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Flashcards in 19 Introduction to Chest Radiology 2 Deck (31)
1

Pattern approach

  • Puzzle
  • Location
  • Pattern

  • Puzzle
    • History
    • Physical exam,
    • Labs
    • PFT
    • CXR / CT
  • Location
    • Lung
    • Pleura
    • Mediastinum
    • Chest wall
  • Pattern
    • Degree of inspiration
    • Lungs too black / white

2

Radoilogic patterns

  • Lungs are too white
  • Lungs are too black
  • Other

  • Lungs are too white
    • Consolidation
    • Ground glass attenuation
    • Atelectasis
    • Reticular / nodular (interstitial disease)
    • Airspace (acinar)
    • Mixed
  • Lungs are too black
    • Air trapping – emphysema
    • Bronchiectasis
  • Other
    • Pulmonary nodule or mass
    • Cyst (multiple): cystic and cavitary disease
    • Pleural effusion
    • Lymphadenopathy
    • Mediastinal widening

3

Air space

  • Gas-containing portion of lung parenchyma, to include acini
  • Exclude the interstitium and purely conductive portion of lung
  • Consolidation: etiology
    • Pneumonia
    • Pulmonary edema
    • Aspiration
    • Near drowning
    • Malignancy

4

Air space consolidation

  • Air in alveoli is replaced by water, blood, pus, or tumor; results in confluent opacity which obscures broncho-vascular margins
  • May be focal, patchy, or diffuse
  • Air-bronchogram:  radiologic appearance of an air-containing bronchus, surrounded by consolidated lung

5

Air space consolidation: differential

  • Edema
  • Infectious 
  • Inhalation 
  • Neoplasm 
  • Metabolic 
  • Other

  • Edema 
    • Fluid overload (heart, renal failure)
  • Infectious 
    • Pneumonia
  • Inhalation 
    • Aspiration, toxic gases, drowning
  • Neoplasm 
    • Adeno CA, lymphoma, mets
  • Metabolic 
    • Alveolar proteinosis
  • Other
    • Pulmonary hemorrhage
    • Adult respiratory distress syndrome (ARDS)

6

Consolidation: radiologic signs

  • Silhouette sign (loss of)
    • Loss of normal lung – soft tissue interface
    • Enables anatomic localization
  • Air-bronchogram sign
    • Air filled bronchi are surrounded by consolidated lung
  • Bulging fissure sign
    • Lobar consolidation with copious pus causes bulging of the fissure

7

“Loss of the silhouette” sign

  • Localize lung pathology
  • When air in lung is When air in lung is tissue (pneumonia), the normal interface between lung and heart is lost

8

Consolidation: strep pneumonia RUL

  • Silhouette sign
    • RUL consolidation obscures normal air – soft tissue interface between lung & heart
  • Bulging fissure sign
    • Minor fissure bows downward
  • Air-bronchogram sign
    • Air-filled bronchus is patent
    • Surrounding lung is consolidated

9

Pneumonia LUL

  • In lingula
  • Lobar
  • Lobar on CT
    • Dense LUL consolidation
    • Mild posterior bulging of L major fissure
    • Most LUL airways are filled with pus
    • Several air-bronchograms

10

"Round" pneumonia: legionella

  • More common finding in kids
  • May mimic malignancy

11

Consolidation

  • Edema
  • Aspiration
  • Drowning
  • Lung cancer

  • Edema
  • Aspiration
    • Contents in stomach or oro-pharynx are inhaled into trachea and lungs
    • Results in consolidation of dependent portions of lung
  • Drowning
    • Aspiration of water
    • Consolidation is not always pna
  • Lung cancer
    • Pneumonic form mimics pneumonia

12

Ground glass opacity

  • Hazy increased lung attenuation
  • Preserved broncho-vascular markings / margins
  • Partial filling of alveoli, interstitial thickening, increased capillary blood flow
  • Individual deposits not detectable
  • “Smeared chalk” appearance
  • Edema, pneumonia
  • Pneumocystis pneumonia
    • Pink frothy exudate fills airspaces

13

Atelectasis

  • Root “ectasia”
    • Aortic ectasia
    • Bronchiectasis 
  • Atelectasis
  • Radiologic findings
    • Direct
    • Indirect

  • Root “ectasia”: dilation, expansion
    • Aortic ectasia - mildly dilated aorta
    • Bronchiectasis - bronchial dilatation
  • Atelectasis
    • Gr. ateles “imperfect” + ektasis “expansion”
    • “Collapse” of lung, volume loss
  • Radiologic findings
    • Direct
      • Displaced fissure
    • Indirect
      • Increased attenuation
      • Displaced trachea, hilum, heart, diaphragm
      • Hyperinflation of unaffected lung

14

Atelectasis: definition

  • Decreased inflation of a segment, lobe, or lung
  • Results in reabsorption of air
  • Involved lung has decreased volume, increased opacity
  • Due to mucous plug, stricture, tumor, or extrinsic compression of bronchus
  • Non-involved lung responds with over

15

Atelectasis

  • “Plate-like” atelectasis
  • RUL atelectasis
  • Lobar atelectasis: RML

  • “Plate-like” atelectasis
    • Subsegmental
    • Linear
  • RUL atelectasis
    • Decreased inflation of segment, lobe, or lung
    • Reabsorption of air
    • Decreased volume, increased opacity
    • Mucous plug, stricture, tumor or compression of bronchus
    • Non-involved lung responds with over-inflation
  • Lobar atelectasis: RML
    • Silhouette sign
    • Displaced fissures

