9/8- Chest Imaging in Lung Disease Flashcards Preview

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Flashcards in 9/8- Chest Imaging in Lung Disease Deck (35):

What is the reference substance for x-ray?



Describe relative absorption of x-rays by different tissues:

- Bone

- Tissue (fluid, muscle)

- Air

- Bone: high absorption (white)

- Tissue (fluid, muscle): grey

- Air: low absorption (black)


What is silhouette sign in x-ray?

Tissues or structures with similar density, adjacent to each other, cannot be differentiated (e.g. blood filled heart) If fluid is obscuring heart/aorta, it's in the same plane as what is no longer seen

(B- see aorta outline but not heart; in plane of heart. C- see heart border but not aorta; in plan of aorta) 


Under what position/conditions is a CXR taken?

- Upright

- Full inspiration

- 72" from x-ray source

- Plate in front of patient


Characteristics of a normal CXR (postero-anterior)?

- Stomach

- Scapula

- Clavicles

- Vertebral bodies

- Lung lobes 

Postero-anterior film

- Air in stomach

- Scapulae at edge of thorax

- Well centered – clavicles equidistant from spinous processes

- Lower vertebral bodies barely visible

- LLL visible (behind heart


What is different in antero-posterior view as opposed to postero-anterior?

- Opposite

- Anterior structure magnified: heart, mediastinum

- Scapula in thorax 


Features of lateral CXR? 


What is abnormal? 

Elevated diaphragm


What can cause an elevated diaphragm?

- Collapse/ volume loss of lung

- Subpulmonic effusion

- Subphrenic abscess

- Herniation/eventration


What are diseases of increased radiographic density?

- Alveolar filling (blood, fluid, cellular components in pneumonia)

- Atelectasis/Volume loss

- Interstitial infiltrates

- Masses


What is seen here? 

Silhouette Sign: RML pneumonia

- We are missing the right heart border


What is seen here? 

Infiltrate in upper lobe

- Opacity above minor fissure (separating upper lobe from middle lobe)

- Possibly additional infiltrate in left lower lobe


Which lobes correspond to:

- Right heart border

- Left heart border

- Right heart border: right lower lobe

- Left heart border: left lingula


What is seen here? 

Uremic lung disease (not a specific finding)

- Diffuse increase in density; bilateral


What is seen here?

Collapsed left lung (due to tumor)

- Ipsilateral pulling of midline structures due to collapse

- Heart, diaphragm, aorta/midline structures are all silhouetted out


What is seen here?

Pulmonary vascular congestion (turns out he had mitral stenosis)

- Predominant upper lobe density

- Bilateral


What does the meniscus sign suggest?

Presence of pleural fluid


What is seen here?

Tumor causing obstruction of right main bronchus

- Trachea and heart deviated to the right

- Right lung is smaller and more opaque


What are diseases of decreased radiographic density?

- Air trapping: asthma, emphysema, foreign body

- Pneumothorax

- Cysts/bullae

- Loss of soft tissue (e.g. mastectomy pts)


What is seen here 

Overinflation- severe bullous emphysema

- Diaphragm low and flat

- Streaks are due to upper lung tissue being pulled down (bullae); crowding of lung markings in lower thorax; absence of lung markings (upper)

- Hilum has been pushed down (below aortic knob)


What is seen here? 

Overinflation- severe bullous emphysema

- Increased retrosternal air space

- Flat diaphragms


What is seen here? 

Pneumothorax- compression atalectasis of the lung

- Right apex might be considered normal (no markings, but mostly collapsed/compressed lung

- See pneumonic infiltrates on right


What is seen here? 


- Can see pleura line on the lower right with effusion just external


What is seen here?

Cavitation of the lung (lucency within density)

- Commonly from infection (also, sometimes from cancers)


What is seen here? 

Cavity with development of air-fluid level... this is an ABSCESS


When would you want decubitus film? 

- Demonstrate pleural effusion fluid layers/air rises

- Sub-pulmonic effusion

- Air/fluid levels

- Subtle pneumothorax


If there is a pleural effusion on the right, which side do you want down?

Want pneumothorax side DOWN


When would inspiratory/expiratory films be helpful?

- Small/subtle pneumothorax

- Unilateral air trapping


CT is test of choice for what?

- Pulmonary embolism

- Vascular malformations


- Evaluation of hilar and mediastinal structures: LNs, tumors, central airways

- Radiologic diagnosis of bronchiectasis


What is seen here? 

- "Generous" hilum


What is seen here? 

Large homogeneous density of a mass/LN


Angiography of the chest shows what vessels?

Contrast studies help diagnose vascular diseases such as pulmonary embolism

- Pulmonary

- Bronchial


- A 41 yo presents with dyspnea for 3 weeks-

- On physical exam there are decreased breath sound, decreased tactile fremitus, and dullness to percussion on the right lower lung field

- Chest x-ray show increased radiographic density and obliterated costophrenic angle.

- You suspect pleural effusion.

- What radiographic test would you order next to confirm the diagnosis?

Pleural diseases, pneumothorax and pleural effusion are better assessed by decubitus films

- For a pneumothorax: air rises when lying on unaffected side, fluid layers when lying on the affected side


How does pneumothorax affect absorption of X-ray photons and what is the resulting effect on the X ray density on the affected side?

Air rises when lying on unaffected side, fluid layers when lying on the affected side


Name 3 respiratory conditions associated with increased and 3 associated with decreased radiographic density.

Increased radiographic density:

- Alveolar filling

- Atalectasis/volume loss

- Interstitial infiltrates

- Masses

Decreased radiographic density:

- Air trapping: asthma, emphysema, foreign body

- Pneumothorax

- Cysts/bullae

- Loss of soft tissue