Visualising the bowel

Question 1

Give the name of different means for visualising the bowel

Answer 1

1. Barium swallow
2. Barium enema
3. Endoscopy
4. Plain X-ray
5. Cross sectional imaging: CT, ultrasound, MRI

Question 2

Barium techniques are used to view which part of the GI tract?

Answer 2

Upper

Question 3

What are the various barium techniques that can be used to view the upper GI tract?

Answer 3

1. Barium swallow
2. Barium meal (double contrast)
3. Small bowel barium enema
4. Double contrast barium enema

Question 4

Where in the GI tract does the barium swallow method allow you to see?

Answer 4

Oesophagus to the stomach

Question 5

Where in the GI tract does the barium meal method allow you to see?

Answer 5

Oesophagus to the small intestine

Question 6

Where in the GI tract does the small bowel barium enema method allow you to see?

Answer 6

Small intestine

Question 7

Where in the GI tract does the double contrast barium enema method allow you to see?

Answer 7

Colon

Question 8

What is the difference between the single and double contrast barium visualisation techniques?

Answer 8

1. Single contrast:
   - Lumen is distended with barium
   - Gives a large vague image
   - There is poor mucosal detail
   - Less sensitive at detecting polyps
2. Double contrast
   - Mucosa is coated with barium and the lumen is distended with air
   - There is better mucosal detail with double contrast due to mucosal coating, allowing you to see smaller lesions e.g. adenocarcinomas

Question 9

What can single contrast barium methods be used for?

Answer 9

1. To check the patient is aspirating (barium swallow)
2. To check the vague outline of the GI tract
3. To check for pharyngeal pouching (pseudodiverticulum) or pharyngeal bar (constriction)

Question 10

How is the double contrast barium method administered?

Answer 10

As a barium meal

1. Patients take carbex with lemon juice which produces gas in the stomach
2. Patient takes barium, then rolls around on the bed to coat mucosa

Question 11

What does the double contrast barium meal check for?

Answer 11

Stomach and duodenal conditions e.g. ulcers and tumours

Question 12

What is a barium swallow used for? Give some advantages and disadvantages

Answer 12

N.B it is single contrast
- It checks for conditions in the upper GI tract e.g. strictures and pouching

ADV: Good for high dysphagia, motility disorders and assessment of anatomy
ADV: Well tolerated by patients

DISADV: Can miss small lesions
DISADV: Limited sensitivity for cancers and inflammation (will miss early lesions)
DISADV: Patient also needs to be fit and mobile (rolling around)
DISADV: Poorly tolerated by elderly/immobile patients

Question 13

How is the barium enema method administered?

Answer 13

As an injection of very dilute barium via syringe

- Can be followed by water to wash it round

Question 14

What are the advantages and disadvantages of double contrast barium enema (DCBE)?

Answer 14

1. Advantages
   - Great quality images
   - Can be zoomed in and out of
   - Safe procedure
   - Mostly tolerated well
   - Good for detecting intrinsic and extrinsic disease
2. Disadvantages
   - Patient must be mobile and able to retain the air
   - Not as sensitive as colonoscopy
   - Not tolerated by some patients
   - Cant take histological samples

Question 15

What is the gold standard for visualising the large bowel?

Answer 15

Colonoscopy

- It is more sensitive than DCBE and you can take histological samples

Question 16

What does a colorectal adenocarcinoma look like?

Answer 16

A lesion which looks like an APPLE CORE

Question 17

What is an endoscopy?

Answer 17

Endoscopy is a procedure in which the GI tract is viewed with a lighted, flexible tube with a camera at the end (endoscope).

1. Tissue samples can be obtained by biopsy
   2 Direct inspection of the mucosa
2. Detects early pathology
3. Allows biopsy/therapeutic procedure

Question 18

Endoscopy vs colonoscopy, what is the difference?

Answer 18

• Endoscopy - Includes colonoscopy and upper endoscopy (gastroscopy)
• Colonoscopy - A type of endoscopy in which the lining of the colon and rectum are viewed by inserting a tube into the rectum

Question 19

What does a gastroscopy (upper endoscopy) allow you to detect?

Answer 19

• Gastritis
• Gastric ulcers
• Duodenal ulcers
• Duodenal erosions

Question 20

What are the limitations of gastroscopies?

Answer 20

1. Not good at assessing anatomy, motility and extrinsic disease
2. Limited view of the pharynx and oesophagus
3. Significant complication rate and very slight mortality rate

Question 21

What are complications of a gastroscopy?

Answer 21

1. Sedation (cardiopulmonary problems)
2. Perforation
3. Haemorrhage
4. Infection
5. Slight mortality risk

Question 22

Why is endoscopy not good for imaging the small bowel?

Answer 22

Because it is not easily accessible, it can only get as far as the duodenum
- This is why barium imaging and cross-sectional imaging are better for looking at the small intestine

Question 23

What is capsule endoscopy?

Answer 23

Capsule endoscopy is where the patient swallows a small capsule with a camera. This sends images to a monitor on the patient’s waist/shoulder, then the images are reviewed. This is used for visualisation of the small bowel:

• Cancers
• Inflammation
• Parasitic infection
• Bleeding

Question 24

In which situation would you not give a capsule endoscopy?

Answer 24

When there is a stricture, as the capsule would get stuck

Question 25

What are the three types of endoscopy that exist for the large bowel?

Answer 25

1. Colonoscopy (colonoscope) - Requires full prep, camera to cecum and terminal ileum 2. Flexible sigmoidoscopy (sigmoidoscope) - Shorter and more flexible, enema prior to use, can reach transverse colon 3. Proctoscopy (proctoscope) - Short and rigid, no prep, able to examine only the rectum

Question 26

Colonoscopies can be therapeutic (intervention) or diagnostic (observation and biopsy), give an example of the use of therapeutic colonoscopy

Answer 26

An example of the use of therapeutic colonoscopy is snaring of a colonic polyp - It becomes ischaemic and is cauterised (removed without bleeding)

Question 27

What are examples of cross sectional imaging?

Answer 27

1. CT - has the highest radiation dose 2. Ultrasound 3. MRI

Question 28

Which disease can MRI be used to image?

Answer 28

IBD | - It can also be used to show extraenteric pathology

Question 29

Explain the process of CT colonoscopy (CTC) | - Give some advantages of CTC

Answer 29

1. Patient CT scanned 2. Bowel distended with air 3. Can reconstruct a virtual fly through using 2D and 3D images ADV - Sensitive at picking up polyps and cancers ADV - No actual colonoscopy ADV - Less invasive However the Cigar trial still proves colonoscopy is the gold standard

Question 30

Why are MRIs and endoscopic ultrasounds unique?

Answer 30

They are the only techniques used to demonstrate the wall layers - They provide high resolution imaging of the bowel wall and can therefore be used in cancer staging