16

Atelectasis

  • Left lung
  • Endobronchial lesions

  • Left lung
    • Heart displaced to left
    • R lung is over-inflated
  • Endobronchial lesions
    • Mucus plugs
    • Malpositioned ET tube
    • Foreign bodies
    • Neoplasms
    • Strictures / stenoses

17

Secondary atelectasis

  • Compressive
    • Pleural effusion or PTX
    • Huge R effusion
    • R lung atelectasis
  • Pneumothorax

18

Interstitium

  • Continuum of loose supporting connective tissue in the lung
    • Broncho-arterial
    • Acinar - between alveoli and capillaries
    • Subpleural - continuous with interlobar septa
  • When diseased, tissues surrounding the air spaces & airways are thickened, with preservation of alveolar air

19

Interstitium

  • Pulmonary edema
  • Pulmonary lobule

  • Pulmonary edema
  • Pulmonary lobule
    • Intralobular septa
    • Reticulations

20

Alveolar ducts and pulmonary acinus

  • Microscopic anatomy
  • Fibrosing alveolitis

  • Microscopic anatomy
    • Terminal airways
    • Alveolar ducts
    • Acini
  • Fibrosing alveolitis
    • Alveolar collapse
    • UIP / IPF

21

Reticulo-nodular pattern

  • Reticulo-nodular pattern
    • Reticular
    • Nodular
    • Reticulo-nodular
    • Honeycomb
  • Nodular pattern

  • Reticulo-nodular pattern (sarcoid)
    • Reticular: interlacing network of fine linear markings that form a mesh & contain air
    • Nodular: discrete, punctate, round 1 - 5 mm deposits
    • Reticulo-nodular: mixture of interstitial linear thickening & nodular deposits
    • Honeycomb: air-containing cystic spaces (5-10 mm) surrounded by thick fibrous walls
  • Nodular pattern
    • Miliary TB

22

Reticular pattern: differential

  • Infectious - viruses, PCP
  • Immune - scleroderma, hypersensitivity
  • Edema
  • Inhalational - asbestosis
  • Airways - COPD with increased markings, cystic fibrosis (bronchiectasis)
  • Drug-induced lung disease
  • Pulmonary fibrosis

23

Nodular pattern: differential

  • Infectious - miliary TB, fungi, CMV
  • Non-infectious granulomatous - sarcoid
  • Neoplastic - lymphangetic mets, lymphoma
  • Inhalational - silicosis

24

Lungs are too black (and too big)

  • General
  • Emphysema
  • Centrilobular emphysema (CLE)

  • Centri- and pan-lobular COPD

  • Retention of excess gas in all or part of lung, especially during expiration
  • Oligemia - reduced pulmonary blood flow
    • Cardiac:  pulmonic stenosis or atresia
    • Pulmonary artery HTN
    • Large pulmonary embolism
  • Over-inflation, air-trapping
    • Emphysema
      • Abnormally expanded air spaces distal to terminal bronchiole, with destruction of walls of involved air spaces
    • Centrilobular emphysema (CLE)
      • Punched out black holes
      • No perceptible wall
      • Pulmonary artery (dot) in center
    • Centri- and pan-lobular COPD
    • Central airway obstruction
    • Small airway diseases

25

Air trapping

  • General
  • Panlobular emphysema
  • Bronchiectasis

  • General
    • Too big and black
    • Retention of excess gas in all or part of lung, especially during expiration
    • Due to partial airway obstruction or abnormal pulmonary compliance
    • Emphysema:  abnormally expanded air spaces distal to terminal bronchiole, with destruction of walls of involved air spaces
  • Panlobular emphysema
    • Large bulla
  • Bronchiectasis
    • Dilation
    • Mixed pattern

26

Cancer

  • Lung transplant
  • Lung cancer
  • Metastatic sarcoma
  • Pulmonary nodule, mass

  • Lung transplant
    • We can live on one lung
  • Lung cancer
  • Metastatic sarcoma
    • Nodules, masses, consolidation
  • Pulmonary nodule, mass
    • Marble, baseball
    • Discrete, circular opacity < 3 cm (T1)
    • Arises in lung
    • Mass: > 3 cm (T2)
    • Solitary vs multiple
    • May cavitate

27

Pulmonary nodule or mass: differential

  • Developmental - AVM, bronchial cyst
  • Infectious - TB, fungal (granuloma)
  • Neoplastic
    • Benign: hamartoma
    • Malignant: lung CA, lymphoma, met
  • Traumatic - hematoma
  • Immunologic - rheumatoid, Wegener's

28

Normal tracheo-bronchial tree

29

Problems

  • PET: radioactive glucose

  • Cavitary septic emboli (infected)

  • PET: radioactive glucose
  • Cavitary septic emboli (infected)

30

Secondary pulmonary lobule

  • Building block of the lung
  • Unit of lung structure, consists of < 12 acini
  • Irregular polyhedral, ~ 1.23 cm
  • Marginated by interlobular septa
    • Pulmonary veins & lymphatics
  • Lobular core
    • Pulmonary arteriole & bronchiole

31

Lymph node enlargement: differential

  • Infectious - TB, fungal
  • Non-infectious granulomatous - sarcoid
  • Neoplasm - lung CA, lymphoma, mets
  • Inhalational - silicosis, berylliosis
  • Metabolic - amyloidosis
  • Reactive

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