Investigating the GI Tract Flashcards
List the imaging investigations for GI tract
- Plain abdominal x-rays
- Contrast x-rays (barium swallow and barium enema)
- Ultrasound
- CT
- MRI
- Ultrasound
- Angiography
Describe how to read an abdominal chest x-ray
- AP projection
- Use ABC approach
- A = air/gas
- B = bowel
- C = calcification - bone and stones
- Bowel gas pattern - any part of hollow tube visible if gas or liquid filled
- Not visible if fully fluid filled
Describe the pros and cons of MRI over CT
- No radiation
- Good spatial and contrast resolution
- Time consuming - 45-60 min
- Can be used alongside contrast to enhance images
List the common reasons for requesting a plain abdominal radiograph
- Acute abdominal pain
- Small or large bowel obstruction
- Acute exacerbation of IBD
Describe the appearance of small bowel on abdominal x-ray
Central position with thin white lines that cross entire wall (valvulae conniventes)
Describe the appearance of large bowel on abdominal x-ray
- Peripheral position containing haustra
- Faeces show dark areas and gas show light areas
- Transverse colon hands down to pelvic
Describe how small bowel and large bowel obstruction are seen on abdominal x-ray
- Small bowel obstruction if diameter > 3cm
- Large bowel obstruction if diameter > 6cm
Describe the difference in colicky pain between small and large intestine obstruction
- Small intestine every 1-5 min
- Large intestine very 10-15 min
How would a volvulus present on an abdominal x-ray
- Twisting around mesentery common in sigmoid volvulus
- Coffee bean sign starting in left iliac fossa towards right upper quadrant
Describe how toxic megacolon would present on an abdominal x-ray
- Acute deterioration with IBD
- Colonic dilation, oedema and pseudopolyps present
Describe a lead pipe colon
Featureless colon with loss of haustra seen in UC
Explain the role of the erect chest radiograph in assessment of the patient with acute abdominal pain
Erect chest x-ray shows gas underneath the diaphragm for bowel perforation
