Radiology

Question 1

Visible structures on normal CXR

Answer 1

1. Trachea
2. Hilum of lungs
3. Lungs
4. Diaphragm
5. Heart
6. Aortic knuckle
7. Ribs
8. Scapulae

9 Breasts

10. Stomach

Question 2

Important invisible structures on normal CXR

Answer 2

Sternum

Oesophagus - can see if dilated

Spine

Fissures - only seen if thickened

Pleura - only seen if abnormal

Aorta - should only see aortic knuckle. Only seen if dilated.

Question 3

Major airways

Answer 3

Trachea and main bronchi visible braching at carina

Right main bronchus more vertical, so aspiration occurs easier there

Carina - burification of right and left main bronchus. Displaced in LV enlargement

Question 4

Costophrenic recess

Answer 4

Formed by hemidiaphragm and chest wall. Contains rim of lung base, lying over diaphragm.

Angle should be sharp

If blunted, fluid may have present

Question 5

Diaphragm

Answer 5

Right hemidiaphragm should be higher than left

Stomach bubble should be seen

Question 6

Heart

Answer 6

Only see borders of heart

R border - RA

L border - LV

Question 7

Heart to thoracic ratio

Answer 7

Should not be more than 60% diameter of thorax

Question 8

Aortic knuckle

Answer 8

Left lateral edge of aorta. Continues as descneding aorta

Question 9

Aorto-pulmonary window

Answer 9

Between aortic knucle and pulmonary artery

Question 10

Ribs

Answer 10

Anterior ribs less clear as have cartilage

Question 11

PA vs AP view, Erect vs Supine, Inspiration vs Expiration

Answer 11

PA: X-rays penetrate pt through back

AP: X-rays penetrate pt through front

PA standard. As heart is closer to fim and less magnified.

Supine: heart more magnified

Should be in inspiration (Expiration: cardiac silhouette enlarged). Should be 9-10 posterior ribs, 6 anterior.

Question 12

Evaluate normal CXR for aquadecy

Answer 12

• Good centreing: spinous processes should be equidistant between clavicular heads
• Correct exposure: Able to see vertebrae through heart shadow
• Side marker

Question 13

Silhouette sign

Answer 13

Nomral adjecent structures of different densities will form crisp contour

Loss of crisp contour can help location pathology

Question 15

Systematic review of CXR

Answer 15

Patient details: Name, DOB, Date of XR, Clinical History

Technical factors:

• PA vs AP
• Rotation
• Inspiration
• Penetration

Interpretation

Question 16

Stages of CHF on CXR

Answer 16

Stage 1 Redistribution

• Redistribution pulmonary vessels
• Cardiomegaly

Stage 2 Interstitial oedema

Stage 3 Alveolar oedema

Question 17

Stage 2: Interstitial oedema

Answer 17

Kerley B lines:

• septal lines, due to fluid in interlobular septa
• short, horizontal lines near costophrenic angle
• transient indicates interstitial pulmonary oedema

Peribronchial cuffing (can see bronchi (usually invisible) due to fluid leaking in peribronchial interstitium)

Hazy contours of vessels (lose defined margin due to surrounding oedema)

Subpulmonary oedema - fluid accumulates under visceral pleura

Question 18

Stage 1: Redistribution

Answer 18

Redistribution of pulmonary vessels

• Normally, vessels of lower lobes bigger than upper

Cardiomegaly

Divide transverse diameter of heart by transverse diameter of lungs. Ratio = 0.5

Question 19

Stage 3: Alveolar oedema

Answer 19

Fluid leads from interstitium to alveolar spaces leading to airspace opacity (visible)

Usually bilateral

Bats/butterfly distribution - perihilar shadowing

Consolidation

Pleural effusions (can obsure heart)