1. Basic Chest Radiology for the TB Clinician
PRESENTATION MATERIALS
Basic Chest Radiology for the TB Clinician
Adapted from the ISTC TB Training Modules 2009

2. Basic Radiology for the TB Clinician
Objectives: At the end of this presentation,
participants will be able to:
Analyze the technical quality of chest X-rays (CXRs) using simple parameters
Identify basic normal CXR anatomy on both frontal and lateral views
Recognize radiographic patterns of disease and describe using appropriate terminology
Describe both the typical and atypical patterns of radiographic presentation for pulmonary tuberculosis 2

3. Basic Radiology for the TB Clinician (2)
Overview:
Technical aspects of chest radiography
Systematic approach to reading CXR
Basic CXR anatomy
Patterns of disease
Radiographic manifestations of tuberculosis (TB)
[Image Credit: Lung Health Image Library/Gary Hampton] 3

4. Chest Radiography: Basic Principles
X-ray photon: Absorbed / scattered / transmitted
X-ray absorption depends on:
Beam energy (constant)
Tissue density
Maximum X-Ray
Transmission
(least dense tissue)
Absorption
(densest tissue)
Blackest
air
fat
soft tissue
calcium
bone
X-ray contrast
metal
Whitest 4

5. Differential X-Ray Absorption
Why we see what we see:
Structures are visible on a radiograph because of the juxtaposition of two different densities  creating an interface
Silhouette Sign
Loss of an expected interface
 No boundary can be seen between two structures because they now are similar in density
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 5

6. Silhouette Sign: RLL Pneumonia
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 6

7. Silhouette Sign: RLL Pneumonia
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 6

8. Assess CXR Technical Quality
Inspiratory effort
9-10 posterior ribs
Penetration
thoracic intervertebral disc space just visible
Positioning / rotation
medial clavicle heads equidistant from spinous process 7

9. Image credit: Curry International Tuberculosis Center, University of California, San Francisco8 9

10. 1 2 3 4 5 6 7 8 9 10
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 8 10

11. 1 2 3 4 5 6 7 8 9 10
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 8 11

12. 1 2 3 4 5 6 7 8 9 10
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 8 12

13. Inspiratory Effort Low Lung Volumes Full Inspiration 9
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 9

14. Exposure Overexposure Proper Exposure 10
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 10

15. Overexposure Proper Exposure 11
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 11 15

16. Rotated (Oblique)
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 12 16

17. Basic Radiology for the TB Clinician
A systematic approach to reading a CXR
Image Credit: Lung Health Image Library/Gary Hampton 13

18. Approach to Reading a CXR
Be Systematic
Lungs
Pleural surfaces
Cardiomediastinal contours
Bones and soft tissues
Abdomen
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 14

19. Worth a Second Look Apices Retrocardiac areas (left and right)
Hilar regions
Below diaphragm 15

20. Apical TB
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 16 20

21. Apical TB (2)
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 17

22. Left Retrocardiac Opacity
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 18 22

23. Nodule Behind Diaphragm
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 19 23

24. Basic Radiology for the TB Clinician
Basic CXR Anatomy
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 20

25. Basic CXR Anatomy Frontal and Lateral Views Heart Aorta
Pulmonary arteries
Airways
Image Credit: Lung Health Image Library/Pierre Virot 21

26. Image credit: Curry International Tuberculosis Center, University of California, San Francisco22 26

27. Right pulmonary artery Left pulmonary artery Trachea & bronchi
Aortic arch
Right pulmonary artery
Left pulmonary artery
Trachea & bronchi
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 23

28. Aortic arch
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 23

29. Right pulmonary artery
Aortic arch
Right pulmonary artery
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 23

30. Right pulmonary artery Left pulmonary artery
Aortic arch
Right pulmonary artery
Left pulmonary artery
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 23

31. Right pulmonary artery Left pulmonary artery Trachea & bronchi
Aortic arch
Right pulmonary artery
Left pulmonary artery
Trachea & bronchi
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 23

32. Basic Radiology for the TB Clinician
Patterns of disease 24

33. Chest Radiographic Patterns of Disease
Consolidation / air-space opacity
Interstitial opacity
Nodules and masses
Lymphadenopathy
Cysts and cavities
Pleural abnormalities 25

34. Consolidation / Air-Space Opacity
Caused by filling of alveoli with fluid, pus, blood, cells (tumor), etc.
May be diffuse, or isolated to segments or lobes of the lung
May be associated with air bronchograms (air-filled bronchus surrounded by opacified lung) 26

35. Pneumonia
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 27 35

36. Interstitial Opacity
Disease localized to pulmonary interstitium, i.e., the alveolar septae and connective tissues that support the alveoli
Hallmarks:
Lines and/or reticulation
Small, well-defined nodules
Miliary pattern
DDX: Pulmonary edema, interstitial lung diseases (e.g., idiopathic pulmonary fibrosis), sarcoidosis, infection, tumor (lymphangitic spread), etc. 28

