Visualising the bowel Flashcards
Give the name of different means for visualising the bowel
- Barium swallow
- Barium enema
- Endoscopy
- Plain X-ray
- Cross sectional imaging: CT, ultrasound, MRI
Barium techniques are used to view which part of the GI tract?
Upper
What are the various barium techniques that can be used to view the upper GI tract?
- Barium swallow
- Barium meal (double contrast)
- Small bowel barium enema
- Double contrast barium enema
Where in the GI tract does the barium swallow method allow you to see?
Oesophagus to the stomach
Where in the GI tract does the barium meal method allow you to see?
Oesophagus to the small intestine
Where in the GI tract does the small bowel barium enema method allow you to see?
Small intestine
Where in the GI tract does the double contrast barium enema method allow you to see?
Colon
What is the difference between the single and double contrast barium visualisation techniques?
- Single contrast:
- Lumen is distended with barium
- Gives a large vague image
- There is poor mucosal detail
- Less sensitive at detecting polyps - 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
What can single contrast barium methods be used for?
- To check the patient is aspirating (barium swallow)
- To check the vague outline of the GI tract
- To check for pharyngeal pouching (pseudodiverticulum) or pharyngeal bar (constriction)
How is the double contrast barium method administered?
As a barium meal
- Patients take carbex with lemon juice which produces gas in the stomach
- Patient takes barium, then rolls around on the bed to coat mucosa
What does the double contrast barium meal check for?
Stomach and duodenal conditions e.g. ulcers and tumours
What is a barium swallow used for? Give some advantages and disadvantages
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
How is the barium enema method administered?
As an injection of very dilute barium via syringe
- Can be followed by water to wash it round
What are the advantages and disadvantages of double contrast barium enema (DCBE)?
- Advantages
- Great quality images
- Can be zoomed in and out of
- Safe procedure
- Mostly tolerated well
- Good for detecting intrinsic and extrinsic disease - 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
What is the gold standard for visualising the large bowel?
Colonoscopy
- It is more sensitive than DCBE and you can take histological samples
What does a colorectal adenocarcinoma look like?
A lesion which looks like an APPLE CORE
What is an endoscopy?
Endoscopy is a procedure in which the GI tract is viewed with a lighted, flexible tube with a camera at the end (endoscope).
- Tissue samples can be obtained by biopsy
2 Direct inspection of the mucosa - Detects early pathology
- Allows biopsy/therapeutic procedure
Endoscopy vs colonoscopy, what is the difference?
- 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
What does a gastroscopy (upper endoscopy) allow you to detect?
- Gastritis
- Gastric ulcers
- Duodenal ulcers
- Duodenal erosions
What are the limitations of gastroscopies?
- Not good at assessing anatomy, motility and extrinsic disease
- Limited view of the pharynx and oesophagus
- Significant complication rate and very slight mortality rate
What are complications of a gastroscopy?
- Sedation (cardiopulmonary problems)
- Perforation
- Haemorrhage
- Infection
- Slight mortality risk
Why is endoscopy not good for imaging the small bowel?
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
What is capsule endoscopy?
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
In which situation would you not give a capsule endoscopy?
When there is a stricture, as the capsule would get stuck
