Lecture 18 - GI Imaging

Question 1

Why request an abdominal X ray

Answer 1

Acute abdominal pain
Small or large bowel obstruction
Acute exacerbation of IBD
Renal colic disease (CT)

Question 2

Projection of AXR

Answer 2

Posterior to anterior

Question 3

ABCDE of AXR

Answer 3

A - air/gas 
B - bowel 
C - calcification or stones 
D - dem bones 
E - everything else - organs and soft tissues and artefacts

Question 4

Air and gas

Answer 4

Where it should or shouldn’t be

Question 5

Bowel

Answer 5

Size and wall thickness

Question 6

Small bowel on XR

Answer 6

Central
Fast transit time due to peristalsis therefore hard to see
Valvulae conniventes = plicae circularise

Question 7

Large bowel on XR

Answer 7

Peripheral
Haustra
Slow transit time as contains faeces and gas

Hepatic and splenic flexure

Question 8

Thickness of small intestine, large intestine and caecum

Answer 8

Small intestine - 3 cm
Large intestine - 6 cm
Caecum - 9cm

Question 9

Sigmoid volvulus

Answer 9

Starts in left iliac fossa
Coffee bean sign
Dilation of proximal bowel

Question 10

Causes of toxic megacolon

Answer 10

Acute deterioration with ulcerative colitis or colitis
Oedema
Pseudopolyps

Question 11

Ulcerative colitis on XR

Answer 11

Lead pipe appearance
Loss of haustra
Or thumb printing with thickened walls and oedematous thickened haustra

Question 12

First line imaging for perforation

Answer 12

Erect CXR - raised diaphragm

CT

Question 13

Causes of perforation

Answer 13

Peptic ulcer perforation 
Diverticulum perforation 
Tumour perforation 
Obstruction 
Trauma 
Iatrogenic

Question 14

L1 on CT

Answer 14

Trans pyloric plane 
Can see:
IMA
Splenic vein 
SMA 
Transverse colon

Question 15

Contracts induce nephropathy

Answer 15

Transient Impairment of renal function after IV contrast administered

• high risk if eGFR is less than 30/45 with RF
• high risk if eGFR is less than 60 with renal transplant patient

Question 16

USS use

Answer 16

Gall stone
Appendix
Liver