This document provides guidance on interpreting chest x-rays by assessing key anatomical structures and features including the lungs, heart, trachea, diaphragm, bones, and soft tissues. It describes the normal appearance of these structures and signs that may indicate abnormalities such as masses, consolidation, cavitation, enlarged organs, fluid, or fractures. A systematic approach is recommended to examine the chest x-ray starting from the lungs fields and working through other areas.

1. Imaging
Dr Md Main Uddin
Assistant Professor
(Medicine)
Cox’s Bazar Medical
College

2. Modalities
• X-Ray
CXR
Plain abdominal x-ray
• Computed tomography
• Magnetic resonance
imaging
• Ultrasound
• Nuclear imaging

4. Points to note when assessing the
chest X-ray
• Name of patient and date (and time) of X-ray
• Position of the patient
• Position of the trachea
• Outline of heart
• Outline of mediastinum
• Diaphragm
• Lung fields
• Bony skeleton

5. Assessing the chest X-ray
• The position of the patient
• Is the patient straight or rotated? If straight, the inner
ends of the clavicles will be equidistant from the
midline of the vertebral body. This is important
because any rotation will tend particularly to alter the
appearance of the mediastinum and the hilar shadows.
• The outline of the heart and the mediastinum
• Is this normal in size, shape and position?
• The position of the trachea
• This is seen as a dark column representing the air
within the trachea. Is the trachea centrally placed or
deviated to either side?

6. The Chest X-Ray
Techniques – Projection
•P-A (relation of x-ray beam to patient)

7. CXR Interpretation
PA vs. AP views

8. Inspiration/Expiration

9. Cardiac Silhouette
1. R Atrium
2. R Ventricle
3. Apex of L Ventricle
4. SVC
5. IVC
6. Tricuspid Valve
7. Pulmonary Valve
8. Pulmonary Trunk
9. R PA 10. L PA

10. Assessing the chest X-ray
• The diaphragm
• Can the diaphragm be seen on each side? Is it
normal in shape and position? Normally, the
anterior end of the sixth or seventh rib crosses
the mid-part of the diaphragm on each side,
although the diaphragm on the right is usually
a little higher than on the left. Are the
cardiophrenic angles clearly seen?

11. The lung fields
• For radiological purposes, the lung fields are
divided into three zones:
• The upper zone extends from the apex to a
line drawn through the lower borders of the
anterior ends of the second costal cartilages.
• The mid-zone extends from this line to one
drawn through the lower borders of the fourth
costal cartilages.
• The lower zone extends from this line to the
bases of the lungs.

12. • Each zone is systematically examined on both
sides, and any area that appears abnormal is
carefully compared with the corresponding
area on the opposite side. The horizontal
fissure, which separates the right upper and
middle lobes, may sometimes be seen running
horizontally in the third and fourth interspaces
on the right side.

13. The bony skeleton
• Is the chest symmetrical?
• Is scoliosis present?
• Are the ribs unduly crowded or widely spaced in
any area?
• Are cervical ribs present?
• Are any ribs eroded or absent?
• As well as the standard AP view, lateral views are
sometimes carried out to help localize any lesion
that is seen.

14. In examining a lateral view
follow this plan:
• Identify the sternum anteriorly and the vertebral bodies
posteriorly. The cardiac shadow lies anteriorly and
inferiorly.
• There should be a lucent (dark) area retrosternally which
has approximately the same density as the area posterior
to the heart and anterior to the vertebral bodies. Check for
any difference between the two, or for any discrete lesion
in either area.
• Check for any collapsed vertebrae.
• The lowest vertebrae should appear darkest, becoming
whiter as they progress superiorly.
• Interruption of this smooth gradation suggests an
abnormality overlying the vertebral bodies involved.

15. Figure 10.8 A lateral chest X-ray

16. The normal chest X-ray

17. The normal chest X-ray
• Chest X-ray PA view showing trachea is
central, lung fields are clear, both hilum are
normal, mediastinum is normal, cardiac
shadow is normal in size and contour, both
costophrenic and cardiophrenic angles are
clear, diaphragm is normal in shape and
position, bony skeleton and soft tissue
shadows are normal.

19. Pneumonia (consolidation) of the right
middle lobe
• CXR PA view showing opacification beneath
the horizontal fissure and loss of normal
contrast between the right heart border and
lung. Suggestive of Rt sided consolidation.

21. RML pneumonia

22. RLL pneumonia

23. LLL pneumonia

24. • Figure 10.18
• Chest X-ray showing a right
basal pneumonia in a previously
fit 40-year-old man with fever,
breathlessness, central cyanosis
and pleuritic pain. Chest signs
included bronchial breathing and
a pleural rub in the right lower
zone. The cyanosis was due to
the shunting of deoxygenated
blood through the consolidated
lung, the increased respiratory
rate leading to a low PaCO2
because of increased clearance
of carbon dioxide by the
unaffected alveoli. Streptococcus
pneumoniae was grown on blood
cultures.

