basics of chest xrays

1. CHEST X RAYS- BASICS
AND INTERPRETATION
DR.ROHAN JOHN JACOB

2. INTRODUCTION
WILHELM
CONRAD
ROENTGEN
Father of x ray

3. Radiographic densities
 Black
 Dark grey
 Light grey
 Off white
 Bright white
- air
- fat
- soft tissue
- bone
- 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 projected over lung fields Above the apex of lung field
Ribs Posterior ribs distinct Anterior ribs distinct
Spine Clearly seen not clearly seen

7. Assessment of image quality
 Inspiration or expiration
 Penetration
 Rotation

8. D/W inspiration and expiration
 The diaphragm should be intersected by the
6th to 8th anterior ribs or 9-11th posterior ribs in
complete inspiration

9. Penetration/Exposure
 It is the degree to which X rays have passed
through the body .
 In a well exposed film ,only the spinous
processes of the first four thoracic vertebra are
seen;others are hidden by the cardiac shadow
.

10. 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

11. Approach to CXR
 Airway
 Bones and soft tissue
 Cardiac
 Diaphragm
 Effusions
 Fields (lung)
 Gastric
 Hila and mediastinum

12. Airway
:trachea
 Trachea gets pushed away from abnormality, eg
pleural effusion or tension pneumothorax
 Trachea gets pulled towards abnormality, eg
atelectasis
 Beware of causes that may increase this angle,
eg left atrial enlargement, lymph node
enlargement and left upper lobe atelectasis
 Trace 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

15. Airway:
mediastinum
 Mass lesions (eg tumour, lymph nodes)
 Inflammation (eg mediastinitis, granulomatous
inflammation)
 Trauma and dissection (eg haematoma,
aneurysm of the major mediastinal vessels)

17. Bones and soft tissue
 Check for fractures, dislocation, subluxation of
clavicles, ribs, thoracic , spine .
 Also check the soft tissues for
subcutaneous air, foreign bodies and surgical
clips
 Be cautious with nipple shadows, which may
mimic intrapulmonary nodules
 Compare from 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

18. 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

20. 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 infiltrates or effusion
If film is taken in erect position , you may see
free air under the diaphragm - intra abdominal
perforation

22. 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

24. Lung zones

25. Fissures in lung

26. Gastric
 Look for free air under the diaphragm
 Look for bowel loops between diaphragm and
liver

27. Hilum
Check the position and size bilaterally
 Enlarged lymph nodes
 Calcified nodules
 Mass lesions

28. Read the CXR

29. How to read a normal CXR
 This is a chest radiograph,PAview 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 . Cardiac
silhouette is within normal limits with normal
cardiothoracic ratio. Mediastinum, costo
phrenic , cardio phrenic angles , dome of
diaphragm and soft tissue shadows are within
normal limits .

30. 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 .

31. Airway abnormality
 Tracheal deviation
Ipsilateral : collapse and fibrosis
Contralateral : apical mass ,pleural effusion and
pneumothorax
 Foreign body

32. Bones and soft tissue
 Bones
Fractures
Dislocation
Malignancy
 Soft tissue
Subcutaneous emphysema
Breast cancer

33. Soft tissue abnormalities
Subcutaneous emphysema
there are often straited lucencies in the
soft tissue that may outline muscle fibres

34.  Breast cancer
increased soft tissue density with a mass
projected on breast and axilla

35. Cardiac abnormalities
Cardiomegaly
Normally ,the cardiothoracic ratio should be
less than 0.5
i.e A+B/C < 0.5

36. Cardiac abnormalities
Left ventricular enlargement
 Left border is displaced leftward , inferiorly ,
posteriorly .
 Rounding of apex

37. Cardiac abnormalities
Right ventricular enlargement
 Rounded left heart border
 Uplifted cardiac apex

38. Cardiac abnormalities
Pericardial effusion:
Globular enlargement ( water bottle
appearance )

39. Cardiac abnormalities
Congenital heart disease (tetralogy of fallot )
wooden shoe or boot shaped
heart

40. Diaphragm abnormalities
Hiatus hernia
it occurs when there is herniation of the
abdominal contents through the
oesophageal hiatus of the diaphragm into
the thoracic cavity

41. Diaphragm abnormalities
Pneumoperitoneum

42. Diaphragm abnormalities
dopneumoperitone
Chilaiditi syndrome
it is a rare condition in which a portion of the
colon is abnormally located in between the
liver and diaphragm . (
pseu um )
Rugal
folds

43. Pleural Effusion
 On an upright film, an effusion will cause blunting
of the lateral costophrenic sulcus and, if large
enough, of the posterior costophrenic sulcus.
 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

45. Massive pleural effusion
 Opacification of entire hemithorax and shifting
of mediastinum to opposite side
 If the effusion crosses anterior border of the
2nd rib,it is said to be massive
 If it crosses 4th rib, moderate
 If it’s below 4th rib, it is said to be mild

46. White out lung

47. Pneumothorax
 Appears in the chest radiograph as air without
lung markings

48. Lung field abnormality
Abnormal whiteness ( increased density )
 Consolidation
 Atelectasis
 Pneumonia
 Pulmonary edema
Abnormal blackness ( decreased density )
 Cavity
 Emphysema
 Cyst

49. 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

50. Air bronchogram
 It refers to the phenomenon of air filled brochi
being made visible by the opacification of
surrounding alveoli

51. Lobar consolidation

52. Atelectasis
 Almost always associated with a linear
increased density due to volume loss
 Indirect indications of volume loss include
vascular crowding or mediastinal shift
towards the collapse
 Possible observance of hilar elevation with an
upper lobe collapse, or a hilar depression with
a lower lobe collapse

54. Miliary TB
 Miliary deposits appear as 1-3 mm diameter
nodules , which are uniform in size and
distribution

55. Pneumonia
 Typical findings on the chest radiograph
include:
Airspace opacity
Lobar consolidation
Interstitial opacities

57. Pulmonary
Edema(interstitial)
There are two basic types of pulmonary edema:
 Cardiogenic pulmonary edema caused by
increased pulmonary capillary pressure
 Noncardiogenic pulmonary edema caused by
either altered capillary membrane permeability
or decreased plasma oncotic pressure

58. Pulmonary edema

59. Interstitial lung
disease
 Ground glass appearance

60. 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 .

61. Pulmonary cavity
 Are gas filled areas of the lung in the center of
a nodule , a mass or an area of consolidation
Cancer – bronchogenic ca
Autoimmune , granulomas – rheumatoid nodules
Infection – pulmonary abcess, PTB

63. Flat diaphragm
 When the maximum perpendicular height from
the superior border of the diaphragm to a line
drawn between the costophrenic and
cardiophrenic angles in PAview is less than
1.5 cm

64. Hilar abnormalities
Hilar enlargement
it may be unilateral or bilateral
eg: TB, lung tumor ,silicosis

65. Hilar abnormalities
 Hilar position
Whether it is pushed or pulled
The left hilum must never be lower the right
hilum.Lower left hilum denotes collapse of either
the left lower lobe or of the right upper lobe