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Chest radiology in intensive care


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Chest radiology in intensive care

  1. 1. Chest Radiology in Intensive Care Medicine Dr. Andrew Ferguson MEd FRCA DIBICM FCCP Assistant Professor, Medicine (Critical Care) & Anesthesia Dalhousie University
  2. 2. Overview <ul><li>Air bronchograms & silhouette sign </li></ul><ul><li>Hilar enlargement </li></ul><ul><li>Alveolar & interstitial infiltrates </li></ul><ul><li>Effusions </li></ul><ul><li>Pulmonary oedema </li></ul><ul><li>Assessment of volume status using CXR </li></ul><ul><li>Lobar anatomy & collapse </li></ul><ul><li>Abnormal air collections </li></ul><ul><li>Lines, tubes and drains </li></ul>
  3. 3. Radiographic anatomy Or LA NOTE In spite of what you May have heard… The right heart border Is formed by left atrium in up to 38% of patients AV TV MV
  4. 4. Air bronchograms <ul><li>Bronchi normally invisible as they are thin-walled, filled with air , and surrounded by air </li></ul><ul><li>Except when alveoli fill with substance with the density of fluid e.g. </li></ul><ul><ul><ul><li>Pulmonary oedema </li></ul></ul></ul><ul><ul><ul><li>Blood </li></ul></ul></ul><ul><ul><ul><li>Gastric aspirate </li></ul></ul></ul><ul><ul><ul><li>Inflammatory exudate </li></ul></ul></ul><ul><li>Bronchi visible when surrounded by diseased lung = air bronchogram </li></ul>
  5. 5. Silhouette Sign <ul><li>When an object is in contact with another of different density the adjoining edge is visible e.g. heart border against aerated lung </li></ul><ul><li>When objects of the same density are in contact the adjoining edge is invisible e.g. heart border against consolidated lung </li></ul>
  6. 6. Silhouette Sign Lobe Silhouetted structure Right middle lobe Right heart border Left lingula Left heart border Right lower lobe Right hemidiaphragm Left lower lobe Left hemidiaphragm Post apical segment left upper lobe Aortic knob Ant segment right upper lobe Ascending aorta
  7. 7. Hilar enlargement <ul><li>Unilateral hilar adenopathy </li></ul><ul><ul><li>Neoplasm </li></ul></ul><ul><ul><li>Primary Tuberculosis </li></ul></ul><ul><ul><li>Sarcoidosis (3-8%) </li></ul></ul><ul><ul><li>Primary pulmonary fungal infection </li></ul></ul><ul><li>Bilateral hilar adenopathy </li></ul><ul><ul><li>Sarcoidosis </li></ul></ul><ul><ul><ul><li>may also see right paratracheal nodes </li></ul></ul></ul><ul><ul><li>Lymphoma </li></ul></ul><ul><ul><li>False positive </li></ul></ul><ul><ul><ul><ul><li>Expiration film </li></ul></ul></ul></ul><ul><ul><ul><li>Pulmonary Hypertension </li></ul></ul></ul>
  8. 8. Alveolar infiltrates <ul><li>Air bronchograms </li></ul><ul><li>“ Fluffy” / indistinct appearance </li></ul><ul><li>Segmental or lobar distribution </li></ul><ul><li>Homogeneous & confluent </li></ul><ul><li>What can fill alveoli? </li></ul><ul><li>Water: pulmonary oedema </li></ul><ul><li>Protein: ARDS, alveolar proteinosis </li></ul><ul><li>Fibrous tissue: BOOP, radiation </li></ul><ul><li>Cells: </li></ul><ul><ul><li>Neutrophils : pneumonia; pneumonitis </li></ul></ul><ul><ul><li>Eosinophils : eosinophilic pneumonia </li></ul></ul><ul><ul><li>RBCs : DAH, contusion, infarction, vasculitis </li></ul></ul><ul><ul><li>Neoplastic : carcinoma, lymphoma, </li></ul></ul><ul><ul><li>Lymphocytes : pneumonitis, sarcoidosis </li></ul></ul>
  9. 9. Rapid Clearance of Alveolar Infiltrate <ul><li>Pulmonary oedema </li></ul><ul><li>Pulmonary haemorrhage </li></ul><ul><li>Aspiration </li></ul><ul><li>Pneumococcal pneumonia (possibly) </li></ul>
  10. 10. Interstitial Infiltrates <ul><li>Inhomogeneous </li></ul><ul><li>Discrete </li></ul><ul><li>No bronchograms </li></ul><ul><li>Reticular (lines) and/or </li></ul><ul><li>Nodular (circles) </li></ul><ul><li>Fibrosis </li></ul><ul><li>Connective tissue disease </li></ul><ul><li>Sarcoidosis </li></ul><ul><li>Radiation fibrosis </li></ul><ul><li>Asbestosis </li></ul><ul><li>Lymphangitis carcinomatosis </li></ul><ul><li>Silicosis </li></ul><ul><li>TB </li></ul>
