17) Imaging of GIT Flashcards Preview

Gastrointestinal Tract > 17) Imaging of GIT > Flashcards

Flashcards in 17) Imaging of GIT Deck (37):
1

What types of imaging can be used for the GIT?

X-ray - abdominal and erect chest
Contrast studies
Ultrasound
CT/MRI
Angiography

2

What types of contrast studies are there?

Barium swallow, enema and meal
Water soluble studies

3

What imaging types are low dose radiation?

Ultrasound, MRI

4

What imaging types are high dose radiation?

Barium enema, CT

5

What are the risks of radiation in imaging?

Carcinogenesis
Genetic
Developmental risk to foetus

6

Why would an abdominal X-ray be requested?

Acute abdominal pain (sometimes)
Small or large bowel obstruction (used as triage)
Acute exacerbation of IBD

7

How is an abdominal X-ray taken?

Patient on back, X-ray from above

8

What features can be seen on an AXR?

Bowel gas pattern
Soft tissue structures
Bones

9

When can hollow tube be seen on X-ray?

If gas filled of gas and fluid filled
Slow transit time in colon and stomach so will be gas filled

10

When it can be seen, what are the features of the small bowel on AXR?

Central position
Valvulae conniventes - lines across entire bowel lumen

11

What are the features of the large bowel on AXR?

Peripheral position
Haustra
Faeces and gas
Transverse colon hangs down into pelvis

12

What is the rule of 3/6/9 in abnormal gas patterns?

Small bowel obstruction if dilated >3cm
Large bowel obstruction if dilated >6cm
Caecum (if ileocaecal valve working) obstruction if dilated >9cm

13

What causes small bowel obstruction?

Adhesions, hernias, tumours, inflammation

14

How does small bowel obstruction present?

Vomiting (early)
Distension
Absolute constipation (late)
Colicky pain

15

What causes large bowel obstruction?

Colorectal carcinoma (unless proven otherwise)
Diverticular stricture
Hernia
Volvulus

16

How does large bowel obstruction present?

Distension
Pain
Absolute constipation
Vomiting (late)

17

What is a volvulus?

Loop of intestine twisting around itself or around its mesentery

18

What is the most common volvulus?

Sigmoid volvulus

19

What can be the outcome of a volvulus?

Bowel loop dilates and can cut off its blood supply (in mesentery) or perforate

20

What can be the treatment for a sigmoid volvulus?

Sigmoidoscopy - passed through twist

21

What inflammation can be seen on AXR?

Mucosal thickening
Featureless colon (UC)
Bowel wall oedema

22

Describe the features of toxic megacolon:

Microvascular ischaemia
Mucosa sloughs off
Colonic dilatation
Oedema
Pseudopolyps

23

What is thumb printing?

Oedematous thickened haustra due to active inflammation (UC)

24

What other organs may be seen on an AXR?

Liver, spleen, kidneys, bladder

25

What other abnormalities may be see on an AXR?

Stones
Masses
Calcification - chronic pancreatitis, vascular
Foreign bodies

26

What condition can a chest X-ray be used to diagnose?

Perforated bowel

27

Why does a chest X-ray need to be used in perforated bowel?

To see diaphragm being elevated from viscera, with air/gas in the peritoneal cavity

28

What can cause a perforated bowel?

Peptic ulcer
Diverticular
Tumour
Obstruction
Trauma

29

When is barium contrast study used and when is water soluble contrast study used?

Barium if healthy
Water soluble if going into surgery

30

What can a barium swallow be used for?

Visualise aspiration, used in elderly

31

What can a barium enema be used for?

Injected rectally, check if anastomoses have healed in removed rectum where ileostomy has been used

32

What is the L1 plane of a CT called?

Trans-pyloric plane

33

What are the advantages of MRI scans?

No radiation
Good spatial and contrast resolution - differentiating between different tissues

34

What can be visualised using ultrasound?

Gall stones
Common bile duct dilation
Liver, portal vein and appendix

35

How is a GI angiography carried out?

Inject radio opaque contrast IV, then use imaging to visualise blood supply

36

What can a GI angiography be used to see?

Bleeding
Ischaemia

37

What can GI stenting be used for?

Removing blockages