any case, the modern approach requires performing HRCT when AOL is detected by radiography, fluorography or conventional CT. Another mandatory step is to find and study any previous lung scans.

The result of these actions may be the identification of a group of patients with an apparently benign process, as evidenced by: the absence of lesion dynamics for > 2 years, the presence of “benign” calcifications, inclusions of fat (hamartoma) or fluid (cyst) in the lesion according to CT data For these patients only observation is necessary. This also includes cases of arteriovenous malformations and other vascular changes, as well as inflammatory processes in the lungs (round tuberculous infiltrate, tuberculoma, mycetoma, etc.), requiring specific treatment.

The second possible result is the detection of signs of a malignant process (a lesion >1 cm with radiant uneven contours, ground-glass lesions and mixed solid type lesions, which should be regarded as potentially malignant), for which morphological verification is necessary in a specialized medical institution.

All other cases are considered intermediate or indeterminate. The largest group among them consists of patients with newly diagnosed ACLs (in the absence of an X-ray archive) measuring >10 mm, soft tissue density, with relatively clear smooth or wavy contours, without any inclusions according to CT data. Clarification of the nature of AOL in such patients can be carried out using biopsy, dynamic CT, PET and PET/CT. Waiting tactics and dynamic observation are permissible here only in exceptional cases, justified by clinical expediency.

A separate group consists of patients with non-calcified lesions identified by CT scanning.<10 мм. Обычно их обнаруживают при КТ, проведенной для исключения пневмонии или уточнения характера эмфиземы, при трудностях интерпретации рентгеновских снимков и т.д. Такие очаги обычно не видны при обычном рентгенологическом исследовании, их верификация с помощью трансторакальной биопсии малоэффективна, а использование ПЭТ сопряжено с большим количеством ложноотрицательных результатов.

In addition, the likelihood of a malignant process with lesions with a diameter of<5 мм не превышает 2%. В связи с этим принята следующая тактика. Очаги размером <5 мм не требуют никакого динамического наблюдения, таким пациентам может быть рекомендовано обычное профилактическое обследование (флюорография или КТ) через 1 год. Очаги размером 5-10 мм требуют проведения контрольной КТ через 3, 6, 12 и 24 мес. При отсутствии динамики наблюдение прекращается, а любые изменения формы, размеров или количества очагов служат показанием для биопсии.

Thus, differential diagnosis when identifying a single lesion in the lungs is a complex clinical task, which in modern conditions is solved using various methods of radiation and instrumental diagnostics.

I.E. Tyurin

Foci in the lung tissue are defined as areas of compaction of a round or similar shape up to 10 mm in size. Foci can be found in numerous infectious, tumor, interstitial and other lung diseases, the total number of which reaches several dozen. The most well-known representatives of focal changes are metastases of malignant tumors to the lungs and disseminated pulmonary tuberculosis.

Characteristics of focal disseminations. Focal changes in the lungs form the anatomical basis of the large radiological syndrome - focal dissemination. The lesions often serve as the only manifestation of the pathological process, but in a significant proportion of patients they are combined with other manifestations of pulmonary pathology, for example, with reticular changes, an increase or decrease in the airiness of the lung tissue.

Focal changes can be local if they occupy up to two segments of one lung, or diffuse if they spread to three segments or more. The predominant localization of lesions in the lungs is very diverse. Focal disseminations are divided into unilateral and bilateral; in the latter case, the pathological process can be symmetrical or asymmetrical, with a predominance of changes in one lung or part of it. Relatively rarely, foci are distributed evenly throughout the entire lung fields (for example, with miliary tuberculosis).

Much more often, dissemination predominates in the upper or lower parts of the lungs, in the hilar or cortical regions. These features have a known differential diagnostic value. Thus, more pronounced changes in the upper lobes are typical for the chronic course of hematogenous tuberculosis, and an increase in changes towards the diaphragm is typical for hematogenous metastases. Hilar localization of lesions is often found in sarcoidosis, while the predominance of lesions in the cortical parts of the lungs is often observed in the subacute course of hypersensitivity pneumonitis.

