x ray basics interpretation

1. Basics and Interpretation Of CXR and Musculoskeletal X-ray
Presenter;
Temesgen W.(R2)
Advisor;
Dr Mihretie K.(Associate Professor Of Pediatrics And Child Health)

2. Objectives
Overview of crucial x-ray principles
ABCDEFG systematic approach for reading x-rays
Common shadow patterns
Terminology overview
 Pneumothorax, Consolidation, Atelectasis, Pleural effusion
Unique imaging findings that indicate certain pathologies
 Respiratory distress syndrome (RDS), Community acquired pneumonia
(CAP), Bronchiolitis, Asthma and cardiac x ray abnormalities
Msk x ray patterns

3. Conventional Radiography
X-rays are a form of radiant energy that is similar in many ways to visible
light
X-rays differ from visible light b/c
 They have a very short wavelength and are able to penetrate many
substances that are opaque to light.
The x-ray beam is produced by bombarding a tungsten target with an
electron beam within an x-ray tube

4. Maximum x-ray
Transmission
(Least dense tissue)
Maximum x–ray
Absorption
(Densest tissue)
Blackest
Air
Fat
Soft tissue
Calcium
Bone
X-ray contrast
Metal
Whitest

5. Naming Radiographic Views
Naming based on the x-ray beam passes through the patient
 PA CXR the x-ray beam passes through the back of the patient and exits
through the front of the patient to expose an x-ray detector positioned
against the patient's chest
 AP CXR is exposed by an x-ray beam passing through the patient from
front to back
Views are additionally named by identifying the position of the patient
 Erect, supine, oblique or prone views may be specified

6. Factors To Evaluate
Penetration
Rotation
Inspiration
Angulations

7. Penetration
The vertebral bodies should be barely visible through the lower part of the
heart silhouette
Why is that important?
 If vertebral body too easily visualized the film is over penetrated
low-density lesions (atelectasis or infiltrates) may be missed
 If vertebral body not visualized at all the film is under penetrated
the lungs will appear whiter or “fluffier” than they really are

8. Over Penetration
These films are taken a few
minutes apart
Note that soft tissues and bony
structures are washed out on the
one on the top
It would be very easy to miss any
water densities such as infiltrates
on this film

9. Under penetration
In the film on the left the diaphragm is
not visible, and the vertebral bodies
barely so, through the heart
The film on the right was taken a few
minutes after the other film – now the
heart,tubes and lines are now visible as
well as a RUL infiltrate

10. Over Exposure Proper Exposure

11. Rotation

12. Rotation

13. Inspiration /expiratory
9-10 posterior visible ribs shows
inspiration film
Better inspiration and the disease
at the lung base cleared
Expiation film will crowding lung
tissue

14. Identification
Confirm laterality with the marker
 Correct patient
Correct date
Correct examination

15. AP vs PA the effect of magnification
PA film heart is closer film AP film heat away form film

16. PA and AP film comparisons

17. Angulation
If the x ray beam is angled to wards the
head the film so obtained is called an
“apical lordotic view”
Anterior structure(like clavicle) will be
projected higher in the film than
posterior structure

19. Anatomy

20. Anatomy of RT lung(three lobes & two fissures)

21. Anatomy of left lung(two lobes)

22. Principles of Interpretation
ABCDEFG system
A-Airways
B-Bones
C-Cardiac
D-Diaphragm
E-Equipment
F-Fields
G-Great Vessels

23. Principles of Interpretation
Airways
Is trachea midline or deviated?
Is anything collapsed or plugged?
Angle of the carina?
Normal = 90

24. Bones
Trace outlines of clavicles & full ribs
for fractures
Follow the curves of ribs
 Posterior ribs more horizontal
 Anterior ribs more curved
How many visible ribs?

25. Cardiac
Size and positioning of the
heart?
2/3 0f heart should lie on the
left side of the chest
Cardiomegaly: width of heart
>1/2 of rib cage width and
>60% in infant b/c of AP x ray
Dextrocardia
Abnormal silhouette?

26. Diaphragm
Does it appear symmetric?
Normal for right hemidiaphragm
to be slightly superior compared to
left
Is the costophrenic angle sharp?
Is there free air inferior to
diaphragm?

