Which radiographic findings are characteristic of emphysema?

Updated: Mar 13, 2019
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD  more...
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Answer

Answer

In moderate to severe emphysema, chest radiographic findings include bilaterally hyperlucent lungs of large volume, flattened hemidiaphragms with widened costophrenic angles, horizontal ribs, and a narrow mediastinum. The peripheral vascular markings are attenuated, but the markings become prominent when the patient has pulmonary hypertension and right-sided heart failure. A lateral view shows increased retrosternal airspace and flattening of the anterior diaphragmatic angle. In addition, bullae and an irregular distribution of the lung vasculature may be present. When pulmonary hypertension develops, the hilar vascular shadows become prominent, with filling of the lower retrosternal airspace due to right ventricular enlargement.

(See the images below.)

Chest radiograph of an emphysematous patient shows Chest radiograph of an emphysematous patient shows hyperinflated lungs with reduced vascular markings. Pulmonary hila are prominent, suggesting some degree of pulmonary hypertension (Corrêa da Silva, 2001).
Schematic representation of 1 criterion for defini Schematic representation of 1 criterion for defining flattening of the diaphragm on the lateral chest radiograph: drawing a line from the posterior to anterior costophrenic angles and measuring the distance from this line to the apex of the diaphragm. If the height is less than 1.5 cm, the criterion of flattening is fulfilled (Corrêa da Silva, 2001).
Schematic representation of another criterion for Schematic representation of another criterion for defining flattening of the diaphragm on the lateral chest radiograph. When the angle formed by the contact point between the diaphragm and the anterior thoracic wall is more than or equal to 90°, the criterion is fulfilled (Corrêa da Silva, 2001).
Schematic representation of another sign of emphys Schematic representation of another sign of emphysema on the lateral chest radiograph. When the retrosternal space (defined as the space between the posterior border of the sternum and the anterior wall of the mediastinum) is larger than 2.5 cm, it is highly suggestive of overinflated lungs. This radiograph is from a patient with pectus carinatum, an important differential diagnosis to consider when this space is measured (Corrêa da Silva, 2001).
Close-up image shows emphysematous bullae in the l Close-up image shows emphysematous bullae in the left upper lobe. Note the subpleural, thin-walled, cystlike appearance (Corrêa da Silva, 2001).
A, Frontal posteroanterior (PA) chest radiograph s A, Frontal posteroanterior (PA) chest radiograph shows no abnormality of the pulmonary vasculature, with normal intercostal spaces and a diaphragmatic dome between the 6th and 7th anterior ribs on both sides. B, Image in a patient with emphysema demonstrating reduced pulmonary vasculature resulting in hyperlucent lungs. The intercostal spaces are mildly enlarged, and the diaphragmatic domes are straightened and below the extremity of the seventh rib (Corrêa da Silva, 2001).
A, Lateral radiograph of the chest shows normal pu A, Lateral radiograph of the chest shows normal pulmonary vasculature, a retrosternal space within normal limits (< 2.5 cm), and a normal angle between the diaphragm and the anterior thoracic wall. B, Lateral view of the chest shows increased pulmonary transparency, increased retrosternal space (>2.5 cm), and an angle between the thoracic wall and the diaphragm >90°. Straightening of the diaphragm can be more evident in this projection than on others (Corrêa da Silva, 2001).

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