  11. 11. Pleural effusions
  12. 12. Pleural Effusion Appearances <ul><li>Subpulmonic effusion </li></ul><ul><li>Blunting of Costophrenic angle </li></ul><ul><li>Meniscus sign </li></ul><ul><li>Layering </li></ul><ul><li>Loculated </li></ul><ul><li>Laminar effusion </li></ul><ul><ul><ul><li>Subpleural between lung & pleura </li></ul></ul></ul><ul><li>Opacified hemithorax </li></ul><ul><li>Air-fluid levels </li></ul>
  13. 13. Subpulmonic Effusion <ul><li>Tented diaphragmatic dome or apex more lateral than expected </li></ul><ul><li>Costophrenic angle more shallow than expected </li></ul><ul><li>Elevated diaphragm appears thicker and more separated from gastric bubble </li></ul><ul><li>Usually < 350 ml volume </li></ul>
  14. 14. Blunting of Costo-phrenic Angle <ul><li>200-300 ml effusion required (AP film) </li></ul><ul><li>100-150 ml blunts posterior angle on lateral CXR </li></ul>
  15. 15. Pulmonary Oedema
  16. 16. Pulmonary Oedema <ul><li>? Upper lobe diversion (“cephalization”) </li></ul><ul><li>Infiltrates </li></ul><ul><ul><ul><li>Batswing </li></ul></ul></ul><ul><ul><ul><li>Diffuse </li></ul></ul></ul><ul><li>Pleural effusions </li></ul><ul><li>Septal lines e.g. Kerley B </li></ul><ul><ul><ul><li>Basal, 1-2 cm long, straight, 90 o to pleura </li></ul></ul></ul><ul><li>Thickening of fissures </li></ul><ul><li>Peribronchial cuffing </li></ul>Interstitial Oedema
  17. 17. Left atrial pressure & CXR signs
  18. 18. < 10% of cases of pulmonary oedema, usually in rapid onset oedema e.g. acute MR
  19. 19. Kerley B lines
  20. 20. Peribronchial Cuffing May be normal finding if right at hilum
  21. 21. Asymmetric pulmonary oedema <ul><li>Chronic lung disease altering vascular flow </li></ul><ul><li>Acute MR - jet to right pulm vein often RUL </li></ul><ul><li>Patient position (gravitational) </li></ul><ul><li>Re-expansion </li></ul>
  22. 22. Vascular Pedicle Width in Pulmonary Oedema
  23. 23. Martin, G. S. et al. Chest 2002;122:2087-2095 Landmarks for measurement of VPW and CTR on a routine CXR
  24. 24. Vascular pedicle width and fluid status in pulmonary oedema
  25. 25. Using Vascular Pedicle Width
  26. 26. VPW/CTR as predictor of PCWP > 18 Criteria Sensitivity Specificity PPV NPV Odds ratio VPW > 70 & CTR > 0.55 54% 83% 76% 65% 3.2 VPW > 70 69% 72% 70% 72% 2.5 CTR > 0.55 63% 50% 56% 57% 1.3
  27. 27. Lobar anatomy and collapse
  28. 28. Lobar anatomy & collapse
  29. 29. RUL collapse
  30. 30. RML collapse Indistinct right heart border
  31. 31. RLL collapse Fissure may be visible Sail-like line behind right heart plus indistinct diaphragm
  32. 32. LUL Collapse Lufsichel sign = Aerated superior segment of left lower lobe interposes between collapsed upper lobe and mediastinum producing lucency around aorta
  33. 33. LLL collapse Sail-like line behind heart – occasionally seen as extremely straight heart border
  34. 34. Total collapse
  35. 35. Abnormal Air Collections <ul><li>Subcutaneous emphysema </li></ul><ul><li>Pneumomediastinum </li></ul><ul><li>Pneumothorax </li></ul><ul><li>Pulmonary interstitial emphysema </li></ul>
  36. 36. Pulmonary Interstitial Emphysema <ul><li>Much more common in neonates, rare in adults </li></ul><ul><li>Alveolar rupture: air dissects into pulmonary interstitium </li></ul><ul><li>Factors associated: </li></ul><ul><ul><li>Anything increasing intrapulmonary pressure </li></ul></ul><ul><ul><li>Ventilation with peak airway pressures > 30 cm H 2 0 </li></ul></ul><ul><ul><li>RDS or ARDS severity </li></ul></ul><ul><ul><li>Associated pulmonary abnormalities </li></ul></ul><ul><li>CXR features : subtle & often hidden by other pathology </li></ul><ul><ul><li>Multiple small and large parenchymal cysts </li></ul></ul><ul><ul><li>Small, mottled or streaky lucencies extending from hilum </li></ul></ul><ul><ul><li>Perivascular halos from air collections </li></ul></ul><ul><ul><li>Intra-septal air </li></ul></ul><ul><ul><li>Subpleural cysts </li></ul></ul>
