Imaging the normal and abnormal lung Flashcards

1
Q

What are the strengths of radiography?

A

Great spatial resolution- especially bone

Cheap & available

Easy interpretation

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2
Q

What are the weaknesses of radiography?

A

Projectional

Ionising radiation

Very limited soft tissue visualisation

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3
Q

What are the 4 tissues you can differentiate on radiography?

A

Air / gas

Fat

Water / soft tissue - all body fluids and tissues except fat and bone

High atomic number calcium iodine barium metals

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4
Q

Can you see blood vessels in a lung?

Can you see airways in a lung?

A

Yes

No

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5
Q

What are the strengths of CT?

A

Cross-sectional

Spatial resolution

Widely available

Weaknesses

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6
Q

Why is CT better than x-ray of the lungs?

A

Shows greater detail

Resolve small structures

Resolve small differences in attenuation

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7
Q

What are the weaknesses of CT?

A

Ionising radiation

Limited soft tissue contrast

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8
Q

How can HRCT be generated?

A

High resolution CT -

Slice thickness

Resolution

Thin section (1mm) is the optimal technique for demonstrating lung

CT thorax 5mm slice thickness

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9
Q

What imaging technique is this?

A

HRCT

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10
Q

What imaging technique is this?

A

HRCT

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11
Q

Label the diagram.

There is a tumour as one of the labels

A

Intravenous contrast white in superior vena cava (1)and grey in ascending 2 and descening 3 aorta and the pulmonary arteries4.. There is a tumour 5 of soft tissue density

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12
Q

Label the lobes

A

Superior

Middle

Inferior

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13
Q

What does this show?

A

Right upper lobe collapse

Normally horizontal fissure runs horizontally to the hilum but the upper right lobe has collapsed

Has lost volume so collapsed upwards and medially towards spine - pulled horizontal fissure up with it

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14
Q
A
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15
Q

The primary pulmonary lobule and acinus ______mm

Secondary pulmonary lobule _______mm diam is the functional unit of the lung.

______ alveoli per adult – total area 143m2

A

6-10

5-20

300 million

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16
Q

What is a secondary pulmonary lobule?

A

A secondary pulmonary lobule is the functional unit of the lung which is surrounded by a connective tissue septum (CTS).

17
Q

What does this picture show?

A

A secondary pulmonary lobule

18
Q

What does this show?

A

This patient has some fibrosis of the connective tissue septum surrounded by red arrows.

Pathology of secondary pulmonary lobule

19
Q

Secondary pulmonary lobules cannot be seen on CT.

True or false?

A

False

Can see secondary pulmonary lobules on CT scanning, particularly when there is a pathology that causes thickening/fibrosis of the connective tissue septum.

20
Q

What are the 4 functions of the lungs?

A

Gas exchange

Ventilation - move air in and out

Perfusion - move blood in and out

Diffusion - moves gases between alveoli and blood

21
Q

How could we obtain a picture of the distribution of ventilation in the lungs?

A

Radioactive gas - Xenon-133, Krypton-81m

Radioactive aerosol - Tc99m-DTPA,

Radioactive dry carbon particles 20nm (0.02 microns) 50micrograms Tc99m

22
Q

Which imaging technique is 2 orders of magnitude below 24 hour permitted atmospheric pollution?

A

Radioactive dry carbon particles 20nm (0.02 microns) 50micrograms Tc99m

23
Q

What does this show?

A

Normal scan

24
Q

How could we produce a steady state image of lung blood flow?

A

Inject nuclear isotope into blood stream

  • 2-500,000 intravenous particles
  • 16-90 micron diameter
  • Macroaggregated human serum albumen
  • Occlude <1% of pulmonary circulation
25
Q

What patient posture would achieve the most uniform distribution of particles throughout the lungs?

A

Lying flat on back

26
Q

What type of scan is this?

A

Ventilation/Perfusion scan

V/Q scan

27
Q

What has happened to the right lung

A

No vessels in right lung field – the lung has collapsed adjacent to the heart and the pleural cavity is full of air - pneumothorax

28
Q

What is this showing?

A

Pleural effusion – liquid in the pleural cavity – typical appearance in the outer bottom corner of the lung field

29
Q

Why this liquid shape facing towards the hilum why not a horixontal line at the top of the liquid

A

Fluid looks like its creeping up at lateral edges because it forms meniscus

30
Q

High temperature & cough

Diagnosis?

A

Shadow limited by horizontal fissure ie it’s in the upper lobe

Can’t always tell what a shadow on a CXR is due to.

Water = blood = pus on radiograph but the radiograph and the symptoms add up to lobar pneumonia

31
Q

What does air space shadowing (consolidation) look like on a chest x-ray?

A

Fluffy blobs

About 1cm dia

Tending to confluence

+/- air bronchogram

32
Q

What could consolidation be on a chest x-ray?

A

Could be oedema /transudate / exudate / pus / blood

33
Q

Diagnosis?

How is the patient breathing?

What might her blood gases be like?

A

Smoke inhalation has caused water in the alveoli due to inflammation. She has a tracheostomy. Her blood oxygen concentration will be reduced.

34
Q

Is this shadow at the front or the back?

Diagnosis

A

Sorry about stripes – ignore. The right heart border has disappeared therefore the shadowing is next to the heart therefore at the front therefore in the middle lobe

Middle lobe pneumonia

35
Q

Is this shadow at the front or the back ?

A

Heart border still visible

Shadowing is at the back in the lower lobe

36
Q

Whats the diagnosis?

A

Many dots in the airspaces – can still make out vessels just about. TB granulomas miliary – blood borne spread – actually all over the body but easy to see in the lungs

37
Q

Whats the diagnosis

A

Intravenous contrast medium shows blood vessels white but grey clot in the pulmonary artery X – pulmonary embolism

38
Q

What is the diagnosis?

A

Ventilation scan at top pretty much normal but defects in perfusion images lower row due to pulmonary emboli blocking pulmonary arteries.