Basic chest X Ray interpretation.

1. Basic Chest X-Ray
Interptation

2. Positioning
• Typical views
– The standard chest examination consists of a PA
(posterioranterior) and lateral chest x-ray.
• Additional views:
– Decubitus - useful for differentiating pleural effusions from
consolidation (e.g. pneumonia). In effusions, the fluid layers
out (by comparison to an up-right view, when it often
accumulates in the costophrenic angles).
– Lordotic view - used to visualize the apex of the lung, to
pick-up abnormalities such as a Pancoast tumour.
– Expiratory view - helpful for the diagnosis of pneumothorax
– Oblique view

7. Lateral Decubitus view

8. Lordotic view
FOR EXAMINATION
OF THE LUNG APEX
Expiratory view
FOR DIAGNOSIS OF
BRONCHIAL ASTHMA

10. Normal chest PA

11. Lung Fissures

14. Lobes and segments of the lungs.

16. Drawing of the pleura on the right side, showing the course of the pleura
on surface of lung. Only the visceral pleura passes into a normal fissure.
The parietal pleura follows the chest wall, except when the course of the
azygos vein is abnormal. Both layers of pleura then pass into the
fissure, which makes this fissure prominent.

17. 1.Cervical part of parietal pleura
2.Costal part of parietal pleura
3.Mediastinal part of parietal
pleura
4.Diaphragmatic part of parietal
pleur

19. 1. Heart
2. Fibrous pericardium
3. Parietal layer of serous pericardium
4. Visceral layer of serous pericardium
5. Pericardial space
6. Pleural cavity and lung

20. 1. Superior vena cava
2. Inferior vena cava
3. Right atrium (blue(
4. Right ventricle (blue(
5. Left ventricle (red(
6. Aorta
7. Pulmonary trunk

23. Frontal and lateral radiograph of the chest shows mediastinal adenopathy
(red arrows) producing lobulated soft tissue masses

24. Radiograph showing a narrowed trachea secondary to an anterior mediastinal mass

26. Different tissues in our body absorb X-rays at different
extents:
•Bone- high absorption (white)
•Tissue- somewhere in the middle absorption (grey)
•Air- low absorption (black)

28. How to read the film correctly

29. Be systematic
1) Check the quality of the film

30. Film Quality
• First determine is the film a PA or AP
view.
 PA- the x-rays penetrate through the back of
the patient on to the film
 AP-the x-rays penetrate through the front of
the patient on to the film.

31. Film Quality (cont)
• Was film taken under full inspiration?
-10 posterior ribs should be visible.
Why do I say posterior here?
When X-ray beams pass through the anterior chest on to the film
Under the patient, the ribs closer to the film (posterior) are most
apparent.
A really good film will show anterior ribs too, there should
Be 6 to qualify as a good inspiratory film.

32. This is A normal X-ray Chest !

34. Quality (cont.)
• Is the film over or
under penetrated if
under penetrated you
will not be able to see
the thoracic
vertebrae.

35. Quality (cont)
• Check for rotation
– Does the thoracic
spine align in the
center of the sternum
and between the
clavicles?
– Are the clavicles
symmetrical ?

36. Verify Right and Left sides
• Gastric bubble should be on the left

37. Gastric bubble

38. Diphragm
• Look at the diaphram:
for tenting
free air
abnormal elevation
• Margins should be
sharp
(the right hemidiaphram is
usually slightly higher than
the left)

39. Check the Heart
• Size
• Shape
• Silhouette-margins should be sharp
• Diameter (>1/2 thoracic diameter is
enlarged heart)
Remember: AP views make heart appear larger than it
actually is.

40. Cardio-thoracicCardio-thoracic
RatioRatio
<50%
One of the easiest
observations to make is
something you already
know: the cardio-thoracic
ratio which is the widest
diameter of the heart
compared to the widest
internal diameter of the rib
cage

41. Sometimes, CTR is more than 50%
But Heart is Normal
Extra-cardiac causes of
cardiac enlargement
Portable AP films
Obesity
Pregnancy
Ascites
Straight back syndrome
Pectus excavatum
Flat / elevated
diaphragm

42. >50%
Here is a heart that is larger than 50% of the cardiothoracic ratio, but it is still a normal heart.
This is because there is an extracardiac cause for the apparent cardiomegaly. On the lateral
film, the arrows point to the inward displacement of the lower sternum in a pectus excavatum
deformity.

43. Obstruction to outflow of the ventricles
Ventricular hypertrophy
Must look at cardiac contours
Sometimes, CTR is less than 50%
But Heart is Abnormal

44. <50%
Here is an example of a heart which is less than 50% of the CTR
in which the heart is still abnormal. This is recognizable because
there is an abnormal contour to the heart (yellow arrows).

45. Cardiac Silhouette
1. Superior vena cava
2. Inferior vena cava
3. Right atrium (blue(
4.Right ventricle (blue(
5.Left ventricle (red(
6.Aorta
7.Pulmonary trunk

47. Ascending Aorta
“Double density”
of LA enlargement
Right atrium
Left ventricle
Indentation for
LA
Main pulmonary
artery
Aortic knob
The Cardiac Contours
There are 7 contours to the heart in the
frontal projection in this system.

48. Ascending Aorta
“Double density”
of LA enlargement
Right atrium
Left ventricle
Indentation for
LA
Main pulmonary
artery
Aortic knob
The Cardiac Contours
But only the top five are really important
in making a diagnosis.

49. Loss of cardiac boarder

50. Check the costophrenic angles
Margins should
be sharp

51. Loss of Sharp Costophrenic Angles

52. Check the Hilar region
• The hilum : – the large
blood vessels going to
and from the lung at the
root of each lung where it
meets the heart.
• Check for size and shape
of aorta, Lymph nodes,
enlarged vessels

53. Elevated Hilum

54. Finally, Check the Lung Fields
• Infiltrates
• Increased interstitial markings
• Masses
• Absence of normal margins
• Air bronchograms
• Increased vascularity

55. Silhouette Sign
When two objects of the sameWhen two objects of the same
density touch each other, thedensity touch each other, the
edge between them disappearsedge between them disappears
A B

56. Using the Silhouette Sign
Right middle lobe silhouettes right
heart border
Lingula silhouettes left heart border
Right lower lobe silhouettes right
hemidiaphragm
Left lower lobe silhouettes left
hemidiaphragm

57. This patient has
had the left lung
removed – a
pneumonectomy.
Fibrous tissue now
fills the left
hemithorax. The
heart is “invisible”
Using the Silhouette Sign

58. The mass (red arrow)
silhouettes the right
heart border which is
to say there is no
longer an edge of the
right heart seen. That
means the mass is (a)
touching the right
heart border (the mass
is anterior) and (b) the
mass is the same
density as the heart
(fluid or soft tissue
density). The mass is a
thymoma.
Using the Silhouette Sign

59. Air Bronchogram
Bronchi are not visible since their walls are
thin, they contain air, are surrounded by air
When something of fluid density fills
alveoli, air in bronchus becomes visible,
e.g.
Pulmonary edema fluid
Blood
Gastric aspirate
Inflammatory exudate

60. Air Bronchogram
The visibility of air in the bronchi because of
surrounding airspace disease is called an
“air bronchogram”
An air bronchogram is almost always a sign
of airspace disease

61. The black branching
structures are the
result of air in the
bronchi, now visible
because density
other than air
surrounds them (in
this case it is
inflammatory exudate
from a pneumonia).

62. Nodular Infiltrates

63. Patchy infiltrates

64. Absence of normal broncho-
vascular markings

65. Masses

66. Absence of normal margins

67. Thank You