Lesions in the lung tissue vary widely in size, density (shade intensity during radiography), structure, and contour patterns. In the domestic literature, it is customary to divide lesions by size into small and miliary (up to 2 mm), medium-sized (3-5 mm) and large (6-10 mm). On radiography, lesions often have an average shadow intensity, which on computed tomography (CT) corresponds to soft tissue density. However, in a number of pathological processes, lesions are displayed on axial sections as areas of low-density compaction - ground-glass lesions. As a rule, they are not visible with traditional X-ray examination and are detected only with thin-slice CT. Such changes in the lungs are observed, for example, with respiratory bronchiolitis or hypersensitivity pneumonitis.

The contours of lesions in the lungs can be clear or unclear, which characterizes the degree of delimitation of the changed area from the surrounding lung tissue. The structure of the lesions can be homogeneous or heterogeneous - due to the presence of calcifications, areas of ossification or decay cavities. Examples include calcified tuberculous lesions, high-density metastases of osteosarcoma with pathological bone formation in them, or disintegrating lesions in septic embolism of the pulmonary vessels.

Despite the well-known patterns of the location of lesions in the lungs and the nature of focal shadows, the capabilities of conventional x-ray examination in the differential diagnosis of such changes are small. As a rule, they are limited to typical manifestations of the most common diseases in the presence of reliable clinical data. The advent of high-resolution CT (HRCT) in the 1980s led to the emergence of a new group of symptoms that significantly simplified the differential diagnosis of focal changes in the lung tissue and significantly increased its effectiveness. Thin-layer CT has great potential in
delineating the nature of focal disseminations in the lungs and determining a method for their verification.

All of the above symptoms of focal disseminations are applicable both to traditional X-ray examination and to CT. However, if with radiography the most important characteristics are the localization of lesions in the lungs and the characteristics of the lesions themselves (their size, shape, contours and structure), then with HRCT a more important characteristic of the pathological process becomes the relationship of the lesions in the lung tissue to the anatomical elements of the secondary pulmonary lobe (SPL) and to the visceral pleura.

Anatomy of the secondary pulmonary lobule. The secondary pulmonary lobule is the smallest structural unit of the lung, completely surrounded by a connective tissue septum. The lobule usually has an irregular polygonal or round shape and sizes from 10 to 25 mm. In the structure of the secondary pulmonary lobule on CT, three components can be distinguished: interlobular septum, root and parenchyma. Each secondary pulmonary lobule is equipped with a separate bronchus and lobular artery, which are located together in the center of the lobule. The lobular artery and bronchus at this level have an outer diameter of about 1 mm. The diameter of the intralobular arteries and terminal bronchioles decreases to 0.7 mm, and the arteries and bronchioles in the acini - to 0.3-0.5 mm.

On axial CT sections, small vessels are located at a distance of at least 3-5 mm from the surface of the visceral pleura; in the cross section they look like dots, and in the longitudinal section they appear as short Y- or V-shaped lines. Venous vessels have a similar image, but at a slightly greater distance from the pleura. Intralobular bronchus and bronchioles are normally not visible on HRCT, since it is impossible to distinguish the air in their lumen from the surrounding air-containing lung tissue. An image of bronchioles can be obtained with HRCT only if their lumen is filled with pathological contents, their walls are thickened, or the lumen is significantly expanded with the formation of bronchiolectasis.

The interlobular septum contains lymphatic vessels and veins. Normally, HRCT can detect only the largest septa - they are located in the anterior and outer parts of the upper, middle and lower lobes, as well as paramediastinal in the lower lobes of the lungs. When the septa thicken due to any pathological process, they become clearly visible on HRCT.

Types of pulmonary lesions. With thin-slice CT, it is customary to distinguish three main types of lesions in the lung tissue, each of which is focused on the anatomical structures of the VLD: chaotic, perilymphatic and centrilobular. The latter are usually divided into two subtypes depending on the presence or absence of visible changes in the bronchioles.

A chaotic distribution of foci is observed in the absence of changes in the pulmonary interstitium. Usually the lesions are displayed against the background of unchanged lung tissue, so their location turns out to be random. Individual elements of the VLD are not visible; it is not possible to establish a connection between such foci and the pulmonary interstitium. A mandatory element is a small number of lesions along the interlobar, costal and mediastinal pleura. This type of distribution of foci is characteristic of hematogenous processes, primarily hematogenously disseminated tuberculosis and hematogenous metastases. In some cases, for example, with hematogenous metastasis, it is possible to establish a connection between the foci and small pulmonary vessels - the “feeding vessel” symptom is most typical for hematogenous metastases and multiple septic embolisms.