27. Equipment
What equipment is actually visible?
 Leads, tubes, wires
Is everything in the correct place?
 Nasogastric tube
Tip should end in stomach (not
esophagus Or bronchi)
 Endotracheal tube
Should end >2cm superior to
carina (not right
or left main bronchus

28. Fields
Which lung and lobe? Multiple?
Unilateral? Bilateral?
Dependent?

29. Great vessels

30. Pattern recognition(teminologies)
Pneumothorax
air between lungs and chest wall
Air where it shouldn’t be
(darkness where it shouldn’t be)
Consolidation:
filled with tissue/fluid debris
•Junk where it shouldn’t be
(radiopacity where it shouldn’t be)
Atelectasis
partial or complete lung collapse
Effusion
accumulation of fluid in confined
space
Pleural, pericardial

31. Pneumothorax
Air between the pleura and chest
wall
Usually a fine edge demarcatesit
Uniformly distributed
Watch for pathologic site of
damage (burst apical blebs)
Almost always unilateral

32. Consolidation
It is the filling of the air spaces of the
lung other than air, namely, water, pus or
blood
Is it bilateral, unilateral?
The CXR appearances reflect the loss of
air, hence the increase in opacity.
The vessels are no longer adjacent to the
aerated lung and become invisible or
indistinct.
The small airways still containing air and
surrounded by opacified lung become
visible creating air bronchograms

33. Consolidation

34. Interstitial patterns
Pulmonary Interstitium
 Alveolar walls
 Septi and subpleural space
 Connective tissue surrounding bronchi and
vessels (peribronchial and perivascular
spaces)
 Linear /septal lines
 Nodular/reticulonodular/miliary shadows/
honey combing, cystic, peribronchial
cuffing, & the ground glass pattern
 Mechanisms:
 thickening of lung interstices
 architectural destruction of interstitium
(honeycomb or “end stage” lung)
Features:
 Linear form
Reticulations (lines in all directions)
Septal lines (“Kerley lines”).
 Nodular form
Rounded opacities: small, sharp, very
numerous, evenly distributed and
uniform in shape
 Destructive form
cyst formation: peripheral, irregular

35. Linear patterns
Reticulonodular pattern
Reticular pattern

36. Linear patterns
General Differential Diagnosis
• “LIFE lines”
Lymphangitic spread of
malignancy
Inflammation
Fibrosis
Edema

37. Nodular pattern
criteria for defining Solitary
pulmonary nodule are
 Size - Less than 3 cms
 Number - Single
 Margin - Sharp
 Shape - Round or Oval
 Lesions
 Granuloma,Hamartoma, AV
fistula, Pulmonary Vein
Varix,Sequestration, Round
Atelectasis, Mycetoma, Hydatid
Disease

38. Reticulonodular pattern
Reticulonodular pattern

39. Ground glass opacity
 As the lung tissue becomes filled with
infiltrates( water, pus, blood or fibrosis)
results an increase in the density of that
lung, which appear on a CXR as an
opacity
If there is insufficient alveolar filling to
generate air-bronchograms or too much
interstitial filling to display reticulation,
the result is termed ground glass opacity
 Areas of ground glass opacity result of an
inflammatory process, such as infection,
due to developing pulmonary oedema
The pulmonary vessels become obscured
but air bronchograms are not seen

40. Ground glass opacity

41. Masses pattern
A mass is defined as an opacity
measuring 3 cm or more in diameter
opacity less than 3 cm in diameter is
called a nodule
A mass may destroy the adjacent lung
 as with invasive lesions, and have ill
defined margins,
 or displace lung as it grows and have
well defined margins

42. Mass pattern
A mediastinal mass
 no definable medial margin
 but tends to have awell-defined
lateral margin as it displaces
adjacent lung
 Masses may hide behind the
diaphragmin

43. Mass pattern
Mass density can be encountered
in
Lung cancer
Benign tumors
Sarcoma
Lymphoma
Wegners
Blastomycosis
Tuberculoma
Round or oval
Sharp margin
Homogenous
No respect for anatomy
Lung Cancer: Large cell

44. Lung collapse/atelectasis
Loss of lung volume secondary to collapse
Volume loss is most important
radiographic sign of collapse
Less air inflating lung and less black
Linear increased density on chest x-ray
Most common cause:
Bronchial obstruction distal gas
resorption , reduced volume of gas ,
alveolar walls collapse, size of area
reduced

45. Lung collapse/atelectasis

46. Pleural Effusion radiologic pattern
Plain film
 CXR (erect)
 blunting of the costophrenic angle
 occasionally, blunting of the cardiophrenic angle
 fluid within the horizontal or oblique fissures
 with large volume effusions, mediastinal shift
occurs away from the effusion
 with underlying collapse, mediastinal shift may
occur towards the effusion
 CXR (supine)
 fluid is dependant and collects posteriorly
 there is no meniscus and only a veil-like appearance
to the hemithorax

47. Shadow of scapula
Don’t jump to pneumothorax
simply because you see a line
Look BEYOND it, do you still see
lung tissue?
If scapula, hypolucentlateral to
demarcating line
Can trace outline of scapula
If pneumothorax, hyperlucent
beyond

