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

2. INTRODUCTION
WILHELM KONARD
ROENTGEN

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

50. Diaphragm abnormalities
Pneumoperitoneum

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

60. Lobar consolidation

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