Perilymphatic foci are localized along the lymphatic vessels and therefore are detected on CT scans mainly in the walls of the bronchi, vessels, interlobular septa and in the layers of the interlobar pleura. Changes in the walls of blood vessels and bronchi create a picture of uneven, “jagged” contours of these anatomical structures, as well as a distinct thickening of the interlobular septa. Such changes are observed primarily in sarcoidosis and lymphogenous carcinomatosis. The lesions, as a rule, are small in size - within 2-5 mm. Their morphological basis is granulomas or metastatic nodules that arise along the lymphatic vessels in the pulmonary interstitium and pleura.

Centrilobular lesions reflect pathological changes in or around intralobular arteries and bronchi. A distinctive feature of such lesions is the absence of changes in the pulmonary interstitium (thickening of the interlobular septa, bronchial walls, layers of the interlobar pleura), as well as the absence of lesions under the visceral pleura. Foci of this type can be represented by two main options.

In the first option, centrilobular lesions are displayed as fairly dense, clearly visible, well-defined structures of round or irregular shape. Their characteristic manifestation is the symptom of “tree-in-bud” (“tree-in-bud”, synonym: “blooming or blossoming tree”) - in the cortical parts of the lung, at a distance of 3-5 mm from the surface of the visceral pleura, Y-shaped or V --shaped structures 1-2 mm thick with thickenings at the ends. The base of these structures always faces the visceral pleura.

The “tree in the buds” symptom is a tomographic display of dilated intralobular bronchioles filled with pathological contents in a longitudinal section. Centrilobular changes of this type are observed with endobronchial spread of pulmonary infections, including tuberculosis, as well as with various forms of non-infectious bronchiolitis, occupational diseases (silicosis, anthracosis), etc.

The second variant of centrilobular lesions is represented by small, ill-defined compactions of low-density lung tissue of the “ground glass” type. Such lesions most often arise as a result of cellular infiltration of peribronchiolar lung tissue and are observed in hypersensitivity pneumonitis and some forms of bronchiolitis. A significant number of such foci, when closely located and partially merging, can create the illusion of diffuse infiltrative changes of the “ground glass” type.

The location of foci in the lung tissue in relation to the anatomical elements of the VLD is of great importance for characterizing dissemination, but this is not enough to determine the nature of the pathological process, even taking into account the usual radiological features of the foci. In some cases, anatomical landmarks of the VLD, which help determine the type of lesions, may not be visible at all (for example, with a chaotic or centrilobular location of the lesions). No less important is the distribution of foci in the whole lung, the relationship of foci to the leaves of the visceral pleura, primarily the costal and interlobar pleura, and the walls of relatively large bronchi and vessels.

The combination of two groups of signs - the type of lesions and their distribution in the lung - allows you to analyze focal dissemination using a relatively simple algorithm, which is aimed at identifying the two or three most likely pathological processes from all possible options.

Diagnostic algorithm. Step one is to identify focal dissemination (or mixed changes in the lung tissue with a predominance of foci). For this purpose, it is necessary to use thin-slice CT - in the form of step-by-step scanning with HRCT or spiral scanning with multi-slice CT. In difficult cases (for example, with difficult to distinguish miliary dissemination), the use of two-dimensional and three-dimensional transformation methods, multiplanar reformations with different layer thicknesses and maximum intensity projections is of great help. Such transformations can only be performed with multi-slice CT and helical scanning protocol.

Step two is to determine the predominant type of lesions. To do this, it is necessary to analyze the condition of the leaves of the visceral pleura, primarily the interlobar, as well as the costal and mediastinal ones. If foci are visible not only in the lung tissue, but along the surface of the pleura, they can be classified as either chaotic or perilymphatic type (the first arm of the algorithm). If the layers of the pleura are not changed, there are no visible foci in them and all focal formations are located deep in the lung tissue, then such changes can be attributed to the centrilobular type (the second arm of the algorithm).

