Radiology Flashcards
Visible structures on normal CXR
- Trachea
- Hilum of lungs
- Lungs
- Diaphragm
- Heart
- Aortic knuckle
- Ribs
- Scapulae
9 Breasts
- Stomach
Important invisible structures on normal CXR
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.
Major airways
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
Costophrenic recess
Formed by hemidiaphragm and chest wall. Contains rim of lung base, lying over diaphragm.
Angle should be sharp
If blunted, fluid may have present
Diaphragm
Right hemidiaphragm should be higher than left
Stomach bubble should be seen
Heart
Only see borders of heart
R border - RA
L border - LV
Heart to thoracic ratio
Should not be more than 60% diameter of thorax
Aortic knuckle
Left lateral edge of aorta. Continues as descneding aorta
Aorto-pulmonary window
Between aortic knucle and pulmonary artery
Ribs
Anterior ribs less clear as have cartilage
PA vs AP view, Erect vs Supine, Inspiration vs Expiration
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.
Evaluate normal CXR for aquadecy
- Good centreing: spinous processes should be equidistant between clavicular heads
- Correct exposure: Able to see vertebrae through heart shadow
- Side marker
Silhouette sign
Nomral adjecent structures of different densities will form crisp contour
Loss of crisp contour can help location pathology
Systematic review of CXR
Patient details: Name, DOB, Date of XR, Clinical History
Technical factors:
- PA vs AP
- Rotation
- Inspiration
- Penetration
Interpretation
Stages of CHF on CXR
Stage 1 Redistribution
- Redistribution pulmonary vessels
- Cardiomegaly
Stage 2 Interstitial oedema
Stage 3 Alveolar oedema
Stage 2: Interstitial oedema
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
Stage 1: Redistribution
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
Stage 3: Alveolar oedema
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)
