This document discusses various radiology methods used to examine the respiratory system including x-rays, CT scans, fluoroscopy, tomography, angiography, ultrasound, MRI, PET scans, and endoscopy. It provides details on positioning and normal anatomy seen on chest x-rays. It also describes signs seen on chest imaging such as the silhouette sign, air bronchogram sign, snowball sign, and signs of mass effect or volume loss that can help determine the location and characteristics of abnormalities.

1. RADIOLOGY
RESPIRATORY SYSTEM

2. METHODS
• Ionizing
• X-ray
• Chest X-ray (CTX)
Plain radiograph
Digital radiograph
• Fluorography
• Fluoroscopy
• Linear tomography
• Bronchography
• Pulmonary angiography
• CT-scan
• CT-Bronchoscopy
• Nuclear Medicine
PET-scan
• Non ionizing
• US
• Endoscopy
• MRI

3. Chest X-ray Chest Fluoroscopy

4. Chest x-ray
Basic views:
PA (posteroanterior)
AP (anteroposterior)
Lateral (LL and RL)
Decubitus

5. PA AP
2 m
1 m
• standing with chest facing detector
• x-ray taken from behind the patient
• detector placed behind patient's back
• x-ray taken from the front

6. • The X-ray beam is divergent and so the resultant
image is magnified. The closer the patient is to
the detector the less magnification is produced.

7. 1. Posteroanterior (PA)
The beam enters from the
back and the image is
acquired in front of the
patient
PA AP
2. Anteroposterior (AP)
The X-ray beam enters the
front of the body and exits
through the back
The rule is ‘put the film on the side of interest’

8. Positioning for PA Chest
Radiograph Normal PA Chest Radiograph

9. PA Chest Radiograph Collimation for
Imaging (Graphic)

10. Positioning for AP Chest
Radiograph Normal AP Chest Radiograph

11. Positioning for Left Lateral
Chest Radiograph
Normal Left Lateral Chest
Radiograph

12. Left Lateral Chest Radiograph Collimation
for Imaging (Graphic)

13. CXR
Lateral projection
Frontal projection

14. AP vs PA
Due to AP magnification:
• the superior mediastinum appears widened
• the heart appears enlarged
• the diaphragm is higher – underinflation
• the scapulas overlap the lungs
• In the lower lung zones there appears to be a bilateral
interstitial infiltrate - also due to underinflation

15. Normal PA Chest Radiograph
on Inspiration
Normal PA Chest Radiograph
on Expiration
On an expiration view, the
hemidiaphragms are higher,
making the heart appear larger
and crowding the basilar
pulmonary vessels.
Good inspiration on a chest x-
ray makes the
hemidiaphragms come down
to about the level of the
posterior tenth or eleventh
ribs.

16. PA Chest Radiograph of Biventricular
Pacemaker

17. Portable AP Chest Radiograph

18. Effect of position on Chest X-rays
• Upright position - the amount of inspiration is greater
in this position, spreading the pulmonary vessels and
allowing clearer visualization.
• Supine position - a normal heart appear large, the
hemidiaphragms are higher.

19. Lateral decubitus position

20. • This could be helpful to assess the volume of
pleural effusion and demonstrate whether a
pleural effusion is mobile or loculated.
• It is also possible to look at the nondependent
hemithorax to confirm a pneumothorax in a
patient who could not be examined erect.
• Additionally, the dependent lung should
increase in density due to atelectasis from the
weight of the mediastinum putting pressure
on it. Failure to do so indicates air trapping.
Lateral decubitus position

21. Female Chest
Left mastectomy Nipple shadows

22. Chest and rib technique
• A - a normal chest x-ray is taken at a relatively high voltage
• B - lowering the voltage of the x-ray beam.
The pulmonary vessels become much harder to see,
and the bones become easier to see.

23. LINEAR TOMOGRAPHY
• The X-ray tube is moved in one direction while the
film moves in the opposite direction,
that blurs the image except in a single plane.

24. LINEAR TOMOGRAPHY

25. BRONCHOGRAPHY
Radiographic examination of the tracheobronchial
tree following introduction of a radiopaque
material; rarely performed today,
having been superseded by high resolution CT.

26. PULMONARY ANGIOGRAPHY
Catheter-directed pulmonary angiography is used
most commonly for the diagnosis of suspected
pulmonary embolism (PE).

