Changes in pulmonary and root patterns

Changes in the lung pattern - a syndrome often observed with lung diseases. Often it is combined with a violation of the structure of the lung root. This is understandable: after all, the pulmonary pattern is formed primarily by the arteries emanating from the root, so many pathological processes affect both the lung parenchyma and its root.

Evaluation of the state of the lung pattern is not an easy task even for a radiologist. This is explained by the existence of different types of branching of pulmonary vessels, considerable age and individual differences. Nevertheless, some general indicators of normal pulmonary and root patterns can be distinguished.

In a healthy person, the pattern is clearly visible in both pulmonary fields. It is made up of straight or arched branching strips, circles and ovals. All these figures are a shadow map of the arteries and veins located in the lungs at different angles to the direction of the X-ray beam. In the radical zone there are the largest vessels, the pattern here is richer, and its elements are larger. To the periphery, the caliber of blood vessels decreases, and only very small vascular spines are visible in the outer zone of the pulmonary fields. For a normal picture, the branching is correct, the fan-shaped deviation of the elements of the pattern from the root to the periphery, a continuous decrease in the size of these elements from the root zone to the outer, the sharpness of the contours, and the absence of cellularity.

Analysis of the figure is advisable to begin with an assessment of the image of the roots of the lungs. The shadow of the root of the left lung is localized somewhat above the shadow of the right root. In the image of each root, it is possible to distinguish artery shadows and light bands corresponding to large bronchi. In the case of the embolism of the lungs and the stagnation of blood in them, the caliber of blood vessels in the roots increases. With fiber fibrosis in the lungs' gates, the shadow of the root becomes slightly differentiated, it does not manage to trace the outlines of individual anatomical elements. The outer contour of the root is uneven, sometimes convex toward the pulmonary field. With an increase in bronchopulmonary lymph nodes in the root, rounded formations with external arcuate contours appear.

Of the various variants of changes in the lung pattern, two play a special role: its amplification and deformation. Strengthening the pulmonary pattern is an increase in the number of elements per unit area of the pulmonary field and the volume of the elements themselves. A classic example is the congestion of the lungs, often observed with mitral heart defects. The resulting changes are bilateral and capture both pulmonary fields all over. In the roots there are enlarged vascular trunks. The branches of the pulmonary artery are widened and traced to the periphery of the pulmonary fields. The correctness of branching of the vessels is not disturbed. Deformation of the lung pattern is a change in the normal position of the elements of the pattern and their shape. This changes the direction of the shadow of the vessels, in some places these shadows have uneven outlines, expand to the periphery (due to infiltration or fibrosis of the perivascular tissue). Such changes can be determined in a limited area and then most often result from a transferred inflammatory process. However, the pathological rearrangement of the pattern may affect pulmonary fields over a considerable extent, which occurs in diffuse (disseminated) lung lesions.

To diffuse (disseminated) lung lesions include pathological conditions in which in both lungs there are widespread changes in the form of scattering of foci, increasing the volume of interstitial tissue or a combination of these processes.

X-ray diffuse lesions are manifested by one of three syndromes:

1. focal (nodular) disseminated lesions;
2. net (reticular) reconstruction of the pulmonary pattern;
3. net-nodular (reticulonodular) lesion.

With disseminated focal lesions on X-ray diffraction, multiple foci are scattered in both lungs. The substrate of these lesions is different - granulomas, hemorrhages, proliferation of tumor tissue, fibrotic nodules, etc. The mesh type of diffuse lesion is expressed in the appearance on the roentgenograms of new elements of the pattern - a peculiar cellular structure, a loop that resembles a multilayer web. The substratum of this pattern is an increase in the volume of fluid or soft tissues in the interstitial space of the lungs. In the reticular-nodal type, a combination of reticular reorganization and numerous focal shadows distributed over the pulmonary fields is determined in the photographs.

In perfusion lung scintigraphy, the main pathology syndrome is a defect in the RFP distribution. By analogy with roentgenological data, it is possible to identify extensive, limited and focal defects. The absence of RFP as a whole is mild or an extensive defect in the image of the lung is most often observed with the central form of lung cancer. The nature of the segmental or lobar defect varies. It can cause a violation of blood flow in the affected segment or lobe due to thromboembolism of the pulmonary artery branch. It occurs when atelectasis and in the area of a cancerous tumor. The accumulation of RFP in the field of pneumonic infiltration and edema has been significantly reduced. Subsegmental defects are often found in obstructive bronchitis with severe emphysema and bronchial asthma during an exacerbation. Focal defects in the image are caused by the same processes as segmental defects, but they are also observed when pressure is applied to the lung of the pleural effusion and in areas of hypoventilation of the lung.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]