Imaging of the digestive system

Question 1

OPG

Answer 1

Images teeth and jaw

Question 2

Divisions of gut and arterial supply

Answer 2

• Foregut: mouth to ampulla in second part of duodenum, IMA
• Midgut: SMA, ampulla to 2/3 along transverse colon
• Hindgut: IMA, distal 1/3 of colon to anus

Question 3

Pharynx divisions

Answer 3

• Nasopharynx: skull base to soft palate
• Oropharynx: soft palate to hyoid bone
• Laryngopharynx: hyoid to cricopharyngeus

Question 4

Where does oesophagus start?

Answer 4

C6

Question 5

Oesophageal waves

Answer 5

Primary oesophageal wave pushes bolus down and second (stripping wave) clears anything not moved down by first, tertiary contraction is unhelpful

Question 6

Volvulus sx

Answer 6

ischaemia, epigastric and chest pain

Question 7

Malrotation

Answer 7

• SMA and SMV can switch and/or rotate - bowel didn’t rotate properly in utero
• • Abnormal duodenojejunal junction
• DJ junction fails to cross the midline to the left of the spine
• DJ junction inferior to duodenal bulb
• Leads to volvulus

Question 8

Crohn’s disease

Answer 8

• Bowel wall thickening
• Increased enhancement
• Vascular engorgement ‘comb sign’
• Fat wrapping

Question 9

Small bowel

Answer 9

Valvulae conniventes: cross entire lumen of small bowel, centrally positioned

Question 10

Large bowel

Answer 10

• Barium enema
• Essentially obselete
• Demonstrates the bowel lumen on x-ray using double contrast
• Haustral folds
• Outpouchings = diverticula

Question 11

Pneumoperitoneum

Answer 11

• Free gas within peritoneal cavity

- Erect CXR probably most sensitive plain radiograph for gas detection

Question 12

CT pneumocolon

Answer 12

• Inflate bowel with CO2
• Faeces appear bright, tumours dont
• Allows you to see polyps clearly when inflated

Question 13

Portal vein

Answer 13

• 75% of liver blood supply
• Carries venous blood from spleen, GIT and associated organs
• Hepatic arteries supply arterial blood to liver (25%)