chest X ray basics and interpretation
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This document provides an overview of chest x-ray basics and interpretation. It discusses key radiographic densities seen on CXRs, different chest x-ray views, and how to assess image quality factors like inspiration, penetration, and rotation. The document then outlines a systematic approach to interpreting CXRs, covering the airways, bones, cardiac structures, diaphragm, effusions, lung fields, and other areas. Common abnormalities are described, such as consolidation, atelectasis, pneumonia, and position of tubes/lines.
chest X ray basics and interpretation
- 1. CHEST X RAY BASICS AND INTERPRETATION Dr. R. SOMASKANDAN FINAL YEAR MEM PG DEPARTMENT OF EMERGENCY MEDICINE VMCH
- 3. Radiographic densities Black - air Dark grey - fat Light grey - soft tissue Off white - bone Bright white - metal
- 4. X ray chest views PA AP Lateral Lateral decubitus Oblique Lordotic view
- 5. D/W PA and AP view PA VIEW AP VIEW Scapula Seen in periphery of thorax Seen over lung fields Clavicles project over lung fields Above the apex of lung field Ribs Posterior ribs distinct Anterior ribs distinct Spine Clearly seen not clearly seen
- 7. Decubitus view Useful for differentiating pleural effusions from consolidation .
- 8. Lordotic view Used to visualize the apex of the lung , to pick up abnormality such as a pancoast tumour
- 9. Assessment of image quality Inspiration or expiration Penetration Rotation
- 10. D/W inspiration and expiration The diaphragm should be intersected by the 6th to 8th anterior ribs or 9-11th ribs posterior is complete inspiration
- 11. Penetration/Exposure It is the degree to which X – ray have passed through the body . In in a well exposed film only the spinous processes of the first four thoracic vertebra are seen ,others are hidden by cardiac shadow .
- 12. Rotation To check is the film well centralized whether the medial end of clavicle are equidistant from the vertebral spinous processes Film must be well centered to comment on Mediastinal shift Cardiomegaly
- 13. Approach to CXR Airway Bones and soft tissue Cardiac Diaphargm Effusions Fields (lung) Gastric Hila and mediastinum
- 14. Airway trachea Trachea gets pushed away from abnormality, eg pleural effusion or tension pneumothorax Trachea gets pulled towards abnormality, eg atelectasis Beware of things that may increase this angle, eg left atrial enlargement, lymph node enlargement and left upper lobe atelectasis Follow out both main stem bronchi Check for tubes, pacemaker, wires, lines foreign bodies etc If an endotracheal tube is in place, check the positioning, the distal tip of the tube should be 3- 4cm above the carina
- 17. Airway mediastinum Mass lesions (eg tumour, lymph nodes) Inflammation (eg mediastinitis, granulomatous inflammation) Trauma and dissection (eg haematoma, aneurysm of the major mediastinal vessels)
- 19. Bones and soft tissue Check for fractures, dislocation, subluxation in clavicles, ribs, thoracic , spine . At this time also check the soft tissues for subcutaneous air, foreign bodies and surgical clips Caution with nipple shadows, which may mimic intrapulmonary nodules Compare side to side, if on both sides the “nodules” in question are in the same position, then they are likely to be due to nipple shadows
- 21. cardiac Check heart size and heart borders Appropriate or blunted Thin rim of air around the heart, think of pneumomediastinum Check aorta Widening, tortuosity, calcification Check heart valves Calcification, valve replacements Check SVC, IVC, azygos vein Widening, tortuosity
- 23. Diaphragm Right hemidiaphragm Should be higher than the left If much higher, think of effusion, lobar collapse, diaphragmatic paralysis If you cannot see parts of the diaphragm, consider infiltrate or effusion If film is taken in erect or upright position you may see free air under the diaphragm if intra- abdominal perforation is present
- 25. Effusion Look for blunting of the costophrenic angle Identify the major fissures, if you can see them more obvious than usual, then this could mean that fluid is tracking along the fissure Check out the pleura Thickening, loculations, calcifications and pneumothorax
- 27. Fields ( lung fields ) Check for infiltrates Identify the location of infiltrates by use of known radiological phenomena, eg loss of heart borders or of the contour of the diaphragm The lingula abuts the left side of the heart
- 28. Cont ….. Identify the pattern of infiltration Interstitial pattern (reticular) versus alveolar (patchy or nodular) pattern Lobar collapse Look for air bronchograms, tram tracking, nodules, Kerley B lines
- 29. Lung zones
- 30. Fissures in lung
- 31. Gastric Look for fee air Look for bowel loops between diaphragm and liver
- 33. Hilum Check the position and size bilaterally Enlarged lymph nodes Calcified nodules Mass lesions
- 35. Read the CXR
- 36. How to read a normal CXR This is chest radigraph , PA view with normal exposure , no rotation and without any apparent bony abnormality . Trachea is placed centrally and lung fields are clear with normal broncho- vescicular markings . Cardivascular silhoutte is within normal limits with normal cardiothoracic ratio. Mediastinum, costo phrenic , cardio phrenic angles , dome of diaphragm and soft tissue shadow within normal limits .