The first arm is the analysis of disseminations in the presence of foci along the visceral pleura. These types of lesions, as a rule, are formed during hematogenous or lymphogenous spread of the pathological process. With hematogenous spread of the process, the foci are located in the lung tissue without connection with the anatomical elements of the VLD. Changes in the pulmonary interstitium (thickening of the interlobular septa, bronchial walls and blood vessels) are weakly expressed or absent altogether. In the costal and interlobar pleura, single foci can be found, while the layers of the pleura themselves, as a rule, are not changed. This type of outbreak is defined as chaotic.

The most important representatives of this kind of dissemination are hematogenous metastases of malignant tumors and hematogenously disseminated tuberculosis. Metastases are characterized by the presence of single or multiple foci in the lung tissue, often polymorphic - having different sizes and even densities. The lesions can have a wide variety of structures (soft tissue density, with calcium inclusions, “frosted glass” type, with decay cavities), as well as clear or unclear contours due to infiltration or hemorrhage into the adjacent lung tissue.

A distinctive feature of most metastatic hematogenous disseminations is the “feeding vessel” symptom, clearly visible on CT. This sign can also be observed with multiple septic embolisms, but it practically does not occur in hematogenous forms of tuberculosis. However, in many cases, the distinction between hematogenous metastases and hematogenously disseminated tuberculosis, especially in its acute and subacute course, is possible only according to clinical and laboratory data.

With the lymphogenous spread of the process, the foci have a clear tendency to be located along the altered structures of the pulmonary interstitium. Foci are detected in the walls of the bronchi and blood vessels, creating a kind of “jaggedness” of their contours, as well as in thickened interlobular septa. Even in cases where the septal lines themselves are not clearly visible, the ring-shaped arrangement of individual groups of lesions follows the shape of the septa. A large number of foci are concentrated in the layers of the interlobar pleura, and usually the layers of the pleura are unevenly thickened and also have a distinct appearance. This picture is formed in the presence of perilymphatic type of lesions.

Such changes are most typical for respiratory sarcoidosis of stage II and sometimes stage III. In a typical picture of sarcoidosis, perilymphatic foci are located predominantly in the central part of the lung, especially along the oblique interlobar pleura. Reticular and infiltrative changes are expressed to varying degrees, sometimes significantly, but thickening of the septal septa is not typical for this disease. Distinctive features are the location of lesions in the walls of blood vessels and bronchi with their simultaneous thickening (peribronchial and perivascular couplings), in the interlobar pleura with thickening of its leaves, as well as frequent enlargement of the peritracheobronchial lymph nodes.

The differential diagnostic range for perilymphatic lesions includes pneumoconiosis, primarily silicosis and anthracosis, which may be indistinguishable from sarcoidosis on CT. Correct diagnosis is facilitated by anamnestic data. Lymphogenic carcinomatosis is also characterized by a perilymphatic location of metastatic foci, but pronounced reticular changes in the form of uniform or distinct thickening of the interlobular septa usually suggest the correct diagnosis. An additional sign of metastatic lesions, in addition to a history of a malignant tumor, is often the presence of fluid in the pleural cavity.

The second arm of the algorithm is the analysis of disseminations in the absence of foci along the visceral pleura. In this case, too, two different types of changes can be distinguished. The key element here is the presence or absence of bronchiolectasis - dilated and filled with pathological contents of intralobular bronchioles, which form typical Y-shaped or V-shaped figures (symptom of “tree in the buds”).

In the first version, such changes are absent, and only focal changes can be detected on axial sections. The lesions are located deep in the lung tissue, and in the cortical sections they can be seen at a distance of 3-5 mm from the visceral pleura. They usually present as peribronchial and peribronchiolar infiltrates or granulomas. Such foci may have soft tissue density and clear contours, for example, with histiocytosis, which in typical cases is accompanied by the formation of numerous cysts mainly in the upper lobes of the lungs, which, in combination with the centrilobular location of the foci, creates a very characteristic picture.

Another option is low density lesions, when they appear on axial sections as small areas of ground glass compaction - for example, in subacute hypersensitivity pneumonitis (exogenous allergic alveolitis) or in respiratory bronchiolitis. This type of change is often difficult to distinguish from the chaotic type of foci during hematogenous dissemination. The key point in the differential diagnosis between them is the presence or absence of lesions along the visceral (primarily interlobar) pleura.

