Radiology Introduction Lecture

Question 1

Describe the attenuation of different organs.

Answer 1

Bone - high attenuation - white

Soft tissues - low attenuation - shades of grey

Lungs - low attenuation - black

Question 2

What is the advantage of CXR over CT?

Answer 2

• Spacial resolution (identifying items as separate) is better in CXR than CT
• Less radiation in CXR
• Anatomical superimposition

Question 3

What is the main advantage of CT over CXR?

Answer 3

Contrast resolution

Question 4

What is the dose of radiation in mSv delivered by a transatlantic flight?

Answer 4

0.08 mSv

Question 5

Compare the dose of radiation of CXR and CT.

Answer 5

CXR - 0.014 mSv

CT head - 1.4 mSv (x100)

CT chest - 6.6mSv (x470)

CT whole spine - 10mSv (x715)

Importnat because these are cumulaive doses and at a particular dose there will be cellular changes.

Question 6

What is shown?

Answer 6

Azygos vein

Answer 7

Subcarinal lymph node enlargement is an important sign that lung cancer may have spread.

Question 8

List some basic signs in chest imaging.

Answer 8

• •Consolidation
• •Ground-glass opacification
• •Reticulation
• •Honeycombing
• •Nodules
• •Pulmonary air cysts
• •Traction bronchiectasis
• •Traction bronchiolectasis
• •Halo sign
• •Reverse halo

Question 9

What are common causes of consolidation?

Answer 9

Bit of ling with no air in it:

• Infection/inflammation
• Tumour (lung cancer, lymphoma)
• Blood

Question 10

What is the cause of ground-glass opacification?

Answer 10

Increased density that does not obstruct lung markings.

• •Airspace
• •Interstitial
• •Both

Question 11

Answer 11

Density and margins: vessels no longer visible

RLL consolidation

CONSOLIDATION:

Replacement of air-spaces by fluid or cells without volume loss.

• •Ill-defined/ fluffy shadowing
• •Confluent
• •Loss of vessel pattern
• •Air-bronchograms.

•Causes: Pneumonia, Oedema, Haemorrhage, Aspiration

Question 12

Answer 12

Air bronchograms e.g. ARDS

Question 13

Answer 13

Hyperattenuation along the horizontal fissure

Lobar pattern of consolidation typical of pneumonia

Question 14

Answer 14

Cannon ball metastases

Non lung primary malignancy

Question 15

Answer 15

Left hilar - primary lung cancer

Single

Spiculated - finger projections

Question 16

Answer 16

Tension pneumothorax

Question 17

Answer 17

Increased density in RL zone

Continuous - starts from bottom and goes up

Question 18

Answer 18

• R Lung collapse
• Tracheal deviation to the right
• Rib crowding is a sign of collapse (mucous plug/foreign object can cause this)