27. CT angiography (CTA)
CTA now is the accepted standard of care for
diagnosis of suspected pulmonary embolism (PE),
in part owing to its superior sensitivity and
specificity.

28. CT scan
• The normal slice thickness (A) of a CT scan of the
chest is 8 mm.
• A high-resolution slice (B) taken at exactly the
same level is 1.5 -0.8 mm in thickness and shows
much greater detail of the vessels and bronchi.

29. Lung biopsy
• Pathologic examination of a biopsy can determine
whether a lesion is benign or malignant, and can help
differentiate between different types of cancer.

30. MRI
MRI of the chest gives detailed pictures of
structures within the chest cavity, including the
mediastinum, chest wall, pleura, heart and
vessels, from almost any angle.

31. CT + PET (right lung cancer)

32. ULTRASONOGRAPHY
• Pleural effusion
CT

33. Endoscopy
• MEDIASTINOSCOPY
• is the direct visualization of the structures that lie
beneath the sternum and between the lungs. These
structures include the trachea, the esophagus, the
heart and its major vessels, the thymus, and the
lymph nodes.

34. • THORACOSCOPY
• is the direct visualization of the thoracic cavity,
which includes the examination of the parietal and
visceral pleurae, pleural spaces, thoracic walls,
mediastinum, and pericardium of the heart.

35. • LARYNGOSCOPY
is used to obtain a view of the vocal cords and the
glottis. Laryngoscopy may be performed to facilitate
tracheal intubation during general anesthesia or
cardiopulmonary resuscitation or for procedures on the
larynx or other parts of the upper airways

36. • BRONCHOSCOPY
is the direct visualization of the larynx, trachea, and
bronchial tree by means of either a rigid or a flexible
bronchoscope. Its purposes are both diagnostic and
therapeutic.

37. Normal anatomy

38. • The riht mediastinal silhouette is composed of
the superior vena cava, ascending aorta and
right atrium.
• The left mediastinal silhouette is composed of
the aortic arch, the left pulmonary artery, the
left atrial appendage and the left ventricle
(heart apex).
• The hila are composed of main-stem bronchi,
pulmonary arteries, pulmonary veins and lymph
nodes.

39. On a frontal radiograph pulmonary arteries are
seen brunching out from the hila. The lower
branches are larger due to the effect of gravity.
The pulmonary pattern is composed of arteries,
veins and lymphatics.
Bronchi in the lung are invisible on a normal
radiograph because their walls are very thin, they
contain air, and are surrounded by air.

40. • The interstitium includes the interlobular septa
with their vessels and lymphatics, the bronchi and
pulmonary arterioles, and the very thin alveolar
walls.
• In the right lung, the oblique fissure separates the
lower lobe from the upper and middle lobe, and
the horizontal fissure separates the middle lobe
from the upper lobe.
• In the left lung, a single oblique fissure separates
the upper lobe from the lower lobe.
• Fissures are composed of the visceral pleura of two
adjacent lobes.

41. Cardiothoracic ratio
The width of the normal heart from its most lateral
borders (A) should not exceed the width of the
hemithorax measured from the middle of the spine to
the widest portion of the inner ribs (B).

42. Polyarcuate diaphragm
This is a common normal variant in which the
diaphragm has several small domes instead of one
large one.

43. Cephalic ribs

44. Signs

45. Silhouette Sign
The silhouette sign refers to the loss of normal
borders between thoracic structures.
It denotes that a mediastinal border or
diaphragm can only be obscured by pathology
which is in direct anatomical contact.
If an abnormality is contiguous with normal
structures, the border between them is lost.
Silhouette sign helps determine the location of
an abnormality in relation to normal structures.

46. Silhouette Sign
Right middle lobe Right lower lobe
Lobe?

47. Right middle lobe pneumonia
• The right heart border is obscured by medial
segment right middle lobe processes.
• Right middle lobe and lingular processes are
projected over the heart on the lateral view.

