9/14/2018 1 Interpretation of Chest Radiographs Sarah Tapyrik, MD Sept 26, 2018 Slides curtesy of Alfred Lardizabal, MD Executive Director Global Tuberculosis Institute
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Interpretation of Chest Radiographs
Sarah Tapyrik, MD
Sept 26, 2018
Slides curtesy of Alfred Lardizabal, MD
Executive DirectorGlobal Tuberculosis Institute
9/14/2018
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Basic Radiology for the TB Clinician
Overview:
• Technical aspects of chest radiography
• Systematic approach to reading CXR
• Basic CXR anatomy
• Patterns of disease
• Radiographic manifestations of tuberculosis (TB)
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Chest Radiography: Basic Principles
Blackest
air
fat
soft tissue
calcium
bone
X‐ray contrast
metal
Whitest
Maximum X‐RayTransmission(least dense tissue)
Maximum X‐Ray Absorption(densest tissue)
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X‐ray photon: Absorbed / scattered / transmitted X‐ray absorption depends on:
• Beam energy (constant)• Tissue density
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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, UCSF 4
Silhouette Sign: RLL Pneumonia
Image credit: Curry International Tuberculosis Center, UCSF 5
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Silhouette Sign: RLL Pneumonia
Image credit: Curry International Tuberculosis Center, UCSF 6
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
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Image credit: Curry International Tuberculosis Center, UCSF 8
1010
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Image credit: Curry International Tuberculosis Center, UCSF 9
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Image credit: Curry International Tuberculosis Center, UCSF 11
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Inspiratory Effort
Low Lung Volumes Full Inspiration
Image credit: Curry International Tuberculosis Center, UCSF 12
Overexposure Proper Exposure
Exposure
Image credit: Curry International Tuberculosis Center, UCSF 13
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OverexposureOverexposure Proper ExposureProper Exposure
Image credit: Curry International Tuberculosis Center, UCSF 14
Rotated (Oblique)Rotated (Oblique)Image credit: Curry International Tuberculosis Center, UCSF 15
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Basic Radiology for the TB Clinician
A Systematic Approach to Reading a CXR
16Image Credit: Lung Health Image Library/Gary Hampton
Approach to Reading a CXR
Be Systematic
• Lungs
• Pleural surfaces
• Cardiomediastinal contours
• Bones and soft tissues
• Abdomen
Image credit: Curry International Tuberculosis Center, UCSF 17
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Interpretation: A-B-C-D-E
A=Air
B=Bones
C=Cardiovascular
D=Diaphragm
E=Everything else
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Worth a Second Look
• Apices
• Retrocardiac areas (left and right)
• Hilar regions
• Below diaphragm
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Apical TBApical TBImage credit: Curry International Tuberculosis Center, UCSF 20
Image credit: Curry International Tuberculosis Center, UCSF
Apical TB (2)Apical TB (2)21
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Left Retrocardiac OpacityLeft Retrocardiac Opacity
Image credit: Curry International Tuberculosis Center, UCSF 22
Nodule Behind DiaphragmNodule Behind Diaphragm
Image credit: Curry International Tuberculosis Center, UCSF 23
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Basic Radiology for the TB Clinician
Basic CXR Anatomy
Image credit: Curry International Tuberculosis Center, UCSF 24
Basic CXR Anatomy
Frontal and Lateral Views
• Heart
• Aorta
• Pulmonary arteries
• Airways
Image Credit: Lung Health Image Library/Pierre Virot25
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Image credit: Curry International Tuberculosis Center, UCSF 28
• Aortic arch
• Right pulmonary artery
• Left pulmonary artery
• Trachea & bronchi
Image credit: Curry International Tuberculosis Center, UCSF 29
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• Aortic arch
Image credit: Curry International Tuberculosis Center, UCSF 30
• Aortic arch
• Right pulmonary artery
Image credit: Curry International Tuberculosis Center, UCSF 31
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• Aortic arch
• Right pulmonary artery
• Left pulmonary artery
Image credit: Curry International Tuberculosis Center, UCSF 32
• Aortic arch
• Right pulmonary artery
• Left pulmonary artery
• Trachea & bronchi
Image credit: Curry International Tuberculosis Center, UCSF 33
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Basic Radiology for the TB Clinician
Patterns of Disease
34Image Credit: Lung Health Image Library/Gary Hampton
Chest Radiographic Patterns of Disease• Consolidation / air‐space opacity
• Interstitial opacity
• Nodules and masses
• Lymphadenopathy
• Cysts and cavities
• Pleural abnormalities
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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)
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PneumoniaPneumonia
Image credit: Curry International Tuberculosis Center, UCSF 37
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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.
