Atelectais

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Atelectais

  1. 1. Atelectasis Gamal Rabie Agmy ,MD ,FCCP Professor of Chest Diseases, Assiut University
  2. 2. Atelectasis The definition of atelectasis is loss of air in the alveoli; alveoli devoid of air (not replaced). A diagnosis of atelectasis requires the following: 1-A density, representing lung devoid of air 2-Signs indicating loss of lung volume
  3. 3. Types of Atelectasis: 1-Absorption Atelectasis When airways are obstructed there is no further ventilation to the lungs and beyond. In the early stages, blood flow continues and gradually the oxygen and nitrogen get absorbed, resulting in atelectasis.
  4. 4. Types of Atelectasis: 2-Relaxation Atelectasis The lung is held close to the chest wall because of the negative pressure in the pleural space. Once the negative pressure is lost the lung tends to recoil due to elastic properties and becomes atelectatic. This occurs in patients with pneumothorax and pleural effusion. In this instance, the loss of negative pressure in the pleura permits the lung to relax, due to elastic recoil. There is common misconception that atelectasis is due to compression.
  5. 5. Types of Atelectasis: 3-Comression Atelectasis Collapse secondary to bullae or large tumour
  6. 6. Types of Atelectasis: 4-Adhesive Atelectasis : Surfactant reduces surface tension and keeps the alveoli open. In conditions where there is loss of surfactant, the alveoli collapse and become atelectatic. In ARDS this occurs diffusely to both lungs. In pulmonary embolism due to loss of blood flow and lack of CO2, the integrity of surfactant gets impaired.
  7. 7. Types of Atelectasis: 5-Cicatricial Atelectasis – Alveoli gets trapped in scar and becomes atelectatic in fibrotic disorders
  8. 8. Types of Atelectasis: . 6-Round Atelectasis An instance where the lung gets trapped by pleural disease and is devoid of air. Classically encountered in asbestosis.
  9. 9. Signs of Loss of Lung Volume: Generalized 1-Shift of mediastinum: The trachea and heart gets shifted towards the atelectatic lung. 2-Elevation of diaphragm: The diaphragm moves up and the normal relationship between left and right side gets altered. 3-Drooping of shoulder. 4-Crowding of ribs: The interspace between the ribs is narrower compared to the opposite side.
  10. 10. Signs of Loss of Lung Volume: Movement of Fissures You need a lateral view to appreciate the movement of oblique fissures. Forward movement of oblique fissure in LUL atelectasis. Backward movement in lower lobe atelectasis. Movement of transverse fissure can be recognized in the PA film.
  11. 11. Signs of Loss of Lung Volume: Movement of Hilum The right hilum is normally slightly lower than the left. This relationship will change with lobar atelectasis.
  12. 12. Signs of Loss of Lung Volume: Compensatory Hyperinflation Compensatory hyperinflation as evidenced by increased radiolucency and splaying of vessels can be seen with the normal lobe or opposite lung.
  13. 13. Signs of Loss of Lung Volume: Alterations in Proportion of Left and Right Lung The right lung is approximately 55% and left lung 45%. In atelectasis this apportionment will change and can be a clue to recognition of atelectasis. .
  14. 14. Signs of Loss of Lung Volume: Hemithorax Asymmetry In normals, the right and left hemithorax are equal in size. The size of the hemithorax will be asymmetrical and smaller on the side of atelectasis
  15. 15. Signs of Loss of Lung Volume: Generalized Shift of mediastinum: The trachea and heart gets shifted towards the atelectatic lung. Elevation of diaphragm: The diaphragm moves up and the normal relationship between left and right side gets altered. Drooping of shoulder. Crowding of ribs: The interspace between the ribs is narrower compared to the opposite side. Movement of Fissures You need a lateral view to appreciate the movement of oblique fissures. Forward movement of oblique fissure in LUL atelectasis. Backward movement in lower lobe atelectasis. Movement of transverse fissure can be recognized in the PA film. Movement of Hilum The right hilum is normally slightly lower than the left. This relationship will change with lobar atelectasis. Compensatory Hyperinflation Compensatory hyperinflation as evidenced by increased radiolucency and splaying of vessels can be seen with the normal lobe or opposite lung. Alterations in Proportion of Left and Right Lung The right lung is approximately 55% and left lung 45%. In atelectasis this apportionment will change and can be a clue to recognition of atelectasis. Hemithorax Asymmetry In normals, the right and left hemithorax are equal in size. The size of the hemithorax will be asymmetrical and smaller on the side of atelectasis
  16. 16. Atelectasis Right Lung Homogenous density right hemithorax Mediastinal shift to right Right hemithorax smaller Right heart and diaphragmatic silhouette are not identifiable
  17. 17. Atelectasis Left Lung Homogenous density left hemithorax Mediastinal shift to left Left hemithorax smaller Diaphragm and heart silhouette are not identifiable
  18. 18. Left Lower Lobe Atelectasis • • • • Inhomogeneous cardiac density Left hilum pulled down Non-visualization of left diaphragm Triangular retrocardiac atelectatic LLL
