6.8 Imaging the Abdomen

Question 1

Describe the utility of AXR

Answer 1

• Decreasing in usefulness
• May be used for patients w/ lower index of suspicion

Question 2

List 3 types of AXR views, and their uses

Answer 2

• Supine (most common; fecal loading etc.)
• Erect (useful for adding in gravity, such as checking for air fluid levels in bowel obstruction)
• Decubitus (lying on side; good for gravity in patients who can’t stand - ICU etc.)

Question 3

Indications for supine AXR

Answer 3

• Abdo pain
• Renal colic
• Foreign bodies
• Suspected bowel obstruction/perforation

Question 4

Indications for erect AXR

Answer 4

• Suspected perforation/obstruction
• Multiple air fluid levels on supine XR

Question 5

Indications for abdominal CT

Answer 5

• Trauma
• Acute abdo pain
• Post-operative complications
• Malignancy (staging/screening)
• Vascular imaging
• Follow up from X Ray

Question 6

IV Ct contrast is based on the element…

Answer 6

Iodine (“IV Contrast” = “Iodine Contrast”)

{This is why IV contrast is associated with an increased risk of Hyperthyroidism}

Question 7

Impairment of which organ is a contraindication for IV contrast? What type of condition doesn’t require contrast

Answer 7

Kidneys (kidney stones don’t need IV contrast. Wonder why…)

And besides, calcified structures will show up easily, like bone, anyway

Question 8

What are the two phases of contrast CT we can use? Indications?

Answer 8

• Arterial phase - good for detecting vascular issues (dissections, aneurysms etc.)
• Portal venous phase - more sophisticated look at vasculature of organs

Question 9

T1 vs T2 MRI

Answer 9

T1: enhances signal of fat
T2: enhances signal of fluid

Question 10

MRI indications

Answer 10

More high resolution soft tissue image, particularly of organs (liver, kidneys, genitourenary)

Question 11

What can ultrasound tell us?

Answer 11

• Background parrenchyma of organs
• Types of tissue (necrotic, calcified etc.)
• Lesions (cystic vs solid), plus shape

Question 12

What is Rigler’s sign? What does it indicate?

Answer 12

• Air both inside the bowel and inside the surrounding peritoneum, causing two clearly-visible bowel edges
• This is a sign of pneumoperiteneum

Question 13

A ‘string of pearls’ appearance on AXR indicates what?

Answer 13

• Many fluid air levels in the small bowel
• Small bowel obstruction

Question 14

Two common exam AXR cases for large bowel obstruction are…

Answer 14

• Sigmoid volvulus
• Caecal volvulus

Question 15

“Thumbprinting” on the large intestine wall indicates…

Answer 15

Colitis