37. Interstitial Opacity: Lines
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 29 37

38. Interstitial Opacity: Lines
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 29 38

39. Interstitial Opacity: Lines & Reticulation
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 30 39

40. Nodules and Masses
Nodule: discrete pulmonary lesion, sharply defined, nearly circular opacity cm
Mass: larger than 3 cm
Describe with qualifiers:
Single or multiple
Size
Border characteristics
Presence or absence of calcification
Location 31

41. Well-Defined Calcification Ill-Defined Mass 32
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 32 41

42. Lymphadenopathy (LAN)
Non-specific terms:
Mediastinal widening
Hilar prominence
Specific patterns:
Particular station enlargement (location)
Important to know what “normal” should look like in order to recognize “abnormal” 33

43. Image credit: Curry International Tuberculosis Center, University of California, San Francisco34 43

44. Image credit: Curry International Tuberculosis Center, University of California, San Francisco34 44

45. Image credit: Curry International Tuberculosis Center, University of California, San Francisco34 45

46. Image credit: Curry International Tuberculosis Center, University of California, San Francisco34 46

47. Image credit: Curry International Tuberculosis Center, University of California, San Francisco34 47

48. Lymphadenopathy Infrahilar window (right hilar and/or subcarinal)
Left hilar
Subcarinal
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 35 48

49. Lymphadenopathy Infrahilar window (right hilar and/or subcarinal) 35
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 35 49

50. Lymphadenopathy Left hilar 35
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 35 50

51. Lymphadenopathy Subcarinal 35
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 35 51

52. Right Paratracheal & Bilateral LAN
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 36 52

53. Right Hilar LAN
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 37 53

54. Right Hilar LAN
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 38 54

55. Subcarinal LAN *
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 39 55

56. AP Window LAN
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 40 56

57. Cysts & Cavities
Abnormal pulmonary parenchymal spaces (“holes”), filled with air and/or fluid, with a definable wall (>1 mm)
Cyst: congenital or acquired
Cavity: caused by tissue necrosis, (inflammatory and/or neoplastic)
Characterize:
Wall thickness at thickest portion
Inner lining
Presence / absence of air / fluid level
Number and location 41

58. TB or Not TB? Cysts and Cavities
Are there radiographic features that suggest benign vs. malignant diagnoses? A C B D
“45 year old man from China with cough, weight loss”
Image credit: Curry International Tuberculosis Center, University of California, San Francisco 42

59. TB or Not TB? Cysts and Cavities (2)
Are there radiographic features that suggest benign vs. malignant diagnoses?
Benign cysts: uniform wall thickness, 1mm, smooth inner lining (e.g., PCP)
Benign cavities: max. wall thickness  4 mm, minimally irregular inner lining (e.g., TB)
Malignant cavities: max. wall thickness 16 mm, irregular inner lining 43

60. Pleural Disease: Basic Patterns
Effusion
Angle blunting to massive
Thickening
Mass
Air
Calcification 44

61. Pleural Effusion 45 61

62. Post-TB Pleural Calcification46

63. Plombage with Lucite balls47

64. Basic Radiology for the TB Clinician
Radiographic Manifestations of TB 48

65. Can this be TB? “Typical Pattern”: Post-primary TB Distribution
Apical / posterior segments of upper lobes
Superior segments of lower lobes
Isolated anterior segment involvement unusual for M.tb (think M. avium complex) 49

66. “Typical pattern”: Post-Primary TB
Patterns of disease
Air-space consolidation
Cavitation, cavitary nodule
Endobronchial spread
Miliary
Bronchostenosis
Tuberculoma
Pleural effusions (empyema most likely in post-primary disease) 50

67. Can this be TB? “Atypical pattern”: Primary TB 51
Distribution : any lobe involved (slight lower lobe predominance)
Air-space consolidation
Cavitation is uncommon (<10%)
Adenopathy is common (esp. children and HIV), predilection for right side
Miliary pattern
Pleural effusions 51

68. Can this be TB? Miliary TB52

69. Radiographic Patterns: Pulmonary TB
TB Pattern
“Typical”
(Post-Primary)
“Atypical”
(Primary)
Infiltrate
85% upper
Upper : Lower
60 : 40
Usually upper in children
Cavitation
Common
Uncommon
Adenopathy
Children common
Adults ~30%
Unilateral > bilateral
Effusion
May be present 53

70. CXR Pattern: Early vs. Advanced HIV
Early HIV
(CD4>200)
Advanced HIV
(CD4<200)
Pattern
“Typical”
(Post-primary)
“Atypical”
(Primary)
Infiltrate
Upper lobes
Lower lobes, multiple sites, or miliary
Cavitation
Common
Uncommon
Adenopathy
Effusion
More common 54

71. Can this be TB? “Old / Healed” TB Ca++ granuloma–Ghon lesion
Ca++ granuloma and hilar node calcification–Ranke complex
Apical pleural thickening
Fibrosis and volume loss 55

72. Basic Radiology for the TB Clinician
Summary:
Remember: Technical quality can significantly impact your CXR interpretation
Develop a systematic approach (and use it every time!)
Practice identifying normal CXR anatomy
Important to characterize and describe lesions—this can help with your differential diagnosis
Whether typical or atypical
 TB can always fool you! 56