Plain films

Question 1

How to distinguish between small and large bowel

Answer 1

Small bowel = valvulae conniventes crossing all lumen in small bowel.

Question 2

Small bowel obstruction on AXR

Answer 2

• Dilated greater than 3cm.

- No air in distal bowel and no air in rectum.

Question 3

Explain Rigler’s sign and when would you see it?

What other Ix would also show cause?

Answer 3

• Gas outlining both sides of the bowel wall, presence of gas in bowel lumen and peritoneum.
• Seen in pneumoperitoneum so can be seen on CXR.
• Perforated bowel.

Question 4

What is seen on x-rays of bones affected by myeloma

Answer 4

Lytic lesions seen as punched out lucencies

Question 5

What does a caveatting lung lesion appear like on xray and name some causes of a caveatting lung lesion.

Answer 5

Fluid level by the cavity.
Carcinoma (bronchogenic, SCC), cystic bronchiectasis, autoimmune disease (granulomatosis with polyangiitis), pulmonary infarction, infections (TB, S.aureus, Klebsiella).

Question 6

How can the location of a ?lung cancer on xray help point to its histology

Answer 6

Small cell = grow rapidly, met fast and usually located centrally.
Adenocarcinoma = no Hx of smoking, slow growing, met early, peripherally located.
SCC = can be located either central or peripherally, slowest growth rate, can invade chest wall!

Question 7

1. Signs of hyperinflation on a CXR.
2. What can cause that?
3. Other CXR signs in most common cause?

Answer 7

1. Heart appears vertical and narrow. Downward push on diaphragm causes it to flatten and be low set (11th and 12 posterior rib), hyper-lucent/dark lung fields.
2. COPD, cystic fibrosis, asthma,
3. COPD = walls of blebs/bullous (thin walled air spaces in emphysema).

Question 8

What is the Ghon focus?

Answer 8

The primary site of pulmonary tuberculosis infection, a calcified granuloma in the lower lobe associated with calcified hilar nodes.