25. 25
154 slides
Right Middle Lobe Pneumonia
25

26. 26
154 slides
Left Lower Lobe Pneumonia
26

29. • Chest X-ray PA view showing the sharply
defined edge of the deflated lung with
complete translucency (no lung markings, no
vascular markings) between this and the chest
wall in the Rt side with shifting of
mediastinum to left.
• Suggestive of Rt Tension Pneumothorax

30. Pneumothorax

32. 32
154 slides
Collapsed Right Lung
Tension Pneumothorax: Requires chest tube
Tracheal Deviation
What would you do with this patient?
32

33. 34

34. 35
154 slides
Inspiration Expiration
35

37. • Chest X-ray PA view showing dense
homogenous opacity at the Rt lung base with
curved upper border, blunting the
costophrenic angle and ascending towards the
axilla. Suggestive of Rt Pleural Effusion
• Around 200 mL of fluid is required in order for
it to be detectable on a PA chest X-ray.

38. Pleural Effusion

39. • Figure 10.17
• Chest X-ray showing a
large left pleural effusion
in a young man with a 4-
month history of malaise,
fever, night sweats and
weight loss. The diagnosis
of tuberculosis was
confirmed on histology of
a pleural biopsy and
culture of the pleural
fluid.

41. 42
154 slides
Large Pleural Effusion
42

43. Emphysema

44. Emphysema
• Chest X-ray PA view showing
hypertransluscencs lung fields, low flat
diaphragm and widening of rib space,
suggestive of Emphysema.

45. 46
154 slides
Enlarged
Retrosternal
Air Space
Flattened Diaphragms
Bullous Emphysema
46

48. Figure 11.32 Left atrial dilatation.
This is a penetrated PA chest X-ray in a patient with mitral stenosis.
The dilated left atrium causes a bulge on the left heart border below
the pulmonary artery which is also dilated, widening of the carina
and the double density sign at the right heart border.

49. Figure 11.31 Pericardial effusion with tamponade:
There is a left hilar mass caused by carcinoma. Pericardial infiltration has
produced effusion and tamponade, evidenced by the severely enlarged
and globular cardiac silhouette. Malignant disease is now the most
common cause of tamponade in most developed countries.

50. Figure 11.35 Chest X-ray in acute left ventricular failure:
the patient had severe pulmonary oedema caused by acute
myocardial infarction. The heart is not yet enlarged, but there
is prominent alveolar pulmonary oedema in a perihilar (‘bat’s-
wing’) distribution. Note the bilateral pleural effusions.

61. Hilar mass

62. Multiple Masses

63. Hilar Lymphadenopathy - BL

64. Pulmonary Fibrosis

65. Air under the diaphragm

66. Cavitating lesion

67. 68
154 slides
Multiple Nodules: Diagnosis? Metastases
68

68. 69
154 slides Normal
Hilar and Mediastinal Lymphadenopathy
Diagnosis?
69

69. 70
154 slides
Hilar Lymphadenopathy on lateral
70
Normal

70. 71
154 slides
Sarcoidosis
71

75. Chest X-ray
An approach to interpreting the chest X-ray
• Name, date, orientation
• Films are postero-anterior
(PA) unless marked AP to
denote that they are
antero-posterior
• Lung fields
• Equal translucency?
• Check horizontal fissure
from right hilum to sixth
rib at the anterior axillary
line
• Masses? Consolidation?
Cavitation?
• Lung apices
• Check behind the
clavicles: Masses?
• Consolidation?
Cavitation?

76. An approach to interpreting the chest X-ray
• Trachea
• Central? (Midway
between the clavicular
heads)
• Paratracheal mass?
Goitre?
• Heart
• Normal shape?
• Cardiothoracic ratio
should be < half the
intrathoracic diameter)
• Retrocardiac mass?
• Hila
• Left should be higher
than right
• Shape? (Should be
concave laterally; if
convex, consider mass or
lymphadenopathy)
• Density?

77. Interpreting the chest X-ray
• Diaphragm
• Right should be higher
than left
• Hyperinflation? (No more
than 10 ribs
• should be visible
posteriorly above the
diaphragm)
• Costophrenic angles
• Acute and well defined?
(Pleural fluid or
thickening, if not)
• Soft tissues
• Breast shadows in
females
• Chest wall for masses or
subcutaneous
emphysema
• Bones
• Ribs, vertebrae, scapulae
and clavicles
• Any fracture visible at
bone margins or
lucencies?

78. Interpreting the chest X-ray
• This is useful for determining the size and
shape of the heart, and the state of the
pulmonary blood vessels and lung fields. Most
information is given by a posteroanterior (PA)
projection taken in full inspiration.
• Anteroposterior (AP) projections are
convenient when patient movement is
restricted but result in magnification of the
cardiac shadow.

79. Interpreting the chest X-ray
• ‘Cardiomegaly’ is the term used to describe an
enlarged cardiac silhouette where the
‘cardiothoracic ratio’ is greater than 0.5.
• It can be caused by chamber dilatation,
especially left ventricular dilatation, or by a
pericardial effusion.