- 37. The obvious abnormality It is often appropriate to start by describing the most striking abnormality . However , once you have done this, it is vital to continue checking the rest of the image . Remember that the most obvious abnormality may not be the most clinically important .
- 38. Airway abnormality Tracheal deviation Ipsilateral : collapse and fibrosis Contralateral : apical mass ,pleural effusion and pneumothorax Foreign body
- 40. Bones and soft tissue Bones Fractures Dislocation Malignancy Soft tissue Subcutaneous emphysema Breast cancer
- 42. Soft tissue abnormalities Subcutaneous emphysema there is often straited lucencies in the soft tissue that may outline muscle fibres . If affecting the anterior chect wall , subcutaneous emphysema can outline the pectoralis major muscle , giving rise to the ginkgo leaf sign .
- 43. Breast cancer increased soft tissue density with mass projected on breast and axilla
- 44. Cardiac abnormalities Cardiomegaly the cardiothoracic ratio should be less than 0.5 i.e A+B/C < 0.5
- 45. Cardiac abnormalities Left ventricular enlargment Left border is displaced leftward , inferiorly , posteriorly . Rounding of apex
- 46. Cardiac abnormalities Right ventricular enlargement Rounded left heart border Uplift cardiac apex
- 47. Cardiac abnormalities Pericardial effusion Globular enlargemenet ( water bottle appearance )
- 48. Cardiac abnormalities Congenital heart disease (tetralogy of fallot ) wooden shoe or boot shaped heart
- 49. Diaphragm abnormalities Hiatus hernia it occurs when there is herniation abdominal content through the oesophageal hiatus of diaphragm into thoracic cavity
- 51. Diaphragm abnormalities Chilaiditi syndrome it is a rare condition in which a portion of the colon is abnormally located in between the liver and diaphragm . ( pseudopneumoperitoneum ) Rugal folds
- 52. Pleural Effusion On an upright film, an effusion will cause blunting on the lateral costophrenicsulcus and, if large enough, on the posterior costophrenicsulcus. Approximately 200 ml of fluid are needed to detect an effusion in a PA film, while approximately 75 ml of fluid would be visible in the lateral view In the AP film, an effusion will appear as a graded haze that is denser at the base A lateral decubitus film is helpful in confirming an effusion as the fluid will collect on the dependent side
- 54. Massive pleural effusion Opacification of entire hemithorax and shifting of mediastinum to opposite side If the effusion crosses 2nd rib anterior border it is said to be massive If it crosses 4th rib it is said to be moderate Below 4th rib is mild
- 55. White out lung
- 56. Pneumothorax Appears in the chest radiograph as air without lung markings
- 57. Lung field abnormality Abnormal whiteness ( increased density ) Consolidation Atelectasis Pneumonia Pulmonary edema Abnormal blackness ( decreased density ) Cavity Emphysema Cyst
- 58. Consolidation The lung is said to be consolidated when the alveoli and small airways are filled with dense material. This dense material may consist of: •Pus (pneumonia) •Fluid (pulmonary edema) •Blood (pulmonary hemorrhage) •Cells (cancer) It may be Lobar Diffuse Multifocal ill defined
- 59. Air bronchogram It refers to the phenomenon of air filled brochi being made visible by the opacification of surrounding alveoli
