11. GI imaging

Question 1

how can the small bowel be identified on X-ray

Answer 1

• difficult to see
• central position in abdomen
• valvulae conniventes (i.e. plicae circulares, mucosal folds that cross full width of bowel)

Question 2

how can the large bowel be identified on x ray

Answer 2

• peripheral position
• haustra (incomplete lines)
• may contain faeces (slow transit time)

Question 3

which changes are seen on x ray in bowel obstruction

Answer 3

• small bowel obstruction: >3cm width
• large bowel obstruction: >6cm width
• caecum obstruction: >9cm width

Question 4

how will Ps with small and large bowel obstruction present differently

Answer 4

Small:

• vomiting (early)
• distension (mild)
• absolute constipation (late)
• colicky pain

Large:

• vomiting (late)
• distension (significant)
• absolute constipation (early)
• pain

Question 5

name 2 situations in which abdominal x rays may be useful

Answer 5

1. bowel obstruction
2. IBD flare ups

Question 6

what is this condition

Answer 6

SIGMOID VOLVULUS: ‘coffee bean’ sign, starting in L iliac fossa pointing to RUQ

Question 7

what is this condition

Answer 7

TOXIC MEGACOLON (acute deterioration of UC):

• colonic dilation
• oedema
• pseudopolyps

Question 8

why should an erect chest x ray be performed in Ps with acute abdominal pain

Answer 8

P should be positioned upright for 10-20 min prior

can show air under diaphragm if perforated viscus = PNEUMOPERITONEUM