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Interstitial Opacity: LinesInterstitial Opacity: Lines
39Image credit: Curry International Tuberculosis Center, UCSF
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Interstitial Opacity: LinesInterstitial Opacity: Lines
Image credit: Curry International Tuberculosis Center, UCSF 40
Interstitial Opacity: Lines & ReticulationInterstitial Opacity: Lines & Reticulation
Image credit: Curry International Tuberculosis Center, UCSF 41
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Nodules and Masses
• Nodule: Discrete pulmonary lesion, sharply defined, nearly circular opacity 0.2 ‐ 3 cm
• Mass: Larger than 3 cm
• Describe with qualifiers:
‒ Single or multiple
‒ Size
‒ Border characteristics
‒ Presence or absence of calcification
‒ Location
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Well‐DefinedWell‐Defined CalcificationCalcification
Ill‐DefinedIll‐Defined MassMass
Image credit: Curry International Tuberculosis Center, UCSF 43
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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”
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Image credit: Curry International Tuberculosis Center, UCSF 45
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Image credit: Curry International Tuberculosis Center, UCSF 46
Image credit: Curry International Tuberculosis Center, UCSF 47
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Image credit: Curry International Tuberculosis Center, UCSF 48
Image credit: Curry International Tuberculosis Center, UCSF 49
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• Infrahilar window (right hilar and/or subcarinal)
• Left hilar
• Subcarinal
LymphadenopathyLymphadenopathy
Image credit: Curry International Tuberculosis Center, UCSF 50
• Infrahilar window (right hilar and/or subcarinal)
LymphadenopathyLymphadenopathy
51Image credit: Curry International Tuberculosis Center, UCSF
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• Left hilar
LymphadenopathyLymphadenopathy
52Image credit: Curry International Tuberculosis Center, UCSF
• Subcarinal
LymphadenopathyLymphadenopathy
53Image credit: Curry International Tuberculosis Center, UCSF
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Right Paratracheal & Bilateral LANRight Paratracheal & Bilateral LAN
Image credit: Curry International Tuberculosis Center, UCSF 54
Right Hilar LANRight Hilar LAN
Image credit: Curry International Tuberculosis Center, UCSF 55
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Right Hilar LANRight Hilar LAN
Image credit: Curry International Tuberculosis Center, UCSF 56
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Subcarinal LANSubcarinal LAN
Image credit: Curry International Tuberculosis Center, UCSF 57
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AP Window LANAP Window LAN
Image credit: Curry International Tuberculosis Center, UCSF 58
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
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TB or Not TB? Cysts and Cavities
Are there radiographic features that suggest benign vs. malignant diagnoses?
A
“45 year old man from China with cough, weight loss”
C
D
B
Image credit: Curry International Tuberculosis Center, UCSF 60
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
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Pleural Disease: Basic Patterns
• Effusion
‒ Angle blunting to massive
• Thickening
• Mass
• Air
• Calcification
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Pleural EffusionPleural Effusion
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Post‐TB Pleural Calcification
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Plombage with Lucite balls
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Basic Radiology for the TB Clinician
Radiographic Manifestations of TB
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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. aviumcomplex)
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“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)
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Can this be TB?
“Atypical Pattern”: Primary TB
• 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
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Can this be TB? Miliary TB
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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 UncommonChildren common
Adults ~30%Unilateral > bilateral
Effusion May be present May be present
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CXR Pattern: Early vs. Advanced HIV
Early HIV (CD4>200)
Advanced HIV (CD4<200)
Pattern“Typical”
(Post‐Primary)“Atypical”(Primary)
Infiltrate Upper lobesLower lobes, multiple
sites, or miliary
Cavitation Common Uncommon
Adenopathy Uncommon Common
Effusion Uncommon More common
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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
Image credit: Curry International Tuberculosis Center, UCSF 73
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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 normalCXR anatomy
• Important to characterize and describe lesions—this can help with your differential diagnosis
• Whether typical or atypical
TB can always fool you!
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Questions?
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