Week 10 - GI Imaging Flashcards Preview

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Flashcards in Week 10 - GI Imaging Deck (26):
1

When do you request an AXR

Acute abdominal pain
Small/large bowel obstruction
Acute exacerbation of IBD
Renal colic (1st line is CT)

2

ABC approach of an AXR

Air - bowel gas pattern
Bowel - and other soft tissue
Calcification - bones and stones

3

Describe the bowel gas pattern

Colon - slow transit as faeces and gas
Small bowel - fast transit as fluid
Stomach - medium transit as fluid and lots of gas

4

Dilation in obstruction of different parts of the GI tract

Small bowel obstruction if small bowel dilated >3cm
Large bowel obstruction if large bowel dilated >6cm or if caecum >9cm (competent ileoceacal valve)

5

AXR appearance of small bowel

Central
Valvulae conniventes across whole lumen
Often not visible

6

AXR appearance of large bowel

Peripheral
Haustra across part of lumen
'Clouds' of faeces and gas visible
Transverse colon hangs down to pelvis (longer in women)

7

Symptoms of small bowel obstruction

Early - vomiting, mild abdominal distension
Late - absolute constipation
Colicky pain every 2-3 mins

8

Causes of small bowel obstruction

Post op adhesions
Inguinal, femoral and incisional hernias
Tumours
Inflammation

9

Symptoms of large bowel obstruction

Early - absolute constipation, significant abdominal distension
Late - faeculant vomiting
Colicky pain every 10-15 mins

10

Causes of large bowel obstruction

Colorectal carcinoma (assume until disproven)
Hernias
Volvulus
Strictures

11

Types of volvulus

Sigmoid (common)
Caecal - if anatomical defect reducing caecum's attachment to abdominal wall

12

Abnormalities that can be visualised with AXR

Obstruction
Inflammation
Toxic megocolon
Lead pipe colon
Thumb printing
Calcification
Foreign bodies e.g nasojejunal tube, colonic stent, ingested objects
Gall/Kidney stones

13

Appearance of inflammation on AXR

Mucosal thickening
Lead pipe colon
Bowel wall oedema

14

What is toxic mega colon and give some causes

Colonic distension with no obstruction
Causes:
Oedema
Pseudopolyps
Acute deterioration of colitis

15

Describe thumb printing

Oedematous thickened haustra often seen in active inflammation

16

When might you see calcification on a AXR

Chronic pancreatitis (fat necrosis)
Atherosclerosis
Calcified lymph nodes
Gall/renal stones

17

Diagnosis of bowel perforation

Erect CXR (need to be sat upright for at least 10 mins)

18

Causes of bowel perforation

Peptic ulcer
Diverticular disease
Tumour
Bowel obstruction
Iatrogenic

19

What are contrast studies

Used to define hollow viscera
May use barium or iodine

20

Give examples of contrast studies and what they are used for

Barium swallow - achalasia, check aspiration
Barium enema - check anastomoses before reversing ileostomy
Barium meal
Water soluble (iodine)

21

Compare abdominal CT, MRI and USS

CT - high dose radiation, better spacial resolution, quick
MRI - no radiation, better contrast resolution , time consuming
USS - no radiation, cheaper, portable, highly user dependent

22

What does the transpyloric plane cross

L1 vertebra
Liver (and round ligament)
Gall bladder
Kidneys
Pylorus
Superior duodenum
Spleen
Pancreas
Transverse colon
Jejunum

23

What is an MRCP

Magnetic resonance cholangiopancreatogram - MRI to visualise gall bladder and biliary tree

24

What can you view with an abdominal USS

Liver
Portal vein
Appendix
Gallstones
Dilated common bile duct

25

What is a GI angiography

IV radio opaque contrast injected to visualise GI blood supply in bleeding and ischaemia

26

Which blood vessels can be seen in a GI angiogram

Aorta
Coeliac trunk
SMA
Iliac vessels