  19. 19. Atelectasis Left Lower Lobe Double density over heart Inhomogenous cardiac density  Triangular retrocardiac density Left hilum pulled down Other findings include: Pneumomediastinum
  20. 20. Atelectasis Left Upper Lobe Mediastinal shift to left Density left upper lung field Loss of aortic knob and left hilar silhouettes Herniation of right lung Atelectatic left upper lobe Forward movement of left oblique fissure "Bowing sign"
  21. 21. Atelectasis Left Upper Lobe Hazy density over left upper lung field Loss of left heart silhouette Tracheal shift to left Lateral A: Forward movement of oblique fissure B: Herniated right lung C: Atelectatic LUL
  22. 22. Atelectasis Right Upper Lobe Homogenous density right upper lung field Mediastinal shift to right Loss of silhouette of ascending aorta Lateral Movement of oblique and transverse fissures
  23. 23. Atelectasis Right Upper Lobe Homogenous density right upper lung field Mediastinal shift to right Loss of silhouette of ascending aorta Lateral Movement of oblique and transverse fissures
  24. 24. RML Atelectasis Vague density in right lower lung field, almost normal RML atelectasis in lateral view, not evident in PA view
  25. 25. Vague density in right lower lung field (almost a normal film). Dramatic RML atelectasis in lateral view, not evident in PA view. Movement of transverse fissure. Other findings include: Azygous lobe
  26. 26. Atelectasis Right Lower Lobe Density in right lower lung field Indistinct right diaphragm Right heart silhouette retained Transverse fissure moved down Right hilum moved down
  27. 27. Adhesive Atelectasis Alveoli are kept open by the integrity of surfactant. When there is loss of surfactant, alveoli collapse. ARDS is an example of diffuse alveolar atelectasis. Plate-like atelectasis is an example of focal loss of surfactant.
  28. 28. Relaxation Atelectasis The lung is held in apposition to the chest wall because of negative pressure in the pleura. When the negative pressure is lost, as in pneumothorax or pleural effusion, the lung relaxes to its atelectatic position. The atelectasis is a secondary event. The pleural problem is primary and dictates other radiological findings.
  29. 29. Round Atelectasis Mass like density Pleural based Base of lungs Blunting of costophrenic angle Pleural thickening Pulmonary vasculature curving into the density Esophageal surgical clips
  30. 30. Round Atelectasis Mass like density Pleural based Base of lungs Blunting of costophrenic angle, pleural thickening Pulmonary vasculature curving into the density
  31. 31. RML Lateral Segment Atelectasis
  32. 32. Sub-segmental Atelectasis
  33. 33. Atelectasis Segmental Anterior sub-segment of RUL "Bronchial wedge"
  34. 34. CT image near the hilum. The convex lateral margin of the collapsed lobe is due to a central mass lesion. CT image through the lower portion of the collapsed lobe The contour of the major fissure is slightly convex; this is normal in the lower portion of the lobe. CT image through the lower portion of collapsed lobe.The contour of the major fissure is concave.
  35. 35. CT image through the upper portion of the left lower lobe. The superior segmental bronchus is patent (arrow) and leads to aerated lung. CT image through the mid portion of the left lower lobe. The hyperinflated superior segment is present posterior to the collapsed basal segments . CT image through the lower portion of the left lower lobe. There is collapse of the basal segments .
  36. 36. CT image. The collapsed superior segment has a typical wedge-shaped configuration with the apex directed laterally. The superior segmental bronchus (arrow) is seen entering the collapse The collapsed lower lobe is surrounded by pleural fluid. The fluid anterior to the collapsed lobe is located within the major fissure. There is also a loculated collection of fluid CT image through the upper portion of the collapsed left lower lobe. The collapsed lobe is surrounded by pleural fluid. As a result of the supine position of the patient, most of the fluid collects posteriorly. The fluid located anteriorly lies within the major fissure .
  37. 37. CT image through the base of the collapsed lower lobe. The central lucency (arrows) is produced by pleural fluid below the collapsed lobe rather than by necrosis within the lobe. CT image at the hilar level. The collapsed middle lobe has a triangular configuration with the apex directed laterally; the triangle is relatively small at this level. The lateral margin of the collapsed lobe has retracted medially from the chest wall. The hyperinflated right upper and lower lobes occupy the area lateral to the collapsed middle lobe. CT image 1 cm below , The triangle is larger at this level
  38. 38. CT image near the level of the hilum. The collapsed upper lobe lies medially against the mediastinum. The major fissure (arrow) separates the hyperexpanded middle and lower lobes. The middle lobe is located lateral to the collapsed lobe; the superior segment of the lower lobe is located posteriorly. There is narrowing and anterior displacement of the right main bronchus . CT scan at the level of the aortic arch. The collapsed right upper lobe lies adjacent to the superior mediastinum. A large mass lesion is visible as an area of relative lucency (arrows) within the collapsed lobe. The mass produces a prominent convex bulge in the contour of the major fissure.

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