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Gastrointestinal angiodysplasia

Last revised by Dr Daniel J Bell on 26 May 2022

Gastrointestinal angiodysplasias (a.k.a. angioectasias) are one of the most common causes of occult gastrointestinal bleeding.

Peak incidence occurs in patients in their 60s-70s 3.

Patients can present with symptoms and signs of upper or lower gastrointestinal bleeding although angiodysplasias are commonly an incidental finding. 

Angiodysplasia refers to dilated, thin-walled blood vessels (capillaries, venules, veins) found in the mucosa and submucosa of the gastrointestinal tract. The pathogenesis is unclear 3. They are multiple in ~50% of cases 1,2, and can be found throughout the gastrointestinal tract, but most commonly on the antimesenteric border of the cecum and right colon.

CT angiography (CTA) of the abdomen can diagnose angiodysplasias with a sensitivity of 70%, a specificity of 100%, and a positive predictive value of 100% 7. This is especially useful in cases of inconclusive colonoscopic evaluation due to intraluminal blood obscuring small lesions 8.

Findings include:

  • focal areas (<5 mm) of contrast enhancement in the bowel wall (most prominent in the enteric phase 3)
  • enlargement of the feeding mesenteric artery (e.g. ileocecal artery in cecal angiodysplasia 8)
  • early filling and/or dilatation of the draining mesenteric vein (e.g. ileocecal vein in cecal angiodysplasia 7,8)

Simultaneous enhancement of the parallel feeding artery and draining vein has been described as a tram-track appearance 4.

The use of maximum intensity projections (MIPs) can facilitate visualization of abnormal mural vessels which can be a subtle finding and hard to see on regular axial slices 7,8.

  • ectatic vessels but no discrete lesion 6
  • early venous enhancement indicating arteriovenous shunting

Approximately 50% of gastrointestinal hemorrhage from angiodysplasia ceases without intervention. Endovascular treatment is generally not effective and first-line treatment is interventional endoscopy. There is a post-treatment bleeding rate of ~25% 2,4.

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Cases and figures

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