48. Shadows-Breast Shadows -Thymus
Always keep in mind Thelarche can be
radiologically evident from as early as 8-
9 yrs
Classic, normal sign of developing
thymus
Can be very large, “sail sign”; benign

49. Pneumonia
Lobar Pneumonia
Bronchopneumonia
Necrotizing Pneumonia
Segmental Pneumonia
Round Pneumonia
Diffuse Alveolar Pneumonia
Diffuse Interstitial Pneumonia

50. Lobar Pneumonia
Most common causes
Pneumococcus
Mycoplasma
Gram negatives
Legionella
Bronchopneumonia
Streptococcus
Viral
Staph

51. Necrotizing Pneumonia Segmental Pneumonia
Most common causes
 Staphylococcal
 Anaerobic infection
 Gram –ve organisms
Most common cause
Post obstructive
Aspiration

52. RDS
Cause
↓ surfactant ↑surface tension
alveolar collapse
Plain radiograph
Mandatory for dx: low lung volumes
(atelectasis -lung collapse)
Diffuse granular opacities (ground
glass), bilateral and symmetrical
hyperinflation excludes the diagnosis

53. Pulmonary Tuberculosis
1° Pulmonary Tuberculosis Patterns
Pneumonia
Adenopathy
 Atelectasis
Pleural effusion

54. Reactivation TB Patterns
Pneumonia
Cavity formation
Transbronchial spread
Bronchiectasis
Bronchostenosis
Pleural disease

55. Asthma
Most asthmatics have a normal
CXR, but a few have large volume
lungs
Asthmatics are prone to
spontaneous pneumothorax,
pneumomediastinum
Mucous plugging which may
cause lung opacification and
collapse

56. Normal cardiac cxr finding
CTR < or equal 50%
 PV distribution 1,2,3
 DPA - 1.6cm male
- 1.5cm female
 Central vessels > peripheral
 Vascular pedicle width (VPW)
4.8cm
 Azygus vein width (Azvw) < o.7cm
 Aortic arch
Five states of circulation
1) Normal
2) PVH
3) PAH
4) oligaemia
5) Plethora

57. PVH
Cephalization
Upward blood diversion
Aquired heart disease
 mitral stenosis
 chronic LT heart failure

58. Plethora
 Increased pulmonary Blood flow
 Prominent upper & lower lobe
vessels
 DPA >1.6cm
 CHD - ASD
- VSD
- PDA
- Trunchus arteriosus
 High flow state like Renal failure

59. Oligemia
Reduced pulmonary vascularity
Obstruction to Rt ventricular out
flow tract
- Pulmonary Stenosis
- TOF

60. Left heart failure
Cardiomegally
cardiothoracic ratio (CTR)= A/B
A = cardiac size, B = thoracic
diameter
heart borders defining the
mediastinal contours correspond
to the left ventricle and right
atrium

61. Left heart failure
Cardiomegally
Left atria enlargement
Interstitial edema
Blood diversion
consolidation
Septal lines
Effusions

62. Left heart failure

63. Left heart failure
left Atrium enlargement
 enlargement of the left atrial
appendage affecting the left
heart border
 a double right heart border
caused by the projection of the
right wall of the left atrium
 behind the silhouette of the
right atrium
 widening of the carina

64. Interstitial oedema
In Lt HF increase in the pressure
within the capillary bed of the lung
resulting in the accumulation of
fluid in the lung interstitium.
On CXR, this is visualized as
reticulation and may be too subtle
to detect with confidence

65. Left heart failure
Blood diversion
increase in pressure and due to gravity
in the interstitium causes compression of
the capillary bed in lower lobe
causing shunting of blood into the upper
lobes.
The result blood diversion, enlargement
of the upper lobe pulmonary veins

66. Pericardial Effusion
a very small pericardial effusion
can be occult on plain film
globular enlargement of the
cardiac shadow(water bottle
configuration)
widening of the subcarinal angle
without other evidence of left
atrial enlargement may be an
indirect clue

67. Which ventricle is enlarged
If Heart Is Enlarged, and Main
Pulmonary Artery is Big then Right
Ventricle is Enlarged
Enlarged PA
MPA projects beyond tangent line
Increased pressure
Increased flow

68. CHD
COARCTATION OF THE AORTA FALLOT’S TETRALOGY

70. Which ventricle is enlarged
The best way to determine which
ventricle is enlarged is to look at
the corresponding outflow tract for
each ventricle
- Aorta for the LV
- MPA for the RV
 If Heart is Enlarged, and Aorta is
Big then Left Ventricle is Enlarged

71. Mss x ray
Skeletal conditions
Fracture
Osteomyelitis
Structural anomalies
Degenerative joint condition
Rule of two
Two view - AP and latral
Two joint – above and below
Two occation – repeat x ray
Two limbs -compare

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