Investigating the GI Tract Flashcards
What contrast x-rays can be used to investigate the GI tract?
Barium swallow = assess swallow, oesophagus
Barium meal = miss 30% of gastric cancer
Barium enema = check healing of anastomosis
Describe ultrasound
Sound waves to generate image
Highly user dependent
Good for assessing the gallbladder
Describe angiography
Assess the vasculature
Via CT or catheter
Inject iodinated contrast into vein
What key structures can be seen in a cross sectional image of the abdomen?
Stomach = J shaped, upper L quad
SI = central, often don’t see due to fast transit time, when visible it has small lines (valvulae conniventes)
LI = peripheral, haustra, faeces and gas, T colon can hang very low in females
What method can be used to evaluate a GI abdo x-ray?
A = air/gas (stomach, bowel)
B = bowel
C = calcification and stones
D = dem bones
E = everything else
List the common reasons for requesting an abdominal x-ray
Acute abdo pain
Small/large bowel obstruction
Acute exacerbation of IBD
Renal colic – but CT now first line investigation
How does a large bowel obstruction appear on x-ray?
> 6cm
How does a small bowel obstruction appear on x-ray?
> 3cm
Explain the role of the erect chest x-ray in assessment of the pt with acute abdo pain
Investigate possible perforation
Erect = gas collects under the hemi-diaphragms
Describe the use of Computed Tomography (CT)
Examine tissue structure – good anatomical resolution
High dose radiation
Can use contrast
Can now perform a virtual CT
Describe magnetic resonance imaging (MRI)
Uses a magnetic field and radio waves
Very good contrast resolution
No radiation
Scan = 45 mins
How does SI obstruction present?
Vomiting (early)
Distension (mild)
Constipation
Colicky pain
What is the most common cause of SI obstruction?
Adhesions
What is the most common cause of LI obstruction?
Colon cancer
Describe the appearance of a sigmoid colon volvulus on imaging
‘Coffee bean’ appearance