The second type of changes in this arm of the diagnostic algorithm is a combination of focal dissemination with changes in small bronchi and bronchioles in the form of a “tree in the buds” symptom. Dilated and filled with pathological contents, the bronchioles are located both deep in the lung tissue and along the visceral pleura, at a distance of 3-5 mm from it. As a rule, this symptom reflects the bronchogenic spread of the pathological process: with bronchopneumonia, pneumomycosis, lung abscess and tuberculosis. The cause of widespread changes of this kind is most often disseminated tuberculosis with bronchogenic spread of infection (from a tuberculous cavity or bronchoglandular fistula).

Thus, among the whole variety of focal disseminations, the given diagnostic algorithm allows us to distinguish four main types of changes: chaotic foci, perilymphatic foci, centrilobular foci without bronchiolectasis and centrilobular.

Rice. 9.12. Subacute disseminated pulmonary tuberculosis. Focal shadows in the upper and middle parts of both lungs. X-ray in direct projection.

The lung and mediastinum often reveal significantly enlarged, compacted, partially calcified lymph nodes.

In chronic disseminated pulmonary tuberculosis, changes on the radiograph are very diverse. A characteristic feature is subtotal or total relatively symmetrical polymorphic focal dissemination (Fig. 9.14).

Multiple focal shadows have different sizes, shapes and intensity, which is due to different periods of formation of the lesions. In the upper and middle parts of the lungs, focal shadows are larger, there are significantly more of them than in the lower ones. There is no tendency to merge lesions. The symmetry of the changes detected on the radiograph is disrupted as new lesions appear. In some patients, decay cavities are visible in both lungs in the form of thin-walled ring-shaped shadows with clear internal and external contours - this is what stamped or spectacled cavities look like (Fig. 9.15, 9.16).

In the upper parts of both lungs, the pulmonary pattern is strengthened, deformed and has a mesh/cellular character due to pronounced interstitial fibrosis. Bilateral cortico-apical pleural layers (shvarts) are clearly visible. In the basal sections, the pulmonary pattern is depleted, the transparency of the lung tissue is increased due to vicarious emphysema. The horizontal position of the ribs and the lower position of the diaphragm domes are noted. Due to fibrosis and a decrease in the volume of the upper lobes of the shadow of the roots of the lungs sym*

Rice. 9.13. Subacute disseminated pulmonary tuberculosis. Large focal shadows in the lungs.

a - radiograph in direct projection; b - CT.

pulled up metrically (symptom of “weeping willow”). The shadow of the heart on the radiograph has a median position, and its transverse size in the area of ​​large vessels is narrowed (“drip heart”)(Fig. 9.17).

Residual changes after subacute and chronic disseminated pulmonary tuberculosis on radiographs look like multiple focal shadows of high intensity in both lungs (Fig. 9.18).

Slow progression of chronic disseminated tuberculosis often leads to the formation of fibroids*

Rice. 9.14. Chronic disseminated pulmonary tuberculosis. Polymorphic focal shadows in both lungs. X-ray in direct projection.

pink*cavernous process. Against the background of gross fibrous changes and polymorphic foci of bronchogenic dissemination, large cavities that are stable in size appear (Fig. 9.19).

The complicated course of all forms of disseminated pulmonary tuberculosis with the development of lobular caseous pneumonia is characterized by the appearance in both lungs of many large (from 5 to 10 mm in diameter) focal shadows of irregular shape without sharp outlines. Well-identified lesions resemble snow flakes. Often the lesions merge with

Rice. 9.15. Chronic disseminated pulmonary tuberculosis. Polymorphic foci and cavities in both lungs. CT.

Rice. 9.16. Stamped cavities in disseminated tuberculosis. CT.

the formation of focuses and large conglomerates. The X-ray picture of lobular caseous pneumonia is often called a “snow storm” in the lungs. When the zones of caseous necrosis melt and the formation of caseous necrotic foci of cavities in place of caseous necrosis, ring-shaped shadows of various diameters are found in both lungs.

At fiberoptic bronchoscopy in patients with hematogenously * disseminated pulmonary tuberculosis, multiple tuberculous tubercles are often found on the bronchial mucosa (Fig. 9.20). Sometimes, with early hematogenous generalization, bronchial tuberculosis or residual changes after its cure are detected. During fiberoptic bronchoscopy, it is possible to obtain bronchoalveolar lavage and perform a forceps biopsy of the bronchus, lung or puncture biopsy of the lymph node. The content of cellular elements in the bronchoalveolar lavage is determined, and the predominance of lymphocytes is considered an indirect sign of a specific process. The tuberculous etiology of the disease can be confirmed by transbronchial biopsy if elements of a tuberculous granuloma are detected.