  37. 37. Pulmonary Interstitial Emphysema
  38. 38. Pneumomediastinum <ul><li>Sources of air </li></ul><ul><ul><li>Intrathoracic </li></ul></ul><ul><ul><ul><li>Trachea and major bronchi </li></ul></ul></ul><ul><ul><ul><li>Esophagus </li></ul></ul></ul><ul><ul><ul><li>Lung </li></ul></ul></ul><ul><ul><ul><li>Pleural space </li></ul></ul></ul><ul><ul><li>Extrathoracic </li></ul></ul><ul><ul><ul><li>Head and neck </li></ul></ul></ul><ul><ul><ul><li>Intraperitoneum and retroperitoneum </li></ul></ul></ul>
  39. 39. CXR Signs of Pneumomediastinum <ul><li>Thymic sail sign (infants/young children) </li></ul><ul><li>Tubular artery sign (AP film) </li></ul><ul><li>“ Ring around the artery” sign (lateral film) </li></ul><ul><li>Double bronchial wall sign </li></ul><ul><li>Continuous diaphragm sign </li></ul><ul><li>Extrapleural air </li></ul><ul><li>Naclerio ’s V sign </li></ul><ul><li>Linear density parallel to heart border </li></ul><ul><li>Dissection of air into neck </li></ul><ul><li>Dissection of air into chest wall </li></ul>
  40. 40. Continuous diaphragm sign
  41. 41. Naclerio’s V sign Lucent band of gas extending along descending aorta and intersecting band of gas that extends along medial left hemi- diaphragm, together forming “V’
  42. 42. Double bronchial wall sign Air on both sides of bronchial wall makes full wall visible
  43. 43. “ Ring around the artery” sign Air around pulmonary artery
  44. 44. Tubular artery sign Air outlining left subclavian & left carotid
  45. 45. Thymic sail sign Thymus outlined by air Also air tracking up into neck
  46. 46. Extrapleural air e.g. pleura peeled off diaphragm
  47. 47. Mediastinal air
  48. 48. Mediastinal air running parallel to descending aorta
  49. 49. Pneumomediastinum vs pneumothorax
  50. 50. Pneumomediastinum vs pneumocardium
  51. 51. Pneumopericardium
  52. 52. Pitfalls – Mach band effect “ The Mach band effect is associated with convex surfaces, appearing as a region of lucency adjacent to structures with convex borders. The absence of an (associated) opaque line, which is typically seen in pneumomediastinum, can aid in differentiation ” Zylak C. Pneumomediastinum Revisited. Radiographics 2000; 20: 1043-1057.
  53. 53. Pneumothorax <ul><li>Apicolateral visceral pleural line </li></ul><ul><ul><ul><li>Generally requires erect/semi-erect film </li></ul></ul></ul><ul><ul><ul><li>Skin fold may be mistaken for pleural line </li></ul></ul></ul><ul><li>Lack of lung markings outside line </li></ul><ul><ul><ul><li>Caution in COPD/bullous disease </li></ul></ul></ul><ul><ul><ul><li>Bullae generally convex </li></ul></ul></ul><ul><li>ICU CXR often supine/semi-erect </li></ul><ul><ul><ul><li>Different criteria for diagnosis </li></ul></ul></ul><ul><ul><ul><li>Often subtle </li></ul></ul></ul><ul><ul><ul><li>WATCH OUT! </li></ul></ul></ul>
  54. 54. “ Occult” pneumothorax Crisp cardiac silhouette with increased lucency
  55. 55. Occult pneumothorax II Cardiophrenic sulcus highly visible Crisp heart border
  56. 56. Potential signs of pneumothorax <ul><li>Pleural line with absent markings </li></ul><ul><li>Double diaphragm sign </li></ul><ul><ul><ul><li>Visible anterior costophrenic recess interface </li></ul></ul></ul><ul><li>Sharpened cardiac silhouette & apex </li></ul><ul><li>Hyperlucent hemithorax </li></ul><ul><li>Inferior edge of collapsed lung </li></ul><ul><li>Deep sulcus sign </li></ul><ul><li>Depressed diaphragm </li></ul><ul><li>Apical pericardial fat </li></ul><ul><ul><ul><li>Discrete lobulated densities (1-1 .5cm) adjacent to cardiac apex </li></ul></ul></ul>
