Common diagnoses on X ray

Question 1

NG tube placement

Answer 1

Tube passes vertically in midline below level of carina
Vertically to level of diaphragm where it passes through gastro-oesophageal junction
Tip of tube must be visible below diaphragm and on left side of abdomen - 10cm or more beyond gastro-oesophageal junction

Question 2

Pneumothorax

Answer 2

Visible visceral pleural edge - seen as very thin, sharp white line
No lung markings peripheral to this line - uniform air density lateral to pleura

Question 3

Consolidation

Answer 3

Non uniform soft tissue density (blotchy white)

Perihilar air bronchogram = visible bronchioles penetrating the consolidated areas (showing its not collapsed)

Question 4

Effusion

Answer 4

Uniform soft tissue density (pure white)
Meniscus sign
Fluid at lung bases

Question 5

Lobar collapse

Answer 5

Uniform soft tissue density (pure white)
Affected lobe is smaller
Tracheal deviation

Question 6

COPD

Answer 6

Hyperinflation 
Flat hemi-diaphragms 
Decreased lung markings 
Black lesions 
Prominent hila

Question 7

Heart failure

Answer 7

Alveolar shadowing (bats wings sign)
B line (interstitial oedema)
Cardiomegaly 
Diversion of blood to upper lobe 
Effusion

Question 8

Perforation

Answer 8

Erect chest X ray better than abdominal for free gas
Large volume of gas under diaphragm seen on erect chest x ray
Rigler’s sign - both sides of bowel wall are well defined due to free intra-abdominal gas

Question 9

Bowel obstruction

Answer 9

Centrally located multiple dilated loops of gas filled bowel
Evidence of previous surgery - suggests adhesions responsible
Valvulae conniventes are visible - confirming small bowel