General clinical blood test in patients with acute disseminated pulmonary tuberculosis, it usually reveals a slight leukocytosis or normal leukocyte count, a decrease in the content of eosinophils and lymphocytes. Absolute and relative neutrophilia with a shift in the leukocyte formula to the left and a significant increase in ESR are observed. As the disease progresses, leukopenia and thrombocytopenia develop. Anemic syndrome is usually absent. IN general urine test sometimes protein and a positive diazoreaction are determined.

Rice. 9.17. “Drip heart” in chronic disseminated pulmonary tuberculosis. Radiographs of the lungs in direct projection (options).

Subacute disseminated tuberculosis is characterized by moderate leukocytosis, lymphopenia, monocytosis, band* nuclear shift and increased ESR. A decrease in the number of red blood cells and oligochromasia are possible. Similar changes in the hemogram are noted during exacerbation of chronic disseminated tuberculosis. When the tuberculosis process is stabilized, inflammatory changes in the general blood test are rare; sometimes the platelet content increases slightly.

Rice. 9.18. Multiple focal shadows of high intensity as an outcome of subacute disseminated pulmonary tuberculosis. X-ray in direct projection.

During immunological research In patients with acute miliary tuberculosis, a significant decrease in the T*lymphocyte population (especially the T*helper subpopulation) and a drop in their functional activity, which is assessed by the blast transformation reaction of lymphocytes, are often detected. The percentage of B*lymphocytes increases. Linked immunosorbent assay often reveals a significant increase in the titer of antibodies to MBT.

Biochemical research Blood tests for disseminated pulmonary tuberculosis sometimes reveal signs of adrenal insufficiency in the form of a decrease in the glucocorticoid fraction and an increase in the production of mineralocorticoids. There may be disturbances in the secretion of progesterone, testosterone and other hormones that can affect cells involved in the immune response.

FVD study in patients with disseminated pulmonary tuberculosis reveals ventilation disorders, mainly of a restrictive nature. They are caused by widespread morphological changes in the lungs and tuberculosis intoxication. When examining patients, an increase in respiratory rate, a decrease in vital capacity, and a decrease in oxygen content in arterial and venous blood are usually noted. The oxygen utilization rate is significantly lower than normal.

In chronic disseminated pulmonary tuberculosis, along with the restrictive type of ventilation failure, obstructive type ventilation failure may develop due to the frequent complication of chronic

Rice. 9.19. Fibrous*cavernous tuberculosis as an outcome of disseminated pulmonary tuberculosis. Radiographs of the lungs in direct projection (options).

sky obstructive bronchitis. These patients usually exhibit signs of chronic cor pulmonale. The ECG reveals an increase, expansion and deformation of the P wave in leads II and III, with echocardiography - increase in wall thickness and volume of the right ventricle.

To verify the diagnosis of disseminated pulmonary tuberculosis, clinical, radiological and laboratory data are often insufficient, so there is a need for morphological confirmation. If this is not possible in a clinical setting, they resort to molecular* biological diagnostics (PCR with an MBT-specific primer). Diagnostic therapy ex juvantibus is also used.

Differential diagnosis. Big variety

Rice. 9.20. Protrusion of the affected lymph node into the lumen of the bronchus. Tuberculous tubercles on the mucous membrane. Sketch of a bronchoscopic picture.

clinical and radiological manifestations of disseminated pulmonary tuberculosis necessitate differential diagnosis with many other disseminated lesions.

It should be taken into account that factors causing an imbalance of immunological mechanisms can be found in many patients with disseminated lung disease, not only of tuberculosis, but also of non-tuberculosis nature.

Clinical manifestations of disseminated lung lesions of various etiologies are quite monotonous - shortness of breath, cough, dry

hoy or with a small amount of sputum, less often hemoptysis. Symptoms of lung damage are often combined with more or less pronounced manifestations of intoxication syndrome. An objective clinical examination of the patient and analysis of laboratory and radiological data often fail to clarify the diagnostic situation.

