S11) Investigating the GI Tract Flashcards

1
Q

What are the 5 different imaging modalities of the GI tract?

A
  • Plain X-rays – AXR, CXR
  • Contrast studies – Barium swallow, enema, meal/follow through, water soluble contrast studies
  • Ultrasound
  • Cross-sectional imaging – CT, MRI
  • Angiography
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2
Q

Why request an abdominal X-ray?

A
  • Acute abdominal pain
  • Small/large bowel obstruction
  • Acute exacerbation of IBD
  • Renal colic
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3
Q

What are the features of an AXR?

A
  • Air/gas
  • Bowel
  • Calcification (bone and stones)
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4
Q

In terms of bowel gas patterns, what kind of structures are visible in an AXR?

A
  • Visible if gas filled / gas and fluid filled
  • Not visible is fully fluid filled
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5
Q

The bowel gas patterns in an AXR varies according to transit time.

Describe this

A
  • Slow transit = colon (faeces ± gas)
  • Medium transit = stomach (fluid + lots of gas)
  • Fast transit = small bowel (fluid)
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6
Q

Identify 5 conditions which produce abnormal bowel gas patterns in an AXR

A
  • Small bowel obstruction (>3 cm)
  • Large bowel obstruction (>6 cm)
  • Paralytic Ileus
  • Volvulus
  • Toxic Megacolon
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7
Q

How does small bowel obstruction present?

A
  • Vomiting (early)
  • Distension (mild)
  • Absolute constipation (late)
  • Colicky pain
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8
Q

What are the causes of small bowel obstruction?

A
  • Adhesions
  • Hernias (inguinal, femoral, incisional)
  • Tumours
  • Inflammation
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9
Q

How does large bowel obstruction present?

A
  • Vomiting (late, faeculant)
  • Distension (significant)
  • Pain
  • Absolute constipation
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10
Q

What are the causes of large bowel obstruction?

A
  • Colorectal carcinoma
  • Diverticular stricture
  • Hernia
  • Volvulus
  • Pseudo-obstruction
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11
Q

What is a volvulus?

A

A volvulus is when the colon twists around mesentery

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12
Q

In 3 steps, describe how a volvulus occurs

A

⇒ Enclosed bowel loop

⇒ Dilates

⇒ Perforation / ischaemia

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13
Q

What is the most common volvulus and how does it occur?

A

Sigmoid volvulus:

  • Starts in LIF
  • Coffee bean sign towards RUQ
  • Dilatation of proximal bowel
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14
Q

AXR is not the gold standard for infection and inflammation. However, one might see acute or chronic changes.

Identify some

A
  • Mucosal thickening
  • Featureless colon
  • Bowel wall oedema
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15
Q

Which soft tissue structures can be seen in an AXR?

A
  • Organs
  • Musculature
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16
Q

Specifically, identify some organs which can be observed in an AXR

A
  • Liver
  • Spleen
  • Kidneys
  • Bladder
  • Lung bases
17
Q

Identify some bones which can be seen in an AXR

A
  • Pelvis
  • Sacrum
  • Coccyx
  • Lumbar spine
  • Lower thoracic spine
  • Lower ribs
18
Q

Identify 5 other abnormalities which can be observed in an AXR

A
  • Stones
  • Organs/masses
  • Calcification (pancreatitis, vascular, nodes)
  • Artefact
  • Foreign body
19
Q

Describe the use of an erect chest X ray

A
  • Erect CXR is a specific examination performed for the assessment of subdiaphragmatic free gas (pneumoperitoneum)
  • It is used to assess patients with acute abdominal pain
20
Q

Perforation leads to pneumoperitoneum.

Identiy 6 possible causes of this

A
  • Peptic ulcer
  • Diverticular
  • Tumour
  • Obstruction
  • Trauma
  • Iatrogenic (laparoscopy)
21
Q

What is the purpose of contrast studies?

A

Contrast is used to define hollow viscera (Barium, water soluble)

22
Q

Identify 4 common GI contrast studies

A
  • Swallow
  • Meal
  • Small bowel enema/follow through
  • Enema
23
Q

Identify the visible abdominal structures in the cross-sectional abdominal CT at T12 below:

A
24
Q

Identify the visible abdominal structures in the cross-sectional abdominal CT at L1 below:

A
25
Q

Identify the visible abdominal structures in the cross-sectional abdominal CT at L3 below:

A
26
Q

Identify the visible abdominal structures in the cross-sectional abdominal CT at L4 below:

A