- 61. Atelectasis Almost always associated with a linear increased density due to volume loss Indirect indications of volume loss include vascular crowding or mediastinal shift toward the collapse Possible observance of hilar elevation with an upper lobe collapse, or a hilar depression with a lower lobe collapse
- 63. Miliary TB Miliary deposits appear as 1-3 mm diameter nodules , which are uniform in size and distribution
- 64. Pneumonia Typical findings on the chest radiograph include: Airspace opacity Lobar consolidation Interstitial opacities
- 66. Pulmonary Edema (intertitial) There are two basic types of pulmonary edema: Cardiogenic pulmonary edema caused by increased pulmonary capillary pressure Noncardiogenicpulmonary edema caused by either altered capillary membrane permeability or decreased plasma oncotic pressure
- 68. Pulmonary edema
- 69. Interstitial disease Ground glass appearance
- 70. Pulmonary mass It is an area of pulmonary opacification that measures more than 3 cm . The commonest cause for a pulmonary mass is lung cancer .
- 71. Pulmonary cavity Are gas filled areas of the lung in the center of a nodule , mass or area of consolidation . Cancer – bronchogenic ca Autoimmune , granulomas – rheumatoid nodules Infection – pulmonary abcess, PTB
- 73. Pulmonary emphysema Flattened hemidiaphragm Narrow mediastinum
- 74. Flat diaphragm When the maximum perpendicular height from the supirior border of the diaphragm to a line drawn between the costophrenic and cardiophrenic angles in PA view is less than 1.5 cm .
- 75. Hilum abnormalities Hilar position Whether it is pushed or pulled The left hilum must never be lower the right hilum . it denotes collapse of either the left lower lobe or of the right upper lobe
- 76. Hilar abnormalities Hilar enlargement it may be unilateral or bilateral ex TB, lung tumor ,silicosis
- 77. Mediastinal abnormalities Aortic dissection Mediastinal widening Irregularity of the aortic contour Double aortic contour
- 78. Mediastinal abnormalities Aortic aneurysms widening of the mediastinum Enlargement of the aortic knob
- 79. Mediastinal abnormalities Pneumomediastinum small amount of air appear as linear or curvilinear lucencies outlining mediastinal contours . Signs of pneumomediastinum Ring around artery sing Tubular artery sign Continuous diaphragm sign Angle wing sign
- 80. Ring around artery sign Air around pulmonary artery and main braches .
- 81. Tubular artery sign Air outlining major aortic branches
- 82. Continuous diaphragm sign Air trapped posterior to pericardium
- 83. Angle wing sign Seen on neonatal PA CXR when thymic lobes are displaced laterally by air .
- 84. Mediastinal abnormalities Masses Thymoma Lymphoma Neurogenic tumor
- 85. Lines and tubes Nasogastric tube Endotracheal tube Central venous catheter Intercostal tube drinage Pacemakers
- 86. Nasogastric tube Correct position – 10 cm distal to the sastro oesophageal junction i.e below the left hemidiapharm
- 87. Endotracheal tube ETT tip 5 cm +/- 2 cm above carina i.e at the level of medial ends of clavicle
- 88. Central venous line Cv line tip in the superior vena cava or at the cavo atrial junction i.e at the level of 1st anterior intercostal space above carina
- 89. Intercostal tube ICD tip lies between visceral and parietal pleura Anterosuperiorly to drain pneumothorax Posteroinferiorly to drain haemothorax
- 90. Pacemakers Single chamber – tip in right appendage or right ventricular apex Dual chamber – tip in right atrium and right ventricular apex Biventricular – tips in right atrium ,ventricle and coronary sinus