In the process of differential diagnosis of disseminated tuberculosis, the most valuable research methods are bacteriological examination of bronchial contents, high-resolution CT and morphological examination of a lung biopsy obtained by bronchoscopy, transthoracic puncture, video thoracoscopy or, most reliably, mini-thoracotomy. Unfortunately, due to objective difficulties, it is sometimes impossible to verify the diagnosis. In these cases, ex juvantibus therapy is used to clarify the possible tuberculous etiology of the process.

Most often, disseminated pulmonary tuberculosis must be differentiated from stage II sarcoidosis, carcinomatosis, bilateral nonspecific focal pneumonia, silicosis, idiopathic fibrosing alveolitis, histiocytosis X, hemosiderosis, congestive lung due to cardiac pathology, and some systemic diseases. It is also necessary to keep in mind the possibility of drug, septic, rheumatic and traumatic lung injuries.

Pulmonary sarcoidosis stage II, like subacute hematogenously* disseminated tuberculosis, it can be asymptomatic. The disease is detected by control fluorography or x-ray examination. In other cases, patients seek medical help due to the appearance of moderate symptoms of intoxication, cough with a small amount of sputum, shortness of breath, and recurrent chest pain. The course of sarcoidosis in most patients is benign with a tendency to spontaneous resolution of granulomatous lesions. When differentially diagnosing disseminated tuberculosis and pulmonary sarcoidosis, it is taken into account that sarcoidosis most often affects women. Often with sarcoidosis, a complete discrepancy is observed between the large size of the intrathoracic lymph nodes and changes in the lungs, on the one hand, and the good health of the patient, on the other. Dyspnea is relatively rare in patients with sarcoidosis. The lesion is characterized by a systemic nature - it is not only the lymphatic system and lungs, but also the eyes, bones, liver, heart, and parotid glands. Erythema nodosum is observed on the skin of the legs in approximately 1/4 of patients. The reaction to tuberculin is negative or weakly positive. Hypercalcemia and an increase in the amount of gamma globulins in the blood are characteristic. X-ray examination, along with an increase in the intrathoracic lymph nodes, reveals the largest accumulation of foci in the middle and lower parts of the lungs. During bronchoscopy, sarcoid granulomas can be detected on the bronchial mucosa. Scanning with the 67 Ga isotope can detect its accumulation in the lymph nodes. The diagnosis of sarcoidosis is verified by biopsy with histological examination of the lymph node, bronchial mucosa or lung tissue. To obtain the material, mediastinoscopy, bronchoscopy, and videothoracoscopy are used. The biopsy specimen reveals a fresh or scarring epithelioid cell granuloma without perifocal exudative inflammation and caseous necrosis. In later stages, sarcoid granuloma undergoes hyalinization and fibrosis.

Multiple small metastases of a malignant tumor to the lungs (carcinomatosis) in most cases, they are observed in patients who have already had surgery or undergone other treatment for cancer. However, sometimes metastases in the lungs are detected earlier than the primary tumor.

The main clinical manifestations of carcinomatosis are persistent dry cough and intractable shortness of breath. The condition of patients usually progressively worsens. X-ray examination reveals a dense small lesion*

vuyu dissemination throughout the lung fields. The lesions have clear and even contours, without a tendency to merge or disintegrate. Unlike tuberculosis, they are larger and monomorphic. If carcinomatosis is suspected, it is necessary to examine the stomach, mammary glands, kidneys, colon, thyroid, prostate and pancreas, and genitals in order to identify the primary tumor. In cases where it is necessary to verify the diagnosis to obtain a biopsy, it is better to use an open lung biopsy by mini-thoracotomy.

Bilateral nonspecific focal pneumonia differs from disseminated tuberculosis in more pronounced symptoms of respiratory damage. Cough, mucopurulent sputum production, numerous dry and moist rales, and pleural friction noise are noted. The number of focal shadows in the lungs detected on an x-ray is usually relatively small; the shadows of the roots of the lungs may be increased. Bacteriological examination of sputum reveals the growth of nonspecific microflora. Antibacterial therapy quickly leads to improvement of the condition and positive radiographic dynamics.

Differential diagnosis of disseminated tuberculosis, stage II sarcoidosis, carcinomatosis, bilateral focal pneumonia is presented in Table. 9.1.