48. Right lower lobe pneumonia
Disease limited to the lateral segment will not obscure the
right heart border.

49. Silhouette Sign
right upper lobe pneumonia lingular segmental pneumonia
Lobe?

50. Lobe?
Left hemi-diaphragm is
obscured The left heart border is visible
Left lower lobe pneumonia

51. Left lower lobe pneumonia

52. Silhouette Sign
Frontal chest radiographs:
• right paratracheal stripe: right upper lobe
• right heart border: right middle lobe or
medial right lower lobe
• right hemidiaphragm: right lower lobe
• aortic knuckle: left upper lobe
• left heart border: lingula segments of the left
upper lobe
• left hemidiaphragm or descending aorta: left
lower lobe

53. Air bronchogram sign
• The appearance of dark branching markings
in abnormal white lung is called the Air
bronchogram sign.
• If an Air bronchogram is present, the lesion
seen must be in the lung.

54. Air bronchogram sign
Pleural effusion Right upper lobe pneumonia

55. Air bronchogram sign

56. Snow ball sign
• The Snow ball sign is
used to determine
whether a peripheral
mass or nodule arises
from the lung or a
surrounding structure.

57. • If the nodule or mass
looks like a snow ball
just before impact, it is
localized in the lung.
Snow ball sign

58. • If it looks like a
flattened snow ball just
after impact, it arises
from surrounding
structure (chest wall,
pleura or mediastium).
Snow ball sign

59. Snow ball sign
Thymoma
Hydatid cyst

60. In this patient, the space occupying lesion was a large right pleural effusion
resulting from tuberculous empyema.
Unilateral total opacification
Mass effect

61. Signs of mass effect
• Signs of mass effect suggest a space-occupying
lesion in a hemithorax. There is shift of the
mediastinum toward the contralateral
hemithorax, as evidenced by shift of the trachea
and left heart border to the left.
• inferior displacement of the hemidiaphragm.
• widened the distance between ribs.

62. Pleural effusion on ultrasound

63. Unilateral total opacification
Signs of volume loss

64. Signs of volume loss
• There is mediastinal shift toward the ipsilateral
hemithorax, as evidenced by shift of the trachea and
the right heart border into the left hemithorax.
• The gastric air bubble is higher in the left upper
quadrant of the abdomen than is normally seen,
because of elevation of the left hemidiaphragm.
• The distance between the ribs on the abnormal side
is slightly decreased.

65. Occlusion
Tumor obstructing right
main-stem bronchus. A
sharp cutoff of the air
column is clearly identified
(arrow). The obstruction has
caused a postobstructive
infiltrate, with resorption of
the air from the right lung,
volume loss, and resultant
shift of the mediastinum to
the right.

66. Atelectasis
• The term "atelectasis" is typically used when
there is partial collapse, whereas the term
"collapsed lung" is typically reserved for when
the entire lung is totally collapsed. There are
three main causes of atelectasis:
Obstruction
Compression
Traction

67. Pneumothorax

68. Lobar atelectasis
• Right upper lobe atelectasis

69. • Right middle lobe atelectasis

70. • Left lower lobe atelectasis

71. • Left upper lobe atelectasis

72. Pulmonary syndromes

73. Aeration of the lungs is often altered by
pathology
• increased opacity (whiter areas)
– less gas in the lungs
• increased lucency (darker areas)
– more gas in the lungs

74. Increased opacity syndromes:
•- extensive lung opacity;
•- limited lung opacity;
•- roundish shadows;
•- ring-shaped shadows;
•- foci and limited dissemination;
•- diffuse dissemination;

75. Increased lucency syndromes:
•- extensive pulmonary lucency;
•- localized pulmonary lucency.
#
•- hilar pathology;
•- pathology of pulmonary pattern.

76. Large opacities within the lungs

77. Pleural effusion types
Transudates
• are usually caused by
increased systemic or
pulmonary capillary
pressure and decreased
osmotic pressure, resulting
in increased filtration and
decreased absorption of
pleural fluid.
Exudates
• occur when the pleural
surface is damaged with
associated capillary leak and
increased permeability to
protein, or when there is
decreased lymphatic
drainage or decreased
pleural pressure.

78. Pleural effusion types
Transudates
• Major causes are cirrhosis,
congestive heart failure,
nephrotic syndrome, and
protein-losing enteropathy.
Exudates
• Major causes are infection,
malignancy, collagen
vascular disease, or acute
pulmonary embolism.

