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Enlightenment of the pulmonary field or its part
Last reviewed: 23.04.2024
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The increase in the transparency of the pulmonary field or a part of it can be caused either by the presence of air in the pleural cavity (pneumothorax), or by a decrease in the number of soft tissues and, accordingly, an increase in the amount of air in the lung or its part. This condition can be the result of bloating of the lung tissue (emphysema) or a decreased influx into the lung (anemia of the lung), which is observed mainly in certain congenital heart defects.
It is not difficult to distinguish these states. In the case of pneumothorax on the background of enlightenment there is no pulmonary pattern and the edge of the asleep lung is visible. With anemia, the pulmonary pattern is depleted, only thin vascular branches are noticeable. Emphysema is characterized by an intensification of the pulmonary pattern due to the expansion of the branches of the pulmonary artery.
Two-sided diffuse increase in the transparency of pulmonary fields is observed with pulmonary emphysema. In the case of severe emphysema, there is a characteristic pattern. The pulmonary fields are enlarged, the diaphragm is flattened and located low. The motion of the diaphragm is reduced. The transparency of the pulmonary fields with inhalation and exhalation varies little. Large branches of the pulmonary artery (lobar, segmental arteries) are widened, but then suddenly their caliber decreases (a "jump in caliber"), which makes the roots of the lungs appear to be chopped off. The sternum extends anteriorly, and the supraorbital space is enlarged. The heart is small in size, which is associated with a decrease in the flow of blood into it. Due to pulmonary hypertension, the contractions of the right ventricle are strengthened.
Computer tomograms reflect impoverishment and fragmentation of the pulmonary pattern in emphysema. X-ray density of lung tissue on inspiration is unusually small (below -850 HU). The difference in density between exhalation and inspiration is less than 100 HU.
A characteristic picture of an increase in the transparency of a part of the pulmonary field is observed with pneumothorax.
A special examination deserves a perforated (spontaneous) pneumothorax. It occurs as a result of a violation of the integrity of the visceral pleural leaflet, when air from the lung suddenly begins to enter the pleural cavity. The cause of pleural perforation may be a rupture of the cavity wall, an abscess, a cyst, an emphysema bladder, etc. According to the radiographs, it is necessary to evaluate the condition of the lung and to establish the localization of the pathological focus. If the analysis of conventional images is not possible, then perform a tomography or computed tomography.
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