Table 9.1. Differential diagnosis of disseminated tuberculosis, stage II sarcoidosis, carcinomatosis, bilateral focal pneumonia

Lesions in the lungs often attack the respiratory organs, since many of their diseases cause the appearance of cavities similar in appearance and purpose to the lesions. Such formation in the respiratory organs is dangerous to health, especially if the patient does not intend to treat the pathology. The causes of the formation of lesions are various ailments that greatly impair the functioning of organs. In most cases, when diagnosing a disease that causes lumps or cavities, it will not be enough for the 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 accurately make a diagnosis.

Lesions in the lungs - what could it be? The opinion that a single or multiple lesion causes only pulmonary tuberculosis is considered erroneous. Many diseases of the respiratory organs can lead to the development of lesions, so you should pay special attention to them when making a diagnosis.

If the doctor notices 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 organs;
• neoplasms in the lungs, which are not only benign, but also malignant;
• pneumonia;
• cancer in which large-scale organ damage occurs.

Therefore, in order to correctly diagnose a sick person, you need to examine him. Even if the doctor implies that the inflammation was caused by pneumonia, before prescribing a therapeutic course, he needs to conduct a sputum analysis in order to be absolutely sure of the correctness of the diagnosis.

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

The genesis of pulmonary lesions is not always favorable for a person; this indicates serious disturbances in the functioning 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 lung damage - what is it? This pathology is a serious disease, during the development of which compactions begin to appear in the lung tissue, resembling lesions in appearance.

Depending on their number, such neoplasms have different names:

1. If only one lesion was noticeable in a patient after tomography, it is called solitary.
2. If several neoplasms were identified in a patient 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 different shapes are found in the lungs, they are called multiple. Doctors call this condition of the body dissemination syndrome.

Today there is a slight difference in the concept of defining what pulmonary lesions that develop in the cavity of the respiratory organs are. This difference is formed in the opinions of scientists from our country and foreign researchers. Doctors abroad believe that a single or secondary lesion noticed in the respiratory organs is a small round lump. At the same time, the diameter of the neoplasm does not exceed 3 cm. In our country, lumps larger than 1 cm are no longer considered foci - they are tuberculomas or infiltration.

It is important to note that examining the affected lung on a computer, called tomography, helps to accurately identify the type, size and shape of tumors that have appeared in the lung tissue. However, we should not forget that this method often has failures.

Polymorphic lesions in the lungs – what is it? Such 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, phlegm, and so on. In order to correctly prescribe treatment, the patient will need to undergo a number of modern procedures that make it possible to accurately determine the type of focal formation.

A lesion in the lungs, what could it be? As mentioned earlier, various diseases can cause the appearance of a lesion. Why do they need to be treated immediately after detection? The fact is that diseases often repeatedly attack the human respiratory organs. In 70% of cases, the secondary disease is considered malignant, which means that incorrect treatment tactics 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 be 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 lesions in the respiratory organs, you will need 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 are carried out.

The classification of lesions in the lungs on CT allows one to understand their type and cause of occurrence, so this procedure must be undergone 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 do doctors not always manage to make the correct diagnosis of a patient? To identify the course of tuberculosis, pneumonia or another disease, the desire of doctors alone is not enough. Even if all the tests are carried out and correctly interpreted, imperfect equipment will not allow identifying some foci of the disease. For example, during a trip to x-ray or fluorography, it is impossible to identify lesions whose diameter is less than 1 cm. It is also not always possible to correctly examine large lesions, which aggravates the diagnosis of pathology.

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

It is important to note that during the first computer procedure, small lesions are missed - this happens in 50% of cases. However, it is possible to judge the course of the disease and prescribe treatment based on large tumors.

Features of the disease

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

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

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

For example, often with pulmonary tuberculosis, the seals are located in the upper parts; during the development of pneumonia, the disease uniformly 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 discovered one or another symptom of pulmonary diseases, you must consult a doctor who will prescribe a series of tests and then prescribe the correct treatment that can benefit the patient’s body.

Signs of development of compaction in the lungs include:

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

It is strictly prohibited to independently diagnose yourself and prescribe treatment if the above symptoms are detected, because this will only aggravate the course of the disease, and will also allow it to develop into an advanced form.