Session 10 - Imagine imaging of the GI tract

Question 1

Give five different types of imaging used to investigate the GI tract

Answer 1

• Plain x-rays
  
  • Contrast studies
  • Ultrasound
  • Cross-sectional imaging
  • Angiography

Question 2

Give two types of x-rays

Answer 2

• Abdominal x-ray

* Erect cheat x-ray

Question 3

Give four types of contrast studies

Answer 3

• Barium swallow
  
  • Barium enema
  • Barium meal/follow through
  • Water soluble contrast studies

Question 4

Give two types of cross sectional imaging

Answer 4

• Computed tomography

* Magnetic resonance imaging

Question 5

What are the risks of imagine?

Answer 5

• Radiation
○ Carcinogenesis
○ Genetic
○ Developmental risk to foetus

Question 6

What is a contrast study used for?

Answer 6

• Defining hollow viscera

Question 7

Give a water soluble contrast

Answer 7

• Iodine used

Question 8

What is a barium enema used for?

Answer 8

• Study where contrast medium is inserted rectally

Question 9

What is ultrasound?

Answer 9

• Use of sound waves to generate an imahe
  
  • Frequency above audible range of human hearing

Usually 2-18 MHz

Question 10

What are the advantages of ultrasound?

Answer 10

• Cheap compared to CT and MRI
  
  • Portable
  • Highly user dependent

Question 11

What can ultrasound be used for?

Answer 11

• To determine if patient has gall stones
  
  • See if common bile duct inflated
  • Liver, protal vein and appendix

Question 12

What is GI angiography?

Answer 12

• Injection of radio-opaque contrast agent intravenously and then using various methods to capture the image
  
  • Used for both bleeding and ischaemia to allow visualisation of the GI tract

Question 13

Give four key features of an abdominal x-ray

Answer 13

• Stomach
  
  • Small and large bowel
  • Soft tissues
  • Bones

Question 14

Give 6 soft tissues that can be visualised on an abdominal x-ray

Answer 14

• Liver
  
  • Spleen
  • Kidneys
  • Psoas major
  • Bladder
  • Lung bases

Question 15

When are the intestines visible?

Answer 15

When filled with gas

Question 16

When are the intestines not visible?

Answer 16

• When filled with fluid

Question 17

Give four common reasons for requesting an abdominal x-ray

Answer 17

• Acute abdominal pain
  
  • Small or large bowel obstruction
  • Acute exacerbation of IBD

Renal colic

Question 18

What are the circular folds of the small bowel called?

Answer 18

• Valvulae conniventes

* Appear as lines that appear to cross the whole of bowel lumen

Question 19

Where is the large bowel seen on an abdominal x-ray?

Answer 19

• Periphery

* Possible to see haustra on the x-ray

Question 20

What does faeces look like on an x-ray?

Answer 20

Clouds in the lumen

Question 21

What is the rule of 3/6/9 in checking the small and large bowel for gas obstruction?

Answer 21

• Small bowel is said to be dilated when it is greater than 3cm
  
  • Large bowel when it is greater than 6cm
  • Caecum (when the ileocaecal valve is working) is said to be dilated when it is >9cm

Question 22

What does small bowel obstruction usually present with?

Answer 22

• Vomiting
  
  • Mild distension
  • Absolute constipation is a late feature

Question 23

Why may you vomit earlier in small bowel obstruction?

Answer 23

• Obstruction closer to mouth

Question 24

Give four causes of small bowel obstruction

Answer 24

• Adhesions
• Hernias
○ Inguinal, femoral, incisional
• Tumours

Inflammation

Question 25

What do people with large bowel obstruction present with?

Answer 25

* Abdominal pain and distension, with constipation as an early feature * Vomiting and faeculance is a late feature

Question 26

What is the abdominal pain like in large bowel obstruction?

Answer 26

• Colicky, but not as frequent as small bowel obstruction

Question 27

Give five causes of large bowel obstruction

Answer 27

* Colorectal cacrinoma * Diverticular stricture * Hernia * Volvulus * Pseudo-obstruction

Question 28

What is a volvulus?

Answer 28

• This is when a viscera twists around itself or the mesentery Most common is a sigmoid/caecum volvulus

Question 29

What happens when a volvulus occurs?

Answer 29

• Twisting occurs and the enclosed loop of bile dilates Increases risk of perforating or cutting of its blood suppl

Question 30

Name 6 abnormalities which can be visualised on an x-ray

Answer 30

* Pancreatitis * Aneurysms * Nodes * Bones * Artifacts * Foreign body * Kidney stones

Question 31

What is an erect chest x-ray useful in diagnosing?

Answer 31

• A perforated bowel

Question 32

Give 6 causes of a perforated bowel

Answer 32

* Peptic ulcer * Diverticular disease * Tumor * Obstruction * Trauma * Iatrogenic

Question 33

Why does the chest x-ray need to be erect for a perforated bowel?

Answer 33

• The diaphragm will only be separated from other viscera by the air rising to the top

Question 34

What is normally found in the peritoneal cavity?

Answer 34

• Small amount of fluid

Question 35

What is an abdominal CT?

Answer 35

* High dose radiation * Good spatial resolution (Poor contrast compared to MRI) Use of IV or oral.rectal contrast

Question 36

What is MRI?

Answer 36

* No radiation * Good spatial and contrast resolution Time consuming

Question 37

What is an MRI scan used to visualize the gall bladder and biliary tree?

Answer 37

• Magnetic resonance cholangio-pancreatogram