79. Right upper lobe pneumonia

80. Infiltrates
• Alveolar and interstitial pulmonary infiltrates

81. Well-defined rounded opacities

82. Lung abscess
• On a chest x-ray, a lung abscess may look to be a solid rounded lesion (A), or, if
it has a connection with the bronchus, an air/fluid level may exist in a thick-
walled cavitary lesion. Computed tomography scanning (B) can be used to
localize the lesion and to place a needle for drainage and aspiration of
contents for culture.

83. Small and numerous opacities within the lungs

84. Cavitation within the mass and ring-shape opacities

85. Increased lucency syndrome

86. Pneumothorax
• A thin line caused by the visceral pleura is seen separated from the lateral
chest wall (arrows). No pulmonary vessels are seen beyond this line and
the line is curved. The pleural line is white.

87. Radiographic imaging findings of
pneumothorax
• The pathognomonic finding is a thin, sharply defined,
visceral pleural “white” line between radiolucent
lung (with vascular markings) and radiolucent “black”
free air in the peripheral pleural space (without
vascular markings).
• If a pneumothorax is seen on chest radiography that
is associated with contralateral mediastinal shift and
inferior displacement of the ipsilateral
hemidiaphragm, the physician caring for the patient
must be notified immediately because a tension
pneumothorax may be present, requiring emergent
treatment to prevent rapid death.

89. TENSION PNEUMOTHORAX (Right)

91. Local areas of increased lucency

92. Tuberculosis
• The classic appearance of reactivation tuberculosis is that of an upper
lobe infiltrate with cavities. Over time, healing and fibrosis will occur,
which will pull the hilum up on the affected side.

94. Silicosis
• Late stage of silicosis. The chest x-ray shows significant parenchymal
disease, predominant in the upper lobes, as a result of progressive
massive fibrosis. The computed tomography scan show both coarse
interstitial and nodular changes.

95. Metastatic disease
• Lymphangitic metastases. The streaky appearance in the lung parenchyma
is due to metastatic disease, in this case, stomach carcinoma. The term
lymphangitic is really a misnomer, because these actually do represent
hematogenous metastases in the pulmonary interstitium.

96. Hydropneumothorax
• When fluid and air are present in the pleural space on an upright chest x-
ray, a perfectly straight horizontal line will extend all the way from the
spine to the edge of the pleural cavity. In this patient, a loculated right
basilar hydropneumothorax is present. The air/fluid interface is easily seen
(arrows).

97. Pleural Effusions
• On this upright posteroanterior chest x-ray (A), blunting of the right
costophrenic angle is due to pleural fluid. On the lateral view (B), fluid can
be seen tracking up into the major fissure (black arrows), and blunting of
the right posterior costophrenic angle is seen (white arrows).

98. Foreign bodies
Aspiration of a nonobstructing foreign body. A metallic straight pin can be
seen in the right lower lobe on both the posteroanterior (A) and the lateral
(B) chest x-rays.

99. Chronic Obstructive Pulmonary
Disease (COPD).

100. Lung Hernia
There is protrusion of lung outside the thoracic cage (black
arrows), This is an acquired, post-traumatic lesion caused by
the previous insertion of a chest tube.

101. How to Look at a Chest X-ray
• Determine the age, sex, and history of the patient
• Identify the projection and technique used:
• AP, PA, lateral, portable, or standard distance
• Identify the position of the patient:
• upright, supine, decubitus
• Look at the inspiratory effort:
• adequate, hypoinflated, hyperinflated
• Identify the obvious and common abnormalities:
• heart size (large or normal);
• heart shape, specific chamber enlargement
• upper mediastinal contours

102. • Examine airway, tracheal deviation
• Lung symmetry
• Мediastinal shift?
• Нilar position
• Lung infiltrates, masses, or nodules
• Pulmonary vascularity (pattern):
• increased, decreased, deformited or normal
• Pleural effusions, blunting of costophrenic angles
• Pneumothorax present?
• Rib, clavicle, and spine fractures or other lesions

103. • Chest wall
• Shoulders
• Recheck what you thought was normal anatomy and
look at typical blind spots behind the heart; behind
the hemidiaphragms; in the lung apices
• Look for old films, not just the last one
• Decide what the findings are and their location
• Give a common differential diagnosis correlated
with the clinical history

104. references
•http://www.stanford.edu/dept/radiology
•https://radiopaedia.org