  57. 57. Tension pneumothorax <ul><li>Flattening of heart border </li></ul><ul><li>Flattening of adjacent vascular structures e.g. SVC </li></ul><ul><li>Mediastinal shift - AWAY </li></ul><ul><li>Diaphragmatic inversion </li></ul>
  58. 58. Double diaphragm sign
  59. 59. Pneumothorax in Supine Patients <ul><li>Anteromedial - unusually sharp outline of: </li></ul><ul><ul><li>Mediastinal vascular structures </li></ul></ul><ul><ul><li>Heart border </li></ul></ul><ul><ul><li>Cardiophrenic sulcus </li></ul></ul><ul><li>Posteromedial </li></ul><ul><ul><li>Lucent band outlining mediastinal surface of a collapsed lower lobe </li></ul></ul><ul><ul><li>Increased visibility of paraspinous line & descending aorta </li></ul></ul><ul><ul><li>Increased visibility of posterior costophrenic sulcus </li></ul></ul><ul><li>Subpulmonic </li></ul><ul><ul><li>Hyperlucent upper abdominal quadrant </li></ul></ul><ul><ul><li>Deep costophrenic sulcus (“deep sulcus” sign) </li></ul></ul><ul><ul><li>Sharp hemidiaphragm despite opacification in lower lobe of lung (if consolidated) </li></ul></ul><ul><ul><li>Visualisation of inferior surface of consolidated lung </li></ul></ul>
  60. 60. Posteromedial Pneumothorax
  61. 61. Subpulmonic pneumothorax Deep sulcus, lucent RUQ Rankine, J. J et al. Postgrad Med J 2000;76:399-404
  62. 62. Anteromedial pneumothorax Sharp outline of mediastinum and right heart border. Right hemithorax has concurrent consolidation and effusion Rankine, J. J et al. Postgrad Med J 2000;76:399-404
  63. 63. Mimics - Skin fold
  64. 64. Subcutaneous emphysema
  65. 65. Lines, tubes and drains
  66. 66. Central line positioning - issues <ul><li>Right upper heart border is left atrium, not the right , in 38% of patients </li></ul><ul><li>Radiographic SVC/RA junction: </li></ul><ul><ul><li>hard to see in 10% </li></ul></ul><ul><ul><li>inaccurate: can be up to 2.8 cm higher than echocardiographic junction </li></ul></ul><ul><ul><li>not all lines within heart shadow on xray are in the RA </li></ul></ul><ul><li>CVC tip should lie </li></ul><ul><ul><li>in SVC </li></ul></ul><ul><ul><li>above pericardial reflection (but no radiographic marker of this structure) </li></ul></ul><ul><ul><li>BUT is acceptable for dialysis line tip to lie at SVC/RA junction or in RA </li></ul></ul><ul><li>Line should lie parallel to vessel wall </li></ul><ul><li>Line tip < 2.9 cm beyond take-off of right main bronchus is always in SVC </li></ul><ul><li>Right tracheobronchial angle is always below junction of brachiocephalic veins </li></ul><ul><li>Carina is mean of 1.3 cm below mid-point of the SVC and up to 0.7 cm below pericardial reflection – is suitable location for line tip </li></ul>
  67. 67. British Journal of Anaesthesia 2006 96(3):335-340
  68. 68. Catheter tips abutting SVC wall – risk of perforation
  69. 70. Malposition – subclavian line into jugular vein
  70. 71. Images to review
  71. 72. Asthma + diversion + peribronchial cuffing
  72. 73. Right Haemothorax with bullet
  73. 74. LUL collapse + LLL collapse
  74. 75. Linear (plate) atelectasis + small bowel obstruction
  75. 76. Bilateral hilar enlargement - lymphoma
  76. 77. Bilateral cavitating lesions with fluid levels - Staph abcess
  77. 78. Chilaiditi's syndrome – colon interspersed between liver/spleen and diaphragm
  78. 79. Deep sulcus sign – left pneumothorax
  79. 81. Diffuse alveolar haemorrhage
  80. 82. Node in aortopulmonary window
  81. 83. Fluid level behind heart – hiatus hernia
  82. 84. Silicone breast implants
  83. 85. Pneumothorax - blocked chest drain
  84. 86. Subcutaneous emphysema, LIJ CVC tip position poor
  85. 87. Residual haemothorax on left with chest tube and LLL collapse/consolidation + air bronchogram: haemothorax on right. Oesophagus displaced to left