Bowel Ischemia and Infarction

Question 1

What are the causes of bowel ischemia?

Answer 1

Arterial occlusion (thrombus/embolus/volvulus/vasculitis/ external compression of mesenteric arteries)

Hypotentsion (related to congestive heart failure, sepsis, or blood loss)

Vasoconstrictive medications (ergotamine, digitalis, or norepinephrine)

Impaired venous drainage (venous thrombosis, tumor, adhesions, or volvulus)

Question 2

Imaging of choice for bowel ischemia

Answer 2

Contrast-enhanced MDCT

Question 3

CE MDCT findings of bowel ischemia

Answer 3

1. Circumferential or nodular wall thickening (>5 mm) with low-density edema or high density blood resulting from mucosal injury
2. “thumbprinting” resulting from this nodular infiltration of the bowel wall
3. Dilatation of the bowel lumen
4. Pneumatosis intestinalis
5. Edema or hemorrhage into the mesentery
6. Engorged mesenteric vessels
7. Thrombosis of mesenteric arteries or veins
8. Poor enhancement of bowel wall
9. Poor or absent mucosal enhancement with thinning of the wall
10. Ascites

Question 4

CE CT finding which is an evidence of bowel ischemia

Answer 4

Poor enhancement of the bowel wall along it mesenteric border

Question 5

CE CT finding - evidence of bowel infarction

Answer 5

Poor or absent mucosal enhancement with thinning of wall

Question 6

This refers to the presence of gas within the bowel wall

Answer 6

Pneumotosis intestinalis

Question 7

Causes of pneumatosis intestinalis (4 categories)

Answer 7

1. Bowel necrosis
2. Muscosal disruption (ulcers, mucosal biopsies, trauma, enteric tubes, IBD)
3. Increased mucosal permeability (related to immunosupression in AIDS, organ transplant, or chemotherapy
4. Pulmonary disease (alveolar wall disruption and dissection of air along interstitial pathways to the bowel wall)