Flashcards in Week 10 